WATER HARVESTINGBrining Green Revolution to Rainfed Areas

Proceedings of the International SymposiumHeld on 23 to 25 June 2008

at the Tamil Nadu Agricultural University

EditorsDr. Arumugam KandiahVisiting Professor, TNAU

Dr. K. RamaswamyProfessor, TNAU

Regional Programme Specialist, UNESCOand

A. SampathrajanDean, Agricultural Engineering College and Research Institute, TNAU

Volume – I

Published Jointly byTamil Nadu Agricultural University, Coimbatore

andUnited Nations Educational, Scientific and Cultural Organization,

New Delhi Office, New Delhi

July 2008

ISBN : 978-81-89218-41-6First Impression : 2011Published by : UNESCO, New DelhiPrinted at : Bal Vikas Prakashan Pvt. Ltd.

This book is a sole subject, to the condition that shall not be away of trade or otherwise, be lent, resold, hired out, or otherwise circulated without the publisherÊs prior written consent, in any form of binding or cover, other than that, in which it is published, and without a similar condition including being imposed on the subsequent purchaser and without limiting the right under copyright, reserved above, no part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise), without the prior written permission of, both the copyright owner, and the publisher of this book.

Copyright © : UNESCO Tamil Nadu Agricultural University, Coimbatore

PREFACE

With a global withdrawal rate of 600 � 700 km3/year, groundwater is the worldÊs most extracted raw

material. Particularly in rural areas of developing countries, in arid and semi arid regions and in the inlands,

groundwater is the most important source of drinking water. Irrigation systems in many parts of the world

strongly depend on groundwater resources. Groundwater is also a reliable resource for industry. However,

managerial control over groundwater resources development and protection is often lacking and that has

led to uncontrolled aquifer exploitation and pollution. Intensive aquifer use affects springs, stream base-flow,

groundwater table, piezometric level, groundwater storage, surface water - groundwater interface, wetlands

and land subsidence. Groundwater vulnerability to the human impacts is therefore recognized as a serious

worldwide social, economic and environmental problem.

It has been estimated that about 80 countries, constituting 40% of the worldÊs population, are suffering

from serious water shortages and that within 25 years two thirds of the worldÊs population will be living

in water-stressed countries. Although long been seen as the only option to improve crop productivity and

thus the quality of life of millions of people, development of irrigation is not always possible because of the

inherent climatic constraints in the arid and semi-arid regions of the world. It is now a well understood fact

that expansion of irrigation, although technically possible, is not always cost-effective or environmentally

friendly. Thus development of rainfed agriculture is not only necessary to improve the food security but also

is a necessary prerequisite for the sustainable development of the world.

UNESCO is working to create the conditions for genuine dialogue based upon respect for shared values

and the dignity of each civilization and culture. The world urgently requires global visions of sustainable

development based upon observance of human rights, mutual respect and the alleviation of poverty, all of

which lie at the heart of UNESCOÊs mission and activities. UNESCO has a mandate to advance hydrological

sciences and their application for improving water security. UNESCO is therefore uniquely placed to work

with other concerned partners to popularize and better study water harvesting technologies. Through its

International Hydrological Programme (IHP), and especially through its Water and Development Information

for Arid and Semi-Arid Areas (GWADI) initiative, UNESCO remains committed to sharing its know-how,

cooperating with others and building new partnerships. In its VIIth Phase, IHP is extensively working in the

field of rainwater harvesting, not only to consolidate existing knowledge, but also to develop cheaper and

more appropriate technologies for water harvesting.

I am confident that this set of proceedings of the International Symposium on „Water Harvesting - bringing

green revolution to rainfed areas‰ will serve as good reference to those who are genuinely committed to bring

green revolution to rainfed areas.

Parsuramen⁄

Armoogum Parsuramen

Director and UNESCO Representative to Bhutan, India, Maldives and Sri Lanka

List of Contributors

1. A. Balakrishnan, Department of Agronomy, Tamil Nadu Agriculture University, Coimbatore, India

2. A. Sarangi, Senior Scientist, Water Technology Centre, IARI, New Delhi, India

3. A. Subba Rao, Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal-462038, Mathia Pradesh, India

4. A.K. Misra, Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal-462038, Mathia Pradesh, India

5. A.K. Tripathi, Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal-462038, Mathia Pradesh, India

6. A.K.Sinha, Professor, Department of Geology, University of Rajasthan, Jaipur, India

7. Arun Balamatti, AME Foundation, No. 204, 100 Feet Ring Road, Banashankari 3rd Stage, 3rd Phase, 2nd Block, Bangalore 560 085

8. B.K. Gavit, Associate Scientist, Maharashtra Remote Sensing Applications Centre- Nagpur, Maharashtra, India

9. Bharat R Sharma, International Water Management Institute, New Delhi Office, New Delhi, India

10. C S Kallimani, AME Foundation, No. 204, 100 Feet Ring Road, Banashankari 3rd Stage, 3rd Phase, 2nd Block, Bangalore 560 085

11. C.A. Madramootoo, Dean of Faculty, Agricultural and Environmental Sciences, McGill University, Ste-Anne-De-Bellevue, Montreal, Canada

12. C.Jayanthi, Department of Agronomy, Tamil Nadu Agriculture University, Coimbatore, India

13. C.R. Shanmugham, Programme Advisor, DHAN Foundation, Madurai, India

14. C.Vennila, Department of Agronomy, Tamil Nadu Agriculture University, Coimbatore, India

15. C.Vijayalakshmi, Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore, India

16. D. Manohar Jesudas, Professor and Head, Department of Farm Machinery, Agriculture Engineering Col-lege &Research Institute , Tamil Nadu Agriculture University, Coimbatore, India

17. G. Sujata, Scientist/ Engr-SD, National Remote Sensing Agency-Hydrabad, Andhra Pradesh, India

18. Gunnar Jacks, Department of Land and Water Resources Engineering, KTH, Stockholm, Sweden

19. Harnath Jagawat, NM Sadguru Water and Development Foundation (NMSWDF), Dahod, Gujarat, India

20. I.Muthusamy, Professor, Department of Soil and Water Conservation Engineering, Tamil Nadu Agriculture University, Coimbatore, India

21. Ian Gale, British Geological Survey, Wallingford, Oxon, UK

22. Indra, Lecturer, E.S.College of Engineering & Technology Villupuram, India

23. J.Diraviam, AME Foundation, No. 204, 100 Feet Ring Road, Banashankari 3rd Stage, 3rd Phase, 2nd Block, Bangalore 560 085

24. J. Venkitapirabhu, Associate Professor (Agrl.Extn.), ODL, Tamil Nadu Agriculture University, Coimbatore, India

25. K.V. Rao, Central Research Institute for Dryland Agriculture, Hyderabad, India

26. K. Arulmozhiselvan, Professor of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural Uni-versity, Coimbatore, India

27. K. Ramaswamy, Professor, Department of Soil and Water Conservation Engineering, Agriculture Engineer-ing College and Research Institute , Tamil Nadu Agriculture University, Coimbatore, India

28. K.G. Mandal, Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal-462038, Mathia Pradesh, India

29. K.Kathirvel, Professor, Department of Farm Machinery, Agriculture Engineering College & Research Insti-tute, Tamil Nadu Agriculture University, Coimbatore, India

30. K.M. Hati, Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal-462038, Madhya Pradesh, India

31. K.Palanisami, Centre for Agricultural and Rural Development Studies (CARDS), Tamil Nadu Agricultural University, Coimbatore, India

32. K.Palanisami, Director, CARDS, Tamil Nadu Agriculture University, Coimbatore, India,

33. K.R. Koundal, Joint Director, IARI and Project Director, Water Technology Centre, IARI, New Delhi, In-dia

34. Koichi Fujita, Professor, CSEAS, Kyoto University, Japan

35. K.P.R. Vittal, Central Arid zone Research Institute, Jodhpur, India

36. Lakshmi Devi, Lecturer, E.S.College of Engineering & Technology Villupuram, India

37. M. Karthikeyan, Team Leader, DHAN Foundation, Madurai, India

38. M. Madhu, Central Soil and Water Conservation Research and Training Institute and Research Centre, Udhagamandalam � 640 004, The Nilgiris, Tamil Nadu, India

39. M. Palanisamy, Programme Leader, DHAN Foundation, Madurai, India

40. M. R. Rajagopalan, Secretary, Gandhigram Trust, Gandhigram, Dindigul, India

41. M.A. Fyzee, Scientist/ Engr-SE, National Remote Sensing Agency-Hydrabad, Andhra Pradesh, India

42. M.Jegadeesan, Visiting project Researcher, CSEAS, Kyoto University, Japan

43. M.Raghu Babu, Assitant Professor, APAU, Bapatla, India

44. Madar Samad, International Water Management Institute, South Asia Regional Office, Hyderabad, India

45. N.Sritharan, Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore India

46. N.Varadaraj, Regional Director, Central Ground Water Board, Chennai, India

47. O.P.S. Khola, Central Soil and Water Conservation Research and Training Institute and Research Centre, Udhagamandalam � 640 004, The Nilgiris, Tamil Nadu, India

48. P. Balasubramaniam, Associate Professor (Agrl.Extn.), ODL, Tamil Nadu Agriculture University, Coim-batore, India

49. P. Pathak, International Crop Research Institute for Semi-Arid Tropics, Pathancheru, Andra Pradesh, In-dia

50. P. Singh, International Crop Research Institute for Semi-Arid Tropics, Pathancheru, Andra Pradesh, India

51. P G.Lavanya, Head of Division, Agricultural Policy and Planning Division, State. Planning Commission, Chennai, Tamil Nadu, India

52. P.K. Mishra, Central Soil and Water Conservation Research & Training Institute, Research Centre, Bellary, Karnataka India

53. P.K.Singh, Associate Professor, Department of Soil and Water Engineering,CTAE, MPUAT, Udaipur, Ra-jasthan, India

54. P.K.Selvaraj, Professor (SWC), Agricultural Research Station, TNAU, Bhavanisagar, India

55. R. Vengatesan, M.Sc.(Ag) Scholar (2005-2007) in Soil Science and Agricultural Chemistry, Department of Soil and Environment, Agricultural College, Madurai, India

56. R. Vijayaraghavan, Professor and Head, KVK, Tamil Nadu Agriculture University, Coimbatore, India

57. R.K. Singh, Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal-462038, Mathia Pradesh, India

58. R.K.Haroon, Planning Officer, Agricultural Policy and Planning Division, State Planning Commission, Chennai, Tamil Nadu, India

59. R.Sakthivadivel, IWMI Senior Fellow & Visiting Professor, Anna University, Chennai, Tamil Nadu, India

60. R.Thangamani, Executive Engineer, Hydrology Division, Central Water Commission, Chennai, India

61. S. Gunasekaran, Team Leader, Holistic Water Development Project, Gandhigram Trust, Gandhigram, Dindigul, India

62. S. K. Gupta, Scientist - D, Central Ground Water Board, Western Region, Jaipur; India

63. S. Mohan, Professor, Environmental and Water Resources Engineering Division, Department of Civil En-gineering, IIT Madras, Chennai, India

64. S.L. Patil, Central Soil and Water Conservation Research & Training Institute, Research Centre, Bellary, Karnataka India

65. S.Manivannan, Senior Scientist (SWCE), ICAR Research Complex for Goa, Ela,Old Goa, Goa, India

66. S.Mohamed Ghouse, Principal, E.S.College of Engineering & Technology,Villupuram and Former Chief Engineer, Agricultural Engineering Department, Nandanam Chennai, India

67. S.P. Wani, International Crop Research Institute for Semi-Arid Tropics, Pathancheru, Andra Pradesh, In-dia

68. S.Senthilvel, Centre for Agricultural and Rural Development Studies (CARDS), Tamil Nadu Agricultural University, Coimbatore, India

69. Sayyed Ahang Kowsar, Emeritus Senior Research Scientist, Fars Research Center for Agriculture and Natural Resources, Iran

70. Subshree, Lecturer, E.S.College of Engineering & Technology Villupuram, India

71. T. Selvakumar, Department of Agronomy, Tamil Nadu Agriculture University, Coimbatore, India

72. T.P.Natesan, Senior Hydrogeologist, TWAD Board, Chennai

73. T.Ramesh, Centre for Agricultural and Rural Development Studies (CARDS), Tamil Nadu Agricultural Uni-versity, Coimbatore, India

74. T.Ramesh, Department of Agronomy, Tamil Nadu Agriculture University, Coimbatore, India

CONTENTS

S.No. Chapter Name Page No.

Parallel Session

Theme 1: Water Harvesting at the Farm level — 1-67

1. Management of Aquifer Recharge � The key to sustainable rural groundwater supply? Ian Gale · 3-11

2. In situ Rainwater Harvesting and Related Soil & Water Conservation Technologies at the Farm Level, P.K.Mishra · 12-33

3. Low Cost On-Farm Indigenous and Innovative Technologies of Rainwater Harvesting, R.K.Singh · 34-41

4. Integrating In-situ Soil Moisuture Conservation Techniques and Supplementary Irrigation for Sustainable Farming in Dryland Areas, K.Ramaswamy · 42-49

5. Conservation of Rainwater and Sustainaility of Productivity through Imporved Land Management and Cropping System in a Vertisol of Central India, K.M. Hati, A.K. Misra, K.G. Mandal, A.K. Tripathi, A. Subba Rao, R.K. Singh, S.P. Wani, P. Singh and P. Pathak · 50-56

6. Implements for Water Harvesting and In-stiu Mositure conservation, D.Manohar Jesudas and K.Kathirvel · 57-61

7. Effect of In-situ Conservations practices on runoff, soil loss and yield performances of chshew in Goa, S.Manivanan · 62-67

Parallel Session

Theme 2: Water Harvesting at Micro-watershed Level - continuation — 68-108

8. Drought Mitigation through Floodwater Harvesting for the Artificial Recharge of Groundwater: Prudence vs Large Dms, Sayyed Ahang Kowsar · 69-72

9. Tank Systems for Water Harvesting, R.Sakthivadivel · 73-78

10. Water Harvesting and Ground Water Recharge, N.Varadaraj · 79-87

11. Potential of Water Harvesting as a Tool for Drought Mitigation, S.Mohan · 88-94

12. Impact of cost effective water harvesting techniques on artificial groundwater recharege through open wells and recharge from natural streams, K.Ramaswamy · 95-103

13. Rain water harvesting, recharging and skimming techniques suitable for saline ground water tracts of South India � Case study, I.Muthusamy and M.Raghu Babu · 104-108

Parallel Session

Theme 3: Enhancing Water Productivity in Rainfed Areas — 109-153

14. Crop Management Options to Enhance Water Productivity of Rainfed Area, S.Natarajan, C.Sudhalakshmi, R.Jagadeeswaran and R.Venkitaswamy · 111-112

15. Opportunity for Enhancing Crop Water Produtivity in Rainfed Areas:: An Assessement for Rainfed Areas of India, Bharat R Sharma, K V Rao and KPR Vittal · 113-118

16. Improving Productivity in Dryland Groundnut Framing � LEISA Otucomes from South India, Arun Balamatti, J Diraviam and C S Kallimani · 119-128

17. Water Productivity at Different Scales Under Canal, Tank and Well Irrigation Systems, K.Palanisami, T.Ramesh and S.Senthilvel · 129-134

18. Integrated Farming System for Increasing Agricultural Wter Productivity, C.Jayanthi, T.Ramesh and C.Vennila · 135-138

19. Generation of regional water harvesting potential scenarios using CLIMGEN model, A. Sarangi, C.A. Madramootoo and K.R. Koundal · 139-142

20. Improving Water Productivity in Maize by Nutriseed Holder Techinque under Micro Sprinkler and Drip Irrigation, K. Arulmozhiselvan and R. Vengatesan · 143-148

21. Aerobic Rice for mitigating water scarity: Physilogical approaches, C.Vijayalakshmi, N.Sritharan and P.K.Selvaraj · 149-153 Parallel Session

Theme 4: Policies, Institutions and Socio-Economic Aspects · 154-188

22. Socio-Economic Issues in Watershed Development Programs, Madar Samad · 155-159

23. Community Resource Management: Much needed strategy in Tank Irrigation system in India, M. Jegadeesan and K. Fujita · 160-168

24. Indigenous Knowledge use in Dryland, P. Balasubramaniam, R. Vijayaraghavan and J. Venkitapirabhu · 169-173

25. Priciples and Policty Perspective of Rain Water Harvesting, P.G.Lavanya and R.K.Haroon · 174-182

26. Impact of National Watershed Programmed for Rainfed Agriculture. A case study in Tamilnadu, A.Balakrishnan and T.Selvakumar · 183-185

27. Holistic Watershed Development � A practical Approach for Creating an Enabling Environment to Promote Waer Harvesting, M.R.Rajagopalan, S.Gunasekaran · 186-188 Parallel Session

Theme 5: Role of Research, Extension and Education — 189-236

28. Natures own water harvesting- Groundwater recharge in some different environments, Gunnar Jacks · 191-194

29. Water Harvesting � A look at the past and vision for the future, R.Thangamani · 195-196 30. Water Resources Management and Sustainability of Drinking Water Resources � TAWD Experience, T.P.Natesan · 197-202 31. Artificial Recharge and Aquifer storage in Lower kantli River Basin Rajasthan, India � A Case Study, S. K. Gupta · 203-212 32. Capacity building � Human resources and institutional development in support of soil and water conservation in India, O.P.S. Khola and M. Madhu · 213-222 33. Otureach programmes on water harvesting and land development for sustainable agricultural dryland watersheds, C.R. Shanmugham, M. Palanisamy and M. Karthikeyan · 223-231

34. Role of Research, Extension and Education in Water Harvesting A case study - Groundwater recharge in hard rock regions of Coimbatore district, Tamil Nadu, India, D.Tamilmani, A.Raviraj and S.SanthanaBosu · 232-236

Theme – 1Water Harvesting at the Farm level

3

MANAGEMENT OF AQUIFER RECHARGE —

THE KEY TO SUSTAINABLE RURAL GROUNDWATER

SUPPLY?

Objectives of MARMAR describes intentional storage and treatment

of water in aquifers. The term Âartificial rechargeÊ is also commonly used, but adverse connotations of ÂartificialÊ suggest that it is time for a new name. Managed Aquifer Recharge is also intentional as opposed to the incidental impacts of land clearance, irrigation and leakage from water mains and sewerage systems.

Managed Aquifer Recharge is carried out all over the world for all kinds of reasons and, in its simplest form involves constraining surface runoff and encouraging infiltration to aquifers through the construction of earthen field bunds. A large percentage of schemes are developed to store water for future use, for drinking water supplies and agriculture.

Other reasons to manage aquifer recharge include the control of saltwater ingress, the augmentation of low river flows, reduction of runoff and soil erosion,

absorption of floodwaters to reduce their destructive capacity and the control of subsidence.

Managed Aquifer Recharge should be regarded as one method to manage water resources in conjunction with a wide range of others, including surface storage, exploitation of groundwater, demand management, wastewater reuse etc.

Managed Aquifer Recharge TechniquesNumerous schemes exist to enhance recharge

of groundwater and they are as varied as the ingenuity of those involved in their construction and operation. These schemes are designed with the prime objective of enhancing recharge (intentional recharge) but aquifers can also be recharged unintentionally (incidental recharge) whilst undertaking other activities, for example irrigation. Intentional methods are aimed at enhancing groundwater supplies but may also achieve other purposes such as flood mitigation and reduced soil

Ian Gale

1

4

erosion. Here the focus is on intentional recharge, the methodologies applied being broadly grouped into the following categories:

Spreading methods

In-channel modifications

Well, shaft and borehole recharge

Induced bank infiltration,

Rainwater harvesting

Many schemes require low levels of technology and can be (and have been for centuries) implemented with little engineering knowledge. Although simple in principle the efficient operation of spreading basins and infiltration schemes needs a good knowledge of the physical, hydraulic, geochemical and microbiological processes in operation and how to mange them for optimum performance. Similar issues need to be addressed in roof top rainwater harvesting. For further details on these types of schemes, e.g. construction, restoration, operation etc. the reader is referred to (Central Ground Water Board, 2000), (CGWB/UNESCO, 2000), (National Institute of Hydrology, 1998), (American Society of Civil Engineers, 2001), (OÊHare et al., 1982), (Huisman and Olsthoorn, 1983), (Pacey and Cullis, 1986) and (United Nations, 1975).

Spreading MethodsWater spreading is applied in cases where the

aquifer to be recharged is at or near to the ground surface. Recharge is achieved by infiltration through permeable material at the surface, which is managed to maintain infiltration rates. In situations where there is a reliable source of good-quality input water, and spreading infiltration can be operated throughout the year, then hydraulic loadings of typically 30 m/yr can be achieved for fine texture soils like sandy loams, 100 m/yr for loamy soils and 300 m/yr for medium clean sands and 500 m/yr for coarse clean sands (Bouwer, 2002). Evaporation rates from open water surfaces range from about 0.4 m/yr for cool wet climates to 2.4 m/yr for warm dry climates so form a minor component of the water balance.

Where the source of water is sporadic from seasonal flow containing high loads of suspended solids, management of the recharge structure becomes increasingly important in order to minimize clogging to maintain infiltration rates and keep evaporation from open water to a minimum.

Infiltration or Recharge Ponds or Basins

An infiltration basin is either excavated in the ground, or it comprises of an area of land surrounded by a bank, which retains the recharge water (e.g. storm water), until it has infiltrated through the base of the basin. If the aquifer material is fine, rapid clogging will occur. In this case, covering the bottom and sides with an approximately 0.5m thick layer of medium sand can delay the clogging process and extend the recharge periods in the facility (Huisman and Olsthoorn, 1983). The same technique should be used on a fissured-rock aquifer, to prevent deep penetration of suspended solids or algae, which could result in irreversible clogging.

The depth of the basin should be shallow enough, to allow rapid draining in cases where cleaning of the basin by drying and scraping is necessary. Water levels should be managed to prevent growth of vegetation or accumulations of algae and consequent resistance to the flow of water. The area of land available for infiltration basins and the infiltration rate determines the volume of recharge achievable.

Clogging of the basin floor is the predominant problem during recharge, creating a filter skin on the bottom and sides of the spreading basin. To counteract this, the following methods should be considered:

Apply a rotational system of water spreading and drying and subsequent scraping of the basin. Drying kills algal growth, and this, combined with scraping of the basin bottom, restores infiltration rates.

Construct ridges on the floor of the basin and control the water level to winnow fines to settle in the troughs, thus maintaining infiltration rates on the sides of the ridges.

Mechanical treatment of the recharge water by primary sedimentation to remove suspended solids. Settling efficiency can be increased by addition of flocculating chemicals

Chlorination of the recharge water to prevent microbial activity Mechanical treatment of the soil by ploughing to increase permeability

Lining the basin with a layer of medium sand to act as a filter to remove suspended solids.

Soil Aquifer Treatment (SAT)Planned reuse of water will become increasingly

important as demand from users and the environment

5

results in wastewater becoming regarded as an asset rather than a disposal problem. Practical research undertaken over the last few decades, notably in Phoenix, Arizona, Bouwer, (2002), has investigated hydraulic, operational and bio-geochemical processes involved in wastewater recharge and recovery. Water quality improvement is often the primary objective to remove all suspended solids and micro-organisms. Removal of nitrogen species through denitrification is also a key benefit as is the reduction in concentration of dissolved organic carbon through biological processes. Phosphates and metals can also be removed but are retained in the soil.

Controlled FloodingIn areas of relatively flat topography water may

be diverted, with the help of canals, from a river and spread evenly over a large surface area. A thin sheet of water forms which moves at a minimum velocity to avoid disturbance of the soil cover. Highest infiltration rates are observed on areas with undisturbed vegetation and soil cover (Todd, 1959).

Incidental RechargeIt is important to take incidental recharge into

account as it can form a significant component of the water balance of a catchment. Leakage from water, wastewater and storm-water systems in urban areas can contribute significantly to groundwater recharge, in some cases resulting in rising groundwater levels and flooding. Irrigation excess water from irrigation canals and fields have historically caused water logging and salinization problems. However, where managed beneficially this incidental recharge can become an asset. For example, in the Indo-Gangetic Plain groundwater levels rose by about 6 m over a ten-year period and the water has been increasingly scavenged for irrigation water outside the surface water irrigation season. IWMI, 2002 estimate that about 60% of the water applied to rice paddy is utilised, the balance percolating to groundwater. Recent studies demonstrated that large canal irrigation systems can be modified to augment groundwater recharge.

The use of urban wastewater for irrigation can have additional problems and benefits. Use of municipal wastewater for agricultural irrigation is widely established in Mexico. Around cities such as Leon and Mexico City itself, groundwater levels are falling rapidly where abstraction to meet demand from a rapidly expanding population, exceeds recharge. However, where the wastewater is used for irrigation, the water tables are

close to ground surface. The wastewater contains industrial pollutants of many types; in Leon the effluent from the tanning industry is a significant component. The main impact on the groundwater quality in the irrigated area is the presence of poor-quality water to depths of 50 to 100 m with chloride concentrations of 800 to 1000 mg/l in the upper portions. Many of the other pollutants in the wastewater are removed or attenuated in the distribution system and the soil zone. This helps to prevent pollutants such as organic carbon, nutrients, heavy metals and pathogens form reaching the groundwater body. The main threat to groundwater is increasing concentrations of chloride being drawn to the municipal supply wells in the area (Chilton et al., 1998).

In-Channel Modifications

Percolation Tanks Behind Check-DamsAn inexpensive way of spreading water can be

achieved by the construction of check-dams across a streambed with the construction material being in situ river alluvium. To avoid annual erosion or destruction of these structures a concrete spillway is often constructed and, to contain and channel surface runoff, bunds are also built. Associated field bunds retard the water flow to the stream and thus create an opportunity for this water to infiltrate into the ground as well as reducing soil erosion.

An example: the AGRAR study, India (Gale et al., 2006)

In order to quantify the impacts of check dam recharge structures on the hydrology of a catchment and the hydrogeology in the immediate vicinity, three research sites were instrumented and monitored. These sites were selected to be representative of a range of hydrological as well as socio-economic environments.

Satlasana, Gujarat (VIKSAT). The Aravalli Hills which surround the villages studied form a well-defined catchment of approximately 20 km2. The area is semi-arid; the average annual rainfall is around 650 mm, with rainfall occurring from late June until the end of September. There are typically 30 to 35 days of rainfall in a year.

The main aquifer in the catchment is formed by shallow weathered and fractured granitic rocks. These are overlain in the upper regions of the valley floor by thick layers of sediment (15-20 m) weathered from the hillsides. The main part of the valley floor is moderately undulating.

6

Kolwan Valley, Maharashtra (ACWADAM). The Kolwan Valley is located on the eastern slopes of the Western Ghats and, as a result, rainfall is 1800 mm/a on average, although highly variable. The rain occurs mainly during a single monsoon season, generally from June to October.The detailed local geology comprises a series of eight basalt units (lava flows). Each unit has a compact, less weathered lower section and a fractured/jointed, more weathered upper section; the latter having the capacity to store more groundwater, being more permeable and therefore a much better aquifer. The check dams at Chikhalgaon are all located on the upper section of one of the basalt units.Kodangipalayam, Tamil Nadu (TNAU-WTC). The Kodangipalayam watershed consists of two micro-watershed with a total area of 5.0 km2. Rainfall occurs in two seasons as a result of the southwest monsoon (June to September) and the northeast monsoon (October to December). The regional average total annual rainfall is 650 mm, measured at Sulur (7 km from Kodangipalayam). The area is underlain by shallow weathered crystalline hard-rocks (charnockites, migmatites and banded gneisses) which have relatively low groundwater storage capacity.

The findings

The additional water that the recharge structures are contributing to the aquifer was quantified and an indication of the distance to which the impacts can be seen were estimated. A measure of the effectiveness of the recharge structures is how this additional recharge compares with the natural groundwater recharge across the whole of the study areas. The studies show remarkably similar results despite the considerable differences in catchment area, rainfall (both quantity and distribution), geology and useage.

The equivalent depth (4.8 to 12 mm) of additional rainfall recharged represents only a small percentage (0.6 to 1.4%) of the available rainfall but is calculated to be a significant percentage increase to that recharged naturally, 13 to 23 %. Check dams therefore can make significant contributions to recharge but need to be distributed so there is sufficient rainfall to be captured, i.e. some dams never appear to fill except in exceptional circumstances. Account also needs to be taken of the redistribution of recharge at the catchment scale as larger tanks, down stream may be deprived of water.

Sand Storage DamsSand dams are best sited in undulating terrain

under arid climatic conditions, where runoff is often experienced as flash floods. The dams are typically constructed in sandy, ephemeral riverbeds in well-defined valleys. A dam wall is constructed on the bedrock, across the width of the riverbed to slow down flash floods or longer ephemeral flow events. This allows coarser material to settle out and accumulate behind the artificial dam wall. The dam wall can be raised after each successive flood event, the height of the wall thereby determining the flood flow and the amount of material accumulating. However, sufficient overflow should be allowed for finer material to get carried away (Murray and Tredoux, 1998).

Subsurface DamsSubsurface dams may be used to detain water in

alluvial aquifers. In ephemeral streams where basement highs constrict flow, a trench is constructed across the streambed keyed into the basement rocks and backfilled with low permeability material to constrain groundwater flow. The groundwater is recovered from wells or boreholes.

Recharge ReleasesWhere flow is very flashy and contains large

amounts of suspended solids, the water may be lost to the catchment or to the sea before it can be given the opportunity to infiltrate to replenish the aquifer. Constructing of larger dams on ephemeral streams to capture and store this flow to reduce the sediment load followed by controlled release of the water into the downstream reaches where groundwater recharge occurs. A good example of this practice is the OMDEL scheme in Namibia.

Wells, Shafts and Boreholes

Open Wells and ShaftsThese structures are used to recharge shallow

phreatic aquifers and where the surface layers are of low permeability and hence spreading methods are not effective. Wells that have run dry are often used for this purpose. Coarse material is sometimes used to fill pits or trenches to act as a filter and can be replaced if clogging becomes severe.

Settlement of the suspended solids in the recharge water is needed prior to recharge in order to

7

reduce the potential for clogging of pores, particularly if the source is storm water. Subsequent abstraction may flush fines out of pores and go some way towards recovering the recharge capacity. The significance of the contribution made by this method needs to be compared to the quantity of recharge occurring naturally, but it could be valuable where shallow, low-permeability layers constrain infiltration from the surface.

Use of wells has the potential to introduce not only suspended solids directly into the aquifer but also chemical (nitrates, pesticides, etc.) and bacterial (including faecal) contaminants. The spreading structures described earlier have the advantage that the water infiltrating from the surface passes through soil and alluvial deposits which can act as extremely effective filter/treatment mechanisms.

Drilled Wells and BoreholesWell or borehole recharge is used where thick,

low permeability strata overlie target aquifers, in order to recharge water directly into the aquifer. Recharge wells are also advantageous when land is scarce (OÊHare et al., 1982). However, recharge water quality requirements are usually significantly higher for borehole injection than for groundwater recharge by means of spreading. A detailed description of this method is beyond the scope of this document, but can be found in (Pyne, 1995. Pyne, 2005). Where the well/borehole is used for both injection and recovery (Aquifer Storage Recovery: ASR), costs are minimised and clogging is removed during the recovery cycle. Water can be injected into a borehole and recovered from another, some distance away, to increase travel time and benefit from the water treatment capacity of the aquifer. This is referred to as Aquifer Storage Transfer and Recovery (ASTR)

Induced Bank InfiltrationRiverbed infiltration schemes commonly consist

of a gallery or a line of boreholes at a short distance from, and parallel to the bank of a surface water body. Pumping of the boreholes lowers the water table adjacent to the river or lake, inducing river water to enter the aquifer system. To assure a satisfactory purification of the surface water in the ground, the travel time should exceed 30 to 60 days (Huisman and Olsthoorn, 1983).

The factors controlling the success of induced infiltration schemes are a dependable source of surface water, of acceptable quality, and the permeability of the river or lake-bed deposits and of the formations

adjacent to the surface water body (OÊHare et al., 1982). Provided that the permeability of the stream or lake-bed and aquifer are high and the aquifer is sufficiently thick, large amounts of groundwater may be abstracted from a well or a gallery without serious adverse effects on the groundwater table further inland (Huisman and Olsthoorn, 1983).

A particular variant of this method is used in coastal zones and is known as inter-dune filtration. Here the valleys between coastal sand dunes are flooded with water from rivers to infiltrate into the underlying sediments and create a recharge mound. The mound can play an important role in preventing saline intrusion as well as providing a source of water that is abstracted further inland. This technique has been used for centuries and is highly developed along the coast of The Netherlands where rivers are the source of water for the recharge. In other schemes, storm and urban wastewater (e.g. S.Africa) and treated wastewater (Factory 21, Los Angeles) are the sources of water.

A key objective of these types of schemes is to improve the quality of the often poor-quality source water and much research has been undertaken to understand and optimise the management of suspended solids, clogging and the attenuation of dissolved solids, including organic compounds, using physical, chemical as well as biological processes.

Rainwater HarvestingRainwater harvesting, in its broadest sense is

the collection of runoff for productive use and usually involves the concentration of rainfall from a larger area for use of storage in a smaller area as soil moisture or groundwater. Roof-top rainwater harvesting is a special case being increasingly used in urban areas for tank storage, urban irrigation and groundwater recharge.

Dry Land FarmingIn semi-arid regions, dry land farming systems

utilise between 15 an 30% of rainfall, the majority evaporating (30 � 50%) and the remainder going to surface runoff (10 � 25%), and groundwater recharge (10 � 30%). Interventions ranging from field bunds, contour ploughing and rock weirs in drainage channels to floodwater diversions into bunded cropping areas all aim to reduce runoff and concentrate the water to be stored in the soil profile or the deeper aquifer. Whichever system is used, the aim is to significantly reduce surface runoff and evaporation in order to enhance agricultural

8

production and, often unintentionally, enhance groundwater recharge.

Roof-Top Rainwater HarvestingRoof-top rainwater harvesting can conserve

rainwater for either direct consumption or for recharge of groundwater. This approach requires connecting the outlet pipe from a guttered roof-top to divert rainwater to either existing wells or other recharge structures or to storage tanks. Drainpipes, roof surfaces and storage tanks should be constructed of chemically inert materials such as plastic, aluminum, galvanised iron or fibreglass, in order to avoid contaminating the rainwater.

Where the water is used for direct consumption, the initial water from a rain shower is often allowed to run to waste to flush accumulated dirt off the collection area and gutters. The main sources of contamination are pollution from the air, bird and animal droppings and insects. Bacterial contamination may be minimized by keeping roof surfaces and drains clean but cannot be completely eliminated. Advantages of collecting and storing rainwater in urban areas is the reduction of demand on water supply systems as well as reducing the amount of storm-water run-off and consequent urban flooding.Sources of Recharge Water

A prerequisite for artificial recharge of groundwater is the availability of a source of water of suitable quality, in sufficient quantity. Several sources of water can be considered for use as recharge water, namely surface water, runoff water, wastewater or water for potable supply.

Surface WaterSurface water can be a consistent source of

recharge water depending on the climatic situation. Under humid conditions moderate variability in river flows can be expected, and perennial rivers are predominant. Under arid or semi-arid conditions ephemeral rivers prevail.

In lakes, water is not flowing significantly and is clear with little or no suspended material. In the absence of pollution by waste discharges or agricultural runoff, and with little algal growth, lake water may be used for spreading directly without any pre-treatment (Huisman and Olsthoorn, 1983). Water from polluted rivers or lakes, in particular those with industrial-waste discharges, should go through pre-treatment processes prior to recharge. In some situations infiltration basins

can be used to improve the quality of water as it recharges, through physical and biochemical processes.

Storm-Water RunoffUrban areas generate significant quantities of

storm-water runoff. The runoff is highly variable in quantity with peak discharges occurring after heavy rainfalls. In order to obtain a more consistent supply, infiltration and storm-water retention ponds, grassed areas, porous pavements and wetlands are recommended for watershed areas (Murray and Tredoux, 1998). The best quality runoff water in urban areas is from roof-tops and increasingly initiatives (e.g. all government buildings in India) are being made to direct this water immediately to groundwater recharge through infiltration galleries wells and boreholes. This not only replenishes urban aquifers that are often over-exploited, but also, introduces good quality water into often-polluted groundwater.

In rural areas, intense rainfall can generate surface runoff from agricultural fields. In some areas (e.g. Saurashtra, India) this runoff is channeled into large diameter hand dug wells to directly recharge the aquifer. Holding bunds are sometimes constructed to reduce the suspended sediment load, but not the dissolved contaminant load. For this reason direct recharge to open wells is to be discouraged in preference to infiltration through a soil or sand layer which can be managed to remove some dissolved constituents.

WastewaterWastewater as a source is of predictable volume

with a fairly uniform rate of flow over time and of constant, but inferior quality (Murray and Tredoux, 1998). Wastewater requires significant treatment before being considered to be of acceptable quality for aquifer recharge and to minimise the extent of any degradation of groundwater quality (Bouwer, 1996). The compounds of concern depend on the wastewater source, i.e. industrial or domestic wastewater. Wastewater as a source offers a significant potential for all non-potable uses. However, with proper pre- and post-treatment or dilution with native groundwater, potable use also can be a viable option (Bouwer, 1996).

Potable WaterPotable water is a major source of recharge

water used in Aquifer Storage and Recovery (ASR) schemes. High-quality treated water is injected through wells, usually into confined aquifers to create a bubble

9

of potable water in the aquifer. These bubbles can be created in non-potable aquifers by displacing the native water and have proved to be a cost-effective and environmentally sustainable method for resolving a wide variety of problems (Pyne, 1995 and 2005). The schemes are usually constructed near treatment works, the source of the recharge water, to save cost and to utilise surplus treatment capacity.

In arid areas, such as the Gulf region of the Middle East, were water demand exceeds the availability of water from renewable resources, freshwater from desalination plants is used to bridge this gap. To ensure water availability during emergencies, for example, when desalination plants are out of commission, large freshwater storage capacities are required. Field trials have been undertaken to evaluate the feasibility of introducing desalinated water into aquifers to build up this freshwater reservoir (Mukhopadhyay and Al-Sulaimi, 1998). Due to the high quality of the desalinated water, no major geochemical compatibility problems are expected as the water can be treated to minimise any potential reactions with the aquifer material; for example the pH can be adjusted to be non-aggressive.

Institutional Issues In order for aquifer recharge schemes to be

successfully implemented and managed as a component of wider watershed management strategies, the institutional, regulatory, economic and livelihoods structures need to be taken into account. A variety of approaches has been employed for implementing natural resource management activities such as artificial recharge, with responsibilities resting (to varying degrees) with the state, local government, development agencies, NGOs and local people. A dominant institutional theme emerging over the last two decades in natural resource management has been decentralisation, in tandem with efforts to promote a more Âbottom-upÊ, participatory planning process (Carney and Farrington, 1998). As the poor are disproportionately dependent on common pool resources, improvements in decentralised management - whether in equity of rights and responsibilities, in resource productivity, or in its sustainability � can contribute substantially to their livelihoods.

Three distinct institutional approaches have varying legitimacy and potential capacity to contribute to such improvements (Farrington et al., 1999).

Informal , often traditional user groups, generally

enjoying de facto rights of access only. In some countries steps have been taken to codify customary rights, though (more typically) the state is reluctant to transfer access rights to local communities or individuals.

Public administration, increasingly in collaboration with local communities. Moves towards forming natural resource management partnerships with communities or Âuser groupsÊ for particular resources are found in many countries. In India, for example, this is now the preferred model for watershed development - in which artificial recharge of groundwater plays an important part.

Local government, operating independently of government departments, but drawing on services from them. In many African countries (e.g. Ghana; Malawi; South Africa), local government is now taking on responsibilities in water supply and sanitation provision, not as a provider but as a ÂfacilitatorÊ in a demand driven process. In India, where administrative decentralisation is now a core feature of watershed development (under the partnership model described above), growing attention is focusing on the interface with political decentralisation through the Panchayati Raj local government reforms.

Why the emphasis on decentralisation? In many countries, state led approaches to natural resource management have been monolithically blamed for the degradation of natural resources. As a consequence, the state is advised to adopt a facilitative rather than a leadership role. Decentralisation and participatory management are clearly linked. Participatory management can be defined as a process whereby Âthose with legitimate interests in a project both influence decisions which affect them, and receive a proportion of any benefits which may accrueÊ (ODA, 1995). It is now generally accepted that to enhance and sustain the productivity of natural resources, those engaged in and affected by managing the resource must participate in planning its rehabilitation and management.

Summary and ConclusionsThe benefits to society of using groundwater have

been clearly demonstrated, particularly in arid and semi arid regions. Aquifers provide a store of groundwater, which, if utilised and managed effectively, can play a vital role in poverty reduction and livelihood stability. Access to groundwater reduces vulnerability to drought, increases agricultural yields and contributes to societal

10

equity where shallow groundwater levels mean access for everyone. Maintaining water resources and shallow groundwater levels through augmentation by Managed Aquifer Recharge contributes to, and maintains the above benefits when used as one mechanism in a broader watershed management strategy.

Where water table aquifers have been over-exploited for irrigation and rural or urban use, decline in water levels are eventually accompanied by a deterioration of water quality. Managed Aquifer Recharge with surplus runoff through surface infiltration structures will usually provide high quality water that will not only replenish resources but can also improve groundwater quality through dilution. Where low-permeability layers are at the surface water needs to recharged through wells or boreholes. The beneficial effects of filtration through soil are lost with these methods and additional pre-treatment is required.

Techniques for applying Managed Aquifer Recharge range from simple field bunds, to capture storm water, to deep injection of highly treated water into confined brackish aquifers. Understanding the hydrogeological, chemical and microbiological processes that apply, combined with the institutional and socio-

economic implications is important for sustainable implementation and management of schemes.

Managed Aquifer Recharge is becoming a vital component of watershed management strategies by optimising the use of water resources (often available only sporadically) through storage of water in depleted aquifers for subsequent recovery and use. Managed Aquifer Recharge often provides the cheapest form of new safe water supply for towns and villages. Uptake has been constrained by lack of understanding of hydrogeology and/or knowledge of MAR but it has the potential to be a major contributor to UN Millennium Goals for Water Supply, especially for village supplies in semi-arid and arid areas.

MAR is part of the groundwater managerÊs toolkit, which may be useful for replenishing depleted aquifers, controlling saline intrusion or land subsidence as well as improving water quality through filtration and chemical and biological processes. On its own it is not a cure for over-exploited aquifers, and can merely enhance volumes of groundwater abstracted. However it may play an important role as part of a package of measures to control abstraction and restore the groundwater balance.

11

ReferencesAmerican Society of Civil Engineers, 2001. Standard Guidelines for Artificial Recharge of Ground Water. EWRI/

ASCE 34-01, American Society of Civil Engineers, ASCE, Reston, Virginia, USA.Bouwer, H., 1996. Issues in artificial recharge. Water Science and Technology, 33(10-Nov): 381-390.Bouwer, H., 2002. Artificial recharge of groundwater: hydrogeology and engineering. Hydrogeology Journal, 10:

121-142.Carney, D. and Farrington, J., 1998. Natural Resource Management and Institutional Change. Routledge Research/

ODI Development Policy Studies.Central Ground Water Board, 2000. Guide on artificial recharge to ground water, Central Ground Water Board ,

Ministry of Water Resources, New Delhi.CGWB/UNESCO, 2000. Rainwater harvesting and Artificial Recharge to groundwater - A guide to follow, Central

Ground Water Board, India. UNESCO, IHP Programme.Chilton, P.J. et al., 1998. Groundwater recharge and pollutant transport beneath wastewater irrigation: the case

study of Leon, Mexico. In: N.S. Robins (Editor), Groundwater pollution, aquifer recharge and vulnerability. Geological Society, London, pp. 153-168.

Farrington, J., Turton, C. and James, A.J., 1999. Participatory Watershed Development: Challenges for the Twenty-First Century. OUP, New Delhi.

Gale et al., 2006. Managed Aquifer Recharge: an assessment of its role and effectiveness in watershed management. British Geological Survey Commissioned Report CR/06/107N. Available at http://www.iah.org/recharge/projects.html#AGRAR

Huisman, L. and Olsthoorn, T.N., 1983. Artificial Groundwater Recharge. Pitman, Boston.Mukhopadhyay, A. and Al-Sulaimi, J., 1998. Creation of potable water reserve in Kuwait through artificial recharge. In:

Peters, J H et al. (Editor), Artificial Recharge of Ground Water. Balkema, Rotterdam, Netherlands, Amsterdam, pp. 175-180.

Murray, E.C. and Tredoux, G., 1998. Artificial Recharge - A Technology for Sustainable Water ResourcesDevelopment. 842/1/98, Water Research Commission, Pretoria.

National Institute of Hydrology, 1998. Review of Artificial Recharge Practices. SR-5/97-98, National Institute of Hydrology, Jal Vigyan Bhawan, Roorkee, India.

ODA, 1995. A Guide to Social Analysis for Projects in Developing Countries, Overseas Development Administration. HMSO, London.

OÊHare, M.P., Fairchild, D.M., Hajali, P.A. and Canter, L.W., 1982. Artificial Recharge of Ground Water. Status and Potential in theContiguous United States. Norman, Oklahoma.

Pacey, A. and Cullis, A., 1986. Rainwater Harvesting - The collection of rainfall and runoff in ruralareas. IT Publications.

Pyne, R.D.G., 1995. Groundwater recharge and wells: a guide to aquifer storage recovery. Lewis Publishers.Pyne, R.D.G., 2005. Aquifer Storage Recovery. A guide to groundwater recharge through wells. Second edition. ASR

Systems Press, Gainsville, Florida 32602 USA.Todd, D.K., 1959. Annotated Bibliography on Artificial Recharge of Ground Water Through1954. 1477, U.S.

Geological Survey.United Nations, 1975. Ground-Water Storage and Artificial Recharge. 2, United Nations, New York.

���

IntroductionAlmost 6.1 billion ha (40%) of the earthÊs

total land surface is dry. Out of this, nearly 5.2 billion hectares are Arid, Semi�Arid and dry Sub�humid lands that are collectively referred to as drylands. It is estimated that 70% of partially productive drylands are threatened by various forms of degradation, impacting the well�being and future of one-sixth of the world population (Harahsheh, 2002). Lack of food security poses a particular burden on people and nations in the dryland regions of the world, particularly in tropical areas of Africa and Asia that are experiencing rapid population growth and/or high population density. Global food demand is expected to be more than double by 2050 because of population growth and increased per capita consumption. While the challenge cannot be met through increased agricultural production alone, increased production is essential as part of the solution. However, in many cases including India, production capacities of dryland countries are deteriorating in the face of rapid population growth, misdirected agricultural practices, and widespread of land degradation (Rao, et al., 2007). The environmental conditions of the worldÊs/IndiaÊs drylands and unpredictability of rainfall

In situ Rainwater Harvesting and related Soil & Water

Conservation Technologies at the Farm Level

P.K. Mishra and S.L. Patil

2

make these areas marginal for intensive agriculture. Land degradation in drylands due to water erosion, loss of soil fertility, ground water depletion and loss of vegetation, results in the decline of both economic and environmental potential in these regions.

The demand for fresh water is increasing globally at an accelerated rate especially for agriculture and various other sectors including domestic, energy and industrial uses. The accelerated demand for rainwater can be met through the efficient rainwater conservation. In the world about 73% of the cropland is rainfed. In India, about 60% of the cultivated area is rainfed and contributes nearly 40% of the total production (mainly coarse cereals, oilseeds, pulses and fruits etc.). In addition to major livestocks production systems, about 93% of cultivated area under sorghum, 94% under pearlmillet, 79% under corn, 87% under pulses, 76% under oilseeds, 64% under cotton and 59% under tobacco in India predominates drylands (Singh et al., 2007). The rainfed/dryland eco-system in India is characterized by erratic rainfall and frequent droughts. In such situations, in situ rainwater conservation plays a greater role for maintaining/increasing crop productivity. In the rainfed areas,

12

13

the rainwater harvesting and management assumes greater priority. It is therefore essential to conserve the rainwater in situ. Therefore the excess runoff is to be stored in farm ponds/tanks/water storage structures constructed along the water courses for reusing the surface water or recharging the ground water depending on the geological formations. The stored runoff is to be recycled as a protective irrigation or continuous irrigation to meet the optimum water requirements of the crops. This results in increased crop productivity in the region/State/Country and meets the demands of the increasing human/bovine food requirements (Mishra et al., 1994).

In India, low yields and crop failures in these drylands often lead to food and fodder scarcity resulting in a near�famine situation that further accelerate the process of land degradation. Alfisols, Entisols, Vertisols and associated soils dominate the SAT areas (Virmani, et al., 1991). These soils are generally highly degraded with low water retentive capacity, and have multiple nutrient deficiencies. In the drylandÊs of Indian human population is likely to reach 600 millions by 2025 from the present 410 millions. Similarly, the livestock population is likely to exceed 650 million by 2025 from the present 509 million. On the other hand, the area under dryland crop production may decrease to 85 million ha by 2025 from the present 97 million ha. Thus, from such a significantly reduced cultivated area, crop production must increase from the present 0.8 to 1.0 t ha�1 to 2.0 t ha�1 by 2025. Furthermore, the quality of the produce must improve the meet the global market standards. Also, the cost of production needs to be reduced in order not only to improve the farmersÊ net income but also remain globally competitive. This would help in maintaining the food security in the years ahead.

Rapid increase in human and bovine population in India has resulted in greater pressure on the natural resources especially rainwater and top fertile soil. It means that conservation of these resources, especially water, is the top priority of the day. In other words, the water resources of our country have to be put for better beneficial use with available technologies at our command. The excess surface water that flows to the sea should be stored and used efficiently for drinking, irrigation, industrial use, navigation etc. without affecting the hydrological cycle. Water conservation basically aims at matching demand and supply of water. The strategies for water conservation may be either

demand-oriented or supply-oriented. Strategies such as creation of storage, long distance transfer and control of water loss through evaporation are the common loss of water in its efficient use before it reaches the sea.

Water and soil conservation practices for agricultural lands includes, in situ or inter�terrace rainwater conservation practices, conservation of rainwater at terrace level through bunds and guiding the excess runoff for safe disposal through grassed waterways to the farm ponds/tanks/dams for its storage and recycling to the agricultural lands. These are called hard ware measures, which are of permanent type provided for improvement of relief, physiography and drainage features. These are executed with major Government support with the purpose to check soil erosion, regulate overland flow and reduce peak flow. The present approach to reduce runoff by adopting suitable in situ management practices includes, tillage practices comprising primary tillage operations i.e. summer or deep ploughing either every year or once in three years depending upon the soil type, land smoothening to avoid local depressions, frequent harrowing and secondary tillage practices with frequent intercultivations. The other rainwater conservation practices include, adoption of small section bunds or vegetative barriers on contour, contour sowing, opening ridges and furrows across the slope, tied ridging, zing terracing, scooping, compartmental bunding, broad bed and furrows, broad bed and ridge, vertical mulching and dead furrow formation in every row or at 3 m interval on contour depending upon the rainfall situations in black and red soils. In addition, evaporation control/in situ rainwater conservation measures using mulches i.e. soil, sand and vegetative mulches have resulted in greater benefits especially in winter (rabi) crops in deep black soils. Apart from these management practices, increasing the infiltration rate and moisture retention capacity of soil by improving their physical conditions with application of amendments and organic materials is of greater importance in the integrated approach for rainwater conservation in rainfed/dryland areas. Adoption of these options depending upon the rainfall, soil type, and land topography/slope would reduce runoff and increase in situ rainwater conservation in rainfed and dryland areas and reduce the ill effects of occasional dry spells (Mishra et al, 1999). All these measures are software measures which are mostly responsible for initiation rainwater conservation and management and are easily and voluntarily adopted by

14

the farmers as they can be made integral part of the agronomic measures/package of practices. In situ rainwater conservation is a vital component of dryland crop management practices. Earlier efforts were mainly concentrated on strengthing and formation of bunds across the slope. This resulted in reducing soil erosion rather than achieving uniform rainwater distribution in the soil profile. Present emphasis is mainly concentrated in increasing the opportunity time of water penetration to soil through land configurations, and applications of amendments and organic materials. With appropriate demonstration and action learning exercise the in situ rainwater conservation measures can be easily popularized. Several indigenous technical knowledge (ITKs) relating to in situ rainwater conservation measures are in practice, befitting the agro-ecological settings. These ITKs can be converted to medium technical knowledge (MTK) by addressing the researchable and extension issues.

The Semi�Arid tracts are mostly characterized with red and black soils. The problems associated with different soil types are different in physical, chemical and hydrologic terms. The red soils have low water holding capacity, higher infiltration and crusting tendency. In black soils even though the water holding capacity is high, low infiltration rate results in greater loss of soil and rainwater. In medium to deep black soils the crack formation results in wetting of subsoil with first showers. In the years of low rainfall, the soil profile wetting is not uniform and results in a dry layer in the profile. This ultimately results in lower crop yields. Major part of the countryÊs rainfed agriculture is fed by the Southwest monsoon in addition to the Northeast monsoon especially for the black soils region of Deccan pleatau of Karnataka, Andhra Pradesh and Tamil Nadu. Hence, its onset, continuity, intensity, volume and withdrawal patterns have a tremendous influence on the agricultural production. High intensity rains produce volumes of water beyond the intake capacity of the soil and may leave the soil dry at lower depths. With intermittent long dry spells this situation affects rainfed crops adversely, even in areas with moderate to high rainfall. Thus improving soil surface conditions to increase infiltration and improving water-holding capacity are two basic requirements in drylands. The inter-terrace management practices for in situ conservation of rainwater and ensuring its uniform distribution within the field and throughout the crop growth period assume paramount importance in dryland crop production.

The research efforts on rainwater management have resulted in identification of several useful technologies for in situ rainwater conservation. However, the choice of the most appropriate practices is a function of the soil type, rainfall characteristics, and topographic features. Hence, in situ rainwater conservation plays a greater role for stabilized/sustained crop yields in the Semi�Arid Tropics of India. This can be achieved with appropriate tillage and in situ rainwater conservation practices at the individual farm level. In this paper the in situ moisture conservation measures including ITKs are discussed.

Tillage Practices

Vegetative Barriers

Mulching

Land Configuration

Crop Residue Management

Soil Amendments

Tillage PracticesCultivation of soil helps to increase pore space

and also keeps the soil loose so as to maintain higher level of infiltration. Musgarve and Free (1936) found that cultivation of the surface greatly enhanced water intake of soil particularly in the beginning of storms. In the absence of cultivation, the highly crusting red soils produce as much or even more runoff than the low permeable Vertisols under similar rainfall situations. Larson (1962) stated that pulling a tillage implement through soil results in the total porosity and thickness of the tilled area being greatly increased temporarily. Surface roughness and micro depressions thus created play greater role in higher retention of water (Unger and Stewart, 1983). Different tillage operations are carried out to incorporate crop residues, conserve the rainwater in situ, recharge soil profile, prepare smooth seed bed for greater seeds to germinate with better root system, to reduce conserved soil water loss (secondary tillage) and its efficient utilization and control weeds/pest or diseases and increase the crop yields (Patil, 1998, Thyagaraj, 1999 and Vittal et al., 1983). Generally the primary tillage operations are carried prior to sowing to prepare the smooth seedbed and secondary tillage are carried out to control weeds, reduce evaporation and support the plants through earthening up.

In general tillage operations make the soil receptive to rainfall through increased infiltration

15

rate. Deep tillage with plough followed by chiselling (Channappa, 1994) opens the hard layers and increase the infiltration rate and water storage capacity and finally results in better crop growth with higher yields in the red soils at Bangalore, Karnataka, India (Tables 1 and 2). Similarly, in the red soils in the farmers fields at Coimbatore, Tamil Nadu, India, the deep ploughing with chisel plough + disc plough + cultivator increased the soil water in the profile at different stages of sorghum growth as compared to soil cultivation with cultivator once or twice i.e. reduced tillage operations (Manian et al., 1999). Primary tillage carried out in the Alfisols at Hyderabad, ICRISAT, India, (Pathak and Laryea, 1995) improved the soil physical properties with better root development (Table 3). In the Alfisols in SAT of India, the residue management represents only a minor part of the cropping system; reduced/minimum tillage concepts are at a disadvantage in dryland cropping. It was also observed that deep tillage reduced the runoff, soil loss and increased the soil water in the red soil profile with increased sorghum yield by 26% over

normal tillage in the Alfisols at ICRISAT, Hyderabad, India (Table 4). The positive effect of deep tillage on rainwater conservation, better root development and increased crop yields were observed for 2 to 5 years after tillage depending upon the soil texture and rainfall. The beneficial effects of off season tillage (Sanghi and Korwar, 1987) are much pronounced (Table 5) during the low rainfall/drought year (43% increase in yield) as compared to mild drought year (31% increase in yield) and near to the normal rainfall year (24% increase in yield).

Crust management in AlfisolsThe crust formation in Alfisols is a major

constraint in seedling emergence/germination and reduces the soil and rainwater conservation and results in greater soil and water losses. The crust formation can be managed through reduction in silt and clay content in the top surface soil layer. This was attributed to a positive relationship between the occurrence and strength of the crust with silt and clay content in

Table 1: Soil water storage in the profile as influenced by deep tillage in red soils

Depth (cm) Soil water percentage (%) (after 81 mm rainfall)

Ploughed area Unploughed area

0-15 10.74 3.59 15-30 13.22 7.13 30-60 12.27 8.59 60-90 13.33 Dry

Source: Channappa, 1994

Table 2: Effect of mould board ploughing on ragi yield, Bangalore, India

Treatments Grain yield (q ha–1)

1981 1982 Mean

Local practice of 2-3 wooden ploughing 12.2 10.4 11.3One additional mould board ploughing in July 16.7 15.7 16.2

Source: Channappa, 1994

Table 3: Effect of subsoiling on root density (cm cm�3) 89 days after emergence of maize (Deccan Hybrid 103) on an Alfisol, ICRISAT Centre, rainy season 1984

Soil depth (cm) Root density (cm cm–3)

Subsoiling Normal tillage S.E.+

00-10 0.55 0.42 0.072 10-20 0.29 0.21 0.022 20-30 0.20 0.09 0.034 30-40 0.15 0.10 0.028 40-50 0.12 0.06 0.016 50-60 0.14 0.05 0.039

Source: Pathak and Laryea, (1995)

16

the surface soil. This indicates that for Alfisols non�turning tillage system is better than tillage with turning plows (inversion brings soil from argillic horizon which contains much higher clay and silt).

In Alfisols crust formation is a major problem from sowing up to the crop canopy formation. During this period higher runoff was observed even when soils were dry. The shallow tillage imposed as additional intercultivations were effective in breaking the crust and increasing infiltration rate in addition to the reduced runoff and soil loss. The significant increase in crop yields due to additional shallow intercultivations was observed only in normal and low rainfall years (Pathak and Laryea, 1995).

Tillage in VertisolsThe most important physical constraints

to rainfed crop production on Vertisols includes (i) narrow range of soil water content for tillage, (ii) high erodibility, (iii) tendency to become water-logged and (iv) poor trafficability (Kampen and Burford, 1980). Vertisols are hard when dry and have very plastic consistency when wet. Tillage at an inappropriate soil moisture content leads to compaction of the sub-soil. Traditionally, rainy season fallowing is quite common on these soils. Reasons for rainy season fallowing of Vertisols are the difficulties that the farmers encounter in preparing the hard dry soil prior to the onset of the rainy season and/or the sticky nature of the wet soil after

onset of the rainy season, which does not permit timely sowing and management of crops. There is common threat of flooding when intense rains are received, and the possibility that rainy season cropping may reduce soil moisture available in profile for growing postrainy season crops are also some of the reasons for fallowing Vertisol during the rainy season (Pathak, 2004).

In the Vertisols the effect of tillage was more pronounced in terms of rainwater conservation and recharge of soil profile especially during drought years as compared to normal and above normal rainfall situations. In the deep black soils of Bijapur, Karnataka, India, deep tillage conserved higher amount of soil water in top 0.60 m soil depth as compared to medium and shallow tillage from sowing up to harvest in winter sorghum. Higher soil water with deep tillage was attributed to increased infiltration rate and decreased bulk density. This results in better development of root and shoot in winter sorghum with deep tillage. Deep tillage recorded higher sorghum yield over medium and shallow tillage (Table 6). The increase in sorghum yield with deep tillage was 27% over medium and 57% over shallow tillage during drought year (1994�95) as compared to increase in yield by 17 and 34% over medium and shallow tillage during normal year (1995�96). These results clearly indicate that the effect of deep tillage is more pronounced in conservation of rainwater, better plant growth and increased yield during drought year as compared to normal year (Patil and Sheelavantar, 2006).

Table 4: Effect of normal and deep primary tillage on sorghum yield, runoff and soil loss on Alfisols at ICRISAT Centre (1983)

Tillage practices Sorghum yield Runoff Soil loss (kg ha–1) (mm) ( t ha–1)

Normal tillage (mould board plowing 12 cm deep) 2160 285 3.27 Deep tillage (cross chiseling 25 cm deep ) 2720 195 2.86

LSD (P=0.05) 386 44.0 0.702

Source: ICRISAT, (1983)

Table 5: Effect of off-season tillage on yields of sorghum in red soils of Hyderabad

Tillage practices Grain yield (kg ha�1)

1977 1978 1979 Mean

No off season tillage 1950 934 1052 1312Off season tillage 2430 1336 1965 1910Percent increase due to off season tillage 24 43 31 46Rainfall in growing season (mm) 595 391 508

Source: Sanghi and Korwar, (1987)

17

Even in the deep black soils of Bellary, Karnataka, India, the conventional tillage conserved greater rainwater and increased the soil water in the profile and winter sorghum yields by 13 and 8% over reduced and low tillage, respectively (Patil, 2007 and Patil and Mishra, 2008). Similar results were also observed in the Vertisols of Solapur with conventional tillage recording higher yields of winter sorghum over reduced and low tillage (AICRPDA, 2006). The water use efficiency (WUE) of winter sorghum in the conventional tillage increased from 8 to 10% over low tillage. The sunflower yield increased by 21 and 33% in conventional tillage over reduced and low tillage in the deep black soils of Bellary during winter season of a dry year (2007�08). Due to higher rainwater conservation, conventional tillage resulted in increased WUE by 16% over reduced tillage and 25% over low tillage (Patil and Mishra, 2008).

Vegetative BarriersTraditional mechanical bunds i.e. contour and

graded bunds are effective in reducing runoff and soil loss. At some places due to poor maintenance these bunds have flattened over the years and became ineffective in conserving rainwater. Hence, research efforts have, therefore, been directed to develop vegetative measures to supplement mechanical measures. Biological measures of conservation have drawn greater attention in recent years because of their long life, low cost and low maintenance needs. Vegetation established on contours obstructs the flow of surface water, as a result soil particles settle on the upstream side and filtered clear water oozes through the barrier more uniformly at a reduced velocity. This results in higher infiltration and more uniform distribution of water. Vegetative barriers would act as a barrier and reduce velocity of the water flow, filter and retain some silt, arrest the

soil erosion; reduce the overall cost of gully control, to protect the banks against damage caused by waves and animals. In combination with earthen bunds or loose boulder structures, vegetative barriers are more effective in conservation of natural resources and increasing the crop productivity.

Vegetative barriers include rows of perennial grasses, hedges, wind brakes and shelterbelts etc. on contours. Barriers across the gully in rows with different species: consisting of close growing grasses, shrubs and fast growing trees that may have some value as fuel, fodder, etc. are preferred. Locally existing vegetative species are more useful as their establishment is easy and local people are well versed with their management. It was observed that growing hedge rows (creating a vegetative barrier) along the contour or on a grade, reduced the runoff and soil loss; at the same time provided additional fodder during off seasons. The effectiveness

of vegetative barriers in conserving rainwater depends upon rainfall, soil type and the growth of vegetative barriers. In the shallow red soils of Anantapur (mean annual rainfall 570 mm), Vetiver alone increased the groundnut yield by 11% and with contour cultivation the yield increased up to 39% with greater conservation of rainwater. While at Bangalore, in deep red soils (mean annual rainfall 890 mm), combination of graded bund and Vetiver performed better and conserved soil and water resource. In the shallow red soils of Hyderabad (mean annual rainfall 750 mm), Cenchrus or Vetiver barriers along with a small section bund recorded higher yields over conventional mechanical measures.

In the black soils of Deccan Pleateau at Bellary, the vegetative barrier proved effective in conserving soil and rainwater and increasing the soil water availability in the profile. The increased water availability (Average of 3 land slopes) has resulted in the better plant growth

Table 6: Effect of tillage practices on infiltration rate, bulk density, root growth and grain yield of winter sorghum in the Vertisols of Bijapur, Karnataka, India.

Tillage practices Infiltration rate Bulk density Root length Grain yield (kg ha–1)

(mm h–1) (Mg m–3) (cm) 1994-95 1996-96 Pooled

Deep tillage 9.7+0.6 1.23+0.03 67.0 1919 1835 1877

Medium tillage 8.0+0.5 1.27+0.02 57.6 1509 1562 1635

Shallow tillage 6.1+0.7 1.31+0.05 41.7 1223 1368 1296

S.Em+ � � � 42 47 32

LSD (P=0.05) � � � 164 186 103

Source: Patil and Sheelavantar, 2006

18

with increased grain yield of winter sorghum by 35% over control (Table 7). The vegetative barrier reduced the runoff by 36% and soil loss by 41% over control (Av. of 8 years for 100 mm rainfall). The vegetative barrier was more effective (Rama Mohan Rao et al., 1999

and 2000) at higher slope (1.5%) and increased winter sorghum grain yield by 66% at 1.5% slope, 25% at 1.0% slope and 26% at 0.5% slope (Table 7).

At Bellary with 500 mm mean annual rainfall the exotic Vetiver was less effective than the native grass (Cymbopogan martinii). The Vetiver requires higher rainfall (>650 mm) and can perform better in well drained red soils with neutral pH as compared to low rainfall with higher pH (>8.5) at Bellary. The native grass (C. martinii) is also not grazed by animals and can be used for thatching, in addition to its medicinal use.

Mulching Mulching is the covering of the cultivated field

with unused organic matter (grown in situ or Ex�situ) with a little additional investment. Mulches are the important organic materials that not only dissipate the kinetic energy of the rain drops and prevent soil erosion (splash erosion) but also facilitate infiltration and reduce runoff and evaporation losses. Besides, this has the major advantages of (i) suppressing weed growth by preventing penetration of sunlight to the ground and (ii) conserving soil and rainwater in situ. By mulching and residue incorporation the biomass is returned to the soil to feed the microbes which help the plants to draw nitrogen and carbon from air and phosphorous

and potash from soil. More importantly, mulching improves the burrowing activities of earthworms and improves air�moisture balance in the soil. Besides improving the physical properties of the soil, like better drainage in clayey soil, mulch returns to the soil the

micro nutrients taken from it. Thick mulch spread over the field conserves moisture in the soil, reduces the evaporation loss and improves the water holding capacity of the soil. As a result supplemental water demand of the crops is reduced.

Surface mulch (Organic and soil mulch) – in deep black soil

Deep black soils in the Semi�Arid Tropics in India are kept fallow in kharif and hence they remain bare by the time intense rains occur in September/October. Beating action of the rain causes structural deterioration which reduces the further intake rate. Besides, the high evaporation losses in the absence of crop canopy in the initial stages of crop growth, the greater runoff and soil loss results in formation of cracks in the soil by mid November to early December and this further accelerates evaporation losses. If these are not controlled, soil water stored in the profile gets lost early and crops dry prematurely.

Application of surface mulch at sowing (Rama Mohan Rao et al., 1985) was found to have a profound positive effect on grain and straw yields (Table 8). Crop residues such as sorghum and maize stubbles, dry grass, wheat straw and pigeonpea stalk, can be used as surface mulch. These mulches prevent moisture loss and prolong the moisture retention period. In

Table 7: Effect of vegetative barrier on resource conservation and sorghum grain yield in black soils at Bellary, India (1988�89 to 1996�97, Av. of 8 years for 100 mm rainfall)

Treatments Slope Average

0.5% 1.0% 1.5%

Runoff (mm)

Up and down cultivation (control) 49.65 54.81 59.14 55.53 �

Vegetative barrier 22.69 39.86 44.10 35.55 (36%)

Soil loss (kg ha�1)

Up and down cultivation (control) 1053 2167 1712 1644 �

Vegetative barrier 500 1372 1027 966 (41%)

Grain yield (kg ha�1)

Up and down cultivation (control) 911 685 475 690 �

Vegetative barrier 1149 848 787 928 (35%)

Source: Rama Mohan Rao et al. (1999 and 2000)

19

Vertisols at Solapur, India, (Av. of 3 years) crop residue incorporation increased sorghum yield by 50 to 70% (Table 9).

Dust mulchDue to the scarcity of organic materials, low cost

method of frequent intercultivation between crop rows are adopted to create dust mulch or soil mulch through tillage during crop growth. The dust mulch is a useful operation that helps in breaking soil crust (especially in red soils). It augments high infiltration and breaks the capillary movement of water to the top layer and minimizes evaporation losses from the soil surface. Research studies at Bellary have indicated the possibility of doubling the water use efficiency and crop yields by providing dust mulch through repeated harrowing

with a bullock-drawn harrow (Table 10). Creating dust mulch up to a depth of 10 cm resulted in 8% more grain yield (1833 kg ha�1) over organic mulch and 96% increase in yield over control in winter sorghum (Table

11). Mulches (organic and soil) increased the sorghum grain and straw yields by 63 and 20% over control and proving their applicability especially during below normal/scarce rainfall situations in the black soil region during post rainy season for the crops cultivated on residual soil water (Rama Mohan Rao et al., 1985).

Vertical mulchSoil water is the main limiting factor for

successful crop production in the rainfed agriculture with inadequate rainfall and/or poor distribution. The problems become much more severe when soils are also

Table 8: Winter sorghum yields as influenced by moisture conservation practices

Treatment Grain yield (kg ha–1) Straw yield (kg ha–1)

Control 1052 1400 Control + Surface mulch 1375 1914 Vertical mulch (4 M) 1719 2405 Vertical mulch (4 M) + Surface mulch 2138 2953

Source: Rama Mohan Rao et al., 1985

Table 9: Effect of surface mulch (5 t ha�1) on yield sorghum (t ha�1) at Solapur

Treatment 1970–71 1971–72 1972–73 Mean

Grain Straw Grain Straw Grain Straw Grain Straw

Control 0.27 2.05 0.69 2.86 1.22 5.40 0.72 3.43Sorghum stubbles 0.56 2.89 0.63 2.08 1.88 8.44 1.02 4.49Redgram stalk 0.80 3.86 0.89 4.98 1.95 7.72 1.21 5.52Wheat straw 0.65 4.05 0.73 3.09 1.70 8.89 1.04 5.34Dry grass 0.73 3.28 0.76 5.48 2.16 8.49 1.22 5.75

Source: Patil et al. (1981)

Table 10: Influence of dust mulch on water use efficiency and grain yield of pearl millet at Bellary

Treatment Moisture used (cm) Water use efficiency (kg ha–1 cm–1) Grain yield (t ha–1)

Dust mulch through harrowing 27.8 67.4 1.74No mulch 22.4 30.7 0.81

Source: Rama Mohan Rao et al. (1985)

Table 11: Winter sorghum yields as influenced by dust and surface mulches

Treatment Grain yield (kg ha–1) Straw yield (kg ha–1)

Control 934 2.43 Organic mulch 1760 2.95 Intercultivation up to 5 cm depth 1243 2.95 Intercultivation up to 10 cm depth 1833 2.95 Intercultivation up to 15 cm depth 1510 2.78

Source: Rama Mohan Rao et al. (1985)

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problematic. The crop productivity in Vertisols can be increased with increased intake rates as nearly 25% of rainfall during crop growth goes as runoff. Adoption of vertical mulch in black soils conserved soil water and increased the winter sorghum yields to the greater extent in the dry/drought years as compared to wet/normal or above normal rainfall years (Rama Mohan Rao et al., 1978 and Ranga Rao et al., 1978). Compared with low yields in control plots (grain: 20 kg ha�1 ; straw: 0.95 t ha�1), mulches spaced at 2, 4 and 8 m produced 390 kg ha�1 of grain and 1.90 t ha�1 of straw in the extremely dry conditions of 1972�1973 (Table 12). However, the increase in grain and straw yields in wet conditions in 1973�1974 was 47 and 15%, respectively. Average over dry and wet years, vertical mulch resulted in 45 and 38% higher grain and straw yields. Higher sorghum yields were attributed to higher soil water content near the mulch and the favorable effects of mulch extended to 1.5 m on either side of the mulch row.

Sand mulchingSand mulching has been practiced by the

farmers in some pockets of Northern Karnataka and Andhra Pradesh. Experiments conducted at Dryland Centre Bijapur and Main Research Station Dharwad (Karnataka State) indicated distinct advantages with sand mulching (Anon. 2000 and Sudha, 1999). The benefits were directly proportional to the quantity of sand applied or mulch thickness (Table 13). Benefits of sand mulching were attributed to the reduction in runoff and increased wetting front. Hagman (1984) attributed improved crop yields in sand mulch compared to non-mulched soil to the increased soil temperature, conservation of rainwater in situ, reduced evaporation and controlled wind and water erosion which in turn increased water content at different stages of crop growth. In the Koppal, Gadag and Bagalkot districts of Karnataka State, sand mulching increased the cropping intensity to 200% especially in the years of drought in this low rainfall region (around 600 mm) with bi-modal

Table 12: Sorghum grain (kg ha�1) and straw yields (t ha�1) as affected by spacing of mulches

Treatments 1972-73 1973-74 1974-75 1975-76 Mean

Grain Straw Grain Straw Grain Straw Grain Straw Grain Straw

2m 523 2.19 1641 3.03 1495 2.94 1027 3.68 1172(40) 2.96(37)

4m 412 2.02 1692 3.25 1775 3.02 1246 3.85 1381(53) 3.04(41)

8m 236 1.48 1614 2.86 1770 3.73 1122 3.64 1186(42) 2.93(36)

Cracks filled with straw 198 1.46 1310 2.70 1240 2.08 982 3.51 929(11) 2.44(13)

Control 017 0.95 1120 2.65 1123 1.89 1085 3.15 836(-) 2.16(-)

LSD(P=0.05) - - 459 0.39 N.S. 0.99 N.S. N.S. - -

Rainfall situations Drought year Normal year Moderate Normal year Mean over years drought year

Source: Rama Mohan Rao et al. (1978)

Table 13: Effect of sand mulch on soil water (cm) and pod yield of groundnut

Soil depth (cm) 30 DAS 90 DAS Pod yield (kg ha–1)

No mulch 0-15 3.56 4.99 960 16-30 3.60 5.14 31-60 7.56 11.29

Sand mulch (5.0 cm) 0-15 4.87 5.66 1376 16-30 5.38 5.80 31-60 11.13 12.74Sand mulch (7.5 cm) 0-15 4.95 5.67 1276 16-30 5.42 5.86 31-60 11.72 12.83

CD 0.05 0-15 0.87 0.29 219 16-30 1.48 0.62 31-60 2.75 NS

Source: Sudha, 1999; Note: DAS: Days after sowing

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distribution. In this region in the medium to deep black soils, farmers who practiced sand mulching could cultivate a short duration greengram compared to non mulched areas. In addition, winter sorghum yields in the postrainy season increased by 60 to 70% with sand mulching as compared to non-mulched areas. The utility of sand mulch therefore needs intensive study.

Land ConfigurationSoon after the execution of soil conservation

structures (terrace level) in the field, it is essential to take up land smoothing in the inter bund area as inter�terrace land treatment. This facilitates filling up of depressions and to remove the humps so as to enable the rainwater to spread uniformly in the field. Land configuration of the inter bund area can be modified for temporary inter plot harvesting of water and facilitate higher infiltration. These modified configurations could be implemented prior to or after the onset of monsoon and continued till sowing or even adopted after sowing and maintained till harvest.

Contour CultivationCarrying out all the field operations and sowing

the crops across the slope following the contours (contour cultivation) provide a series of miniature barriers to water when it moves along the slope and also reduces runoff and soil loss and increases soil water and nutrient storage in the soil profile. The simple contour cultivation in the farmersÊ fields in red soils of Kabbalanala watershed near Bangalore revealed the increased soil water in the profile during cropping season from 35th week up to 43rd week over farmersÊ practice of up and down cultivation (Fig 1). Contour cultivation conserved the rainwater and reduced the runoff and soil loss and increased the yields of sesamum, fingermillet and groundnut in the red soils of Bangalore. The moisture conservation effect of contour cultivation was more felt when crops were supplemented with NPK fertilizers (Krishnappa et al., 1994and 1999) (Table 14). The conservation of rainwater is more beneficial during drought years especially at the reproductive stages of the crop growth. The effectiveness of this practice was compared with up and down cultivation in the farmersÊ fields over a period to 4 years (Table 15). Contour cultivation resulted in 35 and 22% increase in grain yields in sorghum and setaria, respectively in black soils and 66% increase in sorghum grain yields in red soils over up and down cultivation (Rama Mohan Rao et al., 1985).

The simple technology of contour cultivation at Bellary, India was more beneficial (92% increase in yield) over up and down cultivation (Farmers practice) during drought year.

ScoopingScooping out soil to form small basins with basin

listers or with similar implements, helps in retaining water on the surface that recharges the soil profile. At Hagari in Bellary district, inter-cultivation by hoes (with ropes tied around the prongs) was practiced successfully for scooping purpose in a cost effective manner. Scooping helped in reducing the runoff by 50% and soil loss by 65%. The winter sorghum grain yield increased by about 11 to 12% at Bijapur. This method has been found to be effective with compartment formations in the fields. A study conducted at ICRISAT (Pathak and Laryea, 1995) revealed that the scoops reduced seasonal runoff by 69% and soil loss by 53% when compared to the flat land surface. There was a significant increase in pearl millet grain yield by scooping practice (2.42 t ha�1) over flat seed bed (1.79 t ha�1).

Bedding SystemThis is a system having furrow at every few rows

of crops across the slope on a grade of 0.2 to 0.4%. The bed width could be 3 to 6 m depending on the crops, soil type, and rainfall. This is suitable for narrow spaced row crops. Even if a few rows are lost due to the furrow, the yields are made up due to better in situ rainwater conservation. There is no water stagnation in the bedding system. Hence, this system acts both as disposal system during high intensity rains and as a conservation measure during low rainfall situations.

The bedding system of land management (Channappa, 1994) with a furrow opened at the time of sowing the crop at 1.5 to 3 m intervals was found to increase/stabilize yield levels over years by 8 to 10%, apart from better rainwater management at times of low as well as high intensity rains. Modified technique known as paired row pigeonpea�fingermillet intercrop with a furrow in between the pigeonpea rows and 8 to 10 rows of finger millet was found to be the best intercrop as well as inter-terrace management practice for the red soil regions of Karnataka State, India. The relative performance of different bedding systems, i.e. flat bed (FB), broad bed and furrows (BBF), narrow bed and furrow (NBF) and raised-sunken bed (RSB), was studied in black soils at Indore. The results indicated

22

Fig. 1. Soil water in profile as influenced by farmers practice and contour cultivation.

Table 14: Influence of contour cultivation and fertilizer use on yields (t ha�1) of crops

Crop/cultivation practice No NPK Recommended NPK

Sesame

Cultivation along slope 0.22 0.33 (49)b

Contour cultivation 0.29 0.46 (61)b

(28)a (38) a (107)c

Finger millet

Cultivation along slope 0.55 0.79(44)b

Contour cultivation 0.69 1.24 (89)b

(25) a (58) a (126)c

Groudnut

Cultivation along slope 0.57 0.87(53)b

Contour cultivation 0.73 (55) a (137)c

(28)a 1.35(85)b

Source: Krishnappa et al., (1994); Figures in parentheses denote: a = % change over cultivation along the slope: b = % change over no NPK; and c = % change over cultivation along the slope and no NPK.

Table 15: Contour cultivation vs. up and down cultivation (1957-61)

Crops Mean yield (kg ha–1) Contour Up and down % increase

cultivation cultivation

Black soils Rabi sorghum Grain 285 211 +35

Straw 1607 1209 +33

Setaria (H-2) Grain 195 159 +22

Straw 430 390 +10

Red soilsKharif sorghum (K-340) Grain 812 189 +66

Straw 6097 3824 +59

Source: Rama Mohan Rao et al., 1985

23

that the maximum maize yields (2.01 t ha�1 and water use efficiency of 8.81 kg ha�1 mm�1) were observed in BBF system followed by RSB and FB systems. The BBF can be more intensively adopted using tropicultor developed at ICRISAT. This system of bedding is also getting more adoption in the farmersÊ fields in the Indore region of Madhya Pradesh, India, for soybean cultivation in the Vertisols as it is useful in draining excess rainwater during high rainfall years and conserving and mitigating drought during drought years. In the black soils of Bellary also bedding system proved effective in conserving the rainwater, increasing the soil water in the profile and increased the winter sorghum grain yield by 23.7% and safflower yield by 7.7 % as compared to flat sowing (Average of 8 years).

Contour/Graded Border Strips Leveled strips (10 to 12 m wide) are formed

across the slope either on contour or on a grade depending on the annual rainfall. The system is efficient in ensuring uniform distribution of rainwater on the surface and in the soil profile, and increases the crop yields up to 20 to 30%. However, the lay out of border strips needs technical expertise and higher initial investment as the amount of earth work involved is more. In addition, when the land slope is high and the cutting depth increases more than 15 cm, it may result in a drastic fall in productivity in the initial years. These border strips are more suited on lands having < 2% slope.

In the black soils of P.C. Pyapili Watershed (Anantapur district, Andhra Pradesh) lay out of farmers

fields with graded border strips conserved the rainwater, recharged the soil profile and reduced the runoff and soil loss and increased the yields of sunflower and winter sorghum by 23 and 25% respectively (Mean of 2 years). The increase in yield with border strips was

greater during 1992�2000 (drought year) as compared to normal year of 2000�01. The effect of border strip was more pronounced during drought year in better conservation of rainwater than normal year (Table 16). When border strips were supplemented with terrace level measures i.e. graded bunds, the yields of sunflower and sorghum increased further up to 38 and 42%, respectively. These results clearly indicate the benefit of border strips in the Vertisols of Deccan Plateau in South India (Patil et al., 2004).

Zingg Terracing Zingg terracing is adopted in low to medium

rainfall areas in black soil with contour/graded bunds. The lower one third portion of inter bunded area is leveled to spread the runoff water in a large area. Usually water intensive crops are cultivated in the leveled portion (receiving area) while dry crops are cultivated in the unleveled (donor) area. This practice is more useful during drought years. In the leveled one third portions, normal crop can be harvested even during severe drought year and it is possible to cultivate two crops during normal year. This will not only increase the cropping intensity and also increase the crop yields in the region. In the Vertisols of Bijapur, lay out of field with Zingg terrace increased the winter sorghum and safflower yields by 4 and 30%, respectively over control (Anon., 1989 and 1990). The effect of Zingg terrace was more felt in the leveled portion than the unleveled portion. In the leveled portion the yields of winter sorghum and safflower increased by 25 and 44%, respectively over control (Table 17) .

Compartmental BundingCompartmental bunding is usually adopted in

deep black soil areas for in situ harvesting of rainwater. The field is laid out into compartments of 6 m � 6 m to 10 m � 10 m using bund former. The harvested

Table 16: Impact of rainwater conservation practices on crop yields (kg ha�1) in the watershed

Treatment 1999–2000 2000–2001 Pooled

Sunflower Sorghum Sunflower Sorghum Sunflower Sorghum

Control 626 910 474 450 550 680

Graded bund alone 702 1012 529 530 616 771 (12%) (11%) (12%) (18%) (12%) (13%)

Border strips + graded bund 888 1274 631 655 760 965 (42%) (40%) (33%) (45%) (38%) (42%) (26%) (26%) (19%) (24%) (23%) (25%)

Source: Patil et al., 2004; Figures in the parenthesis indicate % increase over control.

24

water in these compartments facilitates high infiltration rate resulting in more soil water retention in the profile. This system is adopted in deep black soils to harvest rainwater received during the rainy season. It helps in better crop production during the postrainy season.

In a field study on Vertisols at Bellary from 2000 to 2003 indicated that the moisture conservation through in situ moisture conservation practices i.e. compartmental bunding and ridges and furrows increased the soil water in the profile and grain and straw yield of winter sorghum (Patil, 2005). The magnitude of increase in grain yield was 28% in compartmental bunding during 2000�01 was attributed to efficient utilization of water, especially conserved water to produce grain yield even though it was moderate drought year. Water use efficiency (WUE) was higher

during 2000�01 (moderate drought year) as compared to 2001�02 (above normal rainfall year) and 2002�03 (severe drought year) indicating that every unit of water was more efficiently utilized to produce grain yield (Table 18). The results (Patil, 2003) of three years mean indicated that the WUE increased by 13% (8.26 kg ha�1 mm�1) over flat bed (7.34 kg ha�1 mm�1). In the Vertisols of Bijapur, lay out of field with compartmental bunding conserved more rainwater and increased the winter sorghum yield by 23% over flat sowing (Patil and Sheelavantar, 2004). The water use efficiency was greater by % with compartmental bunding over flat sowing (Patil, 1998).

Ridges and furrowsCultivation of crops under ridge and furrow

Table 17: Effect of Zingg terrace on winter sorghum and safflower yields during winter season

Treatments Winter sorghum (kg ha–1) % increase Safflower (kg ha–1) % increase (1988–89) (1989–90)

Zingg terrace

Levelled portion 1190 25 720 44

Unlevelled portion 949 �� 635 27

Entire plot 989 4 650 30

Contour bund (Check) 950 �� 500 ��

Source: Anon., 1989 and 1990

Table 18: Water use efficiency of sorghum as influenced by moisture conservation practices

Treatments Water use efficiency (kg ha–1mm–1)

2000–2001 2001–2002 2002–2003 Pooled

In situ moisture conservation practices

8.57 –– 7.24 –– 6.20 –– 7.34 ––Flat bed ––Compartmental bunding 9.86 (15) 8.20 (13) 6.71 (8) 8.26 (13)

Ridges and furrows 10.77 (26) 7.86 (9) 6.82 (10) 8.48 (16)

S.Em.+ 0.54 0.14 0.20 NS 0.53 NSC.D. at 5%

Source: Patil (2003).

Table 19: Effect of ridging on cowpea and ragi yields

Treatment Grain yield (q ha–1)

Cowpea Ragi

Flat on a grade sowing 7.76 34.84

Flat on a grade sowing but later ridging up 7.54 36.66

Sowing of beds (135 cm for cowpea and 150 cm for ragi) 6.73 32.83

Source: Channappa (1978) and Annual Report of AICRPDA, Bangalore Centre, 1978

25

system across the major land slope with a gradient of 0.2 to 0.4% in land having 1 to 3% slope will conserve more rainwater in situ. This is suitable for widely spaced crops with 60 cm or more row spacing. A field length of 60 to 90 m is optimum for cultivation of crops with ridges and furrows. In the Vertisols of Bellary, ridges and furrows were more effective in conservation of rainwater and increased more winter sorghum grain yield during drought year (2000�2001) as compared to normal years of 2001�2002 and 2002�03 (Table 17). The mean WUE increased by 16% (8.48 kg ha�1 mm�1) with ridges and furrows over flat sowing. Studies conducted on moisture conservation for cowpea�ragi double cropping system in the red soils at Bangalore revealed that ridging up after flat on a grade sowing

is more advantageous (Table 19). Formation of ridges and furrows in the Vertisols of Bijapur, India, conserved more water and increased the grain yields of winter sorghum by 26% and water use efficiency by 25% (Patil and Sheelvantar, 2004).

An evaluation of furrows for managing soil and water loss in an Alfisol under simulated rainfall (Mishra et. al, 2008) shows that across slope treatments with row spacing of 60 cm is as effective as 30 cm spacing in containing runoff and soil loss. The interaction of row spacing and rainfall intensity has no significant effect on resource conservation. Opening of furrows down the slope is an inefficient method for conserving water and soil. Cultivators need to be educated to plow and sow across slope following contours.

Table 20: Runoff, soil loss and soil properties as influenced by crop residue incrporation

Treatments Average of 4 years MWD Organic C Available nutrients (1998-99 to 2001-02) (Microns) (g kg–1) 0-15 cm (kg ha–1)

Runoff Soil loss N P K (mm) (kg ha–1)

T-1-Sorghum without disturbance 142 4940 582 3.7 165 12 427(control)

T-2-Sorghum + Dolichos (Dolichos 127 3934 688 3.9 199 16 448cultivated for grain and residueincorporation at harvest)

T-3-Sorghum + Dolichos 129 4339 685 3.8 198 15 442(Dolichos cultivation and residueused as mulch at 45 DAS)

T-4- Sorghum + Dolichos 122 3751 696 4.0 202 16 483(Dolichos incorporated into thesoil at 45 DAS )

T-5-Sorghum with intercultivation 132 4491 589 3.6 183 13 499(Twice soil disturbance)

LSD (P=0.05) · · 35 0.03 26 NS NS

Source: Nalatwadmath et al. (2006); DAS=Days after sowing.

Table 21: Grain yield and sorghum grain equivalent as influenced by residue management

(Mean of 4 years1998-99 to 2001-02)

Treatments Grass yield Straw yield Sorghum grain (kg ha–1) (t ha–1) equivalent

T-1-Sorghum without disturbance (control) 1469 2.64 1807

T-2-Sorghum + Dolichos (Dolichos cultivated for grain and residue 167+495 3.01 4248incorporation at harvest)

T-3-Sorghum + Dolichos (Dolichos cultivation and residue used as 2121 3.27 2535mulch at 45 DAS)

T-4-Sorghum + Dolichos (Dolichos incorporated into the soil at 2301 3.61 275645 DAS )

T-5Sorghum with intercultivation(Twice soil disturbance) 1916 3.05 2303

LSD (P=0.05) · · 397

Source: Nalatwadmath et al. (2006)

26

Crop Residue Management Red sandy loam soils become hard on drying

and result in loss of rainwater and runoff and adversely affect the crop yields in the rainfed area. Red soils are usually poor in organic matter. Increasing organic matter content helps in extra retention of rainwater and in increasing crop yields. At Bangalore, incorporation of maize residue at 4 t ha�1 continuously for three years had its good effect in 1980, a dry year. The moisture content at sowing time in residue incorporated plots was 11.2 and 14.0% in 0�15 and 15�30 cm depths compared to 8.9 and 13.4%, respectively in plots without residue. The ragi yield from the plots with residue was 3497 kg ha�1 compared to 1982 kg ha�1 from control plots. Incorporation of crop residues i.e. paddy husk or powdered ground shells is recommended to increase the infiltration rate and conserve rainwater in the profile. Application of paddy husk at 5 t ha�1 increased soil moisture by around 2% and improved the soil properties. The final infiltration rate increased from 8.2 to 11.0 cm h�1. Application of paddy husk increased the sorghum (1st year), castor (2nd year) and sorghum (3rd year) grain yields by 33, 23 and 14% respectively (Singa Rao, 2004).

In the Vertisols of Bellary, runoff and soil loss was reduced and soil water in profile increased with

incorporation of Dolichos at 45 DAS in the Sorghum + Dolichos cultivated for grain purpose as compared to Dolichos used as mulch or sorghum cultivated without Dolichos. The soil physical properties i.e. mean weight diameter and organic carbon and nutrient availability (N, P and K) was higher in plots with Dolichos incorporation or cultivated for grain or used as mulch along with sorghum as compared to cultivation of sorghum alone (Table 20). Even though sorghum grain yield was higher with Dolichos incorporation at 45 DAS (T

4) the treatment with Dolichos cultivated

for grain purpose recorded 495 kg ha�1 additional Dolichos grain yield in addition to 1674 kg ha�1 of grain sorghum (Table 21). Sorghum grain equivalent was significantly higher (3248) in sorghum cultivated

along with Dolichos for grain purpose as compared to the rest of the treatments. The results of 4 years study indicated that it is better to cultivate Dolichos along with sorghum for seed purpose and incorporate the residues of Dolichos at harvest for better resource conservation and greater returns (Nalatwadmath et al., 2006).

Soil AmendmentsA soil amendment is any material added to a

soil to improve its physical properties, such as water retention, permeability, water infiltration, drainage, aeration and structure. The goal is to provide a better environment for roots.

Gypsum ApplicationUnless the infiltration rate is improved through

improvement of structure, moisture conservation continues to be a problem in the deep black soils with higher clay content (>50%) especially in the Bellary soils of Deccan Plateau. Studies in this direction have indicated a severe water intake problem in soil having Exchangeable Sodium percentage greater than 7.0. This problem could be overcome by reducing ESP to less than 7 through gypsum application at Bellary, India (Anon.,1981) (Table 22).

Tank Silt ApplicationDesiltation of tank silt and its application to the

croplands improves the tank water holding capacity i.e. recharges the groundwater, improves the water holding, soil physical and chemical properties and crop yields-that is reuse and recycling of natural resources. Tanks are eco-friendly and farmersÊ-friendly and deposit of gold mine in the form of tank silt. Recycling of tank silt rejuvenate the tanks and meets the water (thirsty) and nutrients (hungry) of the rainfed crops besides improving the soil properties in a cost-effective manner and in addition, recharges the groundwater. There is also a possibility of substituting inorganic fertilizers with

Table 22: Effect of gypsum application on infiltration rate (mm h�1)

Treatment Crop season

1974 1975 1976 1978 1959

Gypsum 4.10 4.60 4.50 5.50 7.20

No gypsum 0.75 0.75 0.75 1.00 1.00

Source: Anon. (1981)

27

silt as an organic amendment for improving soil quality and its resilience to moisture stress during dry spells in rainfed areas. However, the quality of silt varies with each tank, which is primarily, a function of soil type and land use of the catchment. In general, tank silt application supplies all the nutrients to the crops unlike fertilizers that supply one, two or three at most. By the application of tank silt it reduces the demand for the straight fertilizers. Application of tank silt improves the crop yields on sustainable basis and brings the dynamic changes in the land use pattern in the region (CRIDA, 2006; Dhan, 2004 and Osman et al., 2001 and 2007).

Application of tank silt to cotton increased the benefit-cost ratio (BCR) from 1.43 to 1.86 and in chillies with silt BCR was higher by 11% (2.54) over control (2.28). In a study of ICRISAT, Padmaja et al. (2003) have registered 1.17 as average benefit-cost ratio (for removing tank sediment and estimating value of sediment containing different nutrients) indicating that desilting operations are not only economically viable but also, have additional benefits like environmental protection, increased soil microbial bio-diversity, improved soil quality and increased water storage leading to self-sustained land use planning.

In Andhra Pradesh nearly 40% of the total cultivated area is light textured red sandy loam to loamy sand. Clay content is low (< 15%) with low water holding capacity (5 to 10 cm m�1 depth) and are susceptible to leaching losses. Nearly 80% of the soils are under

rainfed cultivation; their low water storage capacity is a major constraint in crop production. Application of available tank silt or heavy textured soil in the top 50 cm depth resulted in decrease bulk density and increased soil water content by 6.5 to 23.5%. The improved soil water and nutrient status with application of tank silt/clay increased the tomato and ladyÊs finger yields by 10.8 and 10.5%, respectively in the Ranga Reddy District of Andhra Pradesh (Singa Rao, 2004).

Mishra, et al., (2001) studied the changes in physical, chemical and hydraulic properties of bentonite and soil (Alfisol) mixtures in different proportions and reported interesting results which may be considered while deciding the proportions of soil amendments. Addition of bentonite to soil (i.e. 1:10 mixture and higher by volume) would seal the entry of water through the mixture, hence not suitable for crop growth. Bulk density increases up to 1:5 (bentonite: soil) mixture and decreases with decrease in bentonite preparation till 1:50 mixture. Dispersion ratio and surface cracking increased with the addition of bentonite to the native soil.

Recommended Treatments for in situ Moisture Conservation

The research results at both the research Stations and in the farmersÊ fields indicate that the in situ rainwater conservation practices reduce the runoff, soil and nutrient losses and recharge the profile both during rainy and postrainy season and increase the

Table 23: Data of the experiments/demonstrations in the farmersÊ fields at different Dryland Centres/locations on in situ moisture conservation practices

Location Crop Suitable inter-terrace land treatments

Bijapur Safflower Compartmental bunding Chickpea Compartmental bunding, Ridges and furrows Rabi Sorghum Tied ridging

Akola Pigeonpea Opening furrow at 30 DAS after every two weeks

Bellary Rabi Sorghum Compartmental bunding, Ridges and furrows Chickpea Compartmental bunding Safflower Bedding system

Kovilpatti Rabi Sorghum Compartmental bunding

Sholapur Chickpea Compartmental bunding

Bangalore Pigeonpea Ridges and furrows Furrow at 3 m interval

Anantapur Groundnut Dead furrow at 3 m interval Contour cultivation

28

yields of different crops especially during drought years. The suitable in situ moisture conservation practices for different crops at different dryland Centres of India are mentioned in table 23.

ITKs on Soil Moisture Conservation In the context of agriculture, indigenous technical

knowledge (ITK) is defined as the traditional knowledge that farmers have gained through inheritance from their ancestors. It is a farmersÊ derived science and represents their creativity, innovations and skills. This knowledge pertains to various cultural norms, social roles or geographical conditions. This knowledge and farming practices have their own scientific importance as they have stood the test of time and have proved to be efficacious to the individual farmers. In India, since time immemorial these indigenous techniques are in practice for conserving natural resources (Agarwal and Narain, 1999) and maintaining soil productivity on sustainable basis for greater crop yields. It is the time to indicate that some of these ITKs need modifications in different farming situations across the country. The present farming situations warrants the consideration of the ITKs in formulating projects with detail analysis of the missing links in research. Rainwater conservation begins from seedbed preparation. Although farmers practice many indigenous technologies in soil and rainwater conservation, the documentation and refinement of these technologies are the major thrust areas in research for greater crop productivity that ultimately improves the economic conditions of the farming community. Some of the simple ITKs documented on in situ soil moisture conservation adopted in different parts of India are presented in table 24.

Researchable IssuesThe potential ITKs on in situ water conservation

reviewed by Mishra, et. al. (2002) are presented in table 24. The specific researchable issues pertaining to different ITKs adopted in different rainfed regions of India are presented in table 25. A systematic scientific study may change the Indigenous Technical Knowledge to Modern Technical Knowledge (MTK). The research results will benefit both farming community as well as the extension agencies i.e. the Government or non-Government organizations in up scaling the technology.

Up-scaling of ITKsPrevailing ITKs should invariably be given

priority. All the projects on resource conservation and management should focus on the viable and appropriate ITKs relating to soil and water conservation. Exposure visit and farmer-to-farmer interaction results in refinement and greater adoption of these technologies. The stakeholders such as farmers, NGOs, extension officials, scientists, administrators, policy makers and peopleÊs representatives may popularize the ITKs through different programmes for improving soil and crop productivity on sustainable basis. There is also a need for scientist-farmer interaction for large-scale adoption of the ITKs. The ITKs on in situ soil and moisture conservation are not up scaled and are attributed to the constraints in adoption and unawareness of the effectiveness of such practices in different agro-ecological settings. The present documentation process has definite bearing on the future course of action in framing new projects.

Table 24: Some simple ITKs on in situ soil moisture conservation followed in India

Indigenous in situ soil moisture conservation measures Regions of adoption/practice

Deep ploughing in summer for harvesting early shower in situ Black soil region of Maharashtra, Andhra Pradesh, Karnataka, and Tamil Nadu

Pre monsoon harrowing (blade harrow) for breaking soil surface Red soil region of Andhra Pradeshcrust for capturing early showers

Short term fallowing during mid May and June to conserve early Red soils of Anantapur District in Andhrarains Pradesh

Across slope furrowing as a part of seeding operation in sorghum Red soils in Ranga Reddy District of Andhraand castor crop rotation Pradesh

Shallow interculture in rabi sorghum to minimize soil cracking Deep black soil in Bellary, Karnataka

29

2. Validation of appropriate indigenous technologies across diverse agro-ecological settings to qualify as modern technical knowledge through vigorous on-farm research/testing with farmersÊ participation and involving NGOs.

3. Limited energy efficient farm mechanization for timely operations of in situ conservation measures at farm level.4. Water and nutrient balance studies to quantify water use efficiency and validate hydrological and crop models.

5. Role of in situ moisture conservation through better understanding of Soil-Water-Nutrient-Plant relationships for greater crop and water productivity.6. Creation of enabling environment through appropriate Government policies and subsidies to the farming communities adopting in situ rainwater conservation and better crop residue management that reduces land degradation and decreases the fertilizer and energy requirements.

7. Economics of different in situ conservation measures for select ing eco-friendly, economical advantageous and socially acceptable technologies.

The documentation exercise should be in-built in extension and research especially in natural resource management.

The suitable ITKs may be adopted and validated other Agro-ecological regions.

The documented ITKs should be translated in all regional languages and published for the benefit of farming communities.

Suitable modifications of the ITKs through on- farm research would help developing appropriate and acceptable technologies for different Agro-ecological environments.

ConclusionsThis is a brief review of different in situ

moisture conservation measures followed particularly in Indian semi-arid regions predominated with red and black soils. Many other location specific moisture conservation measures are followed in other parts of India and the world. However the principles of moisture conservation remain the same. In the context of in situ rainwater conservation and management the following emerging issues need to be addressed for sustaining the agricultural productive environment.

1. In situ rainwater management as influenced by the temporal climate shift scenario and popularization of weather advisories.

30

Table 25: Researchable issues in potential ITKs on in situ moisture conservation measures

Indigenous in situ water conservation measures Researchable issues

Furrow opening in standing crops for rainwater 1. Modification of implement with different serrated blades andconservation introducing additional tines 2. Effectiveness in conserving soil moisture

Wider row spacing in pearl millet for rainwater 1. Plant geometry and population research in different rainfallconservation and weed control situations

Crop residue management for improving soil organic 1. Quantification soil and water conservation and yieldmatter and water holding capacity advantage 2. Better or improved implements for crop residue incorporation 3. Alternate ways of composting and application

Mulching in turmeric cultivation for rainwater 1. Quantification of soil loss, improvement of soil quality andconservation water availability 2. Use of alternative organic material to Sal leaves as mulch

Broad bed and furrow practice for rainwater 1. Width of broad bed needs to be evaluated for different crops conservation and runoff disposal and rainfall situations 2. Ident ificat ion of suitable low cost tractor/bul lock drawn implement for layout of BBF

Set-row cultivation for soil and rainwater conservation 1. Quant ificat ion of rainwater conservat ion and water useand improvement of soil properties efficiency (WUE) of the crops 2. Improvement in soil health and crop yield over years

Summer/pre monsoon tillage for harvesting early 1. Identification of appropriate tillage implements for soil andrainfall, weed control and initiate timely seeding water conservation 2. Evaluation of root:shoot ratio and quantification of WUE of crops

Formation of Gurr for rainwater and soil conservation 1. Effect of bullock and tractor drawn Gurr on runoff reduction, soil water conservation and crop productivity

Green manuring practice for water conservation and 1. Growing of green manure crop and its management in soil health improvement improving soil health and crop productivity 2. Economic evaluation of the system by addressing issues of sustainability

Tank silt application to improve soil fertility and water 1. Method and quantity of tank silt application in different soilsholding capacity 2. Improvement in soil water and fertility with tank silt application and its effect on crop productivity 3. Cost effect ivene ss of s i l t appl icat ion e special ly w ith GovernmentÊs programme of tank desiltation.

Source: Mishra, et. al. (2002)

31

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���

Low Cost On-Farm Indigenous and Innovative Technologies

of Rainwater Harvesting

34

R.K. Singh

3

IntroductionIndia has been one of the few countries of the

world which showed awareness of the need to conserve and care for the watershed resources of land, water, plants and animals in an integrated manner and the government has invested heavily on soil and water conservation (SWC) measures on watershed basis and many big projects are currently in operation. The results to date of government SWC programmes have been disappointing (Vaidyanathan, 1991). SWC measures installed under special programmes have rarely been maintained; on the contrary, there are many instances where farmers have destroyed these works soon after the departure of the implementing agency. Recent studies have shown, however that in many regions farmerÊs lack of interest in SWC programmes has not been due to their lack of concern about erosion, but because the design of recommended technologies has not been suitable for their small farms (Kerr and Sanghi, 1992 and Reij, 1991). It is now becoming clear that

there are significant difference between farmerÊs and scientistÊs perceptions regarding soil erosion control (Chamber, 1991; Kerr and Sanghi, 1992). Many SWC interventions are not successful because they are not sufficiently rooted in the priorities and perceptions of local farmers (Gupta, 1991; Reij, 1991 and Fujisaka, 1989).

In this context, it is also not out of place to mention that programme planners have time to time introduced number of SWC measures/ rainwater harvesting technologies which are not being tested in the specific areas under particular soil, slope, rainfall, socio-economic conditions and need of the people. Similarly, some of the most adoptable and effective technologies are not being given due importance and left aside because they are slightly costlier, though for such effective technologies farmers could easily be motivated for their reasonable contribution. Studies have revealed that over the generations, farmers themselves have developed numerous indigenous SWC methods specific

35

to particular soil, slope, rainfall and socio-economic conditions (Kerr, 1991). It has also been observed in the area that farmers prefer to pay part of the cost of these indigenous practices even in villages where recommended SWC practices are offered with heavy subsidies.

Low cost indigenous technologies of rainwater harvesting have potential to increase the productivity of arable lands by enhancing crop yields and by reducing the risk of crop failure in arid and semi arid regions, where water shortage are common because of scanty of rainfall and its uneven distribution. In arid and semi arid regions, the occurrence and distribution of rainfall are not only uneven but also erratic, marked by prolong rainless days. The rainfall fails especially at the time when it is required most for agriculture during the year. Under these circumstances, the concept of low cost community oriented indigenous rainwater harvesting technologies both long term and short terms seem to be the only alternative by which water scarcity problem can be mitigated and agricultural production can be increased substantially. The solution therefore, lies is harvesting rainwater through capturing, storing and recycling it and later using it during prolong perched period.

INDIGENOUS TECHNOLOGIES OF SOIL AND WATER CONSERVATION / RAINWATER HARVESTING1. Earthen field bunds

Very commonly found indigenous SWC technique where the farmers construct field bunds almost uniformly on field boundaries, which rarely correspond exactly to contour for minimizing soil erosion; demarcating field and ownership boundaries; producing fodder for animals and other items of economic importance (through suitable vegetative cover); protecting against trespassers and stray animals (through a combination of high bunds and thorny barriers); creating new fields or micro-environments (to reduce risk in rainfed agriculture); making field operations convenient, facilitating land partitioning for inheritance, etc.

In order to make them more effective and in achieving the desired benefits of SWC to the extent of farmers expectations, these bunds may be constructed by keeping the required top height same throughout the bund with a provision of waste weir at suitable site.

2. Stone Bunds

Stone bunds; are most commonly used indigenous practice in highly sloping lands of limited depth of soil for the purpose of increasing crop productivity in rainfed areas. Simple stone bunds of varying sizes are constructed across the slope.

In such type of terraces bunds are formed gradually by allowing erosion on the upper parts of sloping fields and arresting the soil by creating vegetative/ stone barrier on field boundary. By adopting this practice, land with limited depth of soil can safely be put under cultivation without further degradation in sloping areas. In this case the cost of construction is reduced and the decrease in yield in the regular bench terracing is minimized. Downward movement of soil is induced by up and down slope cultivation during first 2-3 years. Presently, such terraces are known as Peurto Rican Terraces.

3. Stone wall terraces (SWT)

In some of the highly sloping areas where soil depth is a limiting factor and also in the cultivable Valleys; stone wall terraces are very common particularly in those areas where stones are readily available in the area. Like stone bunds the stone wall barriers are also put across the slope for developing terraces on down hill slopes and particularly in valleys. Downward movement of soil is induced in similar fashion as stated above. Cross section of SWT is decided by the farmers taking into account the slope of the land, rainfall etc. This practice is also adopted in order to create additional cultivable lands by cutting the hill slopes and to concentrate the soil eroded from the adjoining lands at an appropriate site.

4. Rough Stone Slab Bunds

It is found to be very effective, adoptable and low cost indigenous technology in moderately sloping (0-5%) arable lands where the small stone slabs are easily available at or near the site. In this system 30-45 cm high bunds of rough stone slabs (5-10 cm) thick and 45-60 cm long are put across the slope, uniformly all along the field boundaries. Stone slabs are thoroughly embedded in soil one after the other in dug out furrows of 15-30 cm depth.

5. Rough Stone Bunds

In the absence of the slabs simple stone pieces

36

of 10-20 cm thick, 45-60 cm long and of varying widths are also used. In due course of time the small gaps in between two slabs/ stones are being covered by naturally occurring grasses; also acting as filter strip. Some of the farmers prefer to have such bunds against smaller cross sectional earthen bunds because in this system only a narrow strip of land goes out of cultivation and maintenance is almost nil.

6. Vegetative Peripheral Bunds/ Barriers

Peripheral or boundary bunds/ barriers of Agave sislana locally known as Ram bans/ Gul bans is a commonly used indigenous SWC technology in arid and semi-arid regions and the established bunds are found to be very effective. Barriers of Agave are also very commonly used technique in many of the areas to stabilize the periphery of fields situated on the banks of big nalla or rivers.

7. Smaller Cross-Sectional Earthen Bunds Covered with Flat Stones or Pieces of Stone Slabs

In some of the hilly areas in moderately sloping lands; smaller cross-section earthen bunds of about 30-45 cm height are constructed across the slope almost on contours for enhancing in-situ moisture conservation and also for checking soil erosion from arable lands. The top level is strictly maintained at uniform level throughout the bund length and the top is covered with flat stones or pieces of rough stone slabs to keep the bunds safe from raindrop impact and also from occasional damages caused by over topping. Sometimes all the three sides of the bund are covered/ pitched with stones. As per the requirements of the area, a provision for safe disposal of excess runoff is also kept. The farmers used to maintain these bunds very carefully. In some of the areas these bunds are also established for controlling/ stabilizing gullies.

8. Temporary Sediment Detention Dams (TSDD)

On of the ways adopted in hilly areas of southern Rajasthan to concentrate eroded soil at appropriate location is the construction of temporary sediment detention dams. In such areas most of the badly eroded lands are found in deep and narrow valleys, where due to high concentration of runoff the rate of soil erosion is very high. Under these situations construction of TSDD is adopted by the farmers. Suitable locations are those where the possibilities of sediment trapping is

more. Initially a low height broad based losse rock dam is constructed. The base width is decided keeping in view the rainfall pattern and expected runoff. Over the years the height of these barriers is being increased and new patch of cultivable land is crated within the gullies/ eroded valleys. The height of the dam is increased till the nallah/ valley section reaches to the extent where the gradient remains stable. In some of the areas such bunds have 3-5m or more height. TSDD is also being act as a temporary drop structure.

9. Diversion Ditches

Diersion ditches are small channels with bank on the down slope side having desired grade towards an outlet for safe disposal of runoff from upper reaches in the natural nallah, to prevent runoff from entering lands of lower reaches which are already protected by some kind of soil conservation measures and to separate arable lands from non-arable lands. It is also one of the commonly used indigenous SWC technology, in hilly terrain of southern and also in other parts of Rajasthan state where a good amount of cultivated land exists in the lower reaches. To protect these lands from the damages caused by runoff water and channeling along gradient towards nallah, such diversion drains are being constructed. The cross-section and type of ditches are mainly based on experiences. There are different types of drains considering amount of runoff and other factors. These are as follows:

Excavated ditches with required gradient in the base.

Excavated ditches supported by a suitable sized losses stone bund on down slope side. Required gradient is provided in the excavated ditch.

Only loose stone bunds are installed and desired gradient is provided by scraping land after leaving 15-30 cm berm in the base on upper side of slope.

10. Stone Wall for Nallah Bank Protection

This practice is adopted in those conditions where bank erosion is a problem particularly in arable lands. this technique is primarily used only in those areas where stones are available at sites or very near to sites . suitable cross sectional wall of loose stone is constructed all along the bank or only at vulnerable sites. Erection of such protection wall is done starting from the bed of nallah keeping appropriate foundation .Height of such walls depends on the depth of flow of water in nallah. Some times these are also reinforsed

37

by planting suitable vegetative material such as Agave, Jatropha, Mahadi etc.

11. Dhora Pali

Field bunding is one of the common practices of SWC locally known as ÂDhora paliÊ bund of about 0.5 sq.m. or even of more crosss-section is constructed on field boundaries in arid zone . Some times waste weirs are also provided at suitable site. These areas are mainly put under kharif crops. In due course of time these bunds get stabilized by naturally occurring local grasses. Some times seed of Dhaman grass are also sown during rainy season for stabilization. Venkateswarlu (1991) also reported that existing SWC practices in arid Rajasthan include large peripheral bunds about 1 m height and 70-75 cm wide at base .In some of the area these bunds are strengthened with munj grass / agave.

12. Kana Bandi (Mulching)

In desert areas to keep the arable land productive, efforts are being made to protect the area from wind erosion. Kana bandi is done in the fields after kharif crops are harvested particularly in those fields, which are prone to erosion. The local material like sania, khinp, prunnings of ker, ber, khejri and phog and also local grasses such as sewan/munj are embedded in soil leaving about 30-40 cm length of the material vertically on the ground in line 2-5 m apart. This practice checks the soil erosion to a great extent. Some times kana bandi is done in square or rectangular manner (checker board fashion, 2 to 3 m2) particularly for stabilization of sand dunes after rainy season, the grass seeds are sown on the leeward side of the mulch. The grass grows and gradually replaces the mulch and control the movement of sand. During kharif this organic material is incorporated in the soil, thereby also in help increasing organic matter content.

13. Village Pond/ Talab

A common rural rainwater harvesting technology through the semi-arid region of Rajasthan is the construction of pond/ nadis/ tank etc. Pond is constructed at suitable sites mainly for domestic use and also for recharge of groundwater. Suitable site for an economic viewpoint is selected by the villagers where the largest storage volume is obtained with the least amount of earth fill. Such conditions are generally found where the valley is narrow, side slopes are relatively steep and the slope of the valley floor will permit a large deep basin. Such sites tend to minimize the area of shallow

waters. Surface runoff is the major source of feeding the ponds/ talabs. Villagers also adopt some design criteria viz., determination of capacity, size and shape of embankments, provision of emergency spillways and provision for controlling seepage.

14. Talai - A Small Water Harvesting Structure

Talai is an indigenous water harvesting technique in semi arid regions of India particularly for creating water point for cattle. In this system an earthen embankment of very low height may be of 1-2 m is made at suitable location in a nallah/ natural drainage line, where natural depression exists. The earth required in making embankment is also taken out from the existing depression for increasing storage capacity. Presently this system is advocated and recommended in name of SUNKEN PONDS particularly in NWDPRA projects.

15. Dry Stone Masonry Pond

Dry stone masonry pond, between 1.5 and 2.5 m high, are constructed to collect and store water. In this type of structure the upstream and downstream walls are constructed 3-4 m apart by dry stone masonry after excavating a foundation of appropriate depth. The space in between these two walls is filled with locally available murrum or soil with proper compaction. The filling is done in layers of 20-30 cm. height along with wetting and compaction. The earth fill is kept 10-20 cm above the top of the wall to provide an extra provision for natural settling over a period of time. Proper compaction is one of the important considerations to check seepage through the embankment and to ensure the stability of the structure. The length of the head wall extension depends on the specific site conditions. The height of such structures is restricted up to 2.5 m to avoid overturning due to water pressure. The width of the wall at the bottom is kept 1.5 m and at the top it is only 0.5 - 0.6 m. The reduction in width is maintained uniformly from bottom to top in the inner edge of the wall. The upper portion of the wall (0.30 - 0.5 m high) is constructed with cement mortar to avoid damage to the walls by stray cattle or human activities.

16. Ponds (Nada)

These large ponds are of two categories denoting both ownership and use. The nadas belonging to the Panchayat is for the specific purpose of proving drinking water for animals while the private ones which have been constructed on kabile kasth lands are used for irrigation.

38

These farm ponds are generally constructed by a group of farmers, whose land remain temporarily submerged and after monsoon, i.e. in rabi season crops are sown as tank bed cultivation, when the water has evaporated or percolated. Stored water is some times drained through some indigenously developed surplussing arrangements for sowing of rabi crops.

17. Nadi (Semi-arid/ Aravali Region)

Nadi is a small traditional water harvesting structure constructed at appropriate site to harvest the runoff water of relatively impervious non arable uplands for the purpose of drinking water for animals and ground water recharge of open dug wells situated in the lower reaches. These are also constructed to store water in the monsoonal nallahs in the upper reaches for various purposes and primarily for recharge of groundwater. The depth of such nadis generally do not exceed 3 meters. These structure are constructed in two ways depending upon the available funds. In the first system both side of earthen embankment of appropriate width is supported by dry stone masonry walls. In the second system the upside wall is pakka or masonry using lime or cement mortar. Masonry wall and earth fill is done in arc shape having curvature in the raised by the locally available soil/ murmur. Layer wise wetting and compaction of soil is practiced. The width of earthen embankment and stone walls are decided by the villagers considering the size, topography and other conditions of the catchment areas. A properly designed waste weir of surplussing arrangement is also provided at suitable site.

18. Nadi (Arid Regions)

In arid zone construction of Nadi is an age-old practice of water harvesting. These are small excavated or embankment village ponds, harvesting the meager precipitations to mitigate the scarcity of drinking water. These nadis hold water from two months to a full year after rains depending on the catchment characteristics, the amount of rainfall received, its intensity and distribution. Each village has one or more of such structures, depending on the demand of water and availability of suitable sites. Capacity of such nadis are reduced in due course of time due to sediment deposition.

19. Tanka

Tanka, the most prevailing rainwater harvesting structure in the Indian desert, is a local term for the underground system. The traditional tanks are made

by digging a hole of 3.0 to 4.25 m diameter in the ground and plastering it with lime mortar to a thickness of about 6 mm followed by a cement plaster of 3 mm thick. The top is covered with ber thoms. The useful life of such structure is about 3 years. The catchments are made in variety of ways using locally available sealing materials like pond silt, murrum, coal ash, gravel, etc. Traditional tankas are temporary and are subjected to leakage. Moreover the catchment areas are not in accordance with the amount of rainfall received and runoff generated. The thorn cover does not prevent the water pollution and evaporation losses, capacity of such tankas are also not sufficient to fulfill the demands of a family for water throughout the year.

The CAZRI has designed an improved tanka, of 21000 liters capacity, which gets filled up with annual rainfall of 125 mm. The water is sufficient for a family of 6 persons throughout the year for drinking. It has an useful life of 25 years as it is constructed using cement masonry. The catchment area needed for this capacity is 778 m2.

20. Khadin

From a study of farmerÊs water conservation practices it is evident that they are acutely conscious of the value of rainwater and try to use it to grow at least one good crop during the year. Khadin is one such system, which is extensively used in arid and semi-arid regions of Rajasthan. It is an indigenous water harvesting cum run off farming structure. Khadin system is site specific needing a large natural, high runoff potential catchment in proximity of plain valley land with deep soils. The ratio of khadin catchment area, depending on type of catchment is 1:12 to 1:15. These are constructed on low lying lands where crops are raised by conserving rainwater from the rocky catchments. Cultivation in khadin is done by rationing runoff water over low lying areas through construction of bund across the slope on the lower boundary line of khadin land. Cross-section of the bund depends upon the soil type, area of khadins and discharge form catchments. The water thus collected is allowed to percolate after which an assured post rainy season crop is grown. Sometimes crops are grown in kharif or rabi depending upon the rainfall and runoff received in the khadins. For areas that will always be dependent on rainwater, this water harvesting practice has great relevance. Now the SWC scientists/ engineers have also considered this indigenous techniques as an important and usefull water harvesting practice and

39

developed design criteria. Kolarkar et al. (1983) also reported that „khadins‰ or submergence tanks are the indigenous form of inundation farming in arid regions.

INNOVATIVE TECHNOLOGIES OF RAINWATER HARVESTING 1. Rooftop Rainwater Harvesting

Rooftop rainwater harvesting technique is applied mainly for the domestic purposes or groundwater recharging in the rural and urban areas. In this technique the rainwater of the roof is either collected in the underground tanks or diverted to the wells/ tube wells for groundwater recharging. Since the collected water is generally free from soil pollution, it can be used for drinking as well as domestic purposes. This technique is highly suitable for the low rainfall areas where number of runoff producing rainfall storms is limited and there is scarcity of drinking water.

2. Sub-soiling

Subsoiling is a system of deep tillage by which the subsoil is loosened and disturbed but is not inverted or brought to the surface. The term sub-soiling has also been applied by some workers to any cultivation carried out in the soil below normal ploughing depth. Subsoiling is possible with the help of deep soil loosening equipment, viz., chisel plough and subsoiler. Subsoiling is a totally mechanized operation. At present, subsoilers available in the market can be operated with any tractor equipped with a hydraulic lift. On suitable soils, chiseling is applicable if restrictive soil layers are less than 45 cm deep, whereas subsoiling is applicable if restrictive soil layers are more than 45 cm deep (Fig. 6.6). Contour subsoiling is possible on upto 30% slope but is most satisfactory on slopes below 22-25% (Nag, et. al., 1989, Singh and Mahnot, 1995, Singh and Mahnot, 2004).

3. Chauka System

In Rajasthan, Gram Vikas Navyuvak Mandal, Laporia (GVNML) has been very active in undertaking measures for improving the productivity of pasture and grazing lands significantly in their project area. All this is in keeping with the goal of GVNML, which is to Âsupport integrated rural development on a sustainable basisÊ. Since its inception, GVNML has been active in organizing and mobilizing rural communities to carry out activities such as repair of tanks, plantation programmes, health, education, and pastureland development, and soil and water conservation. Among others, GVNML has now

been actively involved in developing village gauchar (common pasture lands), using ideas · technical and socially oriented · generated by the local people themselves. Importantly, this NGO has developed an innovative concept · the Chauka system · for reducing runoff and preventing soil erosion to augment in-situ moisture conservation, with gratifying success.

4. Double Wall Cement Masonry Structure

This type of structure looks like an anicut. Both the upstream and downstream walls of the structure are constructed with cement masonry. The height of the structure and catchment area is usually restricted upto 2.5 - 3.0 m and 100-150 hectares, respectively. The base width of upstream and downstream walls is generally taken as 1.0 m and 0.8 m, respectively, whereas the top width of upstream and downstream walls is restricted to 0.60 m and 0.45 m, respectively. The width of walls may be increased depending on the site conditions and volume of water to be stored. For low-height structures (1.0 to 1.5 m) the base width of both the walls may be reduced by 20 cm. The width of the concrete bed is generally taken as 20 cm more than the base width of the masonry walls. The downstream wall or the falling side is tapered. The space in between these two walls is filled with locally available murrum or soil with proper compaction. The filling is done in layers of 20-30 cm height alongwith wetting and compaction. Proper compaction is an important consideration to ensure the stability of the structure.

5. Plastic Lined Farm Pond

Plastic lined farm ponds are particularly suitable for those areas where large quantity of water is lost through seepage, especially where the soil is gravelly and porous. In earthen dams there is also a common problem of seepage through the embankment. Under such circumstances, to check the seepage from all such types of farm ponds/ earthen dams, plastic lining is a feasible solution. Polythene sheets of 200 micron may be used as lining material for seepage control in the ponds. The sheets are spread at the bottom and on the upstream side, upto the top width of the pond. An average 10 cm thick soil layer is also kept above the sheet to keep the sheet in proper place, to check external damage and to protect it from exposure to the sun. A permanent and most effective lining material is brick and cement masonry, but it is costlier than other lining materials.

40

6. Subsurface barriers

Subsurface barriers are used to retain or arrest the seasonal subsurface flows and facilitate the abstraction of water through lined shallow wells, especially during periods of water scarcity. The objective is to place an impermeable barrier - either of clay or masonry across the river-bed, from the surface down to the bedrock or other solid impervious layer.

A trench of the required width is dug across the flow direction of the ground water. The earthwork

involved may be carried out by manual labour since the excavation depths are generally not more than 3-6 m. Subsurface dams are generally constructed at the end of the dry season, when there is little water in the aquifer. There is usually some flow, however, and this must be pumped out during the construction work. After the construction of dam, the trench is refilled with the excavated material. It is important that the refill is properly compacted by mechanical means and watering.

41

References

Chambers, R. (1991). FarmerÊs Practices, Professionals, and Participation. In Kerr, J.M. (ed.) FarmerÊs practices and soil water conservation programmes. Summary proceedings of a workshop. 19-21 June. ICRISAT, Patancheru, India.

Fujisaka, S. (1989). A method for Farmer-Participatory Research and Technology Transfer, Upland Soil Conservation in Philippines. Experimental Agriculture 25 : 423-433.

Gupta, A. (1991). Reconceptualising development and diffusion of technologies for dry regions. In Prasad C. and P. Das (ed.) Extension strategies for rainfed agriculture. Indian Society of Extension Education, New Delhi.

Kerr, J.M. (1991) Farmers Practices and Soil and Water Conservation Programmes : Summary proceedings of workshop. 19-21 June, 1991. ICRISAT, Patancheru, India.

Kerr, John and Sanghi, N.K., (1992) Indigenous soil and water conservation in IndiaÊs semi-arid tropics. Gatekeepr Series 34, IIED, London, U.K.

Kolarkar, A.S., Murthy, K.N.K. and Singh, N., (1983) Khadin A method for harvesting water. Journal of Arid Environment, 6:5966.

Nag, K.N., Chandra, A., Mahnot, S.C., (1989) Mechanization Techniques for accelerating afforestation programme on denuded hillocks. Agricultural Mechanization in Asia, Africa and Latin America 20(3) : 78-80.

Reij, C. (1991) Indigenous soil and water conservation in Africa. Gatekeeper Series No. 27, IIED, London, U.K.Singh and Mahnot, (2004) Mechanical Soil Working Techniques for Soil and Water Conservation on Moderately

Sloping Wasteland, Small Farm Mechanization published by ISAE, Rajasthan, pp 98-101.Singh, P.K. and Mahnot, S.C. (1995) Feasibility and cost effectiveness of mechanical soil working techniques for

soil and water conservation measures on moderately sloping wastelands. Ind. J. of Power and River Valley Development July-August : 106-109.

Vaidyanathan, A. (1991) Integrated Watershed Development : Some major issues. FounderÊs Day Lecture. Society for Promotion of Wasteland Development, New Delhi.

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42

Integrating in-situ soil moisture conservation techniques and

supplementary irrigation for the dry land farming-a modeling study

from Tamil NaduK. Ramaswamy

4

Introduction Drylands in India constitute 68.4 per cent of the

cropped area out of the total cultivated extent of 162.03 million hectares. In Tamil Nadu, 55.0 per cent of the cropped area is left under drylands which accounts for 3.1 million hectares. Due to the higher attention given to irrigated agriculture during green revolution, the care for rainfed agriculture has been considered to be minimum. To meet the growing demands for food, the scope for further addition to area under agriculture is possible only through the exploitation of drylands. Bringing the vast stretch of drylands under green cover particularly with hardy tree crops is the immediate need for the ecological restoration.

Drought hardy crops especially perennial fruits with deep root systems are capable of surviving extreme radiation and temperatures and provides income secu-rity, nutritional and food security. Amla, Jamun, Ber, Karonda, Wood apple, etc., are the fruit crops suitable for drylands. At present, under dry land conditions, fruit orchards have been developed with crops that stand water stress. However, effective micro water harvesting practices and utilization of interspaces have not been

adopted. If, an effective water harvesting measure with suitable intercrop of medicinal plants or any other com-petitive crops is arrived at, the technology could be ad-opted by the farmers for obtaining additional remunera-tion.

By taking considering of the above points in mind, a study has been undertaken to evaluate the ef-fectiveness of various in-situ micro water conservation techniques for various dryland fruit trees by developing and testing a suitable root zone water balance model for dryland crops.

Materials & MethodsField trials were conducted with five fruit trees in

different villages of Coimbatore district: Mango (Thon-damuthur), Tamarind (Ajjanur), Sapota (Chettipalayam), Guava (Chettipalayam) and Amla ( Kethanur). Insitu soil moisture conservation treatments (micro catchments for trees) were imposed with randomized block design (RBD) which mainly consists of various types of micro-catchments for trees viz, V- catchments, Semicircular bund compartmental bund, and a control plot without any treatment. Design sizes of microcatchments were

43

calculated based on FAO guidelines of water harvesting as given in the following equation (2.0).

Micro-Catchment sizeBased upon the design procedure of FAO guide-

lines on water harvesting (Critchley and Siegert, 1991), the ratio of the microcatchment area to cultivated area is given by the following relationship.

(2.0)Where,

C = Total size of microcatchment (m2)CA = Area exploited by the root system (m2)CWR = Annual water requirement (mm)DR = Design rainfall (cm)RO = Runoff Co-efficientEF = Efficiency factor

The values of each parameter in the above equa-tion for all the fields were calculated. For Thondamuthur (Mango) field, the area exploited by the root system , CA was taken as 12.57 m2 , considering a radius of 2m. The annual crop water requirement was calculated based on the ET of the crop.

ET crop (Mango) = ETo (Reference ET) � Kc where Kc- Crop coefficient = 4.24 mm/day

Based upon the design rainfall at 50% probabil-ity as 615 mm with ET crop as 4.24 mm/day RO = 0.8, EF = 0.65, the microcatchment size was arrived as 36m2 including the planted area. The bunding was done in the staggered arrangement. Similarly, all other selected crops, the design sizes of catchments were arrived.

Soil moisture content was periodically monitored month-wise at 15 and 45 cm depth and statistically ana-lyzed to understand effectiveness of various conservation treatments. Yield data was monitored after one year of imposing treatments.

Development of a root zone water balance model

Based upon the results of experiments conduct-ed world �wide, the model proposed by the Doorenbos & Kassam (1979) was adopted for finding the root zone water balance on daily basis by taking into account of actual Evapotranspiration of the crop. Scarcity moisture days were worked out below 45cm root zone depth.

AET = PET, θD ≥ (1-p) ASW.D (2.1)

AET = θD.PET/(1-p) ASW.D, θD < ( 1 - p ) ASW.Dwhere, D = depth of root zone (cm) based on the crop,θ = Average moisture content per unit depth (mm/cm), AET = Actual evapotransporation, PET = Potential evapotransporation p = Soil moisture depletion factor, ASW = Maximum available soil water per unit depth

Based on the assumptions listed above, the wa-ter balance in the effective root zone on the ith day of any month is given by:

θiD = θ

i-1D � AET

i, i = 2, 3, ⁄. (2.2)

where, θi-1

D is the soil moisture depth of i-1th day, and AET

i is the actual evapotranspiration of ith day.

For continuous days,θ

i+1D = θ

iD + R

i+1 + I

i+1 � P

i+1 � AET

i+1 (2.3)

Ri+1

represents the infiltrated volume of rain wa-ter on i+1th day, I

i+1 represents the supplemental irriga-

tion applications on i+1th day, and Pi+1

is the excess water percolated out of the root zone on i+1th day.

where, Pi = R

i + I

i � (FC � θ

i-1D), if R

i + I

i ≥ (FC � θ

i-1D)

P = 0, otherwise. (2.4)

Here the rainfall was assumed to have the values of infiltrated volume found out from the infiltration rates for the given rainfall time. As the present model was to compute the root zone water balance in bunded field plots under dryland conditions, the infiltrated volume of rain ÂR

iÊ in the equation (2.4) adopted under the follow-

ing conditions is as follows:

Condition I: Intensity < Average infiltration rate of soilR

i = R

1 = Basic infiltration rate of soil if SMC > FC (i)

Ri = R

2 = Average infiltration rate of soil if FC =SMC= PWP (ii)

and Ri = R

3 = Maximum infiltration rate of soil if SMC < PWP (iii)

(2.5)where, SMC = Soil Moisture Content, FC = Field Capacity, and PWP = Permanent Wilting Point of the soil.

The infiltration time was taken as the duration of the storm and the infiltrated volume of rain water ÂRÊ was calculated as the product of the duration of the storm and the basic, average or maximum infiltration rate based on the existing soil moisture conditions (i), (ii) or (iii) of equation (2.5).

44

Condition II: Intensity > Average infiltration rate of soil

The water balance in this situation was given by:

θiD = CI

i-1 - AET

i, i = 2,3,⁄. (2.6)

where, CIi-1

= cumulative infiltration on the i-1th day, given by modified KostiakovÊs(Kostiakov-Lewis type) equation: CI = Bt

ep + q (2.7)

where, te = sum of duration of rainfall and average time

of infiltration of ponding water after rainfall ceases, B, p and q are constants.

In the above equation 2.7, the time ÂteÊ is consid-

ered as follows:

te = Duration of rainfall + average time of infiltra-

tion of ponding water after rainfall ceases

The average time of infiltration of ponding water after rainfall ceases in the above equation was calcu-lated by quantifying the volume of water ponded to the height of the bunds provided for the field plot or the mi-cro catchment of the treated plot divided by the average infiltration rate.

Results & Discussion The prediction behaviour of the model output

and field observations in respect of soil moisture was depicted in the figures 1 to 4 for the selected mango field under study. From these figures, the following inferences could be drawn:

During the study period, the trend of the soil moisture content predicted from the model for different months was similar as that of the observed values both under control and treatmental plots.

The soil moisture contents in the treatmental plots were always higher than the control plot both in the predicted and observed values .This might be due to the fact that the effective runoff control was created by the micro-catchments, thereby more opportunity for higher infiltration volume and hence better in-situ moisture conservation.

There was a close agreement between the pre-dicted and the observed values as seen from the figures

and also from the results of the non-parametric Chi-square statistical test, showing there was no significan variation between the model and the observed data.

Model predicted Vs field observed soil moisture data in different treatments

Fig. 3. Soil Moisture in Crescent bund

Fig. 1. Soil Moisture in Control

Fig.2. Soil Moisture in V-Catchment

Fig.4. Soil Moisture in Compartmental bunding

45

Runoff

The runoff was obtained as output on the days when the rainfall intensity exceeded the average infil-tration rate of the soil. The runoff was predicted from the model for the Thondamuthur field on two dates and the predicted runoff volumes for the 45cm and the en-tire depth of the root zone were the same. Then those predicted values were compared with the observed field values of runoff as given in table 1.

Scarcity Moisture Day’s Computation

Scarcity moisture days were defined as those days having soil moisture below permanent wilting point at 45cm depth applied to normal field crops.

From the root zone soil moisture balance compu-tation, the soil moisture content below permanent point for two different locations at 45 cm depth in various treatments are given below ( Table.2)

The percentage of scarcity moisture days of two locations (Thondamuthur and Chettipalayem field) is

shown in the following Fig.5 and 6.

Out of the total operational period of 150 days

in the Thondamuthur field, for both 45cm and the entire

root zone depth, the control had more number of scar-city soil moisture days than the micro-catchments like V-catchments, crescent bunds and compartmental bunds irrespective of the depth considered in the root zone. This might be due to the fact that the bunded micro-catchments were able to conserve more moisture than the other treatments.

The supplemental watering given for success-ful growth of the crop was also accounted and the total depth of water utilized including effective rainfall was in-

corporated.

Some experiments in farmers fieldThe sites selected for the research study were

located at Thondamuthur and Chettipalayam, in Coim-batore district of Tamil Nadu, India. Thondamuthur lies to the western part of Coimbatore near to the Western Ghats. It has a sandy clay loam soil type. The area has a mean monthly minimum temperature of 21oC and a maximum of 31oC. The mean annual rainfall is 628.15mm (Appendix I). The water table was very deep (70-90m) (Ground Water Status Report, 1994). Here, a farmer field with dryland Mango plantation was se-

lected for the study. The root zone depth of the Mango crop was 120cm. The area of the field was 2.2 hect-ares, bunded from all sides. The crop grown here was 11 years old. The field was left dry and it depended on

Table 1: Runoff volumes for Thondamuthur (Mango) field

Treatment Predicted runoff (m3) Observed runoff (m3)

Control 14.30 12.35 V Catchments 11.21 11.13 Crescent bunds 11.29 11.21 Compartmental bunds 11.30 11.12 Scattered trenches 13.19 11.56

Table 2: Scarcity moisture days in different moisture conservation treatments (days)

Treatments Thondamuthr Chettipalayam Sandy clay loam (days) Sandy loam (days)

Control 54 100

V- catchments 32 76

Crescent bund 33 83

Compartmental bund 33 83

Fig.5. Sandy Clay loam (Thondamuthur)

Fig.6. Sandy loam (Chettipalayam)

46

rainfall for water.

In-situ moisture conservation treatments with microcatchments given in the field were V-catchments, semi-circular bunds, compartmental bunds, scattered trenches and one as a control plot under a State Land Use Board (SLUB) Scheme on maximizing land and wa-ter use efficiency in dryland horticultural systems operat-ing at the Department of Soil and Water Conservation Engineering, Tamil Nadu Agricultural University. There was a problem of moisture inadequacy; periodical plant withering and no intercrops were able to be grown in between the large amount of interspace available for in-tercrops. Any attempt to improve the moisture status in the field through microcatchment techniques will likely yield a possibility of taking intercrops like pulses/medici-nal plants thereby enhancing the income per unit area. Effects of moisture status with root zone water balance modeling will give the possibility or otherwise of this idea.

Medicinal inter crops attempted in all five loca-tions were Senna - Cassia angustifolia, Periwinkle - Catheranthus roseus, Thulsi - Ocimum sanctum, Keelanelli-Phyllanthus amara

Another field at Chettipalayam was also selected which lies to the eastern part of Coimbatore. It had a sandy loam soil, with medium depth of 0.7 to 1.2m. The area had a mean monthly minimum temperature of 25oC and maximum of 34.5oC. The mean annual rainfall of the region is 450.12mm. The area lies in the dryland region and the crops are mainly rainfed. A farmer field with dryland Guava plantation was selected for the study. The root zone depth of the crop was 100cm. The field was having an areal extent of one hectare, bunded from all sides. In this region, the water table was very deep in the range of 90-100m falling in the hard rock terrain (Ground Water Status Report, 1994). The Guava planta-tion was 4 years old, initially provided with drip irriga-tion facility for one year for establishment and left with

rainfed condition thereafter. The crop was in withering condition, when the moisture conservation treatments were established. Then it showed improvements in its growth after the receipt of monsoon rains (November-December) during the year. This experimental facility has also been utilized for the present field investigation with reference to testing the root zone water balance model. This field was also laid with the same moisture conservation treatments under the SLUB Scheme oper-ating in the Department of Soil and Water Conservation Engineering.

Crop Performance and Economics with Inter Crops

Yield and growth attributes were monitored and final analysis was summarized in terms of water use ef-ficiencies and benefits cost ratio.

Integration of Supplemental irrigation

In order to take soil moisture dryness below wilt-ing point percent moisture at the end of monsoon pe-riods and summer period, a series of dug out ponds were constructed in low lying points of each field and net working of water flow from one to the other has been done along with supplemental pitcher irrigation.

This exercise has been done in 350 ha area under participatory Action Research with private and public lands under Technology development scheme of DoLR, GOI.

A series of dug �out ponds with size varying from 10 m3 to 25 m3 of 6 nos. were constructed with a low cost soil- cement or soil lime mixture stabilization and compaction technique for seepage control and to use stored water for supplemental irrigation for Amla, Rosewood and Mahagony plants. As the water applied per month is 32m3, the total water storage capacity re-quired for 400 plants per ha is estimated to be 200m3. In this, seepage, evaporation and other losses amounting

Table 3: Location of field trials

S. No. Location of the village Soil type Dryland Area Age of the fruit crop (ha) tree ( years)

1. Kembanur (Thondamuthur block) Alfisol Mango 2.8 11

2. Ajjanur (Coimbatore west) Vertisol Tamarind 2.2 7

3. Chettipalayam Alfisol Sapota 1.8 4

4. Chettipalayam Alfisol Guava 1.0 4

5. Kethanur (Palladam block) Alfisol Amla 2.0 4

47

to 60% of the total storage for 2 months was accounted. Hence, filling of the dug- out ponds once in two months during summer months is sufficient to cater the water needs of the plant. This Water application during first two years of establishment given below.

During monsoon/rainy periods the dug-out ponds serve as water harvesting / collection structures. In this experiment, three filling with transported tank water was applied in the dug-out ponds and there was a filling with rainy water for one time. The dug-out ponds

Table 4: Intercrop Yield Increases with Treatments

Intercrops Economic parts Max. yield Control

Senna Leaf (t/ha) 3.1 2.0 Seed(kg/ha) 105.0 81.0

Root (t/ha) 2.3 1.1Periwinkle Stem (t/ha) 3.1 2.1 Leaf (t/ha) 3.3 1.7

Thulsi Leaf (t/ha) 9.5 5.5 Stem (t/ha) 16.3 8.1

Table 5: Benefit-Cost Ratio

Crops combination B-C ratio (Thulsi /Perwinkle)

Anola 4.4 � 5.7 Guava 2.3 � 3.4 Sapota 1.9 � 2.7 Tamarind 1.1 � 1.9 Mango 1.1 � 1.3

Table 6: Cost of Micro catchments

S.No. Treatment Cost/ha (Rs)

1 V-ditches 6000 2 Semicircular bund 4000 3 Compartmental bund 4500 4 Scattered trench 3000 5 Basin listing 3000 6 Broad bed furrow 3000 7 Vegetative barrier 3000 8 Coirpith compost 3000

Table 7: Water Application during first two years of establishment

Water application / plant/ week = 20 lit.

Water applied / month /ha ( 400 plants) = 32 m3

Water application / plant / 8 months in a year 640 lit/ annum

Water was not applied for 4 months monsoon period Water application / ha for 8 months = 256 m3

Area of water application at each plant = 1.57 m2

Annual depth of application = 40.76 cm

Effective rainfall = 43 cm

Total depth of water utilized = 83.76 cm

48

are so arranged in such away that the surplus water from one pond will go to other through interlinked channels. The cost of dug-out pond with low cost lining works out to Rs.80 per m3. The expenditure of water storage dug-out tank per ha is Rs.16, 000/.

Total water storage for 400 plants per ha worked out as 62.5 to 100m2 depending upon the location spe-cific factors, by assuming reasonable 2 m depth. These pits are located in moderate to low lying points of the area as for as possible. Experience of these dug-out ponds with various locations reveal that water lost for 30-45 days only depending up on the type of soil and its stabilization with compaction at bottom and cement-ing material plastering on sides. The performance un-der black-cotton soil with soil-cement lining is extremely poor which was done in one of the nearby locations of the project area. The soil lime mixture was working well with clay soils.

Pitcher IrrigationThe plastic pot pitchers with a hole and 70 cm

length 6mm HDPE pipe with a micro pin hole outlet has been used for this technique by marking locations near the plant and making 50 cm deep pit with a diameter of 45cm.Initial observations on two soils with Periya-naikanpalayam and Somayampalayam series were taken and the data obtained is as follows.

The water filled once in each pot having a ca-pacity of 18 lit lost for 30-36 hours. The cost of pitchers at the rate of 400 Nos/ha including laying cost workout

Rs.10, 000/-.

The following advantages have been noticed in this approach.

Better soil moisture regime without stress for most

of the dry periods.

Number of supplemental watering could be reduced depending up on the soil conditions.(by 50-65%).

This results in reduction of recurring cost to about 50% in conventional watering.

Quick growth and better viguor of plants have been observed without any mortality of plants.

This would facilitate a few low tier crops like water melons, gourds could be grown for initial periods which would meet part of (50-75%) maintenance system (water cost) at least for a 2-3years. The labour cost of watering works out to Rs 5000/= per ha per annum excluding the transport cost from source.This transport cost of water works out upto Rs 8000/- @ Rs 40/m3 for entire summer period excluding in situ rain water utilization.

Modern Plastic Lining TechnologyThe modern technologies like plastic lining with

different thickness depending upon depth of water stor-age could be adopted for controlling seepage and perco-lation losses and to store water atleast for 90-100 days for supplemtal irrigation. An observational study con-ducted in three locations and the following standardiza-tion on conservative side which leads to adoptation in a National Agriculture Development Programme (NADP) in nine focus districts of Tamil Nadu state.

Maximum no. of supplemental irrigations : 2 to 3Capacity of the pond : 2500 m3 (25 lakh Lit )

Cost of storage @ Rs.100 per 1000 Lit : Rs.2.5 lakhsCost of portable sprinkler system : Rs.0.5 lakhsTotal cost : Rs.3.0 lakhsPlastic lining (LDPE) 250 micron (<2m depth)

Table 8: Soil moisture status under Pitcher irrigation

Soil type Field capacity (%) Wilting point (%) Available moisture (%)

Periyanaikan Palayam 24.2 14.5 9.7Somaiyampalayam 6.6 3.1 3.5

Table 9: Soil moisture depletion (50 %) under manual and Pitcher irrigation (days from watering)

Soil type Manual Pitcher

Periyanakayan palayam 10 15Somayampalayam 7 11

49

consistent in all multi location trials laid at five different locations. The model predicted soil moisture relatively better during dry times compared to moist periods pre-vailing as soon as the receipt of the rainfall. This might be due to the moisture redistribution process in the soil after the receipt of the infiltrated rain water, which was not considered in the model.

The moisture conservation and establishment of plants in dry lands is crucial for which additional water-ing mechanisms like pitcher irrigation combined with a net work of dug-out ponds provided its worthiness when these techniques are tried on with micro �catchments like V-Shaped bunds or Crescent bunds around trees or compartmental bunding on field plot boundaries. Though the integration of these three techniques cost

about Rs 35,000 / per ha, this enables productive and remunerative results with high value horticulture and for-estry plantations. There is a potential scope to introduce the above dryland horticulture based model integrating in- situ soil moisture conservation techniques and sup-plementary irrigation in many semi-arid regions.

500 micron (> 2m depth)Summary & Conclusion

The design and laying of micro catchments ac-cording to land slope, soil type and crop water require-

ments would meet the proposed moisture status along with enhancement in yield attributes. The root zone soil moisture budget analysis showed that there is an inevita-ble need of supplemental watering which could be done by proper size of dug-out ponds located at the techni-cally feasible points. The results obtained are almost

Table 11: Average size of catchments and irrigated area of farm ponds under Coimbatore conditions

Catchments area (ha) Irrigated area (ha) Technology

5 1 Clay lining of the pond + surface irrigation of stored water 5 2-2.5 Plastic lining of pond + portable sprinkler irrigation

25

Reference

Critchley, K.N., and C.N.Siegert .1991. FAO guidelines on water harvesting, FAO, Rome, Italy.Doorenbos , J. and A.H.Kassam, 1979. Yield response to water. Irrg. And Drainage paper No:33, FAO, Rome ,

Italy.Ramaswamy, K and Thangaraj, T. 2002. Water harvesting Technologies for Dryland Horticulture Technology Bulletin,

Horticulture College & Research Institute, Periyakulam, Tamil Nadu Agricultural University.���

50

Conservation of Rainwater and Sustenance of Productivity

Through Improved Land Management and Cropping

System in a Vertisol of Central India

K.M. Hati, A.K. Misra, K.G. Mandal, A.K. Tripathi, A. Subba Rao, R.K. Singh, S.P. Wani, P. Singh and P. Pathak

5

IntroductionFor sustainable crop production system under

rainfed condition, the conservation of rainwater and its efficient recycling are imperative. The rainwater can be conserved either in-situ i.e. in the soil itself or ex-situ in natural or man made structures wherefrom it can be used for supplemental irrigation. In-situ rainwater con-servation can be carried out either though tillage or landform management (Singh et al., 2000). Among the various landform management practices like raised and sunken bed, ridges and furrow etc. developed for Verti-sols, broad-bed and furrow (BBF) system is very promis-ing in controlling surface runoff, reducing the soil loss through erosion and increasing infiltration (Pathak et al. 1985; Singh et al. 1999). The BBF landform manage-ment system reduces the velocity of runoff water and thus increases opportunity time for water to infiltrate and reduces sediment losses. Further, during the period of heavy rainfall the furrows allow excess water to drain safely from the plots and thus avoid water congestion to the crop (Kampen, 1982). There is an urgent need to manage the water resources of Vertisols of Central India to control soil erosion and to improve use efficiency of

the rainfall for sustaining crop production. This is pos-sible through adoption of improved land management practices, which will decrease runoff and soil erosion and concomitantly improve crop yield in deep Vertisols.

Stagnation of productivity of soybean based pro-duction systems due to erratic distribution of monsoonal rain and incidence of new insect-pests and diseases is leading to under-utilization of land, water, nutrient and climatic resources. Under this situation the crop diver-sification in the rainy season can be a viable option for stabilizing and enhancing productivity of the system. In winter season, it has been found that chickpea performs better than high water and nutrient requiring wheat crop. In addition, harvesting of run off water in storage pond and its efficient utilization through supplemental irriga-tion to the rainy season crop in case of early withdrawal of monsoon and pre-sowing irrigation to the winter crop holds the promise for increasing the total system produc-tivity and stability. In fact, insufficient attention on rain water harvesting and its recycling hampers efficient utili-zation of nutrients by crops. In order to ensure a pay-off from nutrients, all round augmentation of water resource with watershed as a unit of development is imperative. In

51

this back drop, an experiment was conducted with the following objectives, (i) to assess the effect of landform treatments on loss of rain water through runoff and loss of soil through erosion, (ii) to study soil water dynamics, and (iii) to evaluate the productivity of five soybean and maize based sole and intercropping systems in a verti-sol.

Materials and methodsA field experiment was conducted for four years

from 2003-04 to 2006-07 on broad bed and furrow (BBF) and flat on grade (FOG) land treatments with five different cropping systems viz. Soybean- chickpea, maize- chickpea, soybean/ maize intercropping� chick-pea, soybean/ pigeon pea intercropping and maize/ pigeon pea intercropping and two irrigation levels on a micro-watershed at the experimental farm of Indian In-stitute of Soil Science, Bhopal, Madhya Pradesh (23018Ê N, 77024Ê E, 485m above mean sea level). Soil of the experimental site was deep heavy clay (Typic Haplus-tert). The climate of the experimental site was hot sub-humid type with a mean annual rainfall of 1130 mm and potential evapo-transpiration of 1400 mm. The BBF landform was prepared with the help of a tractor drawn BBF former along the key lines drawn based on a topographic survey. The width of the broad bed was 1.0m with 0.5m wide furrows on either side of the bed. In the first year (2003-04) pigeonpea monocrop was taken in lieu of maize/pigeon pea intercropping. In rainy season crops were grown rainfed while in winter season chickpea was grown with two irrigation levels, (i) one pre-sowing (PS) irrigation to chickpea (I

1) and (ii) one PS

+ one irrigation to chickpea at flowering stage (I2). The

irrigation was provided from the water harvesting pond of the watershed. Recommended doses of NPK fertilizer were applied to each crop and farmyard manure (FYM) @ 5 t ha-1 was applied once in a year to the rainy season crop. The N:P:K doses for soybean, maize, pigeonpea and chickpea were 30:26:25, 120:26:33, 30:26:33, 30:26:33 kg ha-1, respectively. Crops were harvested manually at their physiological maturity and grain yield was recorded from net plot harvest.

Runoff from each landform treatment was mea-sured with automatic runoff recorder (Thalimedes) in-stalled on a H-flume constructed at the lowest contour point. The height of the water passing through the H-flume was continuously recorded by a float operated shaft encoder with digital data logger which was later in-terpreted in terms of runoff volume associated with each

rainfall event (Pathak, 1999). Automatic pumping sedi-ment sampler fabricated at International Crop Research Institute for Semi-Arid Tropics (ICRISAT), Hyderabad, India was used to monitor the temporal changes in sedi-ment losses from each runoff events. The samplers col-lected runoff water with suspended sediments passing through the H-flume and stored in plastic collection bottles at 20 minutes interval. The sediment was floc-culated by adding 10 N HCl. Then these were dried in oven to estimate the suspended particle content. The sediment concentration obtained from each bottle was used for the calculation of total sediment losses associ-ated with each runoff events. Soil water content up to a depth of 90 cm at 15 cm interval was determined thermo-gravimetrically at regular interval during the crop growth period in 2003 and 2004. The water content of individual soil depth determined on weight basis was multiplied with corresponding bulk density and depth of the soil layer to obtain the profile water storage. Analysis of variance (ANOVA) was carried out using split plot de-sign (Gomez and Gomez, 1984) for comparing means of main and interaction effect using least significant dif-ference with 5% significant level.

RESULTS AND DISCUSSIONSeasonal Rainfall, Runoff, and Soil Loss

The amount of rainfall received during the four years of experimentation was highly variable. Total rain-fall received during the rainy season of 2003 between June to October was 1058 mm, which was slightly higher than the long-term average rainfall of 1005 mm for this season, while in 2006, the rainfall received dur-ing the rainy season was 1513 mm, which was 50% higher than the average rainfall. During the rainy season of 2004 and 2005 seasonal rainfall was lower than the long-term average rainfall. In 2004, the distribution of rainfall was also not uniform during the season. In the month of June, rainfall was only 8.5% whereas, July and August received 83% and September and October re-ceived very less rain. Thus the performance of soybean crop was adversely affected because of the soil moisture deficit during the pod development stage of the crop. Moreover, the soybean crop was heavily infested by the insect-pests and yield reduced drastically. In 2005, the onset of monsoon was very late; the month of June received only 26.7 mm i.e. 2.8% of the seasonal total rainfall and most of the rain was received in the month of July (55.7%) whereas the share of August was only 18.4% of the seasonal total in the year.

52

Runoff and soil losses from the field area under broad-bed and furrow (BBF) and flat on grade (FOG) landform treatments were monitored during the kharif seasons. In all the every year, seasonal runoff from the BBF plot was less than that from the FOG (Table 1). This might be attributed to the reduced speed of runoff from BBF plot due to uniform slope, which have resulted in higher opportunity time for water to infiltrate in BBF than FOG treatment. The runoff was 15.4-33.2% and 20.3-57.7% of seasonal rainfall from BBF and FOG landform treatments. The run off under both BBF and FOG was much higher during the rainy season of 2006 because of unusually high rainfall. The soil losses through runoff from BBF and FOG were higher in high rainfall years; the extent of soil loss was to the tune of 1956 and 2837 kg ha-1 from BBF and FOG, respectively in 2003 and 3503 and 6365 kg ha-1 in the corresponding treatments in 2006. However, the soil losses were relatively less, 657 and 1466 kg ha-1 from BBF and FOG, respectively in 2004. BBF landform treatment reduced soil loss to a greater extent (31 to 55%) than its reduction in runoff volume (24 to 32%) as compared with that of FOG over the years. This can be ascribed to lower concentration of sediments in runoff water coming from the BBF than from FOG as velocity of flow of the runoff water was generally lower in BBF. Pathak et al. (1985) and Srivas-tava and Jangwad (1988) have also shown that runoff and soil loss were remarkably reduced in BBF land sur-face management treatment in a long-term watershed study in Vertisol.

Soil Water Dynamics and Moisture Extraction by Crops

Water storage in the soil profile up to 90 cm depth during rainy season of 2003 and 2004 was de-termined gravimetrically throughout the crop growth period. The data revealed that the water storage dur-ing 2003 ranged between the field capacity and perma-nent wilting point (PWP) in all plots. This was because of uniform distribution of rainfall in the rainy season. Even in later phase of crop growth moisture storage in the root zone remained higher than the PWP moisture storage. The average moisture storage in the later part of crop growth (after 64 DAS) was higher in BBF than FOG treatment, but this was not conspicuous in the early growth period. After the withdrawal of monsoon a continuous monitoring of soil moisture extraction was made for two weeks to study the moisture depletion pat-tern during a drying cycle. The results showed that the depletion of soil moisture during the two weeks drying

period was considerably higher in the sole pigeon pea and soybean/pigeon pea intercropping treatment com-pared to sole soybean, sole maize and soybean/maize intercropping treatments (Table 2). Depletion of mois-ture was maximum (60.4 mm) from the sole pigeon pea treatment on BBF. Similar results were recorded under both BBF and FOG landform treatments. This might be due to higher extraction of moisture by pigeon pea, which was approaching maximum vegetative stage dur-ing that period, compared to the other two crops, which were near maturity at that time.

In 2004 water storage in the profile decreased slightly during the first week after sowing and thereafter it increased in all the plots in the month of July with the increase in rainfall. Up to the middle of August, soil water contents remained near field capacity. During this period, treatment effects on water storage were not clear and it followed the rainfall distribution pattern. Among the two land surface management treatments, BBF often retained slightly higher water in the profile than the FOG treatment. This might be due to higher infiltration and better retention of water in BBF than FOG treatment. Singh et al. (1999) also reported higher water storage in BBF during rainy season in soybean-chickpea rotation on a Vertic Inceptisols. After withdrawal of monsoon, from second week of September in 2004, monitoring of profile water at weekly interval was carried out to study the moisture extraction pattern by different cropping systems during this drying period. Like the earlier year the depletion of water during this period was consider-ably higher in soybean/pigeonpea and maize/pigeon-pea intercropping systems compared with sole maize, sole soybean and soybean/maize intercropping systems in both BBF and FOG land management treatments (Table 3). This was due to higher extraction of water from the profile by pigeonpea crop which was near full vegetative stage during that period, while the other two crops viz. maize and soybean were near maturity at that time. Besides this, the deep root system of pigeonpea extracted more water from deeper soil layers than the other crops.

Yield of Rainy Season Crops The grain yield of soybean in sole soybean treat-

ment varied due to differential rainfall amount and its dis-tribution during the years of experimentation. In 2004, the grain yield of soybean was typically low in both broad bed and furrow (BBF) and flat on grade (FOG) land treatments because of less rainfall. However, results

53

revealed that the grain yield of soybean in sole soybean, soybean/maize intercropping and soybean/pigeon pea intercropping systems under BBF was greater than that under FOG for every year of the experimentation. On an average over four years, BBF registered 12.7-18.0% greater grain yield of soybean than FOG under sole soy-bean. The soybean yield in sole soybean and soybean/pigeon pea intercropping was similar, but it reduced in soybean/ maize intercropping. This was mainly due to competition between the crops for light and nutrients in soybean-maize cropping system. But soybean/pigeon-pea intercropping the yield of soybean was not affected, as pigeonpea was a slow growing crop compared to maize and soybean and its growth peaked up after har-vest of soybean and maize. Thus competition between the intercrops was less. Similar trend was observed in total biomass production of crops for sole and intercrop-ping systems under BBF and FOG land treatments.

Grain yield of maize in sole maize treatment un-der BBF was 11.8-16.0% greater than the same treat-ment under FOG land configuration. In soybean/maize and maize/pigeon pea intercropping systems, grain yield of maize was also greater in BBF than FOG. Similar trend was observed in total biomass production of maize for different sole and intercropping systems. In 2003-04, though maize population in soybean/maize intercrop-ping was similar to the sole maize, maize yield was re-duced in intercropping by 203 and 244 kg ha-1 in BBF and FOG, respectively. For other years, maize yield in soybean/ maize intercropping was lower than the sole maize because of reduced plant population, almost half of the sole maize population. In maize/ pigeonpea inter-cropping, maize population was imilar to the sole maize, as pigeonpea was intercropped with maize as in the additive series; thus maize yield was not reduced. This trend was observed in every year since 2004-05.

Soybean equivalent yield (SEY) of rainy season crops was higher in BBF than FOG (Table 4). Higher yield of crops in BBF might be ascribed to higher re-tention of moisture in the grain filling stage, less water congestion, better aeration in the rooting zone. Selva-raju et al. (1999) and Wani et al. (2003) also reported a higher crop yield under BBF land treatment in Verti-sols. In 2003-04, SEY of systems were in the order: soybean/pigeon pea intercropping > sole pigeonpea > sole soybean > soybean/maize intercropping > sole maize both in the BBF and FOG. In the year 2004-05, the order was: maize/pigeon pea intercropping > soy-bean/ pigeonpea intercropping > sole maize > soybean/

maize intercropping > sole soybean, while in 2005-06 and 2006-07, SEY showed the following order maize/pigeon pea intercropping > soybean/ pigeon pea inter-cropping > sole maize = soybean/maize intercropping > sole soybean.

Grain Yield and Water Use Efficiency of Chickpea

In the winter season chickpea was grown in three cropping systems where pigeonpea was not included and with two irrigation levels. The grain yield of chickpea was greater in BBF than FOG in all the four years of ex-perimentation (Table 5). In both the land configuration, yield variation of chickpea was not significant among three cropping systems where it was grown. Thus, the residual effect of previous crops on the performance of chickpea was not significant. However, irrigation treat-ments showed significant variation in the performance of chickpea. The grain yield of chickpea in I

2 (one pre-

sowing + one post-sowing irrigation) was significantly greater than I

1 (pre-sowing irrigation) in both the land

configuration.

Water use efficiency (WUE) was estimated as grain yield divided by seasonal evapotranspiration (ET). Seasonal ET was estimated by water balance method, assuming water loss through runoff and deep drainage during the crop-growing season as negligible. WUE of chickpea was more under BBF than FOG (Table 6). In the year 2003-04, WUE in BBF was significantly higher in I

1 than I

2 irrigation treatment but in FOG the differ-

ence among the irrigation levels was not significant. Re-sidual effect of the previous crop has not shown any significant effect on the WUE of chickpea in both BBF and FOG land configuration. In the years 2005-06 and 2006-07, WUE of chickpea was significantly higher in I2 than that in I

1 irrigation treatment in BBF. This was

probably due to higher increase in seed yield of chickpea compared to corresponding increase in ET with increase in irrigation amount in BBF; however, in FOG irrigation level has not shown any significantly effect on the WUE of chickpea in 2005-06.

Total System Productivity as Soybean Equivalent Yield (SEY)

Irrespective of irrigation to chickpea and crop-ping systems, results revealed that total system produc-tivity (TSP) as soybean equivalent yield was greater in BBF than FOG; and TSP was higher in I

2 (pre-sowing

plus 1 post sowing irrigation) than I1

(pre-sowing irri-

54

gation). Among the 5 cropping systems, there was sig-nificant difference in the total productivity of systems (Table 7). Soybean-chickpea system was found to be the least productive except in the first year (2003-04). After 2003-04, system productivity was not favourable for the soybean-chickpea system, because of constantly lower yield of soybean over years, and at the same time maize yield was considerably higher. Consequently, the systems involving maize crop, either as sole or intercrop (as in maize-chickpea, soybean/ maize intercropping-chickpea and maize/ pigeonpea intercropping systems) gave higher productivity than other systems under both BBF and FOG land treatments. Even the TSP was high-er in maize/ pigeonpea intercropping systems where there was no subsequent chickpea crop. In the event of non-availability of irrigation water to chickpea, maize/ pigeonpea intercropping is better system than sole soy-bean. Thus, these three cropping systems viz. maize-chickpea, soybean/ maize intercropping-chickpea and maize/ pigeonpea intercropping i.e., diversification from

the sole soybean, hold the promise for increasing pro-ductivity in the on-station watershed.

ConclusionsThe runoff and soil loss from broad-bed and fur-

row (BBF) are less than that from flat land treatment. Besides this, BBF also helps in safe drainage of excess rainfall and reduces chance of water congestion to the rainy season crops while it retains higher moisture during the later phase of crop growth after withdrawal of mon-soon and produced higher crop yield than the traditional flat land sowing system. Farmers may adopt BBF land configuration for growing of crops like soybean, maize, pigeonpea and chickpea. The study provides an option for crop diversification from the present predominant soybean based cropping systems to cropping systems where maize is a component, either as sole or intercrop for this region. Water lost as surface run-off could be conserved in watershed ponds and used as supplemental or life-saving irrigation.

ReferencesGomez, K.A. and Gomez, A.A., 1984. Statistical Procedures for Agricultural Research. 2nd ed. Wiley � Interscience.

New York.Kampen, J., 1982. An approach to improved productivity on deep Vertisols. Information Bulletin No. 11, International

Crop Research Institute for the Semi-Arid Tropics, Patancheru, A.P., India. Pathak, P., 1999. Runoff and soil loss measurement. In: Wani, S.P., Singh, P., Pathak, P. (Eds.), Methods and

Management of Data for Watershed Research, Technical Manual No. 5, International Crop Research Institute for the Semi-Arid Tropics, Patancheru, A.P., India, pp. 15-40.

Pathak, P., Miranda, S.M., El-Swaify, S.A., 1985. Improved rainfed farming for semi-arid tropics � Implications for soil and water conservation. In: El-Swaify, S.A., Moldenhauer, W.C., Andrew, L. (Eds.), Soil Erosion and Conservation. Soil Conservation Society of America, pp. 338-354.

Selvaraju, R., Subbian, P., Balasubramanian, A., Lal, R., 1999. Land configuration and soil nutrient management options for sustainable crop production on Alfisols and Vertisols of southern peninsular India. Soil Tillage Res. 52, 203-216.

Singh, H.P., Venkateswarlu, B., Vittal, K.P.R., Ramachandran, K., 2000. Management of rainfed agro-ecosystem. In: Yadav, J.S.P., Singh, G.B. (Eds.), Natural Resource Management for Agricultural Production in India. International Conference on Managing Natural Resources for Sustainable Agricultural Production in the 21st Century, New Delhi, February 14-18, 2000, pp. 669-774.

Singh, P., Algarswamy, G., Pathak. P., Wani, S.P., Hoogenboom., G., Viramani, S.M., 1999. Soybean- chickpea rotation on Vertic Inceptisols I. Effect of soil depth and landform on light interception, water balance and crop yields. Field Crops Res. 63, 211-224.

Srivastava, K.L., Jangwad, L.S., 1988. Water balance and erosion rates of Vertisol watersheds under different management. Indian J. Dryland Agric. Res. Develop. 3, 137-144.

Wani, S.P., Pathak, P., Jangawad, L.S., Eswaran, H., Singh, P., 2003. Improved management of Vertisols in the semi-arid tropics for increased productivity and soil carbon sequestration. Soil Use Manage. 19, 217-222.

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55

Year Rainfall Runoff Soil loss (mm) (mm) (kg ha-1)

BBF FOG BBF FOG

2003 1058.0 163.0 214.9 1956.0 2836.9 (15.4%) (20.3%) 2004 798.2 124.0 183.3 657.0 1466.0 (15.5%) (23.0%) 2005 946.0 177 246 1402.0 3123.0 (18.7%) (26.1%) 2006 1513.0 502 873 3503.0 6365.0 (33.2%) (57.7%)

Values within parentheses indicate the percent of seasonal rainfall

Cropping systems Moisture depletion from 0-90 cm depth (mm)

BBF FOG

Sole soybean 40.8 42.4Soybean/maize intercropping 37.7 35.6Sole maize 33.3 35.0Sole pigeon pea 60.4 57.3Soybean/pigeon pea intercropping 51.2 55.8LSD (P=0.05) 11.3 10.5

Cropping systems Moisture depletion from 0-90 cm depth (mm)

BBF FOG

Sole soybean 62.3 59.3 Soybean/maize intercropping 59.0 56.0 Sole maize 55.6 52.6 Maize/pigeon pea intercropping 70.3 76.6 Soybean/pigeon pea intercropping 74.5 71.5 LSD (P=0.05) 6.2 7.5

Cropping system Soybean equivalent yield (SEY) (kg ha-1)

BBF FOG

2003-04 2004-05 2005-06 2006-07 2003-04 2004-05 2005-06 2006-07

Sole soybean 1831b 641e 1527d 1178d 1581b 543e 1337c 1029e

Sole maize 1212c 2072c 3163c 2590c 1084c 1778c 2726b 2325c

Soybean/maize 1791b 1378d 3244c 2315c 1566b 1194d 2791b 2083dintercropping

Soybean/ pigeon 2615a 2369b 3532b 3134b 2262a 2027b 2912b 2778bpea intercropping

Maize/ pigeon pea 1907b 3385a 4513a 3951a 1646b 2975a 4112a 3659aintercropping*

*There was pigeonpea sole crop in the year 2003-04

Table 2: Depletion of soil moisture during a drying cycle after the withdrawal of monsoon in 2003 as affected by land surface management treatment and cropping system

Table 1: Seasonal rainfall, runoff, and soil loss from different land configuration, broad-bed and furrow (BBF) and flat on grade (FOG)

Table 3: Depletion of soil moisture during a 28 days drying cycle after the withdrawal of monsoon in 2004 as affected by cropping system under BBF and FOG land treatment

Table 4: Soybean equivalent yield (SEY) of rainy season crops

56

Table 5: Yield of chickpea as influenced by irrigation and previous crops

Cropping system Grain yield of chickpea (kg/ha)

BBF FOG

2003-04 2004-05 2005-06 2006-07 2003-04 2004-05 2005-06 2006-07

Irrigation

I1 1893b 1297b 795b 1087b 1259b 1202b 715b 936b

I2 2116a 1557a 1203a 1500a 1588a 1397a 980a 1423a

Cropping systems

Soybean-chickpea 2040a 1468a 1076a 1326a 1340a 1349a 920a 1181a

Maize-chickpea 2062a 1385a 969a 1254a 1453a 1258a 797a 1162a

Soybean/maize -chickpea 1913a 1429a 952a 1301a 1478a 1292a 824a 1195a

Table 6: WUE of chickpea as influenced by irrigation and previous crops

Cropping system WUE (kg ha-1 mm-1)

BBF FOG

2003-04 2004-05 2005-06 2006-07 2003-04 2004-05 2005-06 2006-07

Irrigation

I1 12.38a 9.13a 5.05b 6.75b 8.72a 8.97a 4.74a 6.46b

I2 10.37b 8.00b 6.06a 7.66a 8.58a 7.65b 4.83a 7.81a

Cropping systems

Soybean-chickpea 11.56a 8.64a 5.73a 7.32a 8.18a 8.44a 5.13a 7.15a

Maize-chickpea 11.63a 8.40a 5.41a 7.06a 8.88a 8.08a 4.52a 7.20a

Soy/maize 10.92a 8.66a 5.53a 7.24a 8.87a 8.40a 4.71a 7.06aintercropping-chickpea

Table 7: Total system productivity as soybean equivalent yield (SEY)

Cropping system Total system productivity as SEY (kg ha-1)

BBF FOG

2003-04 2004-05 2005-06 2006-07 2003-04 2004-05 2005-06 2006-07

Irrigation to chickpea

I1 2818b 2747b 3857b 3551b 2257b 2425b 3370b 3165b

I2 2929a 2903a 4196a 3900a 2422a 2542a 3591a 3576a

Cropping systems

Soybean-chickpea 3530a 2109d 3019c 3044c 2698a 1894c 2613c 2691c

Maize-chickpea 2931b 3457a 4507a 4354a 2295b 3036a 3832a 3959a

Soybean/maize -chickpea 3385a 2807b 4564a 4145ab 2798a 2485b 3933a 3765b

Soybean/pigeonpea 2615c 2369c 3532b 3134c 2262b 2027c 2912b 2778c

Maize/pigeonpea* 1907d 3385a 4513a 3951b 1646c 2975a 4112a 3659b

*There was sole crop of pigeonpea in the year 2003-04

57

Implements for Water Harvesting and Insitu Moisture

Conservation

D.Manohar Jesudas and K.Kathirvel

6

IntroductionLand is a major important non-renewable natural resource. The availability of land area per person in Tamil Nadu is only about 60 per cent of the national average. Tamil NaduÊs population is about 7 per cent of the countryÊs population but the net sown area in Tamil Nadu is only 4 per cent of that for the country. The density of population in Tamil Nadu is 572 as against the national average of 221 per sq.km. All these are pointers to indicate that the land resources should be utilized to the optimum extent possible. Since the available land area is limited and finite, the necessity to improve the productivity of the land and to increase the income of the farmer have become important. While considerable importance has been given to increase the productivity of the irrigated lands under green revolution, adequate attention has not been given to increase the productivity of the rainfed areas.In Tamil Nadu the rainfed / dryland is about 3.2 - 3.5 mHa. i.e. about 60 per cent of the sown area. The rainfed agriculture water / moisture is the limiting factor. Rainfall is the only source of water for these lands and hence it is

necessary to maximize its retention. Further the following are the problems in these lands.Inadequate soil moisture is the chief constraint in drylands, where the annual rainfall is 500 mm to700 mm. It is not evenly distributed and highly variable and erratic.The soils are light / medium textured. Their water holding capacity are low. The lands are often rolling topography. Rainwater runs off quickly, carrying during among soil and fertilizers.Subsoil hard pan is formed due to continuous cultivation of crops using implements upto certain depths constantly and due to the precipitation of clay in the subsoil horizon. All put together lowered the infiltration and percolation rates, nutrients, movement and free air transport within the soil profile. It prevents the root proliferation and limits the volume of soil available for nutrients uptake resulting in depleted less fertile surface soil. Due to this, the contribution of subsoil fertility to crop growth is hampered.

58

The first step in land-use planning is to provide for the maximum retention of water / rain that falls on the land. This means as much percolation of rainfall as possible in soil where it falls, controlled removal of excess rainfall and protection of the soil. It is to be emphasized that conservation and optimization of the use of rain water so that it stays in the soil profile for long periods and is released slowly for the use of crops, become important steps for improved dryland farming. Such utilization of rainfall is accomplished through the correct cultural practices and certain engineering structures.Moisture conservation techniques at micro-level. a. vegetative barriers, b. forming ridges and furrows, c. broad bed and furrows, d. forming basins, e. the ridging / random tie ridges, f. forming ponds and. water spreading are advocated. Due to the labour scarcity and cost of labour, these practices are not being adopted and hence development and use of implements becomes necessary. In addition, the subsoil hard pan is to be removed. To over come these problems and to conserve soil moisture the following implements were developed and evaluation trials were conducted in problem soils and in different parts of dry farming areasThe first step in land-use planning is to provide for the maximum retention of water / rain that falls on the land. This means as much percolation of rainfall as possible in soil where it falls, controlled removal of excess rainfall and protection of the soil. It is to be emphasized that conservation and optimization of the use of rain water so that it stays in the soil profile for long periods and is released slowly for the use of crops, become important steps for improved dryland farming. Such utilization of rainfall is accomplished through the correct cultural practices and certain engineering structures.The Department of Agriculture is recommending the following land shaping techniques for moisture conservation at micro-level. a. forming ridges and furrows, b. broad bed and furrows, c. forming basins, d. the ridging / random tie ridges, e. forming ponds and f. water spreading. But due to the labour scarcity and cost of labour, development and use of implements becomes necessary. In addition, the subsoil hard pan is to be removed. To over come these problems and to conserve soil moisture the following implements were developed at TNAU for using them in dry farming areas.WATER HARVESTING IMPLEMENTS1. Chisel PloughDeep tillage using chisel plough is essential for improving the yield of crop especially under dry farming. Deep tillage shatters compacted sub soil layers and aids in

better infiltration and storage of rainwater in the crop root zone. The improved soil structure also results in better development of root system and the yield of crops and their drought tolerance is also improved. Deep tillage is not practiced in India due to the unsuitability of the existing deep tillage tools for operation with 35-45 hp tractors.The developed implement has a sturdy but light structure made of 3 mm thick hollow rectangular tubular mild steel sections. The frame has been designed based on computer analysis of the structure to ensure its strength. The implement is simple in construction and has only three components viz. frame, standard and share. The share has a lift angle of 20 degree, width of 25 mm and a length of 150 mm. The implement is protected by a shear pin which prevents damage from over loading.Salient Features of The UnitThe implement could be used for deep tillage upto a depth of 40 cm for bursting of the sub-soil hard pan, improving the drainage and aerating the soil.Reduces the bulk density of soil (0.20 to 0.4 Mg / m3)Two fold increase in hydraulic conductivity of sub-soilConserves around 30 to 40% more soil moistureRoots proliferation is improved by 40 to 45%Nutrient mobility especially N and K increased by 20 to 30% and 30 to 40% respectivelyEnhances the crop yield by 15 to 20%Residual effect can be realized for three seasonsEasily operated by any 35 to 45 hp tractor2. Influence of Deep Til lage on In-situ Moisture Conservation in Dry FarmingThe subsoil hard pan is formed due to the illuviation of clay to the sub soil horizon in red soil, due to the higher exchangeable sodium content of clay complex in black soil, and due to continuous cultivation of crops using heavy implements into certain depth constantly. All put together lowered the infiltration and percolation rates, nutrients movement and free air transport within the soil profile which effects crop growth and yield. An attempt was made to over come this problem by conducting experiments with different tillage implement combinations at different places. The result showed that there was significant differences between the treatments in plant height, leaf area , root length and yield. Chisel plough plus coirpith application showed its superiority over the other treatments. The in-situ moisture conservation was more in the chisel plough plus coirpith treatment. There was 50 per cent increase in the permeability of the soil due to the vertical storage of moisture. The moisture pattern in the case of Chisel plough + Disc Plough + Cultivator showed drastic improvement in soil moisture storage. The

59

root length in this treatment reached a maximum depth of 25 cm. In Chisel plough + Disc plough + Cultivator, 50 per cent yield increase was obtained, leaf area index increased by 44 per cent and root length increased by 13 per cent. Chisel plough played an important role in root growth and hence increased yield.3. Basin Lister as an Attachment to Power TillerGenerally, yield levels are determined by the amount of precipitation above the basic minimum required to enable the crops to achieve maturity. It is therefore, important in dry land farming to have even a relatively small amount of water stored in soils prior to sowing of crops. Listing is the process of formation of alternate furrows and ridges on land to conserve soil and moisture. Hence a basin lister has been developed for use of power tillers in dry farming.The principle of operation of the equipment is that the basin listing is done by lifting the ridger through a cam and follower arrangement. The cam is mounted to the wheel axle and oscillates the ÂUÊ shaped follower frame hinged at the front of the power tiller chassis on both sides. The ridger tyne is pivoted near the hitch pin of the power tiller and provided with a slider in the transverse direction. The cylindrical slider accommodates itself inside the corresponding slot on each side of the follower frame. When the follower is lifted, the ridger tyne is also lifted along with it by allowing the slider to move longitudinally in the slot. A dead weight box is also attached to the cam follower frame and additional dead weights are added for perfect balancing and uniform penetration. A spiked wheel with castor action provided with support arms from the power tiller handle ensures uniform basin formation by controlling the depth of operation and also removes the drudgery of the operator. The unit is rear mounted and fitted to the hitch bracket assembly of the power tiller. The draft requirement is 75 kg which is within drawbar capacity of the power tiller. Salient Features By basin listing, increased moisture retention of 10 per cent is achieved Significant increase in yield of 10 per cent is observed in both main and inter crop The basins formed prior to the sowing of crop in dry farming at regular intervals conserve adequate soil moisture for the utilization of crop at its critical stages Net benefit by way of increased yield due to power tiller basin listingAn area of 0.6 ha can be covered per dayThe cost of the unit is Rs. 5000.

4. Basinlister / Broadbed Former Cum Seeder Attachment to CultivatorThe basin lister consists of three trenchers of width 30 cm, cams, cam shaft, cam follower, ground wheels and frame. The penetrating portion of the trencher bottoms are provided with a replaceable share point. Each trencher fitted with a cam follower gets lifted up by the cams at equal intervals. The cams are mounted on a common axle at 120 degree difference and supported by ground wheels. The power to rotate the cam is transmitted from one of the ground wheels. To reduce wheel slippage, spring tension has been provided. The basin lister unit is attached to the standard nine tyned cultivator. The seed box along with cup feed type seed metering mechanism is mounted on the cultivator frame and the seeds are dropped in between the basins. Seeds are sown in 4 rows at 45 cm apart. Power to operate the seed metering discs is taken from the ground wheel through a clutch. The seed to seed distance can be changed by changing the sprockets provided in the metering shaft. The operator can stop the dropping of the seeds by disengaging the clutch provided. The same implement can be used to form broad beds separated by furrows by removing he basin lister attachment from the cultivator. The unit consists of two sheet metal floats fixed on both sides of the cultivator tynes to form the broad beds separated by furrows at intervals of 180 cm.Salient Features The basins/ broad beds and furrows formed prior to the sowing of crop in dry farming at regular intervals conserve adequate soil moisture for the utilization of crop at its critical stages Increased moisture retention of 10 per cent is achieved Significant increase in yield is observed in both main and inter crop An area of 3.5 ha can be covered per dayThe cost of the unit is Rs. 15000 (without cultivator).5. Tractor Drawn Channel FormerIn drylands irrigation channel former can be used for forming compartmental bunding at regular intervals for conserving rain water. This is done by human labour which consumes more time and cost. To over come this problem a tractor drawn channel former to form irrigation channels was developed. The main frame of size 22 cm x 65 cm is made of 5.0 cm x 2.5 cm M.S. channels. The channel forming portion consists of two inner blades of size 100 cm x 25 cm and two outer blades of size 130 cm x 25 cm. The front portion of the two inner blades are joint together such that they forms an angle of 30� in

60

between them. At the junction of these two inner blades a cultivator shovel is fixed to penetrate into the soil. The inner blades can be mounted 5 to 10 cm lower than the outer blades so that they forms a furrow at a lower depth than the surface of the bed for the flow of irrigation water. The two outer blades are placed one on each side of the inner blades and at an angle of 60� to the direction of the travel. The soil collected in 105 cm width is formed as bund of size 35 cm on both the sides of the irrigation furrow formed by the inner blades. The unit was evaluated for its performance in forming irrigation channels at 5 m intervals. When the tractor is operated at 3 to 4 km forward speed, the area covered varies from 1.2 ha to 1.5 ha/hr. The field efficiency varies from 70% to 80% depending on the condition of the soil and field size. Salient Features of The UnitCost of the Unit : Rs.6,000/Coverage : 9.0 ha/day of 8 hrsCost of forming irrigation channel at 5 m interval by (i) channel former : Rs.150/ha(ii) manual labour : Rs.350/haSaving in cost : Rs.200/haSaving in time : 11 man days/ha.The necessity to improve the productivity of the land and to increase the income of the farmer have become important since the available land area is limited and finite. While considerable importance has been given to increase the productivity of the irrigated lands under green revolution, adequate attention has not been given to increase the productivity of the rainfed areas. The development of in -situ moisture conservation implements will help in a long way in increasing the productivity in rainfed agriculture.6. Coir Pith ApplicatorDeep loosening of soil and placement of coir pith in the subsoil layers improves the root zone, which will not re compact during subsequent years. The unique property of coir pith to hold 7 to 8 times its weight of moisture helps to improve upon the moisture status of the root zone. The coir pith also acts as an amendment, which helps to build up a biologically active root zone comprising the subsurface layers. Hence, a coir pith mulching applicator was developed as an attachment to the tractor drawn chisel plough to place the coir pith at a depth of 15-25 cm below the ground level which ensures that the coir pith filled trenches are not disturbed by subsequent ploughing thereby preventing the dispersion and disintegration of coir pith. The cost of the unit is Rs.9,000. The salient features of the unit are: uniformity of application is 90%; higher moisture storage (41%) is observed in subsoil-

mulched plots as compared to the control; and yield of crop grown under subsoil-mulched plots are significantly higher.LAND LEVELLING IMPLEMENTS1. Terracer Cum LevellerLand levelling is expected to bring permanent improvement in the value of land. Levelling work is carried out to modify the existing contours of land so as to achieve certain objectives desired for efficient agricultural production system. These objectives include (i) efficient application of irrigation water, (ii) improved surface drainage, (iii) minimum soil erosion (iv) increased conservation of rain water specially on dry lands and (v) provision of an adequate field size and even topography for efficient mechanization. The unit consists of 1.0 m wide curved mild steel blade with a steel cutting edge at the bottom. The unit is attached to the front of the power tiller with the help of a mounting plate. Two solid side support arms made of 25 x 12.5 mm mild steel flat holds the unit rigidly during the operation. The position of the blade with reference to the power tiller chassis can be varied by adjusting the screw provided between the mounting plate and the centre of the leveller. The lifting of the blade can be made by tail wheel adjustment of the rotary tiller while keeping the tilt angle constant. Two side guards are provided to avoid spilling of soil on both sides of the blade. Bottom skids made of 2 mm mild steel sheet are provided below the blade for maintaining uniform load. The width of the blade is 1000 mm with a height of 320 mm. The leveller unit was field evaluated for contour bunding and land levelling works and the salient features of the unit include Simple in design and construction Ease of operation and transport Increases the versatility of power tiller Efficient performance in land levelling with transportation efficiency of 86.6% and field performance index of 0.87. Cost of the unit is Rs.3,000/-. Cost of moving 1 m3 of soil to 1 m distance is Rs.3.30.2. Tractor Drawn Blade TerracerBlade terracer is an implement used for operations like earth levelling, bunding, filling pits, making wide drain and roads, back filling, etc. For application of scientific water management technique, levelling is being increasingly adopted along with the accelerated growth of farm mechanization. Blade terracer is commonly used for this urpose. The unit consists of a frame, blade, mould board, mould board frame, blade tilt, scarifier, side plates,

61

stabilizer kit and a pitch adjusting screw. Size of the terracer may be between 1.5 to 3.5 m, determined by the length of the blade and the length of extension blade.3. Dozer BladeCommercially available tractor front mounted dozer blades and bulldozer with front mounted blades are used for heavy earth moving purposes.ConclusionThe present situation of migration of labour to various scholastic jobs and thrust for more production to feed the increasing population makes dryland cultivation a

tiresome one. This situation necessitates the introduction of a suitable machines for dryland farming. In the dynamic and fast changing agricultural scenario of the country, particularly diversification in the cropping pattern and commercialization of agriculture more efficient and simple implement / equipment are required by the farmers. The potential of dry farming lands can be increased in the near future by adopting a suitable package of practices aimed at optimizing utilization of available moisture through improved soil and water management by utilizing the improved designs of moisture conservation implements.

ReferencesAnonymous. 1987. Annual Report. All India Coordinated Research Project on Farm Implements and Machinery, Coimbatore Centre, Tamil Nadu Agricultural University.Anonymous. 1988. Annual Report of All India Coordinated Research Project on Farm Implements and Machinery, Coimbatore Cen tre, Tamil Nadu Agricultural University.Channappa, T.C. 1994. In-situ moisture conservation in arid and semi arid tropics. Indian Journal of Soil Conservation, 22(1-2) : 26 - 41.Durairaj, C.D., K.Kathirvel, R.Karunanithi and K.R.Swaminathan. 1992. Development of a basin lister actuated by tractorÊs hydraulic system.

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62

Effect of in-situ moisture conservation practices on runoff, soil loss and yield performance

of Cashew (Anacardium occidentale) in Goa

S. Manivannan

7

IntroductionThe State of Goa covers an area of 3702 sq.

km and accounts for about one per cent of the total geographical area of the country. The slope gradients range from 5 to 20 percent and occasionally go up to 40 per cent. Majority of the soil series are coarse to medium textured and well - drained with poor water holding capacity. Plantation crops like cashew, mango, arecanut, coconut etc. are predominantly occupying the steep slopes of lower coastal ghats and central undulat-ing uplands of Goa. Many of the hilly areas in Goa are practically denuded and are still being denuded. With the result of erosion a large quantity of the fertile soil is transported from the fields. Most of the hilly areas in Goa are under perennial horticultural crops with cashew as predominant crop, which is occupying an area of 54,858 ha (Anonymous, 2005). India is the second larg-est producer of raw cashew in the world but conquers the 1st place among the largest producing countries of cashew kernels and also in the maximum area covered that figures to be 7.70 lakh hectares currently. The coun-try provides with around 55 % supply of cashew kernels

in the world. The Indian production of cashews contrib-utes to around 4.6 lakhs tons per annum. The present level of productivity in Goa is only about 466 kg ha -1, which is very less as compared to national average (810 kg ha-1). Experience shows that the major factors for low productivity are loss of fertile soil due to erosion and inadequate moisture in root zones of trees due to excess runoff. Several workers have reported runoff, soil and nutrient losses under different agro-ecological situations in India (Rai and Singh, 1986; Kale et al. 1993). Run-off and soil losses increased with increase in land slope and varied with agronomic cover crops in North Konkan region (Kale, et al. 1993). Badhe and Magar (2004) re-ported that trapezoidal shaped staggered trenches were more effective in reducing surface runoff, soil and nutri-ent losses under hilly terrain in lateritic soils of Konkan region of Maharashtra. On gentle slopes, vegetative bar-riers in different forms can sufficiently reduce runoff and soil loss (Bhardwaj, 1994). Similarly, the surface run-off and soil loss was reduced by vegetative barriers in sloppy land (Subudhi and Senapati, 1996; Subudhi et al.,1998). However, studies on combination of mechani-cal measures with vegetative barriers for reducing soil

63

and water losses in cashew plantations are very limited. Hence, an attempt was made to evaluate the effect of different in-situ moisture conservation measures on run-off, soil loss reduction and impact on yield performance of cashew trees.

Materials and MethodsA time replicated trial was conducted at Research

Farm of ICAR Research Complex for Goa, representing the undulating uplands and lateritic soils of Goa State for a period of six years (2001-02 to 2006-07). The area has a warm tropical climate with an average annual temperature of 26.4ÀC and soil temperature regime is isohyperthermic. The Southwest monsoon yields a total annual precipitation of about 2892 mm from June to October from an average of 122 rainfall events. The soil of the experimental site was acidic (pH -5.4 to 5.7) hav-ing organic carbon content of 1.1 per cent, available N - 86 to 96 kg ha-1, P < 10 kg ha-1 and K 172 to 254 10 kg ha-1 . The mean slope of the experimental site was 14 % and gravel content of the soil varied from 48 to 58 %. The experimental area was divided into runoff plots (75 X 22 m) and the following treatments were imposed.

T1 - Continuous Contour Trenching (CCT) +

Vegetative Barrier [Stylosanthus scabra + Glyricidia maculata]

T2 - Staggered Contour Trenching (SCT) + Veg-

etative Barrier [Stylosanthus scabra + Glyricidia maculata]

T3 - Crescent Shaped Trenches (CST) +Vegeta-

tive Barrier [Stylosanthus scabra + Glyricidia macu-lata]

T4 - Stylosanthus scabra + Glyricidia macu-

lata alone as vegetative barrier

T5 � Control (without any conservation mea-

sures)

Cashew (Goa – 1) was planted at 6 m X 6 m spacing as a main crop during the year 2001. The runoff in each treatment was regularly measured for a period of five years (From 2002 to 2006) by a series of multi-slot devisors. The total runoff collected per day in all the runoff tanks in each experimental plot was thoroughly mixed and a one-liter runoff sample was taken for analy-sis and estimation of soil loss and nutrient loss. Soil and water conservation efficiency of different conservation measures was worked out by comparing the runoff and soil loss of treated and untreated plots. Yield of cashew

was recorded for three years period from 2005 to 2007. Economic viability of different conservation measures was also analyzed.

RESULTS AND DISCUSSIONRunoff

The mean runoff of six years revealed that mini-mum runoff of 320.6 mm was produced in plots with continuous contour trenches and vegetative barrier of S. scabra and G. maculata followed by 391.2 mm in staggered contour trenches with S. scabra and G.maculata and 426.1 mm in crescent shape trenches with S. scabra and G. maculata and 523.4 mm in S. scabra and G. maculata against the mean runoff of 595.3 mm produced in the control plot. Similar trends were reported (Badhe and Magar, 2004) while com-paring the effect of various mechanical measures viz.,ring terracing, platform terracing and staggered contour trenching under cashew plantations. Runoff per cent un-der continuous contour trenches with vegetative barrier of S. scabra + G. maculata reduced to 10.9 per cent of total rainfall from 20.3 per cent under control thus showing reduction of 46.3 per cent. Similarly, staggered contour trenches with S. scabra and G. maculata and crescent shape trenches with S. scabra and G. maculata showed a reduction of runoff by 35 and 29.0 per cent, respectively (Table 1). This reduction in runoff under different bioengineering measures was attributable to their effect, which reduces runoff velocity and increas-es infiltration opportunity time for water.

Soil and Nutrient LossesThe annual soil loss was monitored for five years

period (2002-2006) and furnished in Table 2. More soil loss was recorded in all the treatments during the year 2002 and reduced in subsequent years. This may be due to the disturbance of topsoil by planting operations in initial year. As the soil stabilized in subsequent years, the soil losses were reduced. Overall, conservation prac-tices reduced the soil loss by 3.1 to 6.5 t ha�1 per year. Continuous contour trenches with vegetative barrier of S. scabra + G. maculata showed significant reduction in average soil loss (1.8 t ha�1) followed by staggered con-tour trenches with S. scabra and G. maculate (2.7 t ha�1) and crescent shape trenches + S. scabra and G.maculata (2.9 t ha�1) as compared to the control plot, while a soil loss of 8.3 t ha�1 was recorded under the control plot.

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Data on nutrient losses revealed that all the con-servation measures reduced nutrient losses as compared to control plot. The mean values indicate that minimum nitrogen loss was 11.7 kg ha -1 in the treatment of con-tinuous contour trenches with vegetative barrier of S. scabra + G. maculata followed by 15.8 kg ha-1 in the plot with staggered contour trenches and S. scabra + G. maculata while the maximum nitrogen loss (29.1 kg ha -1) was recorded in control plot. Similarly, potassium losses were minimum (17.9 kg ha-1) in the treatment of continuous contour trenches with S. scabra + G. maculata followed by 21.7 kg ha-1 in the treatment of staggered contour trenches with S. scabra + G. macu-lata as against the maximum potassium loss of 42.2 kg ha -1 recorded in control plot. Phosphorus loss varied from 0.1 to 0.2 kg ha-1 in all the treatments, which may be due to low availability of phosphorus in the experi-mental site as well as the nature of phosphorus which does not move in runoff as fast as other nutrients. The soil and nutrient loss data shows that the continuous contour trenches with vegetative barrier of S. scabra + G. maculata was the best conservation practice to reduce the soil and nutrient loss among all the conserva-tion treatments.

Soil, Water and Soil & Water Conservation Efficiencies

Soil conservation efficiency, water conservation efficiency and soil and water conservation efficiency were worked out during each year and the values are given in Table 3. The mean values of water conserva-tion efficiency of continuous contour trenches with S. scabra + G. maculata, staggered contour trenches with S. scabra + G. maculata and crescent shape trenches with S. scabra + G. maculata were 46.2, 35.2 and 29.4 percent, respectively. Maximum mean SCE of continuous contour trenches with S. scabra + G. maculata, was 79.6 per cent. By and large the high-est soil and water conservation efficiency was observed in continuous contour trenches with S. scabra + G. maculata (62.9 per cent).

Yield Performance of Cashew

The cashew plants commended yielding from fourth year of plantation. Cashew yield was recorded from fourth to sixth years of plantation (2004-05, 2005-06 and 2006-07). Average nut yield per tree and total yield per hectare area were recorded and the effect of conservation measures on these parameters was ana-lyzed. Cashew nut yield per tree and the total yield per

hectare obtained during the three years period under all the conservation measures are furnished in Table 4. All the in- situ moisture conservation measures significantly increased the nut yield per tree as well as total yield when compared to control plot. The data were statistically ana-lyzed and the treatments were found significant.

Maximum cashew nut yield of 6.80, 3.50 and 5.20 q ha-1 were recorded in treatment comprising of continuous contour trenches with S. scabra + G. mac-ulata during fourth, fifth and sixth years, respectively. This was followed by 5.60 q ha-1 (fourth year), 2.80 q ha-1 (fifth year) and 3.90 q ha-1 (sixth year) in SCT with S. scabra + G. maculata treatment. The increased cashew nut yield of 3.2, 1.9, and 1.2 q ha-1, respec-tively were recorded during sixth year in the treatments of CCT, SCT and CST with vegetative barriers. Live bar-rier of S. scabra + G. maculata alone could increase the yield of 0.5 q ha-1 during sixth year. The lowest ca-shew nut yields of 3.0, 1.6 and 2.0 q ha-1 during fouth, fifth and sixth years, respectively was observed in control plot where no conservation measure was adapted. This showed that the soil and water conservation measures helped to reduce surface runoff, soil and nutrient losses and increased the yield of crop under lateritic hilly ter-rain of the region.

Economic Feasibility of Conservation Mea-sures

Net present worth (NPW), Benefit-cost ratio (BCR) and Internal rate of return (IRR) were also worked out by accounting for the cost and benefits for a period of 10 years and are given in Table 5. Maximum NPW of Rs. 1, 64, 900 / ha was obtained under cashew cultiva-tion with continuous contour trenches with S. scabra + G. maculata followed by Rs. 1,27,190 / ha under cashew cultivation with staggered contour trenches S. scabra + G. maculata. The lowest NPW (Rs. 43,410 / ha) was obtained from the cashew field cultivated without adapting any soil and water conservation mea-sure. BCR was maximum (5.07) in continuous contour trenches with S. scabra + G. maculata followed by the treatment comprising of staggered contour trenches with S. scabra + G. maculata (4.64) and crescent shape trenches with S. scabra + G. maculata (4.46). Similarly, maximum IRR of 13 per cent was obtained in the treatment of continuous contour trenches followed by 12.5 per cent of IRR in the treatments comprising of staggered contour trenches with S. scabra + G. macu-late. The least BCR (2.79) and IRR (10 per cent) were

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obtained from the cashew field cultivated without soil and water conservation measure.

ConclusionsResults revealed that in-situ moisture conserva-

tion measures with vegetative barriers are effective in reducing the runoff, soil water and nutrient losses in new cashew plantations. Continuous contour trenches with vegetative barrier of S. scabra + G. maculata reduced runoff by 46 % over all the practices. This treatment led to the retention of 6500 kg of soil and 12 kg of N, 0.2 kg of P and 18 kg of K per ha. This practice would result

in commencing enough soil moisture that would con-tinue to be available to plants for a period of 6 months after the cessation of the monsoon and increase the cashew yield to 2.5 times than conventional practices. BCR and IRR were higher under the continuous contour trenches with S. scabra and G. maculata (5.07 and 13 per cent, respectively). Hence, the continuous contour trenche with vegetative barriers was the best in-situ moisture conservation measures as compared to all other conservation measures for runoff and soil loss reduction and increase in cashew yield.

ReferencesAnonymous. 2005. Estimation of area average yield and production of various crops in Goa State for the year 2004-

05. Directorate of Agriculture, Government of Goa, Panaji. Badhe, V.T. and Magar, S.S. 2004. Influence of different conservation measures on runoff, soil and nutrient loss

under cashewnut in lateritic soils of South Konkan region. Indian J. Soil. Cons., 32(2): 143-147.Bhardwaj, S.P. 1994. Vegetative barriers as an effective economic and eco-friendly measure of erosion control on

agricultural lands. In: 8th ISCO Challenges and Opportunities, New Delhi, India: Pp. 204-205.Kale, S. R, Salvi, V. G, Varade, P.A. and Kadrekar, S. B., 1993. Effect of different per cent slopes and crops on

runoff, soil and organic Carbon loss in latteritic soil of West Cost Konkan - Maharashtra, Annual Convention, Indian Society of Soil Science, Dehradun.

Prasad, S.N., R.K. Singh, Shakir Ali and A.K. Parandiyal. 2005. Comparative performance of grass barriers on erosion and crop yields in medium black soils of Kota. Indian Journal of Soil Conservation, 33 (1): 58-61.

Rai, R.N. and Singh, A. 1986. Effect of hill slopes on runoff, soil loss and nutrient loss and rice yield. Indian J. Soil Cons., 14 (2): 1-6.

Subudhi, C.R. and P.C. Senapati. 1996. Runoff and soil loss under different vegetative measures in Kalahandi district of Orissa. Indian Journal of Soil Conservation, 24 (2):82-83.

Subudhi, C.R., P.C.Pradhan and P.C. Senapati. 1998. Effect of vegetative barrier on soil erosion and yield of rice in Eastern Ghats. Indian Journal of Soil Conservation, 26 (2): 95-98.

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Table 1: Percentage of runoff to rainfall under different conservation measures

Year Runoff (mm)

CCT + VB SCT + VB CST + VB VB alone Control

2002 8.3 9.5 9.2 11.9 16.3

2003 12.8 15.4 17.4 21.4 23.2

2004 9.1 10.3 12.2 14.6 16.1

2005 13.0 16.4 17.2 21.3 24.0

2006 11.4 14.6 15.9 19.4 21.7

Mean 10.9 13.2 14.4 17.7 20.3

Table 2: Annual soil loss as influenced by different bio-engineering measures

Year Soil loss (t ha-1 yr -1)

CCT + VB SCT + VB CST + VB VB alone Control

2002 3.1 4.3 4.3 8.5 12.9

2003 2.3 3.4 3.8 6.9 10.4

2004 1.5 2.7 3 4.2 7.9

2005 1.1 1.7 1.8 3.4 5.3

2006 0.8 1.5 1.6 3 4.9

Mean 1.8 2.7 2.9 5.2 8.3

Table 3: Water, soil and soil and water conservation efficiencies of different conservation measures

Year Treatment

CCT + VB SCT + VB CST + VB VB alone

Water conservation efficiency (per cent)

2002 49.3 41.9 43.3 27.0 2003 45.0 33.6 25.1 7.7 2004 43.5 36.2 24.0 9.5 2005 46.0 31.6 28.2 11.3 2006 47.3 32.9 26.6 10.9 Mean 46.2 35.2 29.4 13.3

Soil and water conservation efficiency (per cent)

2002 76.0 66.7 66.7 51.8 2003 77.9 67.3 63.5 33.7 2004 81.0 65.8 62.0 46.8 2005 79.2 67.9 66.0 35.8 2006 83.7 69.4 67.3 38.8 Mean 79.6 67.4 65.1 41.4

Soil and water conservation efficiency (per cent)

2002 62.6 54.3 55.0 39.4 2003 61.4 50.5 44.3 20.7 2004 62.2 51.0 43.0 28.2 2005 62.6 49.8 47.1 23.6 2006 65.5 51.1 47.0 24.8 Mean 62.9 51.3 47.3 27.3

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Table 4: Cashew yield under different conservation measures during the fourth, fifth and sixth year of plantation

Nut yield per tree (kg) Total yield (q ha-1)

Treatment 2004-05 2005-06 2006-07 2004-05 2005-06 2006-07 (IV th year) (Vth year) (VIth year) (IVth year) (Vth year) (VIth year)

CCT + VB 2.5 1.2 1.9 6.8 3.5 5.2 SCT + VB 2.0 1.0 1.4 5.6 2.8 3.9 CST + VB 1.8 0.9 1.2 4.9 2.4 3.2 VB alone 1.3 0.7 0.9 3.5 2.0 2.5 Control 1.1 0.6 0.7 3.0 1.6 2.0 CV 15.6 17.1 15.9 15.2 16.4 15.0 CD p (0.05) 0.51 0.28 0.37 1.36 0.76 0.96

Table 5: Net present worth, benefit cost ratio and internal rate of return of different conservation measures adopted for cashew crop

Conservation measures NPW BCR IRR (%) (Rs. / ha.)

Continuous Contour Trench + S. scabra + G. maculata 1,64,900 5.07 13.0Staggered Contour Trench + S. scabra + G. maculata 1,27,190 4.64 12.5Crescent Shape Trench + S. scabra + G. maculata 1,09,130 4.46 11.0S. scabra + G. maculata alone 69,090 3.74 10.0Without conservation measures 43,410 2.79 10.0

Theme – 2Water Harvesting at Micro-Watershed

Level-Continuation

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Drought Mitigation through Floodwater Harvesting for the Artificial Recharge of

Groundwater: Prudence vs Large Dams

Sayyed Ahang Kowsar

8

IntroductionIran was the land of floods, droughts and qanats

until 1945, when the inappropriate technologies, cable tool and powerful pumps invaded our groundwater resources. The arrival of rotary drilling machines in the late Ê60s blew coup de grãce to our aquifers (Kowsar, 1991; Mohammadnia and Kowsar, 2003). Not only the lowering of the watertable beneath the qanat galleries made more than 20,000 of them nonfunctional, but also caused saline water intrusion into freshwater aquifers and land subsidence in many plains a common place phenomenon. Kassas (1987) is of the opinion that the falling watertable in arid areas, where most water needs are supplied through underground resources, is a variation of drought. Therefore, we are doubly trapped in the agricultural and hydrological droughts of our own making, and the climatic drought that Nature has forced upon us. Judging our precipitation history from the studies of Vita-Finzi (1979) on the alluvium deposition in the Tehran area, we have over-exploited in less than 60 years most of the groundwater that Nature had bestowed upon us between 38,000 to 6,000 years before present

(BP)! Thus, depleting the very last resort, we have to face a precarious water shortage in the most severe drought in a living memory.

It is inconceivable that our compatriots, especially the policy-makers, are unaware of our climatological history. About 90% of our country is semi-arid, arid and hyper arid. Recurrent and prolonged droughts in such environments are a rule rather than an exception. These periods are usually interrupted by flood-producing downpours that devastate the drought-stricken people, particularly nomad herders who inhabit the low-laying area surrounding water holes. With all these risks, the desert-dwellers have adapted themselves to the vagaries of the climate following the Genesis Strategy. The following historical account is the wake up call for the rulers of drought-prone countries.

The gradual warming of the climate, which attained its optimum range about 8,000 years ago, and perhaps abundant precipitation, brought about the prerequisites for the formation of human societies. Matthews (1976) postulated that high precipitation from 8,000 to 5,000 years ago blessed the present

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African Sahara and the Arabian desert, and provided the groundwork for the evolution of great civilizations in the „Fertile Crescent‰, which extended from Palestine to the Persian Gulf (northern parts of present-day Saudi Arabia). Then, an 800-year drought (5,000-4,200 BP) transformed all this area into a desert, and forced the Semites to migrate to the Levant (present-day Syria). This droughty period affected the Sind Valley and obliterated the Harapan Civilization. This vast area, which was once covered with forests, is now so dry that rainfed farming is impossible over most of it; only a name remains from an outstanding civilization that peaked 5,300 year ago (Linton, 1955). Frequent droughty periods, which occurred from 2500 to 1600 BP, destroyed the North African agriculture and forests of Lebanon and Galilee (Matthews, 1976). Prolonged droughts cause famine, mass starvation, immigration, and finally, termination of the affected civilizations.

Although the most obvious cause of famine is prolonged droughts, other natural phenomena and human-mediated disasters should not be forgotten. Freezing weather, floods, earthquakes, volcanic eruptions, outbreaks of plant and animal pests and diseases, epidemics, wars, and wrongful policies of governments and colonialists are also instrumental in the occurrence of famine. Keeping these exceptions in mind, the records of famine may be used to reconstruct previous droughts.

The first authentic written record is based on the „Stele of famine‰ from 5,500 BP discovered on a tomb in the Nile that describes the lack of Nile flood for 7 years and the vast misfortune caused by the drought (Anon., 1973, p.58-59). The 7 good and 7 lean years during the time of Prophet Joseph, which probably occurred around 1675 BC, have been mentioned in the Bible and the Glorious Koran (the Chapter of Joseph, verses 43-49). Failure of Nile flood for 7 years (1064-1072) resulted in cannibalism in Egypt (Anon., 1973: 58; Anon., 1978). Droughts in India during the 917-918, 1148-1159, 1344-1345, 1396-1407, 1630, 1661, 1669-1670, 1769-1770, 1783, 1790-1792, 1803-1804, 1837-1838, 1861, 1866, 1868-1870, 1874, 1876-1878, 1896-1897, 1899-1901 and 1943-1944 periods caused starvation of millions. Three to 10 million deaths occurred in the drought of 1769-1770 in Bengal, India, which, at the highest estimate, was one-third of the population. India would have suffered a major famine in 1966-67 were it not for the importation of 26 million tons of grain to that country by the U.S., Canada,

and Australia during 1965-1967. Two consecutive poor monsoons resulted in grain crops about 20% below average. China has suffered 1,828 famines from 108 BC to 1911 AD, of which the number of deaths for the 1876-1879, 1892-1894 and 1928-1929 periods were 9-13, 1, and 3 million, respectively. In the great drought of 1921-1922 grain production was less than one-half of an average crop for 2 consecutive years; between 1.25 and 5 million people starved in the former Soviet Union, particularly in the Ukraine and Volga region (Anon., 1973; Anon., 1978).

Nicholson (1978) studied 5 centuries of climatic variations in the Sudano-Sahelian region by analyzing lake-level variations and stream regime changes. Reconstruction of past climates, particularly precipitation events, revealed that the famines of the 1681-1687, 1738-1756 and 1828-1839 periods were due to severe droughts. According to the travel account of Browne (Nicholson, 1978) in 1799, the now dry Bahr el-Ghazal valley of Chad was flooded at that time, since he had traveled the distance between Lake Chad to Borkou by canoe. The level of Lake Chad receded to its lowest in 500 years during the 1828-1839 period.

The 1968-1973 drought resulted in 500,000 deaths in 8 African countries in 1973, from Mauritania in the west to Ethiopia in the east, where 200,000 starved (Anon., 1983; Anon., 1983). Again, about 1 million people starved during the 1984-1985 drought in Ethiopia (Johnson, 1990); the loss in cattle in the 1983-1984 drought numbered 1.5 million (Biswas et al., 1987).

Persian historians and poets have reported the accounts of famines in Iran and parts of the Old World. Ferdowsi (940-1020) discussed the 7-year drought during the reigns of Kaykavoos and Pirooz, son of Yazdgerd, and the 4-year drought during the reign of Bahram-e-Goor (throned 421, died 438). Saadi (1209-1295) mentioned the drought during the time of Khalifa Omar-ben-Abdolaziz and also in Lebanon in 1245. The History of Sistan (Anon., no date) described the story of drought in 835 in Afghanistan and Sistan. Naser Khosrow (1003-1088) reported the droughts in Qazvin (1046), Mecca (1047-1048), and Isfahan (1052). Hamdollah Mostoufi (1329) and Abdollah Vassaf (died in 1330) reported the drought of Qazvin in 1217, and that of 1284-1286 in Fars, respectively; about 100,000 people starved in the Fars famine. Chardin (1643-1713) observed the 1669 Isfahan famine first hand. Fasaii (1895) reported the

71

famines of 1729, 1747, 1866-1867 and 1871 in some parts of Iran, and Khanshaqaqi (1974), told of the 1871 drought in Tehran when the British envoy extraordinary provided relief funds from India and personally distributed bread among the needy. The famines of 1866-1867 and 1871, and also the very high prices of food in 1878 reported by Fasaii were due to the recurrent droughts during the 1860-1880 period that Andreas and Stolze published their report on drought in Iran in 1885 (Reza et al., 1971).

En masse migration of the rural population, abandonment of villages, and their eventual ruin are usually caused by droughts. The famine of 1869-1871 left many homesteads abandoned. The population of Qom, which was 25,382 in 1867, was reduced to 14,000 by 1874 (Lambton, 1953).

Living conditions in Sistan, an extremely arid region in Iran, wholly depend on the precipitation on the Hirmand Watershed, our relationships with Afghanistan, and the general policy of the Iranian Government. The 1948 drought in Afghanistan resulted in heavy losses to cattle herders in the Sistan area (Lambton, 1953). Flooding of Hirmand in 1949 caused a few years of drought. Extensive reed beds and rangeland, which were usually grazed by the cattle and livestock, dried out. This misfortune intensified poverty. Breaching of levees and failure of irrigation systems due to flooding were the

main causes of this disaster. Construction of the Kohak Diversion Dam on the Hirmand during 1965-1966, which misfired and diverted the Iranian share of the flow towards Afghanistan, was another reason for the ruin of numerous farms in the Sistan region.

Short-duration droughts, in which the rainfall is less than the mean annual precipitation, mainly cause livestock and cattle loss due to a relative lack of nutritious forage and subsequent diseases that befall them. Although these events do not cause famine and starvation, the financial loss to farmers and herders is enormous. The drought period that peaked in 1891 caused the loss of 50 million sheep in Australia (Arnon, 1972: 106). During the same period, the rainy 1870s in the American Great Plains was followed by a decade of drought (Dregne, 1977). Iran, India, and Russia experienced famine during the same decade. What would happen if this misfortune repeats itself? „... wherefore take example, you who are endowed with sight‰ (The Glorious Koran, Chapter 59 [Emigration], verse 2), More recently, the livestock population of Algeria, which had risen to 8 million, was reduced to 2 million in 1945 owing to a few lean years (Arnon, 1972: 99).

Wet years with abundant flood-producing rainfalls occur frequently in dry areas too. The Land of Iran has repeatedly experienced devastating flooding, a number of which from 937 to 1950 are reported in Table 1.

Table 1: Some of the notable flooding events of Iran from 937 to 1950 (after Melville, 1984)

Date Locality Remarks

937 Sari All buildings destroyed; inhabitants fled to foothills; local officials warned not to act oppressively

1037 Oct. 24 Zarang (Sistan) Collapse of a bund (dyke or dam) north of the city; poor harvest the next year; city walls rebuilt by 1040-41

1243 Sistan Huge area of Sistan and Hirmand delta affected; Zarang under water for three months; over 300 people died in province

1244 Mar. 31 Sistan Further flooding washes away most of SistanÊs grain 1275 Apr. 25 Yazd Catastrophic flood after 5 days [of] continuous heavy rain; water ruined the districts on the E.

and S. side of town, spilled over the moat and destroyed part of citadel; lasted 36 hrs. Flight to high ground

1371 Tabriz Most of the buildings were ruined1404 May ? Jajarm Caused by early summer snowmelt; flooded qanats; flash flood destroys half town, the citadel

and all the corn lands 1442 Spring ? Karzin Shiraz Fars Heavy rainfall in upper reaches of Qara Aghach, causing floods in Shiraz and Shabankareh

region of Fars. Karzin area inundated; Buyid bridge at Pul-i Arus broken by palm trees carried in spate

1456 Apr. 13 Yazd, Taft Catastrophic flood after weeks of rain; river from hills south of the town broke through flood barrier; qanats from Muhrijird district destroyed; enormous damage to buildings in Yazd; at least 1000 tumans of personal property destroyed apart from loss of houses, gardens and cultivated lands etc. Great damage also at Taft. Miraculously, no lives lost. No relief was given but on the contrary great oppression was shown towards the victims

1493 Apr. 14 Herat Following violent hailstorms on hills to N.E. of the city, a torrent that damaged Gazdi Gah and the plains north of Herat

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1558 Mar. 13 Qazvin Flood ruined 2000 houses in the Darb-i Abhar quarter of Qazvin1593 Summer Sarab Flood after 48 hours [of] heavy rain, completed earthquake destruction1594 Feb. Most of W. Iran Af ter two days of v io lent and de str uct ive N. w inds over (Per s ian) I raq, and the towns on heav y ra in caused extensive f looding of r iver s; Zayandeh-rud over f lowed the edge of the destroying water mi l ls and br idges; ir r igat ion canals f i l led up w ith debr is; Dasht-i kavir much destruction also of buildings and gardens in and around Qum; in Qazvin, the deluge burst

at midnight; attempts to block the spate with planks and boards and doors of houses proved futile, but it was ultimately diverted by carpets, felts and other fabrics draped over large tree trunks, away from the areas containing the government buildings; one or two other quarters were however demolished. The flood also affected Kirman, and Yazd, where a torrent from Taft wiped out all buildings and cultivation, which reverted to desert. Few places in the whole country escaped the effects of this storm and the resultant flood. In the spring, plague broke out in Isfahan, causing heavy mortality and emigration to nearby towns until the autumn; cholera

reported in Qazvin1600 Amul A great flood of the river Haraz destroyed Amul and surrounding villages killing thousands

of people who were caught unawares. Area repopulated with imported Georgian captives. Landslides in the Namarustaq district created a small lake which later drained down to the sea

1630 Shiraz Heavy snow and torrential rains cause heavy flood damage around Shiraz1636 Spring Qum Sudden inundation of Qum river following rainfall in mountains; caused great loss of life and

destruction of 1000 housesDate Locality Remarks1668 Dec. Shiraz Disastrous flood destroyed a third of the town, and prompted its desertion by a number of

the inhabitants; followed by an epidemic1670 Qum Two thousand houses and all the ancient buildings ruined1710 Saveh Town ruined by a deluge1813 Khuzistan Flooding of Karun after heavy rains1832 Spring Khuzistan Heavy floods carried away portions of the bridges at Shushtar and Dizful; the correct date

may rather be 18371851 Apr. 10 Qazvin Four quarters of the town were damaged with the loss of more than 3000 houses; Shah grants

funds for construction of a barrier; heavy and prolonged rain reported from Tabriz in March and April

1867 Apr. ? Kashan district Disast rous f lood ing fo l lows t hree consecut ive days of ra i n ; gardens on W. side of Kashan completely flooded, qanats ruined and ditches filled up, walls collapse and damage to houses; runoff from river and foothills floods villages to the north of Kashan such as Nushabad, Aran and Bidgul, villagers abandon hope but floods cease before the whole district completely destroyed. Total cost of property, damage to houses and gardens, loss of cultivation from break down of water supply and incurred in repairing and cleaning the qanats estimated at 200,000 tumans

1867 May 7 Tehran A flash flood struck Tehran (heavy rain reported the previous week) and filled the city moat, overflowing to flood the low-lying sections, where 120 houses were destroyed, several people lost their lives

1868 Spring Khuzistan Heavy floods in Khuzistan; possibly affecting Sush (Susa). This event should probably more correctly be dated 1870, as below

1870 Mazinan (Khurasan) A torrent from the Kuh-i Chagatai swept away most of Mazinan and other villages, such as Behnamabad, on the fringe of the kavir. Mazinan was rebuilt about half a mile N. of the ruined site and attracted settlers from the other villages thatg were affected

1871 Tabriz Great damage caused in Tabriz; poem written to commemorate the event1871 Aug. 31 Damghan Flood following two days rain; apparently not damaging1872 May Asadabad Flash flood burst through dam and inundated Asadabad to a level of two feet of water; much

destruction of property and loss of life

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Tank Systems for Water Harvesting

R. Sakthivadivel

9

IntroductionWater harvesting and storage has been a key strategy against water scarcity in semi-arid regions of the tropics because of sporadic spatial and temporal distribution of precipitation. As opposed to many modern agricultural systems structured around large reservoirs and distribution systems, small tanks and cascades, predominantly supplied by surface run off have been used for centuries as water harvesting structures at micro- and meso- catchment levelsThe term „water tanks‰ is interpreted differently in different parts of the country. In south India, water tanks are usually called „irrigation tanks‰. These are storage structures built on the ground (with out digging) from which water is let out by gravity flow through sluice out let and overflow spillway. In addition to these tanks, there exists in each village a number of dugout structures called „pondsÊ used for domestic and livestock purposes. In the north Indian context it appears that there is no difference between ponds and tanks and are used interchangeably for any small water holding structure. Both tanks and ponds are included under water tanks discussed here in. Water tanks have been in existence in India over centuries. They have not been constructed at any particular time

period but came into existence as a sequel to population pressure and demand for additional. Water storage to meet peopleÊs livelihood needs. Because tanks were constructed over the land surface without digging, availability of suitable abutting sites to locate a tank played a major role in choosing a site for constructing a tank. The tanks of south India vary over a wide range in their command, catchments and water spread areas (ranging from a few hectares to hundreds of hectares). Their ratio among these three parameters also varies widely (Sakthivadivel, 2004). South Indian Tanks Tanks in south India are classified in a number of ways. They are classified as PWD tanks. Panchayat tanks and Ex-Zamin tanks. PWD tanks have command areas greater then 40ha. While Panchayat tanks have command areas lees than 40 ha. Ex-Zamin tanks are those managed by Zamindars which have now been transferred to either PWD or Panchayat depending on the size of the tanks. Tanks are also classified as „rain fed tanks‰ and „system tanks‰. Rains fed tanks receive their water supply from their own catchments while system tanks receive runoff from its own catchment as well as supply diverted from

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rivers/reservoirs through canals. Then comes the „cascade of tanks‰; these are tanks big and small interconnected and located within a watershed.North Indian Tanks In the North Indian context also, there are big and small tanks. The big tanks which store water recharge the aquifer as well as retain sufficient soil moisture in the unsaturated thick layer of clay tank bed. When the water is emptied from the tank bed, then the tank bed itself is used for taking one winter crop with the soil moisture stored in the tank bed and occasionally supplemented by nearby well water. So, basically tanks are used as inundation tanks. There are also tanks basically meant for rearing fish. In the semi arid regions such as Kutch and Bhal regions in Gujarat, and in some dry areas of Rajasthan tanks are constructed with lined PVC sheets to prevent contamination with underlying saline water as well as to prevent deep percolation losses. These tanks are mainly used for drinking water supplies to humans and animals. Who Owns Water Tanks? Historically water tanks were common property of village community; they were owned, maintained and managed by the beneficiaries. The benefits accruing out of the tank and its water use including usufruct rights were enjoyed by the village community especially women, landless and poor. After the introduction of Ryotwari system by the British colonial regime in 1857, the Government took over the tanks and handed over to PWD and Panchayat for maintenance and management. It then started collecting tax from tank water users and controlling the usufructs from the tanks through Revenue Department. As a result, the villagers lost interest in tank maintenance; and what was once a multiple use tank has come to be known as irrigation tanks because irrigators pay tax for tank water use and they claim usersÊ rights over tanks.Recently with NGOs involvement in tank rejuvenation programme, tanks are again considered as common property resource of the village to provide equal access to all including those landless, women and poor and meant for multiple uses. Tank Performance In the recent past, tank irrigated area is on the decline; tank maintenance and management is abysmal; many tanks have degenerated and become defunct for various reasons. Some of the reasons for under performance are: Because of onslaught of private ground water development and Govt. emphasis on large and medium scale irrigation projects, investment on water tanks and GovtÊs focus on

managing and maintaining these tanks have considerably been reduced. Population pressure coupled with diminishing land per capita has fueled encroachment of waterways and tank beds thereby exacerbating the degeneration of tanks. Physical rehabilitation of tank proper with de-silting of tank beds and repair to the bund is being attempted in a haphazard manner. The impact of such isolated work on tank performance is minimal. Change in tank hydrology due to erratic rainfall distribution and land use pattern changes in tank catchment, large scale ground water development, weakening of tank �institutions and less profitability of tank based agriculture are some of the other major reasons for underperformance of tanks. Tank Irrigation There are 39202 irrigation tanks of varied size and capacity in the state of Tamil Nadu. Of this, 8903 tanks including 3627 system tanks are maintained by PWD presently known as Water Resources Department. The rest of the tanks are in charge of local Panchayat Union. The PWD and the Panchayat Union will look after the source and the tank proper. But the water distribution and water regulation are with the villagers especially the farmers who are the beneficiaries. Being small systems, almost every village may have at least one tank and the villagers who have cultivated with tank water claim some ownership. They have been operating and maintaining these systems through village committees. Due to the neglect on the part of Government and community at large, these tanks fell into the various cycle of „Rehabilitation � Poor maintenance � Deterioration � Rehabitation‰. During the late 1970Ês, the Government of Tamilnadu started to plan a comprehensive modernization of the PWD tanks with assistance from Economic Council and subsequently Panchayat tanks with external funding. The present approach adopted by both the Government and the funding agencies and their impact can be characterized as:(1) Top- down , inflexible and blue print approach with less involvement of local communities in planning, implementing and managing the system.

(2) It is a piece � meal approach focused on tank proper and not the tank system as a whole. The concept that the tank system is embedded in a watershed and as a result, the tank system needs to be considered in the context of

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watershed, taking into account the impact of upstream and downstream effects has not permeated in the planning process.

(3) Tank systems are locally managed systems by local communities. For efficient and effective sustainable management, involvement of local communities from the very beginning of rehabilitation process is imperative. Local institutions are to be created, strengthen, their capacities built and adequate empowerment of rights and responsibilities are to be bestowed upon. At present, the weakest link is between the people who are the real stakeholders of the tank and the government agency who implement the tank program.

(4) During the drought period, the ground water drinking wells gets recharged due to rehabilitation of tanks; provide adequate water and the most benefited of these augmented recharge are the poor and landless people; Otherwise, they need to walk long distances to get a pot of water or they have to pay through their noses to purchase drinking water.

(5) Rehabilitation of tanks and related improvements in the agriculture systems increases the intensity of agriculture, changes the crops and cropping pattern and increases the agricultural production and the livestock population. All these changes increase the demand for labour and by this the landless and the poor people are able to get more number of days of labour work both on- season and off- season.

(6) A number of studies carried out on rehabilitated tanks indicate that the wells in and around the tank get additionally recharged due to increased storage of tank water, stored over a longer period of time. When adequate and reliable supply of water is available, farmers go for crop diversification with high value crops. What was originally used for one crop, now two crops are grown. In this process, there are instances that more than what the recharged water will be pumped out especially during drought year. If the drought continues for more than one year, over extraction takes place; wells dry;

competitive drilling and well digging among farmers take place, wasting their hard earned money. Ground water is considered as private property and as such those who own lands can pump groundwater underneath their land to any extent without government control. Groundwater has to be treated as common property and necessary laws must be enacted to regulate and use the groundwater in conjunction with rainfall and tank surface water. Many farmers in the tank command area who own wells do not participate in the collective action of maintaining and managing the tanks thinking that they have wells which can be depended upon to supply water when there is no tank water. Of late with a deterioration of tank maintenance ground water level in the command is fast declining and shallow wells become dry. There is now a realization among well owning farmers that unless the tank and supply channels maintained properly and tank water is augmented their

wells will not be able to supply adequate quantity of water.

(7) Deforestation, over grazing, soil erosion and siltation have a very great impact on the tank performance and supply of water to the tanks. The impact of siltation on supply channel is very great in that it effectively prevents the water from catchments entering into the tank; added to this is the human intervention in the supply channels such as encroachment, construction of roads and culverts resulting in drastic reduction in water supply to the tanks. One of the major causes of deforestation and overgrazing is increased soil erosion leading to siltation of tank beds causing degeneration of tank and reduced storage capacity. Deforestation has also impact on tank supply, the distribution of which is affected by deforestation thereby affecting agricultural operation in the tank command.

(8) The specific economic benefits that tank development provides in the long run are: increase in agricultural intensity and output; increased fish, milk and bio-mass production and rise in ground water levels.

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(9) One of the major social benefits that the tank rehabilitation can bestow on landless and women is to mitigate migration to other places (both seasonal and permanent). Women have to bear the brunt of most of migration. Other kinds of benefit that can accrue out of rehabilitation are to provide income earning avenues such as fishing rights, right to tank bed cultivation, right to use tank bed silt, right to make bricks and right to have community dug well in the tank bed and share that water among command area of farmers.

(10) The indirect impact is mainly the availability of drinking water throughout the year due to increased recharge from rehabilitated tanks and maintenance of groundwater levels.

Institutions for Tank ManagementThere are different groups which undertake rehabilitation, maintenance and management of tank systems. In some tank systems hereditary leadership maintains and manages the tank system even today. There are tanks which are purely managed by women SHG during rehabilitation (Grama Vikas). Then there are groups formed by the representatives of all tank water users including the landless and women; they work satisfactorily in single caste and multi-caste villages. Some tanks are directly managed by Gram Sabha. There are tanks which are entrusted to certain people in the villages (called kaval maniam and neer maniam) for maintaining and managing the tank systems with clear water regulations evolved over time and regulated by village Panchayats. So there is no single model that one can say that it works in all places under all socio- cultural , economic and political settings. From successfully operating tanks we can infer that the tank management group must be broad based representing the interest of all users and the users must have faith and confidence in the group and they should feel that they are all treated fairly and equitably. Resource mobilization by the user group for tank maintenance and management. The various methods adopted for resource mobiliza tion by the tank user association are: Foreshore cultivation with fast growing tress inter cropped with fodder for livestock. Tank bed cultivation with pumpkin, watermelon, cucumber, napier- grass etc. Tank bed cultivation with coconut and tamarind

trees. Revenue occurred to tank users due to tank usu fructs such as trees, fish, silt, brick etc. Establishing community well in tank bed and selling water by TUA. Annual auctioning of village common land for pri vate use. Charging well owners extra for pumping seepage water from tank. Entrance and annual fees charged from members of TUA. Village common fund for tank use. Income generation through purchase of equipment and hiring it out to farmers. Allow farmers to pump dead storage in the tank and charge them. Governance Structure for Tanks at The State LevelAt the state level, the funding for maintenance and management for tanks is meager resulting in deferred maintenance and leading to rehabilitation with donor funds. Much of the funds provided for maintenance go for administrative expenses leaving very little money for physical maintenance. While implementing donor funded projects, the approach is bureaucratic, top down, no involvement of farmers in all activities of rehabilitation, no expertise is used in institution building exercise and no involvement of NGOÊs. The end result is that the project envisaged is not implemented properly leading to substandard and un-sustainable performance. At the district level there are system tank, PWD tank, and panchayat tanks. In a cascade of tanks, one may come across PWD tanks and Panchayat tanks lying one after the other. Under such situations, rehabilitating PWD tanks alone without attending to Panchayat tanks will delink the supply channels and the full benefits of rehabilitation may not be achieved. The tanks in a river basin irrespective of their size and type, should be handled by one agency at least for planning purposes and such agency must be tagged on to the Basin Authority so that the water in a basin context can be accounted for and the available water can be put to productive uses through integrated planning at the basin level. At Panchayat level too not much of co-ordination exists between Panchayat and TUAs. Further devolution of powers to Gram Sabha level is necessary to have an effective interaction between the lowest level Government bureaucracy and the TUAs.After a period of nearly three decades of implementing rehabilitation projects, the government agencies have realized the importance of involving user community

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in tank maintenance and management. They are ready to transfer these functions without neither empowering the local community to make decisions nor to enjoy the usufructs of tanks. Recent studies by Anna University and others have indicated that farmers are capable of planning, constructing maintaining and managing the system in a more efficient and cost effective manners and capable of integrating indigenous knowledge with modern technological development to get the optimum output in a sustainable manners. The total involvement of farmers in all phases of rehabilitation process is necessary to make rehabilitation process successful and to get the benefits expected out of rehabilitation. Cost Effective Tank RehabilitationTo make tank rehabilitation cost effective four aspects are suggested: 1. Tank rehabilitation work must be planned and implemented by TUAs with support from NGO and the government agencies. Only20 to 25% of the sanctioned budget is utilized or works in the case of contractors implemented projects whereas nearly100%of the fund allocated to TUAÊs through GO goes to work in addition to farmers contribution raging from 10to 25%.

2. The second aspect is whether the tank proper, or tank with its catchment and command area, or integrated watershed treatment with rehabilitation of tank cascade should be taken up and which is cost effective? There is no clear cut answer available to this question. A few experiments carried out in the recent past point to the fact that tank cascade should be taken up for rehabilitation under the watershed development programme.

3. The third aspect is to use machine and men in appropriate mix that will be cost effective for tank rehabilitation.

4. The fourth aspect is de-silting of tanks as a component of rehabilitation. There are arguments for and against de-silting as a component of rehabilitation. A few impact studies carried out recently indicate the selective de-silting of tank improves tank performance. It increases the dead storage for domestic and livestock use, allows to rear fish and provides supplementary irrigation through pumping.

Concluding Remarks Tanks have been existence from time immemorial. Even to-day some of the tanks maintained and managed properly functions well and provides sustainable services. So, tank systems are sustainable if proper maintenance and management is bestowed upon them. Tanks are decentralized systems catering to the needs of local community have played a very important role in irrigation and in the local eco-system in areas with relatively low (annual rainfall of 1000mm or less) such as in most parts of Karnataka, Andra Pradesh and Tamil Nadu. Through the ages, Indian agriculture has been sustained by natural and man-made water bodies such as lakes, ponds and similar structures. It has been estimated that there are more than a million such structures and about 500,000 are used for irrigation. Many of them have fallen into disuse. Many of them have accumulated silt. Many required urgent repairs. The three important factors contributing to the under performance of tanks are : siltation and encroachment; ground water development; weak organizational structure and government interference. Although inscriptional and other evidence indicates that tanks continued to be constructed over a long historical period, the original plan seems to have certainly been a grand one, which considered a large network of interconnected chains of tanks, running all the way from Eastern Ghats down to the Bay of Bengal. It is difficult to imagine that tanks would have been constructed one by one and at some point would have formed perfectly connected systems. Only recently, modern irrigation experts have begun river basin as an appropriate unit for designing irrigation systems. This was an established practice in ancient times. The curvature of the tank bunds designed to be elliptical to give maximum strength to the embankment, the stone facing on the inner side of the bund to minimize the action of waves forces and the tank sluices of plug and rod type are outstanding example of the engineering ability of Indian builders. Closely related to the engineering design of the tanks is the social organizations necessary to maintain and manage the vast network in the tank systems which are important in order to comprehend the related social organization: (i) Each tank irrigates, usually, fields lying within one village or at most a few villages. Hence, each tank needs to be locally managed. (ii) Where tanks are interconnected, which is usually the case, integration of supra-local or supra-village localities must be possible in

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order to maintain and manage the entire chain of tanks. The existing literature indicates that the social and political organizations of pre-British India were designed to meet this need. The historical material on irrigation organization and structures and some recent data on the local and supra-local organization of the pre-British Indian societies together underline the fact that the Indian civilization placed a great value on decentralization of resources and political power which automatically set a limit to the size of irrigation structures. Large scale systems such as modern dams would not have been compatible with the values and goals of the Indian civilization. The traditional irrigation technology of tanks, anaicuts etc were also ecologically the optimal solution for the natural conditions obtaining in certain parts of India. In this sense, traditional irrigation technology is certainly „modern‰ as well as sophisticated. The village institutions, which are reasonably functional even today, ought to be fully involved in any plan to improve irrigation management. In addition, resources which are essential for the healthy functioning of the institutions need to be restored to them. Resources must be appropriately allocated to them to enable them to

function effectively. In the absence of such resources, merely appealing or exhorting the village communities to under take voluntary action to maintain tanks will have no impact, as is evident from the non-functioning of various efforts under taken by the government to make beneficiary commitment to under take maintenance. The governments should make serious attempt to turn over the tank system to the village community with a proviso to enjoy by the community the benefits from usufruct of tank and tank water. Recent research has pointed out that the first effort of the government must be to restore all the old tanks which are gradually dying and disappearing due to urbanization. The result of disappearance is that there is no way of holding rain water and recharging ground water. Instead, during heavy rainfalls, entire residential areas become water logged since they are low lying. In order to be able to effectively rejuvenate and extend the tank system, the most basic requirement is a data base. Appropriate agencies must be created to generate reliable tank data and such data can be generated only by involving knowledgeable individuals from each village which has a tank.

References Sakthivadivel.R (2004) A Study on Tanks and Ponds: Consultancy Report submitted to NOVIB, Netherlands in Association with Dhan Foundation, Madurai.

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Water Harvesting and Ground Water Recharge

N.Varadaraj

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IntroductionThe ubiquitous availability of ground water

coupled with technological advancement in its extraction, institutional supports and deemed considered ownership of ground water as easement to land has led to quantum leap in the ground water development in our country during last five decades. Even though the ever increasing dependence on ground water has ensured countryÊs food security and fulfilled other socio economic needs its over exploitation at places has led to dwindling sustainability of this precious natural resource with emerging adverse environmental consequences. The serious manifestation of over exploitation of ground water resources is evident from the fact that over exploited and dark blocks in the country have increased from 250 in 1985 to 1089 in 2004 besides recording of steep decline in ground water levels in 300 districts over the years. Tamil Nadu is one of the highly water stress state with 142 over exploited blocks out of total 385 blocks. The consequent decline in ground water levels and associated environmental impacts are observed in major parts of the State. The state has 8 saline blocks in the coastal districts of Nagapattinam and Ramanathapuram and fresh water

aquifers are under persistent threat by ingress of saline water through upconing and sea water intrusion in parts of North Chennai, South Chennai, Puducherry and Tuticorin coast. The challenges faced to mitigate the impact of over exploitation of ground water need a sound ground water management policy on scientific considerations. The stand alone regulatory measures though may endorse some positive impact, but holistically, various measures to augment the available ground water resources with adequate level of peopleÊs participation can only have positive impact on long term perspective in minimizing the adverse effects of ground water over exploitations.

Artificial Recharge Of Groundwater – An Urgent Need

Natural replenishment of groundwater storage is slow and is unable to keep pace with the excessive exploitation of groundwater. With increasing urbanization, the land area for natural rainwater recharge is also shrinking and large unutilized runoff carries pollution to the water bodies. Artificial recharge to groundwater aims at augmentation of the groundwater

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storage by modifying the natural movement of surface water, utilizing suitable civil construction techniques to increase the seepage rate exceeding that under natural conditions of replenishment. The rainfall occurrence in India is limited to about 3 months period, ranging from about 10 to 100 rainy days.

In case of Tamil Nadu, the south west monsoon period of June to September as well as North East monsoon during October to December gives rainfall around 1000 mm . The very high rainfall during the year 2005 has recorded highest intensity of 47 cm in 2 days and recorded heavy discharge of precious fresh water to sea. The estimated quantum of 15 months water supply to Chennai was lost to sea. Such surplus run off has to be effectively harvested and put to beneficial use by creating adequate surface storage and recharge to ground water structures. The quantum of water that can be stored in the sub-surface depends on the aquifer conditions and prevailing water level. The rate of infiltration to sub-surface is slow and at many pockets, particularly when torrential rain occurs, the same has to be stored in surface and then allowed to percolate into the ground with proper structures. The natural recharge is restricted to rainy season only. The artificial recharge techniques aim at increasing the recharge period in the post-monsoon for about 3 months to provide additional recharge. This would result in providing sustainability to groundwater development and also check the sea-water ingress.

In hilly areas like north eastern regions and Western Ghats, even though the rainfall is high, scarcity of water is felt in post-monsoon season. Due to steep gradients, a large quantity of water flows out to low lying areas as surface runoff. Springs are the major source of water in hilly areas which gets depleted after monsoon. There is a need to provide sustainability to these springs. Small surface storages above the spring level are effective in providing additional recharge and sustain the spring flow for a longer period.

Central Ground Water Board, under Ministry of Water Resources, Govt. of India, has played a crucial role in initiating artificial recharge in the country and propagating the message to State Governments and public through mass awareness programmes, trainings, seminars and utilizing electronic media. For success of this programme the importance of scientific approach cannot be underrated. Necessary literature in the form of Manual, guides etc. on artificial recharge to groundwater

were issued which include detailed technical aspects of site selection for different types of artificial recharge structures, their suitability to various hydrogeological set ups and climatic conditions etc. Under Central Sector Scheme, financial assistance was rendered to State Government & Non Governmental Organizations to take up construction of artificial recharge structures to augment recharge to groundwater systems. The criteria for selection of sites for artificial recharge structures were as follows.

(i) Need for artificial recharge structures, indicated by declining water level trends or need for improvement of water quality by way of dilution(ii) Scope for artificial recharge, indicated by available uncommitted surplus run off taking into consideration the capacity of existing structures and the ability of groundwater system to accept the recharge and(iii) Economic viability of the schemeAdvantages of Artificial Recharge

Artificial recharge is becoming increasingly necessary to ensure sustainable ground water supplies to satisfy the needs of a growing population. The benefits of artificial recharge can be both tangible and intangible. The important advantages of artificial recharge are;

(i) Subsurface storage space is available free of cost and inundation is avoided(ii) Evaporation losses are negligible(iii) Quality improvement by infiltration through the permeable media(iv) Biological purity is very high(v) It has no adverse social impacts such as displacement of population, loss of scarce agricultural land etc(vi) Temperature variations are minimum(vii) It is environment friendly, controls soil erosion and flood and provides sufficient soil moisture even during summer months(viii) Water stored underground is relatively immune to natural and man-made catastrophes(ix) It provides a natural distribution system between recharge and discharge points(x) Results in energy saving due to reduction in suction and delivery head as a result of rise in water levels

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Implementation of Artificial Recharge Schemes

Successful implementation of artificial recharge schemes will essentially involve,

(i) Assessment of source water,(ii) Planning of recharge structures,(iii) Finalisation of specific techniques and designs,(iv) Monitoring and impact assessment,(v) Financial and economic evaluation and(vi) Operation and maintenanceRain Water Harvesting MethodsThe methodology of artificial recharge through utilizing surplus surface run-off depends mainly on the following factors(i) Hydrogeology of the area including nature and extent of the aquifer, soil cover, topography,

depth to water level and chemical quality of ground water.(ii) Availability of source water, assessed in terms of non-committed surplus monsoon run-off.(iii )Area contributing run-off like area available, land use pattern etc.(iv) Hydrometeorological characters like rainfall pattern, its duration and intensity

The implementation of the recharge schemes at point will have impact to limited extent in the radius of 100 to 750m only. The availability of suitable site for the larger size recharge structures is the main constrain reported in many areas. The micro-watershed level studies and recharge program is essential to make the effective change in the ground water regime in terms of quantity and quality of water. The artificial recharge practices can be grouped into two categories, namely , surface and sub-surface practices as listed in Table-1 . The rain water harvesting is the easiest way of improving our

Table 1: Artificial Recharge Practices

SURFACE PRACTICES SUB-SURFACE PRACTICES

1 St - 2 Nd Order Streams Dug Well RechargeContour Bunding Recharge Shaft/TrenchGully Pluging Injection WellTrenching (i) Gravity Head 2nd-3rd Order Streams (ii) Pressure Injection

Cement PluggingNala Bunding Water Conservation StructuresPlainsPercolation Ponds Sub Surface DykesWater Conservation Structures Ground Water DamsWeirs

RAIN WATER HARVSTING A. ROOF TOP B. OPEN SPACE

I. Direct storage in surface II. Storage in sub- surface I. Storage in sub-surface(Sumps/Syntex tanks) (aquifers) (aquifers)

Drinking Domestic (i) Recharge pit (i) Temple Tanks Filtration End use (ii) Recharge pit with bore hole (ii) Temple tanks with recharge shaft (iii) Recharge pit with tube well (iii) Percolation pondsChlorination (iv) Recharge trench (iv) Percolation pondsEnd use (v) Recharge trench with bore hole (v) Percolation ponds with recharge (vi) Recharge trench with tube well shaft (vii) Existing Bore well with pre cast filters (viii) Existing Bore well with settling pit and filtering pit (ix) Existing Tube well with pre cast filters (x) Existing Bore well with settling pit and filtering pit (xi) Existing dug well with pre cast filters (xii) Existing dug well with settling pit and filtering pit

Table 2: Rainwater harvesting techniques

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water resources which is having two types of approach namely, rooftop harvesting and open space methods as listed in Table-2

Impact Assessment of structuresThe suitability of a particular structure depends

on the local hydrogeological condition and the purpose for which the rain water harvesting is planned. Recharge to ground water is having many advantages and the open area in the country is very large in comparison to the built up area and hence the detailed studies and experiments are oriented in open space harvesting and recharge to ground water. In order to replicate a method with particular design and also to improve the design of various components of the structures the impact assessment of a structure is necessary. The assessment of impacts can generally be enumerated as follows:

(i) Rise in ground water levels due to augmentation of ground water in shallow aquifers. In case where continuous decline of ground water was taking place, a check to this and/or the rate of decline subsequently reduces. The energy consumption for lifting water from abstraction structures also becomes progressively less.

(ii) Ground water structures in the benefited zone of the structures gains sustainability and the wells provide water in lean months. This is reflected by either longer duration of pumping or increase in number of pumping days.

(iii) The cropping pattern in the benefited zone may undergo marked changes due to increased availability of ground water. Further, in spite of having a monsoon failure, the cropped area remains the same.

(iv) Green vegetation cover may increase in the zone of benefit and also along the periphery of the structures due to increase in soil moisture.

(v) Quality of ground water may improve due to dilution.

The observation wells established in the influence area of the artificial recharge structures constructed under CGWB fund were monitored on a regular basis to estimate the rise in water levels and to estimate the quantum of ground water recharge. However, as ground water extraction is taking place from the area together with its recharge, realistic assessment of the quantum of water recharged is considered difficult. Data pertaining to increase in the availability of water in the

existing wells and the increases in the area cropped were collected from the farmers and this data was used to quantify the benefits due to construction of the structure. The background information on hydrogeology and hydrological particulars of each site along with the impact assessment are given in succeeding sections.

Percolation Pond at CLRI, Adyar, Chennai, Chennai District

In order to harvest the available surplus runoff, two percolation ponds are constructed at CLRI campus. The percolation pond constructed at North of Store Block has a surface area of 400 sq.m., depth of 3 m and has a bund of 1.2 m high. The second percolation pond constructed in front of Museum Building is of rectangular with 40 m long, 10 m wide and 3 m deep with a bund 1.2 m high. 3 percolation pits of 3 m Dia and 3 m depth have been constructed in each percolation pond and filled with pebbles for facilitating recharge. These percolation ponds are provided with filtration units at the inlet points to ensure supply of silt-free water. The existing storm water drains in the campus are also been modified to divert the water into the percolation ponds. The total storage capacity of these percolation ponds is of 3850 Cu.m. The project was completed at a total cost of 7.6 Lakhs in June-July, 2002. The surplus water available for recharge was estimated as 12150 cu.m. The recharge pit with filter bed inside the percolation

pond is shown in Fig-1 and the pond with full storage

Fig. 1: Recharge shaft with pebble bed

Fig. 2: Pond after Post monsoon

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of rain water collected from the open area in the CLRI campus with measuring rod is shown in Fig-2.

Impact Assessment In order to study the impact of constructed

percolation ponds on ground water regime, a piezometer was constructed inside the CLRI campus and DWLR was also installed. The impact can be either quantified in terms of rise in water level or reduction in the demand-

supply gap. The hydrographs (DWLR) showing the changes in water level are shown in Fig.3.

From The HydrographIt is seen that a year before construction of

percolation ponds during 2001, the maximum water level was reached to about 10.7 m bgl (Aug.-Sept., 2001) and the minimum of 4.2 m bgl (Nov.-Dec., 2001). But after the construction of these percolation ponds in the CLRI campus, the ground water level is significantly raised and the maximum is of 7.8 and minimum of 2 m bgl within the campus. This shows that there has been rise in the water level in the order of 2-3 m during NE monsoon of 2002, after construction of percolation ponds. From the hydrograph, it is seen that the rainfall received during May 01 to Jan 02 is of the order of 1460.1 mm while during May 02 to Jan 03 it is of the order of 1220.9 mm. The depth to water level during Jan 01 and August 01 was 4.842 m bgl and 10.555 m bgl respectively, while water level during Dec 02 and Aug 02 was 3.0 m bgl and 7.40 m bgl. This shows that there has been rise in the water level in spite of lesser rainfall in the corresponding period, after construction of percolation ponds. The availability of water is estimated as 12150

cu.m and the quantum harvested by the percolation ponds during Northeast monsoon has been computed as 11550 cu.m. the estimated evaporation losses is 937.50 cu.m and net ground water recharge is 10612.5 cu.m.

Vadipatti Tank Improvement, Virudunagar

The existing irrigation tank is having thick cover of black clay and the quality of ground water in this area is brackish. The DTW ranged down to 16.85 m b g l and Quality of water in the dug wells in the tank command area was non potable before the revitalization of the pond with recharge well. The recharge well in tank bed is shown in Fig. 4.

The increase in water level in the downstream side of the tank due to recharge well is monitored from a net work of observation wells and the changes in water level are depicted in Fig-5. The improvement in water quality in the wells are also shown in Fig-6.

CGWB regular Schemes: Gangavalli block , Salem District ( 2006-2008)

The existing irrigation tank is having thick cover of silt and clay and the recharge to ground water is slow. Desilting of two tanks in Gangavalli block through PWD increased the net storage and hence recharge to ground water. Another 39 structures like check dam, percolation pond with recharge shaft/bore is constructed in scientifically selected sites to have improvement in regional ground water level in the watershed. Specific designs for recharging deeper fractures zones, which are

exploited by number of bore wells resulting in complete desaturation of fractures at faster rate than the natural

Fig. 3: Impact of Percolation Pond at CLRI, Chennai

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recharge, are devised and implemented.

The impact of the structures in ground water regime is evaluated by monitoring the water levels in a network of existing irrigation wells and also the increase in crop productivity by sustained ground water resources is noticed. The monitoring of the total impact in the water shed with the recharge structures are made and analysed. The estimated increase in ground water storage varies from structure to structure depending on the water spread area, number of days of water storage and rate of infiltration. The run off generated from the catchment from the rainfall and local hydrogeological condition like depth to water level and thickness of aquifer and extraction pattern of ground water by dug wells and bore wells are playing important role in the water storage in structure. In fact, the recharge structures will be more effective if its water retention period is short and percolation rate is high. The number of fillings and its percolation is the controlling factor in many of the structures in which the rain fall run off is being collected.

Only few rainfall days is seen with higher intensity of more than 20 mm to generate required run off to fill the water spread area and in the study area good rain fall occurs only in 10-20 days from which, the volume of water equal to 3 to 5 full storage of percolation ponds and check dams is estimated as potential addition to ground water storage. The check dams in major stream will surplus after full storage level and continuous flow in streams are limited to 30 days. The rate of infiltration is found to be low in many check dam sites and percolation ponds due to silt deposit with time. The experimental filter bed with recharge bore in check dam and percolation pond has shown good result and a small percolation pond with recharge bore ( Fig-7) has indicated the impact in more than 2 km down slope and the faster infiltration through fractures made it feasible for total recharge to

ground water from impounded water and obviously low

evaporation.

The unit cost per cubic meter of additional ground water storage created is calculated from the estimated life of structure as 20 years and the present construction cost which is low for the percolation ponds with bore well and desilting of existing tanks which is around Rs 1.5 per cu.m. It is very high for the check dams in the order of Rs 10 to 15 / cu.m and will be uneconomical when flash floods in streams totally wash the structure or create bank erosion as noticed in Gangavalli in November 2007. The maintenance of the structures is very crucial for the continuous benefit and silting of recharge bore wells and vandalism on the structures by miscreants for vested interest are also to be tackled properly.

Recharge to Coastal aquifer

Fig. 7: Percolation pond with recharge bore , Nagiampatti, Gangavalli, Salem District.

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The Chennai coastal aquifer system is prone for sea water ingress and such quality threat needs proper recharge program. Tiruvanmiyur area is one such coastal aquifer system which is over exploited and the regulation on transporting water from this area has marginally reduced the stress but local increase in population and construction of more wells and bore wells resulted

in lowering of water table. A well planned battery of recharge tube wells is recommended for such case and the improved recharge well design is given in fig-8.

Dug well rechargeThe simplest way of recharge to ground water

is diverting the water from the catchment area to the existing dug well, which may be in use or abandoned. In order to ensure sustainable water resource management and assured irrigation facilities in the over exploited, critical and semi-critical areas, dug well recharge scheme under state sector is prepared by Ministry of water Resources, Govt. of India and being implemented. The scheme will be implemented in XI th plan period for 3 years at an estimated cost of 1798.71 crores in seven states including Tamil Nadu. The main objectives of the scheme are as follows.

GW recharge through existing dug wells in agricul tural field

Increase sustainability of wells during lean period

Improve quality of groundwater especially in the fluoride affected area

Over all improvement in water resource manage

ment with people participation

Experience sharing in replication in similar recharge programmes

The recommended recharge well designs by CGWB for implementation in Tamil Nadu is given in Fig. 9.

The recommended dimensions of the recharge pit of 2x2x2 m at a safe distance from well may be made flexible to suit the area of water collection and rainfall intensity depending on land holding and its positions with local terrain condition (morphology). The larger collection pit for area with more catchment / land to be used for diverting surplus run off. Clayey soil will

Fig. 8.

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have more run off than other area. The rate of likely collection of water depends on the field condition and about 20 to 40 % of the rainfall when it exceeds 10 mm is expected to generate over land flow. It is estimated that a rain fall of 50 mm will generate a flow of 80,000 liters in one acre of land with more sand and loam. It will be as high as 140,000 liters in case of clay covered area. The rapid sand filter proposed can convey 20,000 liters per hour and the time required will vary from 4 to 7 hours . The rise in water level will vary from 4 to 7 meters for 5m dia. well and in the absence of weathering, the dissipation will be minimum. The inflow of the water from well to aquifer depends on the nature of weathering. Thus dimensions of collection pit and filter media and well will control the inflow and rise in the water level of the well . Regulatory measures like silt trap, diversion channel for excess collection, protection to motor, parapet of well are essential.

ConclusionsThough a major headway in governmentÊs

initiatives has been made for broad identification of nationwide feasible recharge worthy areas vis a vis design consideration of ground water structures in diversified hydrogeological environments through experimental studies, efficacy of such technology needs to be replicated at grass root level for other areas on micro level considerations.

The need for artificial recharge to ground water in Tamil Nadu is needless to be emphasized. The area suitable for recharge depends on the prevailing water level and water quality as well as local natural recharge conditions. The unfavorable situation is prevalent in high grounds of hard rock areas and deeper aquifers of coastal zone. The priority areas are the locations covered by black soil like Virudunagar, Coimbatore, Ramanathapuram districts and 142 over exploited blocks and 33 critical blocks spread over the state. The deeper aquifers in Cuddalore, Oratanadu aquifer in Tanjore and Pudukottai districts, Tiruvadanai aquifer in Ramanathapuram and Sivagangai districts and Udankudi aquifer in Tuticorin district needs major recharge tube well program to match the ongoing ground water development in these areas.

There is also need to further step up the awareness activities and capacity building programme at grass root level with active peopleÊs participation to promote rain water harvesting in the country. Modernization of tanks in brackish zone area like Vadipatti with recharge wells

can improve the quantum of water available for irrigation and also improve the water quality.

The innovative techniques practiced in the country as well as in other parts of the globe needs proper evaluation and local site specific design has to be identified and implemented.

The impounding of rain water in surface in check dams, percolation ponds, lakes and reservoirs over years has given us valuable information on the cost benefit and socio economic conditions. The studies at micro-watershed level by number of agencies are to be properly documented and shared with the local community and all stake holders. The experience of CGWB in Gangavall block, Salem district has shown the effective recharge of ground water by providing bore wells with filter beds in the check dams and percolation ponds . The quality improvement in irrigation wells downstream side of the tank with recharge well at Virudunagar is the success story of increase in ground water recharge coupled with quality improvement.

The dug well recharge scheme is implemented jointly by state and Central government in 7 states including 232 overexploited, critical and semi-critical blocks in Tamil Nadu by direct subsidy of Rs 4000 to Marginal and Small farmers and Rs 2000 to other farmers will increase the point recharge structures in each micro water shed and improve the ground water potential in large scale.

The rain fed areas need supplementary irrigation from ground water to improve the crop productivity. The limited ground water potential in the dry lands can also be effectively harnessed and adopting the modern irrigation practices like sprinklers etc will save the crops from failure of rains in critical period of water needs. The artificial recharge structures by integrated scientific methods will improve the ground water system and even in poor ground water potential areas, the conjunctive use of surface and ground water will improve the soil moisture availability to the crops.

AcknowledgementsThe author expresses his sincere thanks to

Shri B.M.Jha, Chairman, CGWB, Faridabad for his encouragement and permission to present this paper. The author is also grateful to Dr S.C.Dhiman, Member (ED&MM) and Shri A.R.Bhaisare, Regional Director (HQ) for their constant encouragement.

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References CGWB. 2007 : Hydrogeological condition of Neyveli basin, Tamil Nadu, Unpub. Report.CGWB. 1998 : Ground water exploration in Tamil nadu and U.T. of Pondicherry as on 31.03.1996, Unpub. report

of CGWB. 255p.CGWB, 2007 : Manual on artificial recharge of ground water, CGWB Technical series, 198 P.

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Potential of Water Harvesting as a Tool for Drought Mitigation

S. Mohan

11

IntroductionWater is one of the most important natural

resource and is vital for all living organism and major ecosystems, as well as human health, food production and economic development of a nation. Due to increasing human population, use of water for various purposes such as, domestic, industrial development, hydropower generation, agriculture, recreation and environmental services has increased considerably over time. Water table in various states of India has gone down due to recurrent droughts, deforestation and unsustainable utilization of water resources. Therefore, the availability of safe drinking water for rural as well as urban habitation has become a major issue and challenge to the government.

In India, the per capita average annual freshwater availability has been reduced from 5177 cubic meters from 1951 to 1820 cubic meters in 2001 and it is estimated to further come down to 1341 cubic meters in 2025 and 1140 cubic meters in 2050 (Ministry of Water Resources, GOI, 2003). The main source of freshwater in India is the rainfall including the snowfall at the higher altitude in Himalayan region. During the

previous century, the Indian arid zone experienced agricultural drought in one part or the other during 33 to 46 years which suggests a drought once in three years to alternate year. Often drought persists continuously for 3 to 6 years as prolonged drought faced by this region during 190305, 1957-60 1966-71,1984-87 and 1997-2000. Such prolonged droughts put tremendous stress on natural resources arid lead to severe scarcity of food, fodder and water.

Droughts impose a serious threat to agricultural production and off-farm economic activities in the affected region. In China, over 50 million tons of agricultural production was lost due to drought of 2000. The monetary losses in Iran during extensive 1999-2000 droughts were estimated at US$ 3500 million. In India, severe droughts affecting more than 40% of the countryÊs geographical area occurred 6 times since 1918 and during pre-Green revolution period, losses in food grain production due to drought used to be as high as 25% of total produce. In southwest Asia as a region, more than 100 million people get affected during extensive droughts.

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The ability of the local communities and governments in developing countries and international relief agencies to deal with droughts is constrained by the absence of reliable data and tools, information networks and the professional and institutional capacities. The important shift is necessary in drought management policies in general � a shift form contingent drought relief to drought preparedness. Water harvesting and conservation measures should be seen in this context of proactive drought management approach as a measure of risk control.

DroughtDrought is a long period with no rain or with less

rainfall than normal for a given area. Drought usually originates from a deficiency of precipitation (rainfall) over an extended period of time, resulting in water shortage for some activity or group. It may last for a few months or in some cases many years. Also, drought is a normal, recurrent feature of climate, and not a rare or sudden event. It can lead to an acute shortage of water, which is caused by deficiency of surface and subsurface water.

Drought is a recurring natural climatic event, which stems from the lack of precipitation over an extended period of time from a season to several years. It is considered to be the most complex, but least understood natural hazard, affecting more people than any other hazard (Hagman, 1984). Being normal feature of climate, its recurrence is inevitable. It occurs in all geographical regions, but its impacts and frequency are more pronounced in arid and semi-arid regions (e.g. Baluchistan and Sindh provinces in Pakistan; western and southern lowlands of Afghanistan; parts of Rajasthan and Gujarat states in India; large parts in Iran, China, Australia and sub-Saharan Africa). Drought extremity is frequently characterized according to the deficiency of rainfall. In India, a severe drought is defined as the condition in which more than 51 per cent of rainfall deficiency prevails in more than 20 per cent of the geographical area under study. Every drought is a meteorological drought, but definitions of various droughts are mainly centered around the demand and supply of water for different sectors. The following are the typical classification of droughts.

Meteorological DroughtMeteorological drought is the amount of dryness

and the duration of the dry period. Atmospheric conditions that result in deficiencies of precipitation

change from area to area. Meteorological Droughts are normally induced by natural causes. Several types of weather changes can alter the normal rainfall pattern in an area and cause drought. Water that evaporates from the ocean is brought inland by the wind to the regions where it is needed. Droughts can also occur when air currents do not flow their normal pattern or cycle and do not bring clouds to the area that requires rainfall.

Agricultural DroughtAgricultural drought mainly effects food

production and farming. Agricultural drought and precipitation shortages bring soil water deficits, reduced ground water or reservoir levels, and so on. Deficient topsoil moisture at planting may stop germination, leading to low plant populations.

Hydrological DroughtHydrological drought is associated with the

effects of periods of precipitation shortages on water supply. Water in hydrologic storage systems such as reservoirs and rivers are often used for multiple purposes such as flood control, irrigation, recreation, navigation, hydropower, and wildlife habitat. Competition for water in these storage systems escalates during drought and conflicts between water users increase significantly.

Socioeconomic DroughtSocioeconomic drought occurs when the

demand for an economic good exceeds supply as a result of a weather-related shortfall in water supply. The supply of many economic goods, such as water, forage, food grains, fish, and hydroelectric power, depends on weather. Due to variability of climate, water supply is sufficient in some years but not satisfactory to meet human and environmental needs in other years. The demand for economic goods is increasing as a result of increasing population. Supply may also increase because of improved production efficiency and technology.

The major causes of agricultural droughts in the Indian and zone are its geographic location not favouring abundant monsoon rainfall, poor quality and excessive depth of groundwater limiting its use for irrigation, absence of perennial rivers and forests, poor water holding capacity of soils, arid huge drawl of limited groundwater resources. Because of lack of substantial irrigation facilities, the agriculture is mostly dependent on rainfall. The increased pressure of both human (400%) and livestock (127%) population during

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twentieth century has put tremendous pressure on land, and surface and groundwater resources. Therefore, the impact of drought is felt much more severely in the arid region compared to other parts of the country.

As the water storage is dependent on the scanty and erratic rainfall, the duration of availability of water in surface water resources is reduced significantly in drought years. In drought affected areas, the groundwater table is declining @0.2 to 0.4 m/annum in almost three-fourth of the region, consequently shallow wells dry up during droughts and deep wells become deeper. Also the quality of groundwater deteriorates and sometimes the concentration of undesirable substances such as fluoride and nitrate increase to harmful/toxic levels. Grazing herds of animals quickly remove the scanty grass cover that come up with meagre rainfall, thus aggravating the problems of soil erosion and desertification. Widespread crop failures lead to acute shortage of food and fodder. Both human and livestock suffer from malnutrition and consequently become victim of host of diseases. As most of the people of this region depend on agriculture and pastoralism, drought leads to decline in income and employment opportunities. Large-scale migration with livestock or in search of employment is a common feature during prolonged droughts.

The effects of droughts may be categorized in terms of Economic, Environmental, or Social as listed below.

Economic EffectsLoss of national economic growth, slowing

down of economic development

Damage to crop quality, less food production

Increase in food prices

Increased importation of food (higher costs)

Insect infestation

Plant disease

Loss from dairy and livestock production

Unavailability of water and feed for livestock which leads to high livestock mortality rates

Range fires and Wild land fires

Damage to fish habitat, loss from fishery production

Income loss for farmers and others affected

Unemployment from production declines

Loss to recreational and tourism industry

Loss of hydroelectric power

Loss of navigability of rivers and canals.

Environmental EffectsIncreased desertification

Damage to animal species

Reduction and degradation of fish and wildlife habitat

Lack of feed and drinking water

Disease

Increased predation.

Loss of wildlife in some areas and too many in others

Increased stress to endangered species

Damage to plant species Increased number and severity of fires

Wind and water erosion of soils

Social EffectsFood shortages

Loss of human life from food shortages, heat, sui cides, violence

Mental and physical stress

Water user conflicts

Political conflicts

Social unrest

Public dissatisfaction with government regarding drought response

Inequity in the distribution of drought relief

Loss of cultural sites

Reduced quality of life which leads to changes in lifestyle

Increased poverty

Population migrations

DROUGHT MITIGATION1. Drought is a natural hazard, it has a slow

onset, and it evolves over months or even years. It may affect a large region and causes little structural damage. Drought impacts are generally more severe on livestock than on human beings.

The impacts of drought can be reduced through preparedness and mitigation. Some of the preparedness and mitigation measures are

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1. Water Conservation and Vegetation

Water conservation is the simplest and most useful measure. By preventing misuse of water and encourage recycling of water the problem can be tackled to a little extent.

Some Water conservation measures are:

• Ensure that the overhead tank never over flows.

• Repair leaking taps immediately

• Try to make reuse of water for activities like watering fields and bathing animals.

To minimize the suffering of human and livestock, relief measures are taken by the respective State Governments and NGOSÊ on a large scale. These measures mainly aim at provision of drinking water, supply of food grains through Public Distribution-System at subsidized rates, supply of food arid fodder for livestock, human and livestock healthcare, etc. Efforts to create direct and indirect wage employment through food for work barely sustain the living of the rural poor who suffer most due to drought. However, some long-term preventive measures need to be given increased attention for integrated development of drought-prone areas and to tackle the problem on permanent basis. Some of these direct measures are long-term forecast of monsoon, suitable lad use system, water harvesting, soil and water conservation, contingency crop planning, adoption arid improved technologies for dryland crops, efficient irrigation methods, enrichment of cereal straw as fodder, etc. In addition to these, human and livestock Population pressure needs to be reduced through education, alteration ways of employment generation arid disposal of unproductive livestock.

As water is the scarce resource in the Indian arid zone, efficient irrigation technologies like sprinkler and drip system should be popularized which aim at minimizing production per unit of irrigation water. Adoption of improved agronomic practices like use of improved varieties, timely weed control, use of fertilizers along with farm yard manure, in-situ rainwater harvesting, etc. can give good yields even in below normal rainfall years. Cultivation of water intensive crops should be discouraged.

Environmental improvements help to restore ecology in the region. Vegetation Cover helps the rain water to seep underground. This would increase the water

table and over the time precipitation is also increased due to the vegetation cover. Besides natural resources, livestock and permanent Vegetation Such as grasses and trees are strengths for survival of mankind in the arid regions. Management of grasslands with Lasiurus Sindicus, Cenchrus ciliaris arid Cenchrus setigerus and top feed specie such as Prosopis cineraria, Acacia sengal and Tecornella undulata need priority attention. Such a silvi-pasture system survives annual droughts and provides rich fodder. Quality of fodder particularly the wheat straw given to cattle during drought is usually very poor. The fodder quality can be improved through urea/molasses treatment, thus improving animal health and productivity with very little investment. Management of common property resources such as grazing lands, dams, village ponds, etc. needs top priority by the people for themselves to combat drought in and regions.

2. Water Storage

A long term defense against drought is construction of dams and reservoirs for artificial storage of water. This water is then supplied to the water supply source through these storage reservoirs. Water is stored n the reservoirs during the high rainfall time and then used during the lean rainfall period. Village Ponds and Tanks are also good strategies to combat effects of droughts.

No one understands the value of single drop of water better than the desert dwellers. Rainwater harvesting is traditional way of life in arid regions. Various techniques of rainwater harvesting have been developed/refined by research workers. Improved designs of water harvesting structures have also been developed. These technologies should be popularized among the people of this region. Utilizing flash floods/ surplus rainwater for artificial recharge of groundwater to augment the dwindling water table is need of the hour. Integrated watershed management, which aims at utilizing the rainfall wherever it falls should be the unit for planning and implementation of the development programmes. The measures like afforestation, pasture development, livestock management, field crops, water Storage, etc. are undertaken in the watershed areas identified as suitable for Such measures. The capacity of these ponds and reservoirs will decrease due to the deposition of silt which is carried with the water that comes to the reservoirs. This gets settled at the bottom. Thus Periodic cleaning of these reservoirs is necessary as the capacity of these ponds, reservoirs etc will decrease by the deposition of silt which is carried it water at the

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bottom.

3. Watershed Management

The land area that sheds water into a particular river is called its watershed. The surface runoff from this area ultimately finds its way to the river. When watershed of the river is heavily forested, the surface runoff is less. Roots of the trees and littered leaves on the ground help in absorbing water. However in deforested areas, the run off from the watershed is considerable. Water here is not retained in the watershed and thus flows into its river and then to the sea. This leads to less groundwater replenishment and the wells also get dry during lean season. It is therefore important to grow more and more trees where ever possible or build embankments which will also help p to reduce soil erosion.

The root cause of weak monsoon in India is related to the widespread, persistent atmospheric subsidence, which results from the general circulation of atmosphere. Better understanding and mathematical modeling of the monsoon phenomenon would be very helpful in early long-term forecast of monsoon to enable planners and arid farmers to plan accordingly.

With the increased pressure oil land, marginal lands are being brought under cultivation, which is a disastrous trend. Concerted efforts have to be made to adopt Suitable land use systems keeping in consideration tile rainfall, soil type and need of the people. Growing of crops, fruits, trees and grasses various combinations minimize the risk of crop failure and provide stability to farm income. Suitable combinations of these components for different rainfall zones and soil types should be preferred over traditional crop cultivation alone.

4. Rainwater Harvesting

Rainwater harvesting is the collection of rainwater. Rainwater thus collected can be stored for either direct use or can be recharged in to ground. In other words it implies catching rainwater for use at the place where it falls. Rainwater harvesting via roof top and ground catchments is an ancient technique of providing domestic water supply (Agarwal and Narain, 1997) and it is still used, especially in tropical islands and in semi-arid rural areas. It is a best option and preferred as an alternative source of domestic water supply where the ground water is inaccessible due to certain technological & environmental problem. State Governments in India have been encouraging the people to adopt the domestic rooftop water harvesting through

subsidized schemes. The water thus collected can meet the immediate domestic needs. Rainwater harvesting has assumed overriding significance all the more in view of the depleting ground water levels during the recent droughts in various parts of India (Ariyabandu, 2001).

There are two methods to store rainwater namely Roof top water harvesting, and recharging ground water. In the Rooftop water harvesting, the rainwater is collected using house roof and stored it to in storage tank. Water from roof top rainwater harvesting can be directly used as drinking purpose. On the other hand, Recharging ground water through tube wells can be achieved by diverting the farm water towards the tube well through filter system. In rainy season all rainwater will go under the tube well. There are still many problems that occur in rain water harvesting need good technical solutions. Rainwater harvesting system for domestic purpose has been operated and managed well but for the irrigation projects, awareness and capacity building is necessary for most of the farmers. Demonstration, training on the irrigation methodology, as well as the market service should be carried out to help the rural households to get better profit from the Rainwater harvesting irrigation system.

Water Scarcity and Public Health IssuesReclaimed water is an alternative water resource.

Water reuse can be a tool in managing scarce water resources. Recycled water is being used as substitute for many traditional non potable uses and for sources that provide raw water for drinking water production (Table 1). Such use can help conserving drinking water by replacing it or the water taken from drinking water sources, and by enhancing sources such as reservoirs and groundwater. The improvements in treatment of wastewater have opened new possibilities to reuse treated wastewater. Hence, the indirect recycling of water used in many parts of the world has been largely practiced for many years.

Although treated wastewater has been an important mean of replenishing river flows in many countries and the subsequent use of such water for a range of purposes (Fig.1) constitutes indirect reuse of wastewater, it is becoming increasingly attractive to use reclaimed or treated wastewater more directly. In addition, reclamation of wastewater is attractive in terms of sustainability since wastewater requires disposal if it is not to be reclaimed. Treated wastewater may be used as an alternative source of water for agricultural irrigation.

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Agriculture represents up to 60 % of the global water demand while the requirements arising from increasing urbanization such as watering urban recreational landscapes and sports facilities, also creates a high demand. The treated wastewater can be efficiently utilized in agriculture, irrigation of green spaces, including those used for recreation in which individuals may come into contact with the ground. Concerns related to the reuse of treated wastewater are similar to the reuse of sludge, in particular the risks of contamination. Treatment plants are typically only equipped for biological treatment which does not eliminate the chemical substances in the waste water.

In urban environments, treated wastewater may also be used for fire-fighting purposes or street cleaning. In industry, the use of recycled or reclaimed water has extensively developed since the 1970Ês, for the dual purpose of decreasing the purchase of water and avoiding the discharge of treated wastewater under increasingly stringent emission regulations. This trend started with wash-water recycling but now incorporates the treatment of all types of process waters. Virtually, all industrial sectors are now recycling water, with examples in pulp and paper, oil refinery, etc. Consequently, together with overall shifts in the industrial sector, a 30 % reduction of industrial water consumption could be achieved in many developing countries.

Table 1: Water recycling and reuse definitions

Use Definition

Reclaimed water Treated wastewater suitable for beneficial purposes such as irrigation

Reuse Utilization of appropriately treated wastewater (reclaimed water) for some further beneficial purpose

Recycling Reuse of treated wastewater

Potable substitution Reuse of appropriately treated reclaimed water instead of potable water for non potable applications

Non-potable reuse Use of reclaimed water for other than drinking water, for example, irrigation

Indirect recycling or indirect potable reuse Use of reclaimed water for potable supplies after a period of storage in surface or a groundwater

Direct potable reuse conversion of wastewater directly into drinking water without any intermediate storage

Figure 1. Different applications of reuse

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Final RemarksWhen entering the new millennium, India

has put forward the overall goal of setting up a well-off society in the whole country. Thus the rain water harvesting approach has faced serious challenges to meet this goal. Can the rain water harvesting approach help the population in the rural mountainous area to raise their life to a standard conforming to this goal? For example, the current amount of water supply by the rain water harvesting system can only meet the demand of human basic need. Can the rain water harvesting system be enlarged to produce enough water for a much more comfortable life? Quality issue will be another

challenge. Some institutes have studied the water demand of rural household with low, medium and high standard and the possibility of meeting the demand with rainwater harvesting system. To meet the goal, it is of first importance to reduce the water consumption and at the same time to keep the necessary standard of a well off life. Water in the rainwater harvesting system is very limited it should be used in a conservational way. In the rural area, the dry ecosan toilet can be good solution to avoid using of any water for the toilet. For the production water use, one of the criteria for selection of crop should be the maximum output of unit production. Water from the rainwater harvesting system should be used to irrigate the high value crops.

ReferencesAgarwal, A. and Narain, S.: Dying Wisdom: The Rise, fall an Potential of India’s Traditional Water

Harvesting System. Centre for Science and Environment, Delhi (1997).Ariyabandu, R. D. S.: Varieties of water harvesting. In: Making Water Everybody’s Business: Policy and

Practice of Water Harvesting. Centre for Science and Environment, Delhi (2001).Sharma, P. C. and Sen., P. K.: Domestic roof (rain) water harvesting technology. In: Proceedings of Delhi

Workshop on Roof Water Harvesting. Delhi (2001).Water Resources of India and World, Newsletter on Fresh Water Year, 2003. Ministry of Water R.

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Impact of Cost Effective Water Harvesting Techniques on

Artificial Groundwater Recharge Through Open Wells and

Recharge from Natural Streams

K.Ramaswamy

12

IntroductionThe acute water scarcity of the Western Ghats

region of Tamil Nadu coupled with soil erosion and siltation of reservoir makes not only the fertile soils of the cultivated land unproductive but also makes many people in eastern sides of hills consisting of tribal population to the poverty driven subsistence livelihood. Below poverty Line conditions, destabilisation of agricultural base and employment problems are noticed in general. The rainfall in the rain shadow parts of Western Ghats region varies from 600 to 800 mm. Though this rain is nearly adequate for drinking and agricultural production, due to the inadequate treatment and improper in for large parts of the area, even the drinking water is not available in foothills. Many towns, depending on river flow originate from hills. Though there are many Central and State government watershed development projects operating in this area, most of them are confined to drainage line treatment measures with limited application in the cultivated lands. Moreover, there is lack of adequate maintenance of development measures after the project is withdrawn. Given meager or nil participation of local

people, limited water availability in farmers holdings, the sustainable agricultural production measures with farming system perspective is an essential one. This is possible only by improving hydrological regime of the area for the enhanced agricultural production and income generation. Hence, a proper agricultural land use by growing horticulture / forest species with increased soil moisture retention storage and suggesting water harvesting measures for improved ground water regime is the main aim of this project funded by science of society division of DST ,GOI.Which may likely bring additional net revenue for the farmers. Three tribal villages have been selected and the holistic water harvesting (Terrain of village habitats, roads and cultivated fields) mechanisms are generated with the involvement of people from the planning to maintenance stage.

The selected villages are:

(i) Tholampalayam

(ii) Neelampathi

(iii) Mottiur

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There are many wells in these villages having yields range from 0.5 to 2.0 Lps and the depth of water table is 20 to 30 m below ground level in bore wells and 8 � 12 m in open wells. The water stored lasts only for 6 or 7 months in a year with 1 to 2 hours daily supply with 5 Hp Pump sets. The aquifers present are mostly unconfined nature. Some wells were abandoned / dried. The people particularly tribal farmers often mi-grate from these areas to far off distance for about 4-5 months or remain idle, facing a lot of food crisis and poverty issues. Under these circumstance even if a well with common lands available is properly utilized, a part of revenue through herbal/ horticultural plants can be generated & maintained. To accomplish this, a compre-hensive live water harvesting and conservative water use model in each selected village farm holdings with total involvement of people has been developed through this project.

METHODOLOGY & SYSTEMS AP-PROACH ADOPTED

This project has been carried out in farmerÊs field with their involvement in planning and implementation and with their contribution in terms of labour / cash to a level of 9 to 11 % of the cost of water harvesting mech-anisms, using locally available materials & techniques.

The tribal villages selected lie in the foothills or lower range of Western ghats in Coimbatore district.

(i) Quantification of Surface Runoff

Quantifying maximum excess surface runoff at farm level from long-term data for monsoon seasons in three tribal villages located in Western Ghats of foot hills was carried out by curve number method after analysis the long term rainfall data of 27 years.

Rainfall Data and Runoff Analysis

Monthly rainfall data for 27 years from 1979 to 2005 was obtained from Avinasilingam Krishi vigyan Kendra, Vivekanandhapuram nearly 10 km away from the project area. Rainfall was analysised seasonwise viz., Northeast monsoon (Oct-Jan), Southwest mon-soon (June-Sep), summer season (Feb-May) and annual rainfall for 27 (1979-2005) years and average monthly rainfall was calculated. The maximum (1466.68 mm) and minimum (588.40 mm) rainfall were received dur-ing the years 1979 and 1989 respectively. The average annul rainfall for 27 years data was 848.11 mm. During pre monsoon period the average rainfall received was 211.65 mm. It was 24.96 % of average annual rainfall. The average rainfall received during Northeast monsoon and Southwest monsoon was 440.52 mm and 195.94 mm.

The percentage of rainfall received during

Northeast monsoon and Southwest monsoon was 51.94 % and 23.1 % of average annual rainfall. Frequency analysis of 27 years annual rainfall was done by WeibullÊs.distribution. For 1, 2, 5, 10 and 27 years return period

Month Rainfall (P) Runoff (Q) (mm)

Well-1 Well-II Well-1II

January 20.71 0.54 0.27 0.22

February 19.24 0.74 0.42 0.36

March 39.20 0.63 1.10 1.23

April 82.82 14.32 16.77 17.34

May 70.38 9.00 10.89 11.34

June 23.16 0.27 0.09 0.06

July 20.96 0.50 0.24 0.20

August 37.74 0.46 0.87 0.98

September 114.08 31.08 34.81 35.66

October 210.47 149.76 155.69 155.72

November 173.30 115.15 120.60 120.63

December 39.04 7.74 9.28 9.29

Table 1: Runoff Estimation (January to December)

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the rainfall received was 588.40,818, 945,1100 and 1467 mm respectively.

(ii) Collection mechanism

(a) Design and execution of most efficient hydraulic sections with vegetated open channels and pipes for conveying the excess surface runoff and run-off from roof catchments safely into the wells located in farms/ villages outskirts using both scientific data and heuristic knowledge of local people.

(b) Development of economical filter mechanism for screening sediments/ silts/ eroded materials entering into the open wells (abandoned/ partially used).

(c) Evolving efficient and economical design methods of „Recharge tube wells‰, „injection wells‰ and other runoff injection techniques into the bore wells wherever necessary.

Proposed technologies are different from existing ones

(a) Excess runoff collected from upstream area is channalised through an economical conveyance system to a filter bed which are connected to ground water wells.

(b) Vegetative water ways and the minimum length of pipe conduits with the varying economical cross sections based upon the hydraulic design were employed in this study.

(c) In this approach, channel erosion was less. The silt materials conveyed to the filters was also minimum.

These techniques cost are effective

(a) Moreover, costlier constructional materials meant for drinking water filters are being used in the already existing techniques whereas the locally available stone materials were used with proper filter bed design for meeting irrigation needs in this project.

(iii) Field Monitoring of Soil Moisture / Groundwater Recharge and Quality

Installing observation wells/ use of nearby wells in different directions of test wells and observation of water table data, retention period of water and Quality improvement (EC& pH of groundwater).

Analyzing the zone of influence of recharge effect using tracer technique.

Monitoring soil moisture data and the effective zones of moisture distribution from the developed wells.

Sediment deposition in collection stream / chan- nels.

Water table fluctuation � specific yield approach to quantify the ground water recharge and recuperation studies have been taken up for assessing the perfor-mance of wells. Also period of availability of water in wells before and after imposing the treatment would be monitored.

(iv) Analysis of Data and Allocation Strategy

Analyzing the existing cropping systems and crop water requirements for matching with the maximum possible Ground water supplies including the recharge facility by suitably allocating the areas under different crops. „Allocation area strategy‰ arrived by scientific method shall be advocated to the tribal farmers for adoption.

Low-Cost Recharge Structures Implemented

(a) Vegetated open channels with inverted stone filters.

(b) Composite earthen and lined channels with an array of silt traps and with a separate collection storage filter bed.

(c) Telescopic pipe conduits and collection systems.

(d) Recharge tube wells with sloped section casing pipes wrapped with coir fibre and gravel pack.

(e) Recirculation arrangement of over flow water for wells located in low-lying tracts.

Field Work DoneFive open wells in Neelampathy and Motiyur

were selected with tribal farmers. The water availability in three farmers wells are very less, not even meeting the crop water demands for a crop season of four months. Their lively Good condition is very pathetic and their income level is below poverty level. In order to enhance the annual water availability for a major period in a year, channeling the runoff water to this wells have been planned by arranging group discussion of local farmers along with the five beneficiaries. The locally available stones of different size were collected with participation of beneficiaries. Proper inlet and outlet pipes were placed

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in position inside the filter bed so that the harvested rain water from the upstream fields of the well were collected, filtered and then pass into the wells.

People Participation(i) Initially group meetings were arranged to

understand the project by the local community with the help of Panchayat raj President and other local leaders.

(ii) Baseline information was generated and thereby problems and felt needs with people were ana-lyzed by group discussion which made them to give the willingness to participate in the programme.

(iii) It has been shown the impact of such technology to these tribal community people for taking them to the nearby area where one recharge well is func-tioning effectively by arranging exposure visits.

(iv) Finally many people were interested to have this technology to be implemented in their field by contributing their labour and rendering requisite

cooperation by contributing approximately 10 % for this project.

(v) One lady farmer was also very much co-operated in first phase itself, though she did not receive ay formal education.

Base Line Information about Tribal FarmersFarmer Name : Mrs.Rangammal (Neelampathi Village)Total area : 2ac

Irrigated area :0.7 ac

Fallow : 1.3 ac

Open Well : 5 HP, discharge � 30,000 lit/hr

Water Requirement per Irrigation : 40 mm (01-15 days and 75-90 days)

: 50 mm (16-75 days)

Water demand and supply for Vegetables

Sl.No Crop Period Water Demand (m3) Daily available pumping period (minutes) Water Supply (m3) 1 01-15 days 113.3 45 112.5 2 16-30 days 141.6 45 112.5 3 31-45 days 141.6 30 105.0 4 46-60 days 141.6 30 105.0 5 61-75 days 141.6 30 105.0 6 75-90 days 113.3 15 52.5 Total 793.0 592.5

Sl.No Crop Period Water Availability (m3)

1 1-15 days 120 2 16-30 days 120 3 31-45 days 80 4 46-60 days 80 5 61-75 days 80 6 75-90 days 56 Total 536

Table 2: Water availability in Mrs. Rangammal field

Table 3: Water availability in Mrs. Rangan field

Farmer Name : Mr. Rangan (Neelampathi Village)Total area : 4 acIrrigated area : 2 acFallow : 2 acOpen Well : 5 HP, discharge � 32,000 lit/hr

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Q = Well yield m3 / hr

Results and DiscussionCostlier constructional materials meant for

drinking water filters are being used in the already existing techniques whereas the locally available stone materials was used with proper filter bed for meeting irrigation needs. Under these circumstances even if a well with common lands available is properly utilized, a part of revenue through less water consuming horticultural plants can be generated & maintained. Vegetative waterways with silt traps and the minimum length of pipe conduits with the varying economical cross sections based upon the hydraulic design were employed. In this approach, channel erosion was less. The silt material conveyed to the filters was also minimum. The existing long- term water harvesting technologies of ground water recharge particularly through tanks and ponds consume a huge quantum of evaporation loss during storage. As the harvested water is directly let into the aquifers, the transmission efficiency of water through fissures and cracks

In a similar hydrogeological condition at Somayampalayam (nearby area), the single abandoned well recharge technique through this method resulted in more available water with a pumping duration of 1 hr per day by raising water table of 15 m in a deep well

Sl.No Farmer Name Crop Area (ac)

1. Mrs.Rangammal Banana with Drip System 0.25

Vegetables 0.45

2. Mr.Rangan Banana with Drip System 0.25

Amla 1

Vegetables / Fodder crops 0.75

Table 4: Proposed and executed Crop Plan in field

Table 4: Experimentation in Observation wells

(Brinjal,Bhendi)

Hydraulic Performance of Wells

Farmer’s name Doraiswamy

Depth of Well 18.29m Depth of Water (H) 15.24m Depth of Water Pumped (h1) 6.2m Depth of Water after Recuperated (h2) 4.5m Total time of pumping (T) 2.9 hrs Radius of well 2.4 m Area of Well (A) 18.27 sq.m Well Yield (Q) Calculated discharge 8.47 lit/ sec Measured discharge 7.1 lit/ sec Radius of influence 114 m

Table 5: Testing of Wells in farmers field

Sl.No. Particulars Well 1 Well 2 Control Well

Well Well Well Yield Yield Yield (m3/hr) (m3/hr) (m3/hr)

1 Open Well Depth (m) 10.67 13.72 13.72 7

32.49 26.00 2 Area of the Well (m2) 7.07 9 9

3 Depth of Water before 3.67 3.13 3.05 12.93 3.96 11.86 Implementation (m)

4 Depth of Water after 9.14 9.20 6.27 30.68 5.50 16.97 Implementation 20th Oct 2006 (m)

5 Depth of Water after Implementation 10.06 11.14 7.01 37.15 5.80 18.74 10th Nov 2006 (m)

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of 60 m for eight months in a year. One hour extra pumping hour with enhanced water availability (5 HP pumpset) resulted in approximately additional irrigated area of 0.4 ha with conventional method of irrigation. If it is conjunctively operated with modern irrigation systems like drip, it will irrigate twice, thereby irrigated area will be doubled (0.8 ha additional area per farmer).In short, the technology package would be convergence of technologies on water harvesting.

Benefits Derived From the DST Project on Water Harvesting and Ground Water Recharge (For the Tribal Community of Karamadai Block of Coimbatore Dis-trict)

Out of ten wells selected for the detailed study on the water table fluctuation with reference to water harvesting and storing the excess runoff water in the aquifers, five wells were installed with water harvesting structures and low cost filter mechanisms. Owing to the enhanced ground water recharge due to water harvesting and letting the filtered runoff water directly into the open wells, the cropped area has been increased and thereby the net income of farmers have also been increased.

Two specific cases of tribal farmers under the project and the success towards the improved income as a consequence of the result of the project is briefly given below:

I. Mrs. Rangammal (Lady farmer)

(i) Additional pumping duration with 5 HP in the existing well pumpset due to the water harvesting intervention = 1 hour

(ii) Area under irrigation after the techno-logical interventions = 0.8 ha

Crop cultivated with Drip System = 0.4 ha

(Tissue culture Grandnaine variety of banana)

(iii) Yield of 1200 plants from 0.4 ha

= 36000 kg.

Gross Income @ Rs. 6.00 per kg. = 2,16,000

Cost of Cultivation including crop management and harvest @ Rs. 30 per plant = 36,000

(Net Income ) = Rs.1,80,000/-

Mrs. Rangammal field 0.4 ha (1, 80,000 Rs.)

Net increased income = Rs. 1.8 lakhs / acre = Rs. 4.5 lakhs / ha

She has never seen such a huge financial benefit as related from her past agriculture profession.The net annual farm income before intervention project was only Rs. 25,000 to 30,000 /- from her entire field of 2 ha

II. Mr. Rangan (Farmer)

Gross Income = Rs. 21,500

Cost of chilly cultivation = Rs. 10,000

Net Income = Rs. 11,500

Net income from 0.1 ha Banana = Rs. 45,000

Total Net Income = Rs. 56,500

Benefits for Mr.Rangan1. Uncultivated dry area is brought under

irrigation due to enhanced water availability in the wells.

2. 0.2 ha area was cultivated with chilies and 0.1 ha banana with drip irrigation brought under the cultivation.

3. Likely net income from additional area installed is Rs. 56,500/- from 0.3 ha.

III. By seeing the successful results, the nearby farmers, they are voluntarily approaching to get the technology package and three farmers have already started doing similar water conservation and efficient utilization of well water. (Otherwise most wells are dried during summer season due to shallow depth and uncon-fined nature).

Natural recharge techniquesThe study of water table in one year indicates

the well yield is increased due to bio check dams artificial recharge through abandoned wells and existing irrigation wells.

An earthen embankment with vegetation (Agare americana and notchi) across the natural streams and diversion of excess runoff through channel and further letting into the same stream downstream of the earthen barrier across the stream were constructed in series in two natural gullies. This could facilitate improving of water table last for 8 to 9 months when the earthen embankments have been properly located at hard strata. This is the most cost effective structure (Rs.5000/-) the

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cost of similar structure and dimensions costs out of to be Rs 50000 to 65000.

The size of earthen embankments called „bio check dam‰ adopted across the gullies are given below:

Bottom Width =18m

Top Width = 2.7m

Height =3.5m

Slope =1:1.5

Recharge from streamsAn assessment was made to quantity the

recharge from the natural stream with benefits as these is considerable increase in water table in the open wells.

Poulbarinora � KochinaÊs (1962) inverse method was employed to quantify the rate of seepage from the perimeter of the stream (per unit length of the stream) when the aquifer is assumed to extend downward to a highly pervious stratum at infinity and also impervious lower boundary of the aquifer.

The rate of seepage q per unit length of the stream extended downwards to a highly pervious stream at infinity through its perimeter is given by the equation

q = K (Bw + 2dc) (1)

Where,

q = Rate of seepage, m3/day

K = Hydraulic conductivity, m/day

B w = Top width of the stream, m

dc = Depth of water at the centre of

the stream, m

Based up on the field investigation, the K value was estimated as 0.7m/day; Bw = 15 m,

dc= 1.6, Bw/d

c = 9.375

Now with respect to the x and y values the shape of the stream is given by Polubarinova-Kochina (1962) as follows

(2)

Plotting the stream boundary in accordance with

the above equation with the x and y values as tabulated below

When the lower boundary is impervious at infinity, then the rate of seepage q per unit length of the stream can be obtained by the following equation

q = K (Bw � 2dc) (3)

(4)

S.No. Month Depth of water in the well (m)

1. Past 30 years (1975 to November 2005) Nil

After developmental work

1. December 06 22.50

2. January 07 20.90

3. February 07 19.20

4. March 07 17.30

5. April 07 15.20

6. May 07 14.60

7. June 07 15.20

8. July 07 10.50

9. August 07 7.50

10. September 07 5.00

11. October 07 10.00

Table.8. Quantum of water recharged

Y -√dc2-y2 (Bw+2dc)/n cos-1(y/dc) X

1.6 0 0 0

1.5 -0.556 2.059 1.503

1.4 -0.774 2.927 2.153

1.3 -0.932 3.605 2.673

1.2 -1.058 4.186 3.128

1.0 -1.248 5.188 3.940

Table 9: Stream boundary co �ordinates as per equation

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Then plotting the stream boundary in accordance with the above equation with the x and y values as tabulated below

Table 10: Stream boundary Co-ordinate obtained when impervious layer is at lower boundary

Y �“dc2 � y2 (Bw � 2dc)/ n cos-1 (y/dc) x1.6 0 0 01.5 0.556 1.334 1.8901.4 0.774 1.898 2.6721.3 0.932 2.337 3.2691.2 1.058 2.714 3.7721.0 1.248 3.364 4.612

The above two methods could be used for the calculation of the seepage rate but the tabulated values with respect to the equ. (3) are more reliable compared to the equ. (1), so we consider the equ (3) was considered

for the seepage rate calculations.

The shape of stream as estimated by the co-ordinates when the impervious lower boundary (eqn.3) closely matches with the actual observations and hence, the equation 2 was used to quantify the recharge by the actual fields investigations of depth of water in the stream throughout the observation period of 11 months.

Quantum of Harvested Rainwater Directly Fed into The Open Un-pumped Abandoned Well

During the study period, three times excess rain water harvested at the downstream of the area was let into the open dried well (two decades dried without any storage) through a filter bed(2x2x2m size)filled with stones and small pebbles.

The quantity of water fed into the well were

estimated immediately after the three major rainfall events when filtered rainwater was let into the well by measuring depth of water in the well.

Depth of Water Table Rise in The WellWater table data from the ground surface of the

abandoned well prevent in the downstream of the area were observed and presented which showed cumulative recharge effect of all the above mentioned technological measures.

Salient Findings of The Project• Costlier constructional materials meant

for drinking water filters are being used in the already existing techniques whereas the locally available stone materials were used with proper filter bed for meeting irrigation needs.

• Vegetative waterways with silt traps and the minimum length of pipe conduits with the varying economical cross sections based upon the hydraulic design were employed. In this approach, channel erosion was less. The silt material conveyed to the filters was also minimum.

• The existing long- term water harvesting technologies of ground water recharge particularly through tanks and ponds consume a huge quantum of evaporation loss during storage. As the harvested water is directly let into the aquifers, the transmission efficiency of water through fissures and cracks in rocks for groundwater recharge will be maximum in the this technique due to the elimination of water movement through the vadose zone.

• In a similar hydrogeological condition at Somayampalayam (nearby area), the single abandoned well recharge technique through this method resulted in more available water with a pumping duration of 1 hr

Table 11: Calculation seepage rate value

SI. No. Co- ordinates obtained Co-ordinate obtained when Impervious Observed co-ordinates by eqn (2) layer is at lower boundary (4)

x y x y x y

1 0 0.16 0 0.16 0 0.16

2 1.503 1.5 1.890 1.5 1.7 1.5

3 2.153 1.4 2.672 1.4 2.8 1.4

4 2.673 1.3 3.269 1.3 3.1 1.3

5 3.128 1.2 3.772 1.2 4.0 1.2

6 3.940 1.0 4.612 1.0 4.8 1.0

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per day by raising water table of 15 m in a deep well of 60 m for eight months in a year.

• One hour extra pumping hour with enhanced water availability (5 HP pump set) resulted in approximately additional irrigated area of 0.4 ha with conventional method of irrigation.

• If it is conjunctively operated with modern irrigation systems like drip, it would irrigate twice, thereby irrigated area would be doubled (0.8 ha additional area per farmer).

• In short, the technology package would be convergence of technologies on water harvesting and modern water saving irrigation techniques.

ConclusionsThe well yield is increased due to artificial recharge

through existing irrigation wells in the tribal areas. The comparison of water table data in nearby wells outside the study area indicated that the influence of recharge is limited to below 100 m. Individual farm well recharge

through effective water harvesting method with the efficient utilization of harvested water through micro irrigation techniques with appropriate crop selection with bring sustainability of natural resources namely soil and water and will likely improve the farm income

Poulbarinova � KochinaÊs (1962) inverse method was employed to quantify the rate of seepage from the perimeter of the stream (per unit length of the stream) when the aquifer is assumed to extend downward to a highly pervious stratum at infinity and also impervious lower boundary of the aquifer. The impervious lower boundary predicted the shape of the stream more accurately and hence, this boundary condition was used to quantify the groundwater recharge in the natural streams. Eleven months water table observations in an abandoned well in the area revealed that there was a substantial increase in groundwater status to a tune 22.5 m due to integrating effect micro cements and the recharge from natural stream with vegetated earthern embankments(bio-checkdams).

ReferenceBianchi, W.C and D.C.Muckel. 1970. Ground �water Recharge Hydrology, Agricultural Research Service41-161,

U.S. Department of Agriculture, Washington.Doorenbos, J. and A.H. Kassam. 1979. Yield response to water. Irrigation And Drainage paper No: 33,FAO, Rome,

Italy.Polubarinova and Kochina , P.Y. Theory of ground water movement, 1962. Princeton University Press. Princeton,

N.J.���

104

Rain Water Harvesting , Recharging And Skimming

Tecniques Suitable For Saline Ground Water Tracts Of South

India

I. Muthuchamy and M. Raghu babu

13

IntroductionIn this paper, the research activities carried out

on water harvesting, recharging in Aruppukottai centre and skimming activities carried out in the coastal areas of Andhra Pradesh and Tamil Nadu in India are pre-sented.

RechargeArtificial Recharge Studies

The government schemes for enhancing ground-water recharge from rainwater through measures like contour bunding, percolation tanks, check dams, are be-ing carried out but more scientific evaluations are needed to estimate the effects. Similarly a large-scale programme of artificial recharge through existing dug wells has been initiated in Saurashtra region of Gujarat by a number of non-government organizations and about one lakh dug wells are recharged during every monsoon. Present technique of recharging through dug wells consists of diversion of runoff towards the well through a sediment trapping pit. It has the drawback that the recharge water carries suspended matter which clogs the well and the

aquifer. Hence Improvements in this regard are needed.

After studying the topography, soil type, rain-fall pattern etc., a model Recharge Research Structure (Percolation pond) was developed at Regional Research Station, Aruppukottai under the Tamil nadu Agricultural University, coimbatore, India.

Rain water harvesting and recharging system for Farmstead.

Catchment Area

A catchment area of 100 acres was delineated inside the farm after careful study of the topography, soil type, and rainfall pattern. The catchment is of „good catchment category‰. The runoff generated in the catch-ment during rainfall drains towards northern direction of a stretch of 770m East West direction. The run off is collected by means of a trapezoidal earthen channel running to a length of 770m East West direction at the northern downstream side of the catchment.

Conveyance Channel

The conveyance earthen channel was designed below ground level on the down stream side of the catch-

105

ments in East West direction to a stretch of 770 m to collect all the run off produced during rainfall in the catchments area.

The earthen conveyance channel was designed as Trapezoidal shape with the cross section of 1m bot-tom width, 2.64 m top width with 0.9m depth (below ground level) to catch and convey the rainwater to the Recharge pond (Percolation pond) at the Eastern end of the channel. A longitudinal slope of 0.5 in 1000 is maintained in the Trapezoidal earthen channel towards percolation pond in order to drain runoff into percola-tion pond. A spoil bank was made with the dugout soil on the down stream side of the Trapezoidal channel in order to control the runoff inside the channel during peak flood.

The spoil bank was designed to have the dimen-sions of 1m bottom width, 0.5m top width with 1m height. Excavator (JCB) formed the earthwork excava-tion and spoil bank simultaneously. The JCB type exca-vator is suitable for formation of channel below ground level and to form spoil bank simultaneously.

Recharge Structure (Percolation Pond)A Recharge structure (Percolation pond) was de-

signed at the eastern end of the trapezoidal conveyance earthen channel to collect all the runoff produced in the catchment and conveyed through the channel. The recharge structure (Percolation pond) was designed to impound one third of peak runoff produced during the rainy season and throughout the year. The percolation pond can stagnate 3000m3 of rainwater at a time

An earthen embankment of size 4.9 m bottom width, 1m top width with 5m height was designed and was formed with the chain type bulldozer for effective consolidation of the embankment for percolation pond. A waste weir was provided to drain excess water from the percolation pond and the excess water goes to the existing jungle stream inside the farm. Six numbers of bore wells are there in the vicinity of the percolation pond to utilise the recharged ground water. Chain type Bulldozer available in the Agricultural Engineering de-partment, Govt. of Tamil Nadu was used for forming percolation pond. The total volume of soil removed was 3107m3 from the place for formation of Recharge struc-ture (Percolation pond). The chain type dozer is suitable for formation of percolation pond. The total surface area of the pond is 3249m2. An amount of Rs. 59,063/- was spent to establish the percolation pond.

Response Borewells (6 Nos. of Existing Borewell)

Six number of bore wells are there in the vicinity of the percolation pond to utilise the recharged ground water and monitored the watertable trends before and after installation of recharge structure. The rising trends of watertable from well bottom in few wells indicate the influence of recharge structure.

System ProfileThe catchment area receives rainfall and gener-

ates runoff and this runoff goes towards the convey-ance channel and the conveyance channel discharges the runoff to the recharge structure (Percolation pond) and the runoff water is finally impounded in the percola-tion pond and is allowed to recharge into ground water source. The excess water in the percolation pond goes out and joins to the existing jungle stream through the waste weir. During the travel of runoff water along the conveyance earthen channel it recharges the open well by means of recharge bed created near the open well along the conveyance channel.

Roof Water-Harvesting System for FarmsteadRoof Top Catchment Area

The rooftop of Trainees hostel building of RRS was selected for the roof water catchment area.The RCC terraced top was already plastered with weathering tiles to prevent leakage and seepage of rainwater. Required very gentle slope was already provided towards outer sides of the wall (Super structure). Necessary rainwater drain outlets were provided. The roof top catchment area is 379m2.

Conveyance (Vertical and Horizontal PVC Pipeline)

The conveyance component of vertical and hori-zontal pipeline was selected with 110mm OD PVC pipe-line with required „L‰ bends, ÂTÊ joints and couplings. The rainwater is collected from the rooftop through the rainwater outlet and conveyed vertically downwards along the PVC 110mm pipe fixed on the wall. The vertical conveyance pipes were joined to the horizontal conveyance pipe by means of ÂTÊ joints. The horizontal conveyance pipeline was placed 0.8m below the ground level in order to prevent mechanical damages to the pipeline. The conveyance PVC pipeline was designed

106

to run for 150m to reach a Filter cum Recharge bed near an existing bore well. The rainwater harvested could run through the conveyance pipe and reach the filter cum recharge bed.

Roof Top Catchment (Trainees Hostel)A Filter cum Recharge bed of 320m3 capacity

was designed and established below ground level adjacent to an existing bore well. The recharged rainwater could reach the groundwater resources through the Filter cum Recharge Bed. The Filter cum Recharge bed was estab-lished with the help of JCB type excavator. The JCB type excavator is most suitable for establishing filter cum Recharge bed below ground level.The recharge effect on groundwater resources is being monitored through two numbers of existing bore wells at the vicinity of the Filter cum Recharge bed.

System ProfileThe Roof top catchment area receives rainfall

and generates runoff and this runoff goes to the verti-cal conveyance PVC 110mm OD pipes and joins to the horizontal conveyance PVC pipeline of 110mm OD bur-ied below ground level. The rainwater in the horizontal conveyance pipeline goes to the Filter cum Recharge bed created adjacent to the existing bore wells and per-colates into the ground water resources to augment the bore wells.

Abandoned Open Well Recharge System for FarmsteadAbandoned Open Well

An open well available in the RRS farm was uti-lized for recharging the open well through the wayside Filter cum Recharge bed attached with the conveyance earthern channel. The open well dimensions are 7.32m × 10.78m × 12m.

Filter Cum Recharge Bed

The conveyance Trapezoidal earthen channel was aligned in such a way that the channel was attached with a Filter cum Recharge bed established very near to the existing abandoned open well. The harvested rain-water can stagnate in the Filter cum Recharge bed dur-ing the travel in the conveyance earthen channel. The Filter cum Recharge bed was designed to have 112m3 of rainwater and established below ground level. The JCB

type digging and earth moving machinery can be de-ployed to establish the Filter cum Recharge bed.

System Profile

The catchment area receives rainfall and gener-ates runoff and this runoff goes towards the conveyance channel and the conveyance channel discharges the runoff to the percolation pond through the Filter cum Recharge bed established very near to the existing aban-doned open well. Thus the Filter cum Recharge bed recharges the harvested rainwater into the groundwater resources, which will be realized in the abandoned open well.

Conclusion

The recharge effects on ground water resources was being monitored htrough the existing bore wells at the vicinity of the recharge structures for four years fri-om 2001- 2004.Due to thos the water level in the bore wells rised in the range of 0.6 to 3 m, the EC of the water decreased in the range of 0.5 to 1.5 ds/m and the PH decreased in the range of 1 to 2 in the wells in and around 3KM radius of RRS Research Farm, Arrup-pukottai, India.

Skimming

Induced seepage in coastal areas due to non-judicious pumping gradually diminishes the productivity of agricultural lands. The salt water intrusion problems in coastal regions may occur both on a regional and local scale. The regional effects encompass large areas due to movement of the interface of fresh and saline ground water in an upward and/ or inland direction. The lo-cal small scale effects relate to gradual deterioration in ground water quality due to upconing or rise of relatively more saline ground water from deeper levels with in the domain of abstraction wells.

Under such a situation, it is imperative not to disturb saline water but selectively skim the fresh water accumulated over the saline aquifer due to recharge from rainfall, irrigation and or canal seepage over the native saline ground water by conventional wells or modified forms of radial wells. Sustainability of fresh ground water under these hydrodynamic conditions is influenced by the interface between the fresh and saline water layers. For stabilization of interface, the management strategies are to be evolved with the present and future demand scenario.

107

Skimming StructuresVarious skimming well configurations such as

single, multi-strainer, radial collector, compound and re-circulation wells are possible to exploit the fresh water overlying the saline ground water. A single tube well/filter point is commonly used in unconfined aquifers. While using these wells in saline ground water regions, well penetration is deep into the fresh water layer with a large gap between bottom of well and fresh- saline water interface. A multi-strainer well, which is relatively shallower penetration than a single well, can be used to harvest fresh water layers of restricted depth.

In Andhra Pradesh, about 1.74 lakh ha coastal sandy soils are characterized by good quality water float-ing over saline ground water at shallow depths of 0.5- 6.0m, which cannot be extracted by with conventional tube wells or deep wells. These soils occur in a 10 km wide and 972km long eastern coastal strip extended from Ichapuram in Srikakulam district to Tada in Nellore district. During summer months the water table in these soils fall up to 1.8 � 3.0 m, below ground level (bgl). The ground waterget recharged during the monsoon season and accumulates in the sandy soils. By middle of No-vember the ground water rises up to 0.3 to 0.5 m bgl in most of the belts.

Doruvu TechnologyThe farmers in these areas dig conical pits called

doruvu’s and harvest the recharged water for grow-ing of vegetables, tobacco, paddy nurseries and flow-ers. Each Doruvu occupies an area of 160-200 m2 (4-5 cents) and will meet the irrigatio requirements of about 800m2 .Ten such doruvu’s are required to irrigate 1 ha.area, which occupy an area of 2000 m2 i.e., about 20% of the cultivable area. Performance of shallow wells in the sands is constrained with thin aquifer of fresh water, seasonal and limiting recharging rate and semi-confined/perched conditions due to clay base in bottom levels. Thus, scarcity of irrigation water at critical growth stages is the major impediment for obtaining optimal crop yields from rabi groundnut and other crops. Simi-lar situation exist in coastal parts of Tamil Nadu and farmers tap good quality waters by ÂOothuÊ. In Tamil Nadu, the coastal region is spread over an area 0f 0.74m ha. The coastal belt has a length of more than 700km, stretching from Pulicat lake in the north to Cape Coma-rine in the south.

Improved Doruvu TechnologyTo overcome the situation, the skimming well

technology popularly known as Improved Doruvu Tech-nology was developed to skim the limited fresh water floating with out disturbing the hydro-dynamic condi-tions. With this system, sufficient water is expected to be made available to rabi and plantation crops and optimum usage of water through sprinkler and drip ir-rigation methods can be practiced. Depending on the watertable head above the collector pipes, the collectors are continuously charged with fresh water throughout their length and about 2 -15 lps of water flows into the sump under gravity.

About 64 such skimming wells covering 141 ha cultivable area were installed in 17 villages of Guntur and Prakasam districts of Andhra Pradesh. Three Skim-ming wells were exclusively installed in Repalle Mandal of Guntur district for drinking water purpose. Under Na-tional Agricultural Technology Project, the Tamil Nadu Agricultural University introduced the skimming technol-ogy in Prataparamapuram and Vettangudi of Nagapat-nam and Myladuthrai districts by installing 2 wells after detailed investigations on a pilot scale. Also few shal-low depth multi-strainer wells were installed in Andhra Pradesh and Tamil Nadu coasts during the recent years for study purpose.

For construction of Skimming well, a sump of 1.2- 1.8 m (4-6Ê dia) width and 4.5- 5.5 m depth is to be installed in the identified location. On either side of the sump, a trench is made and 100 mm (4‰ dia) corrugated PVC pipe (CPVC) with 5 rows of perforations is laid at a depth of 2.1 � 4.0 m over a lenth of 35-50m. At the designed depth holes are made to the sump and the CPVC pipe collector lines are laid at 0.1% slope, starting from the holes. 60 number Nylon mesh is used as pipe envelope material. In fine sandy soils 10 cm thick gravel packing around collector is also required. Af-ter installation of the collector lines, the trench has to be back filled. Depending on the water table head above the collector pipes, the collec-tors are continuously charged with fresh water throughout their length and about 2 -15 lps of water flows into the sump under gravity.

Advantages of Skimming Well (1) The up- coning of Saline ground water is

avoided as the collectors harvest only the shallow depth fresh water available above the collectors.

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(2) Over exploitation of ground water is not possible.

(3) Wastage of water through evaporation from the excavated pits/doruvuÊs is avoided.

(4) Availability of more area for cultivation.

(5) Facilitates the adoption of water saving, modern irrigation practices like drip and sprinkler and improves the water use efficiency in crop production.

Installation CostDepending on the size of sump and depth of the

installation of collectors, the cost of system vary from 26,000 to 40,000/- (Annexure 1).

Villages of Tamil Nadu. Also under rural drinking water Scheme(RDS), Skimming wells were installed in five different locations of Andhra Pradesh.

Improvement in The Installation of Skimming Well

In the past, the manual installation of skimming well involving construction of sump and laying of stoneware pipe collector line was a process of 10 � 12 days. But now, with semi mechanization and use of Excavator besides easy installation materials such as Corrugated PVC pipe, the well is being constructed in 3-4 days.

Constraints in Popularization of Technology

Though the technology has been demonstrated at a number of sites, itÊs adoption by the small and mar-

ginal farmers is constrained due to non availability of funds, laborious process of installation and small farm holding/ leasing of lands.

Community Skimming Wells In order to minimize the installation cost as well

as to provide opportunity to small and marginal farmers 3 skimming wellshave been installed in an area of 5 ha., covering individual holdings of thirteen farmers at Tim-mareddypalem. The use of skimmed water in these wells is on rotation basis. The farmers successfully operated the wells and produced high yields of groundnut as well as chillies during 2002-04.

Conclusion With skimming well, it is possible to irrigate

0.5 ha. daily with use of 6 � 8 sprinklers. Each skim-ming well can irrigate 2 ha. of I.D crop under sprin-klers or 4 ha. of plantation area under drip system dur-ing rabi. Chillies, groundnut, pulses, colacasia, paddy nursery, flower plants, coconut nurseries and vegetables are some of the crops grown under these wells.So far more than 64 skimming wells covering 141 ha area were installed in 17 villages of Guntur and Prakasam districts of Andhra Pradesh and 2 wells covering 4 ha in 2.

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Theme – 3Enhancing Water Productivity in

Rainfed Area

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Crop Management Options to Enhance Water Productivity of

Rainfed AreasS.Natarajan, C.Sudhalakshmi, R.Jagadeeswaran and R.Venkitaswamy

14

Rainfed agriculture occupies 100 m ha out of 143 m ha of net sown area in India. It contributes 40-45 per cent of the total food production and supports 60 per cent of cattle heads. Evergreen revolution crops such as rice and wheat still have 50 per cent and 19 per cent under rainfed conditions.

Water productivity of rainfed crops can be im-proved by better crop management options. Suitable selection of crops and varieties is important to harness the available rainfall. In regions receiving 350 � 600 mm rainfall with an effective growing season of 20 weeks only single cropping and if more than 750 mm rainfall is received, double cropping is possible. Intercropping can be practiced to minimize the risk of single cropping system. Groundnut + sorghum in North Eastern zone, Groundnut + redgram in North Western zone, Cotton + redgram in Western zone, Cotton + blackgram in south-ern zone are some of the intercropping systems. Seeds can be hardened with KH

2PO

4, KCl, NaCl, CaSO

4 to

induce resistance to drought and adverse weather condi-tions. Proper time of seeding is an important factor in rainfed cultivation. Planting redgram after onset of south

west monsoon had recorded the highest mean seed yield as compared to the planting on second fortnight of July. Rainfall use efficiency could be increased with premon-soon sowing. Seed drill sowing is more useful in view of precision in the depth of sowing, uniformity in spac-ing and rapid coverage compared to common broadcast sowing.

Surface configuration as tied ridges is used to trap runoff when rainfall exceeds infiltration in drought prone shallow alfisols. Ridges are advantageous in some nutrient deficient soils to concentrate the fertile top soil and to conserve water. Broad bed and furrow systems can be practiced for moisture conservation and for in-creasing crop yields in vertisols. Compartmental bund-ing produce higher grain yield of pearl millet compared to flat bed method of sowing in vertisols. Mulching is practiced to reduce soil evaporation and to conserve soil moisture. Residue mulch prevents direct impact of rain drop on soil aggregates, maintains porespace and high infiltration rate. Surface mulching with different organic mulches such as sorghum stubble, pearl millet straw, paddy straw, saw dust, groundnut shell and dust mulch

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showed that mulching increased the soil moisture con-tent by 3 %. In cotton, saw dust mulch of 2.5 cm thick-ness recorded higher moisture content and was on par with groundnut shell mulch and stubble mulch.

Research data of the past 25 years in rice, maize, sorghum and pearlmillet revealed that grain yield re-sponse was higher for balanced nutrition with nitrogen, phosphorus and potassium fertilizers. Calcium nutrition in rainfed groundnut, gypsum for oilseeds, micronutrient mixture @ 12.5 kg ha-1, zinc enriched FYM and iron en-riched FYM application proved to be beneficial in rainfed areas. Drilling or point placement method in the root zone and split application were found to result in higher N recovery (by 25 %) than surface application or basal incorporation. Foliar spray of 2 % DAP and 0.5 to 1 % KCl at flowering enhances the productivity of rainfed pulses and horticultural crops respectively. Application of Farm yard manure @ 12.5 t ha-1, addition of farm wastes or tree loppings viz., Leucaena, Glyricidia etc., or composted coir pith, pressmud / biocompost @ 5 t ha-1 in addition to the recommended dose of fertilizers was found to improve moisture retention and result in enhanced yields in pure cropping as well as rainfed inter-

cropping systems. Application of tank silt was found to improve soil fertility and result in increased yield in rain-fed ragi and groundnut. Azospirillum, Rhizobium and VAM are the commonly recommended biofertilizers for better seed germination, enhanced seedling vigour and crop establishment. Temperature tolerant strain Az.t.II was developed specially for rainfed areas by TNAU which aid in fixation of atmospheric nitrogen even at 45oC.

Legume based intercropping systems are rec-ommended and Integrated farming system with rainfed crops, bund trees, goat, biogas unit resulted in effective recycling of farm resources and better remuneration. Combination of suitable techniques for weed control has a complementary effect. Application of glycel (1 %) fol-lowed by summer ploughing 15 days after during fallow period and application of Metalachlor 1.0 kg a.i /ha + one hand weeding on 40 DAS for kharif groundnut recorded maximum yield. Crop rotation plays an important role in the management of host specific weeds. Contingent crop planning has to be adopted in aberrant weather conditions. Mechanization can be practiced from sowing to harvest to prevent the drudgery of labour and improve the productivity of rainfed farming systems.

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Opportunities for Enhancing Crop Water Productivity in

Rainfed Areas: An Assessment for Rainfed Areas of India

Bharat R Sharma, K V Rao and KPR Vittal

15

IntroductionRainfed agriculture generates about 65-70% of

the worldÊs staple foods, but it also produces most food for poor communities in developing and least favoured areas. Rainfed areas in South Asia and Africa, home to the worldÊs largest proportion of drought prone ar-eas (about 44%), have extremely low yield levels. The distinct feature of the rainfed agriculture in developing countries is that both productivity improvement and ex-pansion has been slower relative to irrigated agriculture (Rosegrant et al., 2002). But as Pretty and Hine (2001) suggest that there is a 100% yield increase potential in rainfed agriculture in developing countries, compared to only 10% for irrigated crops. This calls for increased ef-forts to upgrade rainfed systems globally and especially in developing countries where governments and com-munities are struggling to provide enough and affordable food (and nutrition) to the vast populations.

India ranks first among the rainfed agricultural countries of the world in terms of both extent ( 86 M ha) and value of produce. Due to low land and labour

productivity poverty is concentrated in rainfed regions. Yield gap analysis, undertaken by the Comprehensive Assessment, for major rainfed crops found farmers yield being a factor of 2-4 times lower than achievable yields of over 4-5 t/ha (Falkenmark and Rockstrom, 2000). The large yield gap between the attainable and potential yield shows that a large potential of rainfed agriculture remains to be tapped (Molden, 2007). Besides several other factors related to agriculture sector as a whole, ad-verse meteorological conditions in long dry spells and droughts, unseasonal rains and extended moisture stress periods with no mechanisms for storing and conserving the surplus rain to tide over the scarcity/ deficit periods were the major cause for non-remunerative yields and the associated distress. As such productivity of water is very low in rainfed agriculture. Whereas in the arid zones (< 300 mm/ annum) absolute water scarcity constitutes the major limiting factor in agriculture, in the semi-arid and dry-sub humid tropical regions on the other hand, total seasonal rainfall is generally adequate to significant-ly improve agricultural productivity. Here managing ex-treme rainfall variability in time and space is the greatest

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water challenge and the opportunity.

Supplementary irrigation is a key strategy, so far underutilised, to unlock rainfed yield potentials and improving crop water productivity in rainfed areas. Objective of supplemental irrigation is not to provide stress-free conditions throughout the crop growth for maximum yields, but to provide just-in-time irrigation to tide over moisture scarcity at critical growth stages to produce optimum yields per unit of water. The existing evidence indicates that supplemental irrigation ranging from 50-200 mm/ season (500-2000 m3 / ha) is suf-ficient to mediate yield reducing dry spells in most years and rainfed systems, and thereby stabilise and optimise yield levels. Since irrigation water productivity is much higher when used conjunctively with rainwater (supple-mental), it is logical that under limited water resources priority in water allocation may be given to supplemen-tary irrigation. Collecting small amounts using limited macro-catchments water harvesting, local springs, shal-low groundwater table or most importantly the conven-tional water harvesting can achieve this.

Rainfed areas in India are highly diverse and yield differences between irrigated and rainfed areas are more pronounced when the crop is grown under variety of agro-ecological regions compared to its concentration in few and similar districts. On-farm trials and evaluation reports of watershed projects (Joshi et al., 2004; Sastry et al., 2004) suggest that the effect of supplementary irrigation on rainfed crop yields is considerably higher Therefore an assessment was made under an IWMI-CR-IDA study to identify opportunities at the national level for India for water harvesting and supplemental irrigation to overcome dry spells during mid/ terminal droughts so as to stabilize the production. The assessment presented in this study presents estimation of available (surplus) rainfall runoff during August (second fortnight)/ Sep-tember required mainly to mitigate the terminal drought. The study identified the dominant rainfed districts for different crops (contributing upto 85% of total rainfed production), made an assessment of the surplus/ runoff available for water harvesting and supplementary irri-gation in the identified districts, estimated the regional water use efficiency and effect of supplemental irrigation on increase in production of different crops and finally a preliminary estimate of the economics of water harvest-ing for supplemental irrigation in rainfed areas. For a national/ regional level planning on supplementary ir-rigation, one needs to make an assessment of the total and available surplus runoff and potential for its gainful

utilization. In the present study, both crop season-wise and annual water balance analyses were done for each of the selected crop cultivated in the identified districts. Whereas, annual water balance analysis assessed the surplus and/or deficit during the year to estimate the water availability and losses through evaporation; the seasonal crop water balance assessed changes in tempo-ral availability of rainfall and plant water requirements. Water requirement satisfaction index was used for as-sessing the sufficiency of rainfall vis-à-vis the crop water requirements.

The total surplus from a district is obtained by multiplication of seasonal surplus with the rainfed area under the given crop .Total surplus available from a cropped region is obtained by adding the surplus from individual dominant districts identified for each crop. An estimated amount of 11.5 M ha-m runoff is generated through 39 M ha of the prioritized rainfed area. Out of the surplus of 11.5 M ha-m, 4.1 M ha-m is generated by about 6.5 M ha of rainfed rice alone. Another 1.32 and 1.30 M ha-m of runoff is generated from soybeans (2.8 M ha) and chickpea (3.35 M ha), respectively. Total rainfed coarse cereals (10.7 M ha) generate about 2.1M ha-m of runoff. Based on the experiences from watershed man-agement research and large-scale development efforts, practical harvesting of runoff is possible only when the harvestable amount is larger than 50 mm or greater than 10% of the seasonal rainfall (CRIDA, 2001). Therefore, surplus runoff generating areas/ districts were identified after deleting the districts with seasonal surplus of less than or equal to 50 mm of surplus and those districts generating runoff of less than 10% of seasonal rainfall. Table 1 shows the summary of surplus and deficit for various crops after deletion of districts, which generate less than the utilizable amount of runoff. This consti-tutes about 10.5 M ha of rainfed area which generates seasonal runoff of less than 50 mm (10.25 M ha) or less than 10% of the seasonal rainfall (0.25 M ha). Thus the total estimated runoff surplus for various rainfed crops is about 11.4 M ha-m (114.02 billion cubic meters, BCM) from about 28.6 M ha which could be considered for water harvesting. Among individual crops, rainfed rice contributes higher surplus followed by soybeans. Deficit of rainfall for meeting crop water requirements is also visible for crops like groundnut, cotton, chickpeas and pigeon pea.

Based on this available surplus, irrigable area was estimated for single supplemental irrigation of 100 mm (including conveyance/ application and evapo-

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ration losses) at reproductive stage of the crop both for normal and drought years. Runoff during drought years is assumed to be 50% of runoff surplus during normal rainfall years (based on authors estimates for selected districts and rainfed crops). However, farmers tend to use the water more prudently during drought years and save larger cropped areas. The potential irrigable area through supplementary irrigation for both scenarios is given in Table 2. Out of 114 billion cubic meters avail-able as surplus about 28 billion cubic meters (19.4 %) is

needed for providing supplemental irrigation to irrigate an area of 25 million ha during normal monsoon year thus leaving about 86 M ha-m (80.6%) to meet river/environmental flow and other requirements. During drought years also about 31 billion cubic meters is still available even after making provision for irrigating 20.6 million ha. Thus it can be seen that water harvesting and supplemental irrigation do not jeopardize the available flows in rivers even during drought years or cause signifi-cant downstream effects in the identified areas.

Table 1: Potentially harvestable surplus runoff available for supplemental irrigation under different rainfed crops of India

Crop group Crop Rainfed crop area (‘000 ha) Surplus (ha-m) Deficit (ha-m)

Cereals Rice 6329 4121851 0

Finger millet 303 153852 0

Coarse cereals Maize 2443 771890 0

Pearl millet 1818 359991 0

Sorghum 2938 771660 0

Total (Coarse cereals) 7502 2057393 0

Fiber Cotton 3177 757575 8848

Castor 28 14489 0

Groundnut 1663 342673 1646

Linseed 590 306360 0 Oilseeds Sesame 1052 416638 0

Soybeans 2843 1329251 0

Sunflower 98 11811 0

Total (Oilseeds) 6273 2421222 1646

Chickpea 3006 1304682 9166

Pulses Green gram 458 80135 0

Pigeon pea 1823 659328 238

Total (Pulses) 5288 2044145 9404

Grand total 28,568 11,402,186 19898

Table 2: Irrigable area (Â000 ha) through supplemental irrigation (@100 mm per irrigation) during normal and drought years under different rainfed crops

Crop group Crop Rainfed crop area Irrigable area during Irrigable area during normal monsoon drought season

Cereals Rice 6329 6329 6215

Finger millet 303 266 224

Coarse cereals Maize 2443 2251 1684

Pearl millet 1818 1370 837

Sorghum 2938 2628 1856

Total (Coarse cereals) 7502 6515 4601

Fiber Cotton 3177 2656 1725

Castor 28 25 22

Groundnut 1663 1096 710

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Production projections were made for different crops in the respective rainfed districts using the informa-tion on regional rainwater use efficiency both for Âbusi-ness as usualÊ scenario (only application of supplemen-tary irrigation) and under Âimproved practicesÊ scenario (limited follow-up on recommended package of prac-tices). Additional production (Table 3) was a product of irrigable area (Table 2), regional rainwater use efficiency and the amount of supplemental irrigation. The irrigable area through supplemental irrigation for different crops during drought season varies between 50-98% (98% for rice crop to 50% for sunflower growing districts) of the

irrigable area during normal season. Under improved management practices, an average of 50% increase in total production cutting across drought and normal seasons is realizable with supplemental irrigation from rainfed area of 27.5 M ha. Production enhancement in drought season in case of rice crop is high due to higher water application efficiency and due to sufficient surplus to bring almost entire rice cultivated area under supple-mental irrigation. This would also indicate that large tracts of rainfed rice cultivated area are covered under high rainfall zones with sufficient surplus for rainwater harvesting. Significant production improvements can be

Oilseeds Sesame 1052 919 741

Soya beans 2843 2843 2667

Sunflower 98 59 30

Total (Oilseeds) 5684 4942 4171

Chickpea 3006 2925 2560

Pulses Pigeon pea 1823 1710 1374

Total (Pulses) 4829 4634 3934

Grand total 27520 25076 20647

Table 3: Yield increases with supplemental irrigation (SI) in normal anddrought seasons (based on WUE of improved technologies)

Crop group Crop Rainfed Traditional Irrigable area Additional production cropped production area (‘000 ha) (‘000 tons) (‘000 tons)

Normal Drought Normal Drought season season season season

Cereals Rice 6329 7612 6329 6215 4141 4357

Finger millet 303 271 266 224 124 112

Maize 2443 2996 2251 1684 1744 1408

Pearl millet 1818 1902 1370 837 836 555

Sorghum 2938 3131 2628 1856 2439 1864

Coarse cereals Total coarse cereals 7502 8300 6515 4601 5144 3939

Fiber Cotton 3177 430 2656 1725 294 206

Castor 28 10 25 22 6 6

Groundnut 1663 1182 1096 710 284 203

Sesame 1052 365 919 741 202 176

Soya beans 2843 2607 2843 2667 1429 1443

Sunflower 98 49 59 30 12 7

Oilseeds Total oilseeds 5684 4214 4942 4171 1933 1834

Pulses Chickpea 3006 2367 2925 2560 1061 1000

Pigeon pea 1823 1350 1710 1374 282 245

Total Pulses 4829 3717 4635 3934 1344 1244

Grand total 27,520 24,272 25,076 20,647 12,856 11,581

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realized in rice, sorghum, maize, cotton, sesame, soy-beans and chickpeas. The success of Green Revolution in irrigated areas is one solid example built upon irriga-tion and improved technologies. Everyone of the stake-holder from supplier to farmer to market responded with equal enthusiasm. A second Green Revolution is not in the offing for long time for the reason that this needs to be staged on water scarcity/insufficiency zone.

Economics of Water Harvesting and Supplemental Irrigation

Supplemental irrigation has substantive poten-tial for increasing production from rainfed crops across different districts, yet its adoption on a large scale shall depend upon its economic worthiness. Numerous such structures have been built under varying agro-climatic conditions under state sponsored programs, by non-gov-ernmental organizations and with individual initiatives. The cost of provision of supplemental irrigation through construction of water harvesting structures varies a great deal between different states/ regions and loca-tions between the same state (Samra, JS, 2007; per-sonal communication). Hence a simple analysis based on the national average cost for rainwater harvesting structures (INR 18,500/ ha) was carried out for provi-sion of supplemental irrigation to the rainfed crops. In the calculation of annualized cost, rate of interest as well as depreciation cost for the structures has been deduct-ed. An assumption was made that rainwater harvested would be utilized for the existing crop and accordingly returns were considered for existing crop only. However, in actual practice the farmer makes much better use of the created water resource by planting high value crops and plantations and investments in livestock and aqua-culture. The annualized cost for each crop and gross and net benefits with supplemental irrigation to each crop are shown under Table 8. It suggests that an estimated INR 50 billion annually is required to provide supplemental irrigation to around 28 M ha of rainfed cultivated land and half of that amount is required for rice and coarse cereals only. The data suggests that gross and net ben-efits are quite high for cotton, oilseeds, pulses and rice. However, the coarse cereal group in general and pearl

millet in particular exhibit lower gross and net benefits even with SI and improved practices. This indicates the need for better varieties of these crops, which are more responsive to irrigation and nutrition.

Conclusions In spite of the rainfed lands having the highest

unexploited potential for growth, the risk of crop fail-ures, low yields and the insecurity of livelihoods is high due to random behaviour of the rainfall. Rainfed agricul-ture is mainly and negatively influenced by intermittent dry spells during the cropping season and especially at critical growth stages coinciding with terminal growth stage. District level analysis for different rainfed crops in India showed that difference in the district average yields for rainfed crops among different rainfall zones was not very high indicating that total water availability may not be the major problem in different rainfall zones and for each crop there were few dominant districts which contributed most to the total rainfed crop production. The most potential strategy to realize the potential of rainfed agriculture in India (and elsewhere) appears to harvest small part of available surplus runoff and reuti-lize it for supplemental irrigation at different critical crop growth stages. The study identified about 27.5 M ha of potential rainfed area, which accounted for most of the rainfed production and generated sufficient runoff (114 BCM) for harvesting and reutilization. It was possible to raise the rainfed production by 50% over this entire area through application of one supplementary irrigation (28 BCM) and some follow up on the improved practices. Extensive area coverage rather than intensive irrigation need to be followed in regions with higher than 750 mm/ annum rainfall, since there is a larger possibility of alleviating the in-season drought spells and ensure second crop with limited water application. This com-ponent may be made an integral component of the on-going and new development schemes in the identified rural districts. The proposed strategy is environmentally benign, equitable, poverty-targeted and financially at-tractive to realize the untapped potential of rainfed agri-culture in India.

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ReferencesDavid, Molden (eds.).2007. Water for Food, Water for Life: A Comprehensive Assessment of Water Management in

Agriculture. London: Earthscan, and Colombo: International Water Management Institute.Falkenmark, M., Rockstrom,J.1993. Curbing rural exodus from tropical drylands. Ambio 22(7): 427-437.Joshi, P.K.; A K Jha, SP Wani; Laxmi Joshi, RL Shiyani. 2005. Meta analysis to assess impact of watershed program

and peopleÊs action. Comprehensive Assessment Research Report 8, International Water Management Institute, Colombo.

Oweiss, Theib.1997. Supplemental irrigation: A highly efficient water-use practice. Aleppo, Syria: International Center for Agricultural Research in Dry Areas.

Pretty, J, R. Hine. 2001. Reducing Food Poverty with Sustainable Agriculture: A Summary of New Evidence. Final report of the „safe World‰ Research Report. University of Essex, UK.

Reij,C .1988.Impact des techniques de conservation des eaux et du sol sur les rendements agricoles:analyse succincte des donnees disponsibles pour le plateau central au Burkina faso. CEDRES/ AGRISK.

Rockstrom ,J.; Falkenmark,M. 2000. Semi-arid crop production from a hydrological perspective- Gap between potential and actual yields. Critical Reviews in Plant Sciences, 19(4): 319-346.

Rosegrant, Mark; C.Ximing, S.Cline, N.Nakagawa.2002. The Role of Rainfed Agriculture in the Future of Global food Production. EPTD discussion Paper 90. International food Policy Research Institute, Washington D.C. (www.ifpri.org/divs/eptd/dp/papers/eptdp90.pdf )

Samra, J.S.2007. Personal communication. Role of watersheds and Minor Irrigation in Food and Livelihood Securities. Presentation made before the Planning Commission. Government of India. New Delhi. June 29,2007.

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Improving Productivity in Dry Land Groundnut Farming –

LEISA Outcomes from South India

Arun Balamatti, J Diraviam and C S Kallimani

16

IntroductionGroundnut is a major commercial crop in India.

It was introduced in the country in the sixteenth cen-tury (Reddy, 1996). India is one of the largest producers of groundnut in the world. It was cultivated in 6.74 m ha with an annual production of 7.99 million tonnes in 2005-06 in the country (AgStat, 2006-07). The area under irrigation is very much limited (< 17%). Ground-nut is a major livelihood crop, as it has higher market value compared to millets, serves as good source of fod-der and comes well in marginalized lands if there is well distributed rainfall. Its nitrogen fixation ability helps in building soil fertility as well as requires lower quantity of nutrients as compared to other oilseed crops.

The Situation in Deccan PlateauGroundnut is the only crop, which is grown by

around 80 per cent of the dry land farmers, who de-pend on it as a major source of livelihood. With negli-gible presence of other crops and livelihood options, it is a classical case of Âputting all the eggs in one basketÊ for the large majority of small and marginal farmers. In

the most degraded ecosystem, the recurring droughts have had their heavy toll not only on depleting biomass, dwindling livestock population, and eroded soil fertility, but also on farmersÊ attitude to farming in general. The routine production practices can be best explained as reflection of deep-rooted pessimism, lack of creativity and innovativeness resulting in inefficient use of natural resources and as a result, poor yields.

A major challenge farmers facing in this area is the adoption of farming systems that both cope with pe-riods of low rainfall, bearing in mind the fact that drought is a natural and recurring phenomenon, and capitalize on years of above rainfall.

Farmer Field School (FFS): It is a unique extension tool based on discovery-based learning that has been popular in promoting IPM aspects to farm-ers, particularly for irrigated crops like rice, cotton, veg-etables, etc. There have been little efforts in the past for using FFS apart from promoting IPM, like on inte-grated soil and nutrient management and conservation (FAO, 2000), livestock management (Groeneweg et al., 2006).

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About AME FoundationAME Foundation, a development-oriented, non-

government organization, is committed to improving the livelihoods of resource-poor farm families in dry land areas through promotion of ecological agriculture. AME has been involved in addressing productivity improve-ment in groundnut and livelihood of dry land farmers in Deccan Plateau covering the three states of Karnataka, Andhra Pradesh and Tamil Nadu since 1994, with the initiation of a PTD process in Dharmapuri district with 60 farmers through a NGO, followed by Chittoor district of AP in 1996 and Raichur district in Karnataka during 1997 (Prasad et al., 1999).

LEISALEISA is the abbreviation of ÂLow External In-

put Sustainable AgricultureÊ. LEISA refers to viable small scale farming, which is a major part of rural livelihoods and thus contributes significantly to developing econo-mies. LEISA is about finding technical and social options open to farmers who seek to improve productivity and income in an ecologically sound way. LEISA is about op-timal use of local resources and natural processes and, if necessary, safe and efficient use of external inputs.

Details about The StudyThe present paper reports work done in the

Deccan Plateau covering three states, viz., Karnataka, Andhra Pradesh and Tamil Nadu. The details of the study area are given in Table 1.

Baseline Information: Problems Identified in Groundnut Cultivation

Across the three states, the situation in Deccan Plateau is more or less similar. Various PRA tools were employed in the study area to identify the various prob-lems in groundnut cultivation.

Based on the analysis of the outcomes, the fol-lowing issues were identified in groundnut farming sys-tem:

Poor or No Efforts in In-Situ Moisture Conservation

Though summer ploughing (Fall ploughing) is a well-known practice, most of the farmers are not prac-ticing it for different reasons, Frequent tillage is not being practiced leading to crust formation, Sowing across the slope is another practice that is not being practiced by many farmers.

Poor Soil Fertility ManagementApplication of compost/FYM is irregular and

inadequate. The available FYM is applied once in three years and the quantity varies between two to three tons per acre. Lack of knowledge in composting also led to non-application of compost. Also cutting of trees in bunds and non-cultivation of biomass trees led to re-duced available manurial biomass.

Improper or Inadequate Agronomic Practices

(a) Time of sowing: In the areas where early or delayed onset of monsoon, erratic rainfall distri-

bution and mid-season dry spells are common, the best practice would be to sow groundnut immediately after good showers in July. However, despite favourable con-ditions for sowing, many small and marginal farmers in

Particulars Karnataka Andhra Pradesh Tamil Nadu Area Unit Bellary Madanapalli Dharmapuri Dstricts covered Bellary, Chitradurga Chittoor Dharmapuri, Krishnagiri Normal annual Bellary 623 mm 934 mm 855 mm

Rainfall in the district Chitradurga 540 mmActual rainfall in Bellary 393 mm 788 mm 706.6 mm2007 season Chitradurga 827 mm Rainfall distribution Chitradurga - Uneven Timely onset, distribution Due to delay in onset ofin 2007 season distribution of rainfall good, with an average rainy monsoon , sow i ng was affected the crop growth days of 10 days per month delayed by 15 to 20 days and yield. Bellary -Timely beyond season. Dry spell of and even distribution about a month occurred occurred. during middle of the crop period. Soil type Red sandy to gravely soil Red sandy loam Red sandy loam

Table 1: Details of the study area

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the watersheds are not able to sow in time.

The major reasons are lack of bullock pairs and labourers during this peak season. It is believed that small and marginal farmers have to wait as long as 8-15 days for sowing before the other farmers in the village complete their sowing operations so that the bullock pair and the labourers are available. By this time, the soil moisture is lost and so the crop germination and subsequent crop stand gets affected at the very initial stage itself.

(b) Seed rate: The farmers were using spreading type of groundnut earlier before shifting to the now prevalent bunch variety (TMV 2) in Karnataka and Andhra Pradesh. The spreading type requires relatively less seed rate compared to bunch type. It appears that the farmers were used to this kind of sowing and hence instead of 40-50 kg of groundnut seeds per acre in the case of Karnataka, they are using only 27-30 kg, which means a yield compromise of 25 to 30 per cent at the time of sowing itself.

Lack of knowledge regarding seed rate, depen-dency on money lenders and other external sources for seed material and hurried sowing practice to complete the sowing early so as to save on labour expenses are common reasons attributed to this gap. Also, the farmers start separating kernels from the pods well in advance in anticipation of normal onset of monsoon (mid July).

(c) Spacing and plant population: Ide-al spacing should be 30 x 10 cm (for bunch type). Farm-ers, though are able to maintain the row-to-row spacing, they fail to ensure uniform intra-plant spacing due to defective sowing methods. The ideal plant population, with 30 X 10 cm spacing, should be around 1,20,000 per acre but the farmers are not able to maintain this population. The number of plants per square meter should be 33, whereas the observed plant population ranges between 16 - 27 plants in most of the farmersÊ fields. The gaps occur mostly due to the undue hurry in sowing, the women labour keep fetching seeds from the bag while on the move, when the bullocks walk faster when beaten etc.

(d) Gap filling: Under good soil moisture condition, germination can be seen in 5-6 days. It is only after about 9 days that the gaps could be identified. By the time, the farmers would have either no seeds left or they think it is too late for gap filling with groundnut. Very recently farmers are coming forward to try the gap filling with other suitable crops.

Inter-culture operations: In a normal ground-nut season an average of two intercultural operations are taken up to control weeds as well as for the purpose of earthing up. During dry spells, many farmers think that inter-cultivation will lead to moisture loss due to aera-tion. Intercultivation actually helps to conserve soil mois-ture by breaking the capillary pores and the dust acting as mulch. However, under dry soil condition, inter-culti-vation will not serve the purpose of earthing up as the soil merely gets rolled up and does not move toward the plants. Poor earthing up leads to the flowers, particu-larly the second and third set, not getting converted into pegs and pods thus affecting the yield very significantly.

Pest and Diseases Pest incidence in groundnut crop is less severe,

however few pests like root grub, leaf miner, Spodoptera and red headed hairy caterpillar are becoming menace depending on the location. Peanut bud necrosis disease (PBND) and Sclerotium rots are the important diseas-es bothering groundnut crop. Also the incidence of the pests/diseases largely depends on the microclimate. For example, incidence of PBND, transmitted by thrips is severe under low moisture regime; it is also the same in the case of the pest, leaf miner.

Low Yields and Less ReturnThe average productivity of groundnut pod rang-

es from 200 to 400 kg/ac, where as the potential yield goes up to 500 - 700 kg/ac for those varieties cultivated by farmers. However in the case of improved varieties like VRI 2, the potential yield goes even higher than 700 kg/ac. The net return of small and marginal farmer is about Rs. 10000/- per annum, which is not sufficient to lead quality life.

The summary of the baseline outcomes from the three states is given in Table 2. When the problems were analyzed, it was clearly evident that it was not one or two factors that led to reduced productivity in groundnut, but a whole range of factors acting in tandem that caused the situation. Hence, a few selected practices alone can-not help in tiding over the situation, but a combination of basic operations covering on-farm rainwater manage-ment, soil fertility up gradation, modified cropping prac-tices and income generation (IG) activities are required for improving the productivity as well the livelihood of small and marginal farmers.

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The Capacity Building ProcessThe experiences gained by AME Foundation

over the years on FFS (Vijayalakshmi et al., 2003), specifically the MToF programme helped in shaping the curriculum to suit dry land crops including ground-

nut (Balamatti and Hegde, 2007). Simple experiments laid out in the FFS class room sessions and in farmersÊ fields helped farmers to understand complex concepts on natural resources management. In the participating farmersÊ fields, experimental plots were laid out with the various long-term experiments, to study the best-suited

practices/combination of practices. The list of short and long-term experiments conducted in a typical dry land groundnut FFS is given in Table 3.

The curriculum covers all the aspects in ground-nut production from preparatory activities to post har-

vest as well as on IG activities. The curriculum followed in one of the FFS is given in Appendix I.

The details of FFS conducted on groundnut, farmers reached in the three working areas are given in Table 4.

Particulars Karnataka Andhra Pradesh Tamil Nadu

Moisture Poor soil moisture Poor soil moisture Poor soil moistureconservation conservation methods conservation methods conservation methodsRainfall Uncertainty of rainfall Uncertainty of rainfall Uncertainty of rainfallSoil fertility Poor soil fertility Low Soil fertility due Low FYM availability to poor nutrient Low nutrient applied management practices

Biomass awareness Poor Poor Poor

Pest and disease PBND disease root PBND, root grub, Leaf miner, PBND, grub, leaf miner, RHC, stem rot root grub, red hairy Spodoptera caterpillar, root rot

Seed quality Poor quality of seed. Poor quality of seed. No improved varieties No improved varieties No improved varieties

Plant population per 25 - 27 16 - 18 26sq. m.

Yield (average) kg/ac 400 kg/ac 200 kg/ac 330 kg/ac

Table 2: Summary of baseline outcomes on groundnut productivity

Short studies Long term experiments (LTEs)

1. Ploughing across slope 1. Farmers practice Vs LEISA practices trial

2. Water holding capacity of soil 2. Varietal trial

3. Small section bunds 3. Methods of sowing

4. Mulching 4. Insitu soil moisture conservation trial

5. Seed treatment with biologicals 5. Impact of green manure in dry land on groundnut production

6. Pitfall trap/ Yellow sticky trap 6. Strip cropping (Groundnut & Ragi or Bajra)

7. Anti transpirants spray 7. Maintaining optimum plant density (seed rate)

8. Botanicals spraying 8. Nutrient management trial

9. Mushroom cultivation 9. Composting methods

10. Deworming for livestock

11. Azolla feeding experiment for cattle

12. Nursery raising for biomass trees

Table 3: List of short studies and Long term experiments (LTEs) conducted in the FFS

Table 4: Details of FFS events and farmers covered under FFS

Particulars Karnataka Andhra Pradesh Tamil Nadu

No. of FFS 89 50 23

No. of Farmers 1818 834 564

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The FFS LearningsFarmers apart from learning about LEISA prac-

tices through discovery learning also learnt the practice of Agro Eco-System Analysis (AESA). This analysis helps farmers in making informed decisions. During each stage of the crop, farmers decide on various interventions to be taken up in the crop to ensure maximum output at mini-mum cost, without affecting the ecosystem. The farmers make observation in the field and prepare AESA charts during every session. These charts will be referred on a continuous basis till the harvest of the crop.

LEISA PracticesAME Foundation has identified proven LEISA

practices based on PTD experiences in all the three states. The various practices given as options for farm-ers to adopt are based on AMEF Guidelines 6 (AMEF, 2005). These practices when taken up in combination lead to better management of natural resources and hence improvement in productivity. The combination of such practices followed in each of the three areas is given in Table 5.

THE OUTCOMESLEISA Practices Trial vs Farmers’ Practice Trial

The overall results of the field trials are present-ed in Table 6, Fig. 1 - 2. The study results revealed that

a combination of LEISA practices helped in getting im-proved productivity as compared to farmersÊ practice. For example in Andhra Pradesh and Tamil Nadu there was an increased yield of 44%, 38%, respectively, while in Karnataka, it was up to 12% in the case of LEISA practices plot over farmersÊ practice plot. The cost of cultivation was marginally higher in the case of LEISA plot in all the working areas due to the formation of rainwater conservation structures, use of Enriched FYM, biologicals for seed treatment, increased application of FYM. However, the net returns in the LEISA plot is ap-preciably higher than that of the farmersÊ practice plot.

The results in Tamil Nadu was clearly evident, as the investment in farmers practice plot did not lead to increase in net returns, due to prolonged dry spell in the middle of the season. While in the case of LEISA plot, the yield was better due to the adoption of improved practices in combination.

Similarly in Karnataka, the reasons for reduced yield in farmersÊ practice plot are reduced seed rate of 30 � 35 kg/ac, low soil fertility, incidence of diseases, par-ticularly Sclerotium rot and PBND. In the case Andhra

Pradesh, the reduction in yield was due to improper agronomic practices like reduced plant population, ab-sence of gypsum application and absence of soil fertility improvement measures in the farmers practice plot.

Particulars Karnataka Andhra Pradesh Tamil Nadu

1. Rainwater Summer ploughing, Trench Deep summer ploughing, Ploughing across slope,management cum bunding, Bund Ploughing across the slope, bunding, small sectionpractices strengthening, Intercultivation, Bunding and bund repair, bunding Sowing across the slope, Dead furrow, Intercultivation Dead furrow (Groundnut: red gram ratio 9:2)2. Soil fertility FYM, PSB, Neem cake, FYM application (4t/acre once FYM 5 t/ acre, EFYMimprovement Fertilizers application, Gypsum in a year), Tank silt application, application @ 300 kg/ac,practices application, Foliar spray Balanced nutrient application, legumes as intercrops, Green (organic/vermiwash) Use of biofertilizers, legumes manure, compost application, inter/Border crops, Gypsum biomass production, Gypsum application, Compost application application3. Crop specific Spacing (30x10cm), Seed rate Use of good quality seeds Improved varieties, production (40kg/ac), Seed treatment (40 kg), Maintenance of Seed treatment with biologicals,practices with Trichoderma, Rhizobium, optimum plant density, Use of Nutrient management (fertilizer Gap filling, Inter & mixed crops, improved varieties, Strip application based on soil test Border crop, Sequential crop cropping, Diversified cropping results) MN mixture, IPM system, introduction of minor millets, Border crop with cereals-3 rows

Table 5: Basket of options of LEISA practices for groundnut productivity improvement

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Results of Long-term ExperimentsApart from the overall comparison, few long-

term experimentsÊ results are presented below to un-derstand the importance of selected traits/practices Âin isolationÊ in productivity improvement.

Varietal Trials/ PTD in Groundnut- Madanapalli (AP)

In order to identify drought tolerant varieties, field trials were conducted in 15 villages with 4 varieties as LTEs in Farmer Field School. The four varieties were VRI 2, K1375, K 1271 and JL 24.

The results revealed that among the four variet-ies tested, K1375 was able to tolerate drought up to 40 days. In the case of VRI 2, there was less incidence of PBND and it also recorded the maximum yield of 5.8 q per ac (Table 7, Fig. 3).

Groundnut varietal trial in Bellary (Kar-nataka)

The continuous use of local seeds for the decades resulted in resurgence of pest and diseases and genetic erosion resulting in decreased yields of groundnut. After understanding this seven farmers took up varietal trials across the working villages.

The maximum yield of 6.5 q/acre pods and 14.60 q/acre of fodder were observed in VRI 2 when compared to GPBD 4 and Local (TMV 2) (Table 8; Fig. 4). The incidence of PBND was also low in VRI 2 com-pared to the local variety. Farmers in that area accepted

the new variety, VRI 2 for future use.

Strip CroppingWith a view to minimize the risk from mono

cropping of groundnut, strip cropping, which not only assures food security but also, improve the soil health was tried on an experimental basis. This system also

ensures fodder and income security to the farmers. In this trial, 105 farmers across working villages adopted Strip cropping.

Some of the important outcomes from the trials were: strip cropping helped in getting 5 quintals of ad-ditional fodder therefore reducing the expenses towards purchased fodder. Purchase of food crops like Ragi, fox-tail millet and Bajra were avoided, as these are essential food grains for the family.

Farmers, observing the results, opined that apart from Ragi, other cereals could also be used for strip cropping, as the Ragi crop requires more moisture to germinate in the initial period.

Finally, even though farmers got less income from strip cropping with cereals (Table 9), the new crop-ping system helped them to realize the importance of food, fodder and income security that strip cropping as-sures. Farmers tried strip crops such as Bajra, Ragi and foxtail millet with Groundnut crop.

Particulars Karnataka Andhra Pradesh Tamil Nadu

LEISA Farmer LEISA Farmer LEISA Farmer plot practice plot practice plot practice

Yield (kg/ac) 233 209 460 320 455 330

Yield increase % 12 44 38

Cost of cultivation (RS/ac) 2774 2078 6280 5545 4420 4305

Gross returns (Rs/ac) 6807 5219 9600 6800 10,237 7,425

Net returns (Rs/ac) 4066 3141 3320 1225 5871 3120

Table 6: Economic benefits in the three working areas (mean of all the FFS events)

Particulars VRI 2 K1375 K1271 Jl 24

Plant population 30 28 29 23

No. of Pods/plant 38 31 35 18

PBND (%) 6 10 10 13

Yield/ acre (q) 5.8 4.1 4.9 3.6

Table 7: Varietal performance in farmersÊ field in Madanapalli

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Impact of Green Manure and Catch Crop on Productivity of Groundnut

Farmers in Bellary studied the impact of harvest-ing the pre monsoon showers on groundnut productiv-

Observations GPBD-4 VRI-2 Local (TMV-2) Remarks Growth parameters at the time of harvestPlant height (cm) 17.60 20.00 20.00

No. of branches 6.10 5.76 5.76 Yield parameters at the time of harvestAverage no. of plants per m2 area 9.00 12.00 14.00 Germination % was poor in VRI-2

Avg. No. of pods per plant 24.00 27.00 24.00 & GPBD-4, which were procured

Wet Wt of pods (qtls/ acre) 16.00 21.75 19.00 from KOF, Haveri. Cost economicsMain crop yield (q/acre) 4.75 6.50 6.00

Fodder yield (q/acre) 11.65 14.60 13.00 Rs.2300/qt pod &

Cost of production (Rs./acre) 3625 3625 3450 Rs.166/qt fodder.

Gross returns (Rs /acre) 12859 17373 15958

Net returns (Rs /acre) 9324 13748 12508

Table 8: Varietal performance in farmersÊ field in Bellary

Table 9: Impact of strip cropping in farmersÊ fields in Bellary

Parameters SA/ICM practice Farmers practice RemarksPractices adopted Groundnut, Ragi and Groundnut- Mono Groundnut: Ragi: Bajra Bajra crop (8:4:3)Cost of production (Rs./1.25 acre) 4388 4313 Main crop pod yield (qt) 3.60 5.60 4 strip groundnut Strip crop (Ragi) grain yield (qt) 1.20 0.00 3 strips ragi Strip crop (Bajra) grain yield (qt) 1.80 0.00 4 strip & border Bajra.Main crop fodder yield (qt) 10.44 16.25Strip crop (Ragi) fodder yield (qt) 5.00 0.00Strip crop (Bajra) fodder yield (qt) 6.00 0.00Gross returns (Rs./1.25 acre) 12878 15577 Ragi @ Rs. 800/qt grain and

Rs. 75/qt fodder. Bajra @ Rs.600/qt grain and

Rs. 75/qt fodder. Groundnut Rs. 2300/qt pod & Rs.166/qt fodder.

Net Returns (Rs./1.25 acre) 8491 11264

Parameters T1 T2 T3 Remarks

Practices adopted Fall ploughing, bio Fall ploughing. Fall ploughing. In T1 Plot sun hemp fertilizers & bio Bio fertilizers & bio was incorporated and agents. Inter crop Agents. Mixed crop inT3 plot Taken green (red gram), Mixed (Castor). Gypsum gram as Catch crop crop (castor) Gypsum and T2 control

Cost of production 3610 2800 7030 Rs. 4200 cost of (Rs./acre) cultivation of green gram.

Main crop yield 6.30 5.40 5.80(q/acre)-Groundnut.

Crop yield (q/acre)-Green ·- ·- 2.40gram.

Intercrop/mixed crop yield Red gram, Castor. ·- Castor. Yet to harvest.(q/acre)

Net Returns (Rs./acre) 12880 11420 16770

ity, by growing short duration green gram or a green manure crop sun hemp. In the case of green gram, the crop was harvested, while sun hemp was incorporated in the field. The results clearly demonstrated that maxi-

Table 10: Impact of green manure and catch crop on the productivity of groundnut

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mum yield of groundnut was obtained when sun hemp was incorporated in the field prior to sowing of ground-nut (Table 10). Growing of groundnut followed by green gram also gave higher yield as compared to groundnut alone. The details of the trial results are given below.

Note: T1=Sowing groundnut after incor-poration of sun hemp along with all SA prac-tices.

T2= Control

T3= Sowing groundnut after green gram crop along with all SA practices in ground-nut.

The higher yields were due to the effective har-vesting of the rainwater and its usage.

The cultivation of catch crop also gave additional income. The last year experience impressed five farmers to adopt the technology during this Year 2007.

Environmental and Social BenefitsApart from economic benefits, environmental

and social benefits were also achieved in this process. A summary of them is given in Table 11.

Social BenefitsLinkages for farmers (particularly women) with

agricultural departments

Collective activities (input mobilization, field work)

Created common platform to share FFS learn-ings (adopted farmers, sharing meetings, sharing in SHG meetings, field days)

Informed decision making skills

Active participation of women

Improvement of communication, organization, managerial and leadership skills

External agencies (input dealers) dependency re-duced

DiscussionIn this study, the rainwater harvesting practices

in combination with other LEISA practices gave better yield as compared to less interventions in farmersÊ prac-tice. Similarly, Chakravarti et al., (2005) studied the effect of mulches, type of planting on groundnut pro-ductivity. He observed higher productivity in groundnut plots, when mulched with paddy straw or water hyacinth and when planted in ridge method than flat bed meth-od.

One of the important philosophies behind FFS is „Grow a healthy crop‰ that can tolerate biotic and abiotic stresses (Pontius et al., 2000). The LEISA prac-tices adopted help one-way or other, either directly or indirectly for harvesting the moisture required for crop growth. The principles lying behind the LEISA practices

adopted on moisture conservation and utilization are summarized in Table 12.

The impact of FFS in building the capacity of farmers as well as empowering them in LEISA prac-tices particularly on rainwater management are clearly evident based on the results of the field trials. Earlier, FFS approach was employed successfully in Ugan-da for community based groundnut seed production (Obuo, 2004).

Particular Farmers practice Improved practice Outcomes

Pesticide spray 2 Nos. Endosulfan + 1 No. NSKE =Rs. 490 60 % decreaseto intercrops Quinalphos = Rs. 1230

Crop diversity Sorghum, Redgram, cowpea Sorghum, Red gram, cow pea, More predator population 2 � 3 crops Field bean, Castor, bajra (Ladybird beetle, Spider), 5 � 6 crops Improvement in soil fertility, 25% area under crop rotation

Use of bio-agents No Seed treatment with PSB, Less incidence of fungal diseases Rhizobium, Trichoderma (Root and stem rot)

Chemical Complex 50 Kg or DAP SSP 100 kg, Gypsum 200 kg Balanced application of nutrientsFertilizes used 50 kg/ac In case of AP, reduced to nil application of fertilizers

Others No relay crops Relay crop (20%) with Horse gram

Table 11: Environmental benefits

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The systematic approach towards addressing the moisture conservation, soil fertility and crop manage-ment yielded the desired results. Although, the LEISA practices tried were mostly proven under experimental farms of mainstream agencies (Vittal et al., 2003), they were largely unknown among resource poor farmers of the Deccan Plateau. The group approach helped in cross learning among farmers. Apart from group farm-ers in the village, other farmers in the village also were targeted for disseminating the knowledge through farm-ers sharing on field days. Also FFS participants adopted members of their village for regular sharing of the LEISA

Key operation LEISA practices Expected output related to soil moisture conservation/proper utilization

Rain Water Management Deep summer ploughing Conservation of in-situ soil moisture Cultivation across the slope Compartmental bunding Dead furrow Trench cum bunding and bunding Conservation of the fertile top soil to hold maximum moisture

and utilizing the moisture to raise bund plants for biomass enhancement

Inter cultivation Conservation of soil moisture and to reduce the moisture loss

Soil fertility improvement FYM 5 t/ acre and Compost application Increased water holding capacity of soilpractices Tank silt application Green manuring Utilization of soil moisture effectively of summer showers and

enhanced soil organic matter to increase the water holding capacity of soil

EFYM Ensured better root growth and to uptake moisture from greater depth; to withstand during drought.

Legumes as intercrops Utilization of soil moisture at various depths. Reduction of water evaporation from soil by acting as live mulch.

Border crops Reduction of wind speed to avoid moisture evaporation from soil

Crop management practices Improved varieties Varieties suitable to drought situation. Seed hardening Ensured drought tolerance of the crop during dry spell Seed treatment with biologicals Ensured better root growth, nodulation to produce a healthy

crop Strip cropping Contingency crop plan to avoid crop loss during severe

drought situation Maintenance of optimum plant density Utilization of soil moisture effectively without wastage and

competition Balanced nutrient application and MN E n s u re d b e t t e r c rop g row t h to w i t h s t a n d mixture drought situation. Gypsum application Avoided hard pan of soil to enhance better aeration and

moisture holding. Sequential crop Utilized residual soil moisture effectively

Table 12: Summary of the effect of LEISA practices on moisture conservation and utilization by groundnut crop.

technologies. The collaboratorÊs field also was a demon-stration plot for the village farmers to know about the improved practices.

The FFS apart from addressing NRM, also dealt on other livelihood issues such as family health/nutri-tion through kitchen gardening, mushroom cultivation, increased intensity of pulse cultivation, IG activities such as animal husbandry, fodder cultivation, biologicals pro-duction. Hence, livelihood improvement of small and marginal groundnut farmers could be achieved through the above FFS programme.

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ReferencesAgStat 2006 �07, http://dacnet.nic.in/eands/agStat06-07.htm

AMEF 2005. Towards a Sustainable Dryland Farming – An Operational strategy. AME Founda-tion Guidelines 6.

FAO, 2000. Guidelines and reference material on integrated soil and nutrient management and conservation for farmer field schools, FOOD and AGRICULTURE ORGANIZATION of the UNITED NATIONS, Land and Plant Nutrition Management Service, Land and Water Development Division, Rome, 2000

Balamatti, A and R. Hegde 2007. Our experiences with modified Farmer Field Schools in dryland areas. LEISA Magazine 23.4 December 2007.

Chakravarti, A. K., Chakraborty, P. K. and Chakraborty, A. 2005. Study on the efficacy of some bio re-sources as mulch for soil moisture conservation and yield of rain fed groundnut ( Arachis hypogaea ). Archives of Agronomy and Soil Science, Volume 51, Number 3, June 2005 , pp. 247-252(6).

Groeneweg, K., Buyu, G., Romney, D. and Minjauw, B. 2006. Livestock Farmer Field Schools – Guidelines for Facilitation and Technical Manual. International Livestock Research Centre: Nairobi, Kenya.

Obuo J.E. P. 2004. Community Based Groundnut Seed Production, and Dissemination for Sustainable Small Holder Agriculture in Teso Farming System. Final Technical Report. Serere Agricultural and Animal production Research Institute (SAARI), P.O. Soroti. pp 19.

Pontius, J., Dilts, R. and Bartlett, A. 2000. From Farmer Field Schools To Community IPM, FAO Com-munity IPM Programme Jakarta.

Prasad, K.V.S., Suresh, C. and Lanting, M. 1999. A platform for groundnut mprovement, ILEIA Newslet-ter, September, 1999.

Reddy, P.S. 1996. Groundnut. In 50 Years of Crop Science Research in India. R. Paroda and K. Chadha, eds. Pp. 318-329. New Delhi: ICAR.

Vijayalakshmi, B, Ravi Kumar, G., Pattabiraman, S. and Daniel Anand Raj. 2003. Farmer Field Schools � Experiences from Tamil Nadu. LEISA INDIA, vol 5, no. 1, March 2003, pp. 11 � 13.

Vittal, K. P. R., Singh, H.P., Rao, K. V., Sharma, K.L., Victor, U. S., Chary, G. R., Sankar, G. R. M., Samra, J. S. and Singh, G. 2003. Guidelines on Drought Coping Plans for Rainfed Production Systems. All In-dia Co-ordinated Research Project for Dryland Agriculture, Central Research Institute for Dryland Agriculture, Indian Council of Agricultural Research, Hyderabad 500 059. 39 pages.

Acknowledgements: The financial support of FAO is gratefully acknowledged. The authors are thankful to the AME Foundation Team members of the three Area Units for their contribution in making this FFS programme a success. We are also thankful to the participated farmers, NGOs and Govt officials without whose cooperation, this programme objectives could not have been achieved.

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Water Productivity at Different Scales Under Canal, Tank and

Well Irrigation SystemsK.Palanisami, T.Ramesh and S.Senthilvel

17

IntroductionBy and large, the term Âwater productivityÊ refers

to the magnitude of output or benefit resulting from the input quantum of water as applied on a unit base. It is defined as Âcrop productionÊ per unit Âamount of water usedÊ (Molden, 1997). In the domain of agriculture, it is expressed as the net consumptive use efficiency in terms of yield per unit depth of water consumed per unit area of cultivation. If the field water conveyance, application, storage and distribution efficiencies are accounted to de-pict the seepage, run-off and deep percolation losses (not consumed by plant; evapo-transpiration loss is in-cluded as an implicit component of field water balance) it would be termed as the gross irrigation water use effi-ciency. Agricultural water productivity can be expressed either as a physical productivity in terms of yield over unit quantity of water consumed (tonnes per ha.cm of water or kg yield per kg water consumed) in accordance with the scale of reference that includes or excludes the losses of water or an economic productivity replacing the yield term by the gross or net present value of the

crop yield for the same water consumption (Rupees per unit volume of water).

The magnitude and meaning of the term Âwater productivityÊ is often changes with its scale of reference. Isolated scales of reference in agricultural domain can be plant/crop scale, field scale, project/basin/command scale, state scale and the country scale. By the same token, the industrial domain, drinking water supply and other usage domains can hold their own scales of refer-ence. An increase in production per unit of water divert-ed at one scale does not necessarily lead to an increase in productivity of water diverted at a larger scale. The classical irrigation efficiency decreases as the scale of the system increases (Seckler et al., 2003). The definition of water productivity is scale-dependent. Increasing water productivity is then the function of several components at different levels viz., plant, field, irrigation system and river-basin. An increase in production per unit of wa-ter diverted at one scale does not necessarily lead to an increase in productivity of water diverted at a larger scale. The classical irrigation efficiency decreases as the scale of the system increases (Seckler et al., 2003).

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In India, the on-farm irrigation efficiency of most canal irrigation systems ranges from 30 to 40% (Navalawala, 1999; Singh, 2000) whereas, the irrigation efficiency at basin level is as high as 70 to 80% (Chaudhary, 1997). Basin water productivity takes into consideration ben-eficial depletion for multiple uses of water, including not only crop production but also uses by the non-agricultur-al sector, including the environment. Here, the problem lies in allocating the water among its multiple uses and users. Keeping this view, an investigation was under-taken to assess the water productivity at plant, field and distributory level under different irrigation systems.

Materials and MethodsIn the present study, water productivity under

different scale levels viz., plant, field and distributory lev-el were studied in three different irrigation systems viz., canal, tank and well irrigation. In canal irrigation system, four river basin areas of Tamil Nadu viz., Parambikulam Aliyar Project (PAP), Lower Bhavani Project (LBP), Peri-yar Vaigai and Tampiraparani river basins were taken to work out the water productivity at different scale of references. Data were collected using field visits to the canal commands and also necessary information was collected from the project records. Wherever possible measurement were taken and verified. In the case of tank irrigation, Srivilliputhur Big tank in Ramanathapuram district of Tamil Nadu was taken for the study as the data on most of the parameters of water productivity calcu-lations were available. Similarly, the water productivity under well irrigation system was studied at farmersÊ fields of Coimbatore district where well irrigation is being pre-dominantly practiced. Maize and banana were the major crops considered to workout the water productivity. Well irrigation system is having different field crops as well as allied enterprises whereas other systems are having pre-dominantly rice crop only except Parambikulam Aliyar Project (PAP), where groundnut is the major crop. The detailed methodology used for this study is described as follows.

Field/Farm ScaleAt a field scale, processes of interest are differ-

ent: nutrient application, water conserving tillage prac-tices, field bunding, puddling of paddy fields etc. Wa-ter enters the field domain by direct rainfall, subsurface flows and irrigation from a source of storage. Rainfall alone is considered in case of rain fed agriculture. A field or farm scale water productivity (WP (f)) is influenced by the inevitable irrigation conveyance, application, stor-

age and distribution losses/efficiencies. Hence the total water diverted from storage accounting for these losses is taken as the consumptive usage. Technically,

WP (f) = WP (p)/(η),

where (η) is the overall irrigation efficiency of the farm with gravitational irrigation system layout. In case of a micro-irrigation layout, the value of (η) will be more than 95 % and almost 100% if the design is perfect.

Since the scale of reference expands, the unit may be chosen as tonnes per cm of water consumed (t/cm).

Conveyance Efficiency η.c = Wdf/Wds

× 100 ... (1)

Application Efficiency η.a

= Wsr/Wdf × 100 ... (2)

Storage Efficiency η.s = Wsr/Wnr

× 100 ... (3)

Distribution Efficiency η.d = (1-Y/d )

× 100 ... (4)

Water Use Efficiency WUE = (Y/A)/Wdf ... (5)

Where,

Wds = Volume of water diverted from the irrigation source, in m3 or ha.cm; the source may be a well, canal distributory outlet, tank sluice outlet etc.

Wdf = Volume of water delivered on to the field, in m3 or ha. cm

Wro = Volume of run off, m3 or ha. cm

Wdp = Volume of deep percolation m3 or ha. cm

Wsr = Wdf � (Wro + Wdp) = Volume of water stored in the effective root zone m3 or ha. cm

Wnr = Volume of water needed in the root zone, m3 or ha. cm = A × d

d = design depth of irrigation, cm =

× ASMP %

A = Area irrigated

d = Average depth of water stored in root zone after irrigation, cm

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Y = Average of the numerical devia-tions of individual depth of water stored at different loca-tions in the farm/field from the average depth of water stored, cm

The overall field irrigation efficiency η.e

= η.

c × η.

a ... (6)

Project/Command Area ScaleIn Tamil Nadu, three distinct kinds of command

areas are in vogue viz., Canal (or Reservoir) command, Tank (system and non-system) command and Well (Groundwater) command. While the canal and tank com-mands mostly fall intact under a project operation, well commands occur in a scattered fashion. When water is distributed in an irrigation system at a major scale like this, the important processes include allocation, distri-bution, conflict resolution and drainage. Allocation and distribution of irrigation water are primarily for irrigation farmers besides meeting the non-agricultural demands lie domestic, industrial, livestock and fisheries use.

Canal Command / Project Water Pro-ductivity (WP(c))

The overall productivity of this scale of reference depends ultimately on the total quantum of water re-leased from storage over the base period, the area cov-ered and the project yield. The storage duty (S) includes the losses during conveyance, distribution and applica-tion over and above the field duty (Δ) in a canal network project.

Field duty (Δ) is expressed as the seasonal water requirement for crop and related activities, in cm, at the tail most end area of the canal network.

Δ = CU/η ... (7)

where, η represents the farm/field efficiency.

Then, the storage duty (S) = Δ/η(c), where η(c) represents the overall conveyance efficiency of the canal network/project.

The flow duty (D) in ha/cumec is devised in ac-cordance with S and Δ to cover the given command area (A) over the base period (B) of the project water supply, as,

D = (864B) / Δ , and S = A . Δ / η(c) ... (8)

As the command area/project scale is expand-

ing the apparent losses like run-off and / or deep perco-lation would be considered for recycling or conjunctive use with canal flows. Then, the water productivity will be based on the total volume of water diverted from the irrigation source or simply the storage duty (S).

WP (c) = Y / S ... (9)

Where,

Y = project yield, in tonnes and S = Storage duty, in ha.cm

If S is expressed in cm as SÊ then, SÊ = S/A

So that WP(c) = Y / SÊ ... (10)

Tank Command Water Productivity WP (t)

Nearly 39,000 tanks exist in Tamil Nadu State as natural surface water harvesting structures since the olden king regimes for the purpose of irrigation and other water usage. Earlier the tank system had clearly defined channel network originating from the storage outlet point and in due course of time these channels have disappeared owing to encroachments and other formidable reasons. The tanks commonly come under a non-system (isolated or interconnected battery) with in-dependent or combined catchments or a system tank arcade hooked along rivers or streams or canals, in which water at select points is diverted into the tank. Streams emanating from their own catchment basins during rains feed the non-system tanks and the water thus stored is utilized for irrigation and other purposes during the non-rainy season. In case of a battery of interconnected non-system tanks, water spilling from previous tank is diverted to the subsequent tank. System tanks are fed by flow diversion from natural river streams or from a project canal network as and when surplus flows occur. The gross volume of water depleted from the tank stor-age (Sd) or the equivalent depth (SdÊ) in cm, over the crop growth season forms the base (denominator) for productivity calculations.

WP (t) = Y/Sd ... (11)

where,

Y = the overall tank command yield in tonnes

Sd = depleted volume of water from tank stor-age, ha.cm or Million cubic metres

SdÊ = equivalent depth in cm of water depleted from tank storage

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Well Command Water Productivity WP (w)

Unlike the canal or tank commands, well com-mands are isolated and scattered and may also occur within a canal command or tank command. Absolute water productivity from an area fed by wells alone can be worked out if that area is away from a canal or tank command. But if the wells function within a canal or tank command, the conjunctive water productivity will be assessed on the premise that losses from canal or tank flows, contribute to groundwater recharge over a certain lag period i.e. loss is transformed into a gain. Recycling this gain of water as a conjunctive use of groundwater with surface waters will help increase the irrigation area thereby increasing the absolute productiv-ity of the region. Water table fluctuations are periodically assessed to determine if the area comes under a dark zone or gray zone or a white zone for having exploited the groundwater potential and leading to a critical stage of minimum or controlled pumping with possibilities for introducing artificial recharge means and structures. Wa-ter table fluctuations, pumping hours, discharge varia-tions, power of pumping unit, mode of conveyance and application, type of crop and method of irrigation would contribute for the fluctuations in productivity. The pro-ductivity can be improved if lined channels or pipelines are used for conveyance and micro-irrigation systems are used for application.

WP (w) = Y/Wd ... (12)

Where,

Wd = volume or equivalent depth in cm of water depleted from well storage by pumping = (Pump discharge * total duration of pumping over the crop growth season) / Area of cultivation

All the above scales of reference shall be suitably formatted for input data, processing models and output units of productivity. The overall physical or economic productivity of a region shall then be worked out inte-grating the above scales.

Results and discussionWater productivity under different scale levels

viz., plant, field and distributory level were studied in three different irrigation systems viz., canal, tank and well irrigation. In canal irrigation system, four river basin areas of Tamil Nadu viz., Parambikulam Aliyar Project (PAP), Lower Bhavani Project (LBP), Periyar Vaigai and

Tampiraparani river basins were worked out and pre-sented in Table 1. In canal irrigation system, ground nut is a predominant crop in Parambikulam Aliyar Project (PAP), whereas in the other three river basins rice is the major crop.

From the results, it is clearly understood that there was a considerable reduction in water productivity under field level (0.20 kg groundnut/ m3 of water in PAP, 0.40 kg rice / m3 in Lower Bhavani project (LBP), 0.24 kg rice / m3 in Vaigai and 0.27 kg rice / m3 in Tampira-parani river basin) as compared to individual plant/ crop level (0.39 kg groundnut/ m3 of water in PAP, 0.73 kg rice / m3 in LBP, 0.70 kg rice / m3 in Vaigai and 0.60 kg rice / m3 in Tampiraparani river basin) mainly due to losses through seepage, deep percolation and runoff in the canal irrigation systems. Among the four canal ir-rigation projects, Lower Bhavani project was recorded higher productivity at plant level (0.73 kg/m3) as well as at farm level (0.40 kg/m3) compared to other projects. At distributory level, conveyance losses caused reduction in water productivity which means that more quantity of water is being used for crop cultivation. So water pro-ductivity has a negative relationship with the scale of reference that is expansion of boundary of command area.

In the case of tank irrigation, Srivilliputhur Big tank in Ramanathapuram district of Tamil Nadu, the re-sults showed that there was a reduction in water pro-ductivity when the scale of reference has increased. The physical water productivity of rice was higher under individual plant level (0.47 kg / m3) followed by field level water productivity (0.30 kg / m3) and compara-tively lower water productivity was recorded under tank system level.

Similarly, the water productivity under well irriga-tion system was studied at farmersÊ fields of Coimbatore district where well irrigation is being predominantly practiced. Maize and banana were the major crops con-sidered to workout the water productivity. Well irrigation system is having different field crops as well as allied enterprises whereas other systems are having predomi-nantly rice crop only except Parambikulam Aliyar Project (PAP), where groundnut is the major crop. So multiple water uses was studied in well irrigation system under different farm enterprises at farmersÊ holdings in working out the water productivity. Farms with crops alone, crop + dairy and crop + fishery were analysed in this study. The results showed that the farm, which is having al-

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lied enterprises along with crops registered higher water productivity over the farms with crops alone. Compar-ing the different combination of farm enterprises, crop + fishery system has resulted in higher water produc-tivity (Rs.41.43/m3) followed by crop + dairy combina-tion (Rs.11.27/m3) and the lower water productivity of Rs.9.64/m3 was observed with crops alone.

In sum, among the different irrigation systems, well system has comparatively higher water productivity both in physical and economic terms due to controlled irrigation application, comparatively higher crop yields and multiple crops/ enterprises combinations. Whereas in canal and tank system, mono cropping, uncontrolled irrigations, and scarcity of water during critical crop pe-riods result in lower water productivity.

References Chaudhary, T.N., 1997. Vision-2020. DWMR Perspective Plan. Directorate of Water Research, Patna, India, 73 p.Molden, D., 1997. Accounting for water use and productivity. SWIM Paper 1. International Irrigation Management

Institute, Colombo, Sri Lanka.Navalawala, B.N. 1999a. Improving management of irrigation resources. Yojana, January: 81-87.Seckler, D., D. Molden and R. Sakthivadivel. 2003. „The Concept of Efficiency in Water Resources Management and

Policy‰. In: Water Productivity in Agriculture: Limits and Opportunities for Improvement. (Eds) Kijne.J.W., R.Barker and D.Molden. CABI Publishing. UK. pp 37-53.

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Scale of References Total water used (m3) Output Water Productivity

Physical Economic Physical Economic (kg) (Rs.) (kg/m3) (Rs./m3)

I. Canal system1. Parambikulam Aliyar Project (PAP)Plant/crop level 0.013 0.0051 0.0312 0.39 2.40

Field level (0.4 ha) 3388.8 680 4160 0.20 1.23

Distributory level 1335283.7 185661 1135810 0.14 0.85

2. Lowe Bhavani Project (LBP) Plant/crop level 0.0180 0.0131 0.029 0.73 1.61

Field level (0.4 ha) 5473.5 2200 7000 0.40 1.28

Distributory level 833824.4 213796 621952 0.26 0.75

3. Vaigai River BasinPlant/crop level 0.020 0.014 0.033 0.70 1.65

Field level (0.4 ha) 6931.25 1650 4390 0.24 0.63

Distributory level 2486534.4 396000 1053600 0.16 0.42

4. Tampiraparani River BasinPlant/crop level 0.028 0.017 0.068 0.60 2.43

Field level (0.4 ha) 7909.4 2100 7100 0.27 0.90

Distributory level 37647968.0 3549038 12066949.5 0.09 0.30

II. Tank systemPlant/crop level 0.0202 0.0095 0.007125 0.49 0.35

Field level (0.4 ha) 11608.1 3160 2375 0.27 0.20

System level 3099174 821000 954750 0.26 0.30

III. Well systemPlant/crop level

Maize 0.048 0.050 0.21 1.04 4.38

Banana 6.6 8.5 59.70 1.28 8.99

Field level

Crops alone (0.9 ha) 12003.0 15833.33* 115752 1.31 9.64

Crops + Dairy (1.0 ha) 10068.4 32116.67** 115752 3.19 11.27

Crops + Fishery (1.20 ha) 16352.0 72045.83* 678350 4.41 41.43

* Banana equivalent yield ** maize equivalent yield

Table 1: Physical and economic water productivity under different irrigation systems with different scale of reference in Tamil Nadu

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Integrated Farming System for Increasing Agricultural Water

ProductivityC.Jayanthi, T.Ramesh and C.Vennila

18

IntroductionAt the dawn of new millennium, many chal-

lenges surmount agriculture to achieve sustainable food security with shrinking land resources. Now we have to produce an additional 50 million tonnes of food grains to meet the requirement of the prognosticated popula-tion of 1060 million by 2020AD. Because of declining per capita availability of land in India, there is hardly any scope for horizontal expansion of land for food produc-tion. Only vertical expansion is possible by integrating appropriate farming components requiring lesser space and time and ensuring periodic income to the farmer. On the other hand, modest increments in land produc-tivity are also no longer sufficient to the resource poor farmers. Hence, efficient management and allocation of resources are important to alleviate the risk related to land sustainability. Moreover, proper understanding of interactions and linkages between the components help to improve food security, employment generation besides nutritional security. This concept which has got transformed into farming systems approach, envis-

ages the integration of agro-forestry, horticulture, dairy, sheep and goat rearing, fishery, poultry, pigeon, biogas, mushroom, sericulture and by product utilization with crops, with the primary goal of increasing the income and standard of living of small and marginal farmers.

One of the ways to make farming a viable propo-sition is to bring diversification in agriculture. The pre-conditions for diversifications are water resources devel-opment and growing of crops which have better market opportunities. In addition to growing vegetable and fruit crops, livestock, pisiculture, bee keeping, poultry, rab-bitary and floriculture can further provide boost to the overall improvement in the farming business.

The great challenge for the coming decades will be the task of producing more profit per drop of water, particularly in countries with limited water resources. In addition, growing demand for water for industry and municipalities, combined with environmental problems results in less water for agriculture in the future. One of the approaches to meet the future water shortages will be increasing water productivity through multi uses of

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water in a farm with the introduction of different agri-culture production systems instead of crops alone in a farm.

The concept of water productivity (WP) is of-fered by Molden,(1997) and Kijne et al. (2003) as a robust measure of the ability of agricultural systems to convert water into food. While it was used primarily to evaluate the function of irrigation systems � as Âcrop per dropÊ - it seems useful to extend the concept to include other types of livelihood support, such as mixed crop-ping, pasture, livestock, fisheries or forests.

Agricultural water productivity can be expressed either as a physical productivity in terms of yield over unit quantity of water consumed (tonnes per ha.cm of water or kg yield per kg water consumed) in accordance with the scale of reference that includes or excludes the losses of water or an economic productivity replacing the yield term by the gross or net present value of the crop yield for the same water consumption (Rupees per unit volume of water). Producing more crops, dairy, fish and forest products per unit of agricultural water use holds a key to both food and environmental security. However, Molden et al (2003) stated the importance of working out water productivity within agriculture, water use by fisheries, forests, dairy and field crops and concluded that analyzing each water use independently often leads to false conclusions because of these interactions.

An attempt was made to estimate the water pro-ductivity in integrated farming system through on-sta-tion and on-farm research at TNAU, Coimbatore, Tamil Nadu. On- station field investigation to estimate water productivity for rice based systems and the allied activi-ties like poultry, pigeon, fish and mushroom linked in lowland integrated farming systems was carried out at Tamil Nadu Agricultural University, Coimbatore, India.

The components were selected bearing in mind their popularity and suitability to lowland situations of Tamil Nadu. For fishery, fingerlings belonging to six spe-cies were stocked at 400 numbers per 0.04 ha area of pounded water. Water level in all the ponds was main-tained at 50 cm height initially at the time of release of fingerlings and subsequently raised to 60, 70, 80 and 90 cm at an interval of 30 days. From fourth month onwards, water level in the pond was maintained to 90 cm till the harvest of grown up fish to compensate the evaporation and seepage loss through pumped water every week. For poultry, twenty numbers of eighteen weeks old Bapkok chicks were sheltered in a shed. For

Pigeon, forty pairs of pigeon were sheltered near that second fishpond. Birds were allowed to go for open grazing in the fields in and around the system and not been supplemented with any other material. For mush-room, mushroom cultivation was carried out with a ca-pacity of 2 kg day-1 allowing recycling of paddy straw from the component. Water requirement of the com-ponents was worked out and the productivity of com-ponents was converted to rice grain equivalents on the basis economics.

Results revealed that cultivation of rice-green gram-maize and rice-sunhemp-maize cropping systems (conventional cropping systems) each in 0.50 hectare consumed 182 ha cm of water totally in a year. Whereas 201 ha cm of water was needed for rice-soybean-sun-flower and rice-gingelly-maize cropping systems in 0.45 ha each involved in integrated farming systems. Poultry, pigeon, fish and mushroom components utilized 0.02, 0.04, 15.84 and 1.37 ha cm of water for their produc-tion in a year. Integration of cropping with pigeon + fish + mushroom utilized 218 ha cm as against 182 ha cm of water with conventional cropping system alone. Integra-tion of poultry and pigeon required very little quantity of water and total water requirement in integration of improved cropping with fish + mushroom + poultry / pigeon was lesser than the water requirement of rice based cropping alone in one hectare land area. Results on system productivity (rice equivalent yield) as a whole revealed that integration of rice based cropping with pi-geon + fish + mushroom produced 154.7 kg of rice per ha cm of water, while conventional cropping systems recorded 60.2 kg of rice per ha cm.(Table 1). Hence, integrating allied components with cropping results in effective water productivity in lowland systems (Jayan-thi.et.al.2000).

Multiple uses of water was studied in different ag-riculture production system viz.crop alone, crop + dairy and crop + fishery at farmersÊ holdings in western zone of Tamil Nadu, India. The results revealed that the farm, which was having allied enterprises along with crops registered higher water productivity over the farms with crops alone. Gross volume of water used in the farm was 12003, 10068.4 and 16352 m3 under crops alone, crops + dairy and crops + fishery respectively (Table 2). Farm with only crops have produced total physical out-put of 15833 kg banana equivalent yield whereas crops + dairy and crops + fishery farms produced total physi-cal productivity of 32117 kg maize equivalent yield and 72046 kg banana equivalent yield respectively. Higher

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profit of Rs.677550/- was obtained in fishery-integrated farm (1.20 ha) than dairy integrated farm (Rs.113425/- in 1.00 ha) and farm with crops alone (Rs.115752/- in 0.90 ha).

Water productivity in fish culturing have found comparatively higher (Rs.65.83m3), than dairy rearing (Rs.37.67/m3) and crop cultivation. While comparing the different combination of farm enterprises, crop + fishery system produced higher water productivity (Rs.41.43/m3) followed by crop + dairy combination (Rs.11.27/m3) and the lower water productivity of Rs.9.64/m3 was noticed where crops alone was raised (Table 3). Higher quantity of physical production and high market demands are the reasons for better economic water productivity

of fishery-integrated farm. Among the allied enterprises, fishery component could produce higher physical yield, better market price coupled with minimum water re-quirement, which in turn had resulted in higher water productivity per unit of water. Hence, water productivity under irrigated dryland ecosystem can be improvised by introducing fishery component along with field crops.

From the results of the study, it could be con-cluded that integration of allied enterprises like fishery or dairy along with crop cultivation leads to increased eco-nomic water productivity of a farm and it should remain as one of the strategies for accomplishing the objective of more profit per drop in Coimbatore region of Tamil Nadu.

ReferencesJayanthi,C, A. Rangasamy and C. hinnusamy.2000.water budgeting in lowland intergrated farming systems.Madras

Agric.J. 411-414Kjine, J.W., Barker, R. and Molden, D. (eds.) 2003. Water Productivity in Agriculture. CABI, WallingfordMolden, D., 1997. Accounting for water use and productivity. SWIM Paper 1. International Irrigation Management

Institute, Colombo, Sri Lanka.Molden, D., H. Murray-Rust, R. Sakthivadivel and I. Makin, 2003. A water productivity framework for understanding

and action. In: Water Productivity in Agriculture: Limits and Opportunities for improvement (eds). J.W.Kijne, R.Barker and D.Molden). CAB International. pp 1-18.

Palanisami, K., T.Ramesh and S.Senthilvel. 2007. Water productivity at farm level under differential agricultural production systems. In: 3rd International Groundwater Conference. Centre for Agriculture and Rural Development Studies, Tamil Nadu Agricultural University, Coimbatore � 641 003. p 306.

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Table 1: Water requirement (ha cm) of integrated

Component water requirement (ha cm) SystemFarming system requirement Crop Poultry Pigeon Fish Mushroom (ha cm)

FS1: Cropping alone 182 � � � � 182.00 (60.2)

FS2: Crop + Poultry + Fish + ushroom 201 0.02 � 15.84 1.37 218.23 (145.1)

FS3: Crop + Pigeon + Fish + Mushroom 201 � 0.04 15.84 1.37 218.25 (154.1)

FS4: Crop) + Fish + Mushroom 201 � � 15.84 1.37 218.21 (123.1)

(Figure in parentheses indicate rice grain equivalent yield kg ha cm�1) Souce: Jayanthi et al. (2000)

FS1 Rice � greengram � maize 0.50 ha Rice � sun hemp � maize 0.50 ha

FS2 to FS4 Rice � soybean � sunflower 0.45 ha Rice � gingelly � maize 0.45 ha

Table 2: Details of water used &yield of different farm enterprises at different farms

Farm type Enterprises Area (ha) Water (m3) Yield (kg)

Crops alone Banana-surface irrigated 0.60 8320.8 10500 Banana-drip irrigated 0.20 2823.2 5000 Leaf vegetable 0.10 859 500

Total farm 0.90 12003 15833*

Crops + Dairy Rose- surface irrigated 0.40 5444 306000 Nos. Rose- drip irrigated 0.40 3388.4 340000 Nos. Maize 0.20 796.4 800 Dairy 1 No. 439.6 3300 litres

Total farm 1.00 10068.4 32117**

Crops + Fishery Grapes-drip 0.40 1196 2500 Banana -drip 0.40 6699.2 14400 Fishery 0.40 8456.8 26670

Total farm 1.20 16352 72046*

*Banana equivalent yield ** maize equivalent yield, Souce: Palanisami et al. (2007)

Table 3: Economics &water productivity of different farm enterprises at different farms

Farm type Enterprises Area Income Cost profit WP WP (ha) (Rs.) (Rs.) (Rs.) (kg/ m3) (Rs./ m3)

Crops alone Banana-surface irrigated 0.60 126000 52248 73752 1.77 13.80 Banana-drip irrigated 0.20 60000 21000 39000 1.26 8.86 Leaf vegetable 0.10 4000 1000 3000 0.58 3.49

Total 0.90 194000 115752 1.31 9.64

Crops + Dairy Rose-surface irrigated* 0.40 76500 30000 46500 56.2* 8.54 Rose-drip irrigated* 0.40 85000 35000 50000 100.3* 14.76 Maize 0.20 4800 1500 3300 1.00 4.14 Dairy 1 No. 26400 12775 13625 7.75 litres 37.67

Total 1.00 192700 113425 3.19 11.27

Crops + Fishery Grapes-drip 0.40 25000 12000 13000 2.10 10.87 Banana -drip 0.40 172800 65000 107800 2.15 16.10 Fishery 0.40 666750 110000 556750 3.15 65.83

Total 1.20 842050 677550 4.41 41.43

*Physical water productivity is in numbers. Souce: Palanisami et al. (2007)

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Generation of Regional Water Harvesting Potential Scenarios

using CLIMGEN ModelA. Sarangi, C.A. Madramootoo and K.R. Koundal

19

IntroductionSpatio-temporal variability of precipitation

amount at both regional and global scales is being ob-served due to climate change. Such variations in water resources in general and reduced water availability of some regions in particular will definitely jeopardize many human activities, because, water is the elixir of life. This necessitates a detailed investigation to ascertain such changes of precipitation and quantify the hydrologi-cal variability of surface water resources due to climate change at regional scales for its judicious allocation to different water demanding sectors in a sustainable man-ner. One of the first weather generators developed for rural water quality modelling purposes is called WGEN (Richardson and Wright, 1984). Numerous other weath-er generators have developed since then. CLIGEN, the weather generator incorporated within the WEPP (Wa-ter Erosion Prediction Project) model, is based on the weather generation methods used in WGEN (Nicks et al. 1990). CLIGEN, however, adds the capability of gener-

ating rainfall intensity and duration or „breakpoint‰ rain-fall data necessary for the Green and Ampt infiltration model used in many of todayÊs hydrologic and soil loss prediction models including WEPP. With an aim to study the trend of precipitation, Yu et al. (2006) analysed the long-term rainfall data (1904-2001) from 33 rain-gauges at different time scales (annual, seasonal and monthly rainfalls) in Taiwan. The statistical tests, such as cumula-tive deviations, Mann-Whitney-Pettitt statistics and the Kruskal-Wallis test, were employed to determine whether annual rainfall series exhibit any regular trend. Both tests identified the trend and the identified the change points in the data series. Basistha et al. (2007) prepared the normal annual rainfall maps for 44 raingauge stations in Uttarakhand state lying in Himalayan region of India based on the recorded data from the year 1901 to 1950 to study the spatial distribution of rainfall. A compara-tive analysis of interpolation techniques like Inverse Dis-tance Weighted, Polynomial, Splines, Ordinary Kriging and Universal Kriging showed that the Universal Kriging with hole-effect model and natural logarithmic transfor-

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mation with constant trend having Root Mean Square Error (RMSE) of 328.7 was found to be the best suitable method for interpolation of rainfall in this region. The validation of the predicted values with the observed data revealed that the variability of rainfall in plains exhibited minimal error as compared to the hilly terrains of Great Himalayas. The results indicated that the spatial vari-ability models could not predict the variability of rain-fall in hilly regions. Livada and Assimakopoulos (2007) used the Standardised Precipitation Index (SPI) to detect drought events in spatial and temporal basis over the Greek territory. The monthly precipitation data from 23 stations well spread over Greece and for a period of 51 years (1950�2000) was used and a classification of drought was performed, based on its intensity and dura-tion of precipitation. The results indicate that, mild and moderate droughts reduce from north to south and from west to east on the 3- and 6-months time scale, while for the class of severe drought; the frequencies in the southern part of Greece were higher than in the other parts of the country. Shahid (2007) analysed the spatial and temporal characteristics of precipitation in the west-ern part of Bangladesh for a periof from 1961 to 1999. A standardized precipitation index method was used to compute the severity of droughts from the rainfall data recorded in 12 rainfall gauge stations. An artificial neu-ral network model was used to estimate the missing rain-fall data and GIS was used to map the spatial extent of droughts with varying severities in multiple time scales. Analysis of rainfall was also carried to find the mini-mum rainfall during monsoon and dry months in differ-ent parts of the study area to avoid rainfall deficit. The study showed that the north and north-western parts of Bangladesh were most vulnerable to droughts. Keeping in view of the research work pertaining to analysis of rainfall data, the present study was carried out to inves-tigate the changes in daily precipitation amounts using a long term daily rainfall data base of a rain gauge sta-tion in Indian Agricultural Research Institute (IARI) farm, New Delhi, India. Daily rainfall data available at Water Technology Centre (WTC) observatory of IARI farm for a period from 1972 to 2007 (36 years) was acquired and converted to digital format for subsequent analysis us-ing ClimGen model. Assessment of the spatio-temporal variability of precipitation would assist in quantification of the surface runoff and the harvestable runoff water for agriculture and allied activities.

Operation of The Climate Generation (ClimGen) Model

Weather generators have been developed in re-cent years to help reduce the time required to prepare weather input data sets. Weather generators are com-puter programs that use existing climatic records to pro-duce a long series of synthetic daily climatic data. The statistical properties of the generated data are expected to be similar to those of the actual data for a station. Un-like historical weather data files which may be missing data due to equipment servicing or malfunction, gener-ated weather input provides a complete data set and can be produced for any desired period of time, enhancing their use as input for continuous-in-time models. Clim-Gen model, which is a modified version of WGEN is developed by Gaylon S. Campbell of Washington State University, USA. ClimGen generates daily maximum and minimum temperature, and precipitation from ei-ther daily weather data, if available, or from monthly summaries. The model is written in C++ using Borland C++ builder and the technical support is provided by Dr. Roger Nelson, Biological Systems Engineering De-partment, Washington State University, Pullman, WA, USA (Stockle et al., 2003). A copy of the most recent version of ClimGen is available and may be download-ed from the ClimGen website. The website address is „www.bsyse.wsu.edu/climgen‰. Those interested in us-ing the model are encouraged to visit the site, download and test the model in their own setting, and provide feedback to the developers on its use. In this study, the ClimGen model ver. 4.04.15 is used for analysis of the rainfall data (Fig.1).

ClimGen uses weather generation approaches that are similar to those applied in other popular weath-er generators. ClimGen is generally used to generate the key weather input variables needed for hydrologic and crop growth modelling. In this study, daily precipi-tation depths were generated and analysed using the ClimGen model. Generating precipitation data involves approaches that can assess the likelihood of both the occurrence of precipitation on a particular day as well as the amount. Rainfall intensity and duration within the rain event may also need to be generated for some appli-cations. ClimGen models the daily precipitation occur-rence using a two-state Markov chain model to generate the number and distribution of precipitation events. The probability of a wet day following a dry day and the prob-

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ability of a dry day following a wet day is also estimated by ClimGen. These probabilities are calculated for each month of the year for the station being characterized by analyzing a stationÊs historic long-term precipitation data provided by the model user. On days when pre-cipitation is determined to occur, ClimGen assumes the cumulative probability of precipitation amount follows a Weibull distribution. The advantages of ClimGen over other weather generators are summarized as follows:

• ClimGen includes routines that allow it to automate the task of parameterizing historical weather data from new stations of interest. All that is required is sufficient historical observed data for a station formatted in a manner that can be read by the ClimGen software. The minimum data requirement for good precipitation generation is at least 25 years of real precipitation data. With one or more years of data, the parameterization will be achieved, but with any less than 25 years of real precipitation data, the generated precipitation should only be considered as estimates.

• Daily precipitation amounts are assumed to follow a Weibull distribution in the model, which is observed to be superior to other probability distributions of daily precipitation amount (Selker and Haith,1990).

• A spline-fitting approach is used in Clim-Gen. This is an improvement over the one-term Fourier series used by many of the other weather generators to model seasonal variations in climate data.

• Developers of the ClimGen model are available and were interested in supporting and enhanc-ing ClimGen as a weather generation tool for use under a range of geographic locations and applications, includ-ing the Canadian setting.

Results and DiscussionsDaily rainfall data of the WTC observatory for

a period of 36 years available in form of rainfall charts and tabular formats were digitized and prepared in the Universal Environment Database (UED) format using the ExcelTM spreadsheet. Further, the ClimGen model was parameterized using the daily rainfall data of 30 years (1972-2001) and incorporating the location informa-tion (78.450 longitude and 27.360 latitude) of the ob-servatory at WTC besides other input parameters. The parametrized model was further used to generate the daily rainfall data for a period for 42 years (2002-2043) (Fig. 2). The generated data for the period from the year 2002 to 2007 was compared with the recorded data of

the said period. The coefficient of determination (R2) of the fitted trend line for all the years ranged from 0.76 to 0.93. The validation results for the year 2007 is shown in the Fig.3. It is observed from Fig.3 that the ClimGen predicted rainfall depths for the year 2007 was in line with the observed daily rainfall depths and the model over predicted the total annual rainfall depth by a small margin of 25mm. The randomness, trend and periodic-ity of the daily rainfall data of the observed and predicted sets for the year 2007 were almost in line. Further, a non-parametric statistical test i.e. Mann-Kendall rank correlation test was carried out on the predicted data for the period from 2008 to 2043. The test showed that there was an increasing trend of precipitation amounts for the projected period. The annual monthly rainfall data of both the historical recorded set and the ClimGen generated set were plotted along with the trend line, which is shown in Fig 4. It was observed from the Fig. 4 that the annual rainfall depths exhibited an increasing trend of rainfall for the period from the year 2008 to 2043. Subsequently to understand the variability in the number of the rainy and non-rainy days in every year before and after the base year 2007, the rainy and non rainy days were calculated form the data set of 76 years and are shown in Fig. 5. It was observed from Fig. 5 that there was a significant variability in the rainy and non-rainy days during the 36 years period prior to 2007 with a range (R) of 57 days, where as the range was 25 days for the ClimGen generated data base of 36 years after the year 2007. The probability of a wet day followed by a dry day and consecutive wet day and dry day rainfall analysis carried out on the data sets revealed that the probability of dry day followed by a wet day was less for the period from the year 2008 to 2043. This result indi-cate that the water harvesting potential of the region will increase due to saturated soil conditions prevailing for an extended period as compared to the periods prior to 2007. However, to ascertain these findings, the evapo-transpiration and rainfall data from other peripheral sta-tions and the solar radiation along with the soil and land use information are also essential.

ConclusionsClimGen model was successfully parameterized

using the recorded daily precipitation data of WTC ob-servatory and was subsequently used to generate the pre-cipitation amount for extended 36 years period. Analysis of the data for both the periods before and after the year 2007 revealed significant information about the trend of precipitation corroborating the change of climate and its

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impact on availability of water resources in future. The daily rainfall amounts were observed to be higher for the period from 2008 to 2043 as compared to very few higher events as observed from 1972 to 2007. These findings corroborated the GCM predictions of having high intense storms resulting in elevated daily rainfall amounts. There preliminary investigations carried out using the ClimGen model can be used to generate the

daily precipitation amount besides the probability of wet day and dry days to estimate the water harvesting potential of a region comprising of a network of rain gauge stations. Also, the meteorological and agricultural drought indices can be developed to advocate the farm-ing community for judicious dry land farming to enhance agricultural production.

ReferencesBasistha, A., Arya, D. S. and Goel, N. K. (2007) Spatial Distribution of Rainfall in Indian Himalayas � A Case Study

of Uttarakhand Region, Water Resource Management, DOI 10.1007/s11269-007-9228-2Livada, I. and Assimakopoulos, V. D. (2007) Spatial and temporal analysis of drought in Greece using the Standardized

Precipitation Index (SPI). Theoretical and Applied Climatology 89, 143�153. DOI 10.1007/s00704-005-0227-z

Narasimhan, B. and Srinivasan, R. (2005) Development and evaluation of Soil Moisture Deficit Index (SMDI) and Evapotranspiration Deficit Index (ETDI) for agricultural drought monitoring. Agricultural and Forest Meteorology 133:69�88.

Nicks, A.D., C.W. Richardson, and J.R. Williams. 1990. Evaluation of the EPIC model weather generator. In EPIC – Erosion/Productivity Impact Calculator, 1. Model Documentation, USDA Technical Bulletin No. 1768, Eds. A.N. Sharpley and J.R. Williams. 105-124. Washington, DC, U.S.A.

Richardson, C.W. and D.A. Wright. 1984. WGEN, A Model for Generating Daily Weather Variables, USDA ARS Bulletin No. ARS-8. Washington, DC, U.S.A.: Government Printing Office.

Shahid, S (2007) Spatial and temporal characteristics of droughts in the western part of Bangladesh, Hydrological Processes 21, 0�0 DOI: 10.1002/hyp.6820.

Stockle, C.O., M. Donatelli and R. Nelson. 2003. CropSyst, a cropping systems simulation model. Europ. J. Agronomy 18:289-307.

Yu, P., Yang, T., and Kuo, C. (2006) Evaluating Long-Term Trends in Annual and Seasonal Precipitation in Taiwan, Water Resources Management 20: 1007�1023. DOI: 10.1007/s11269-006-9020-8.

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Improving Water Productivity in Maize by Nutriseed Holder

Technique under Micro Sprinkler and Drip Irrigation

K. Arulmozhiselvan and R. Vengatesan

20

Introduction Globally maize is the top ranking cereal in po-

tential grain productivity. India ranks fifth in maize area (6.42 m ha), fourth in production (11.47 m t) and third in productivity with average yield of 1790 kg ha-1 among cereals (SAI, 2000). Fertilizer rates and placement of nu-trients are important factors to be considered to produce maximum yield of maize. Particularly deep placement of nutrients might be beneficial to corn growth. The meth-od of N, P and K placement has typically been found effective over broadcasting on the top of the soil, and it is also influenced by the amount of water used for irriga-tion (Howard et al., 2002). A fundamental approach is to reduce water use to grow maize by proper irrigation management. Recently drip irrigation methods are be-ing tested to save water by eliminating continuous seep-age and percolation, and reducing evaporation.

Maize responses to N, P and K fertilizer applica-tions are typically greatest in moist conditions (Nelson et al., 1992). Combining nutrients in a balanced proportion

has been found to enhance fertilizer use efficiency. Fer-tilizer tablets made out of dry granulation or compaction of urea individually with muriate of potash, zinc sulphate, DAP and ammonium chloride with ordinary tabletting machine, was found to reduce NH

3 volatilization upto 44

per cent, relative to urea, and would be a feasible cost-effective technology (Purakayastha and Katyal, 1998). Asha (2003) made a pioneering approach of deep plac-ing NPK fertilizers just below the germinating seedling with an aid of tubular holder called Nutriseed Holder, which contained sprouted seeds on top and fertilizers at bottom. This study with 15N tracer demonstrated a 57.1 percent of fertilizer N recovery, which exceeded two folds of recovery noted for surface broadcast (26.1 %). Subsequently Deivanai (2005) experimented with Nutri-seed holder having seed, enriched manure and fertilizers together, which gave 42-58 per cent increase in yield of rice grown in soil column, when compared to surface broadcast method, under submerged water regime.

In spite clear evidences on improvement in ef-ficiency, the deep placement methods have not been

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fully tested under different moisture status particularly under upland condition. Hence, in the present study the design of Nutriseed Holder developed for rice (Asha, 2003 ; Deivanai, 2005) was further improved and stud-ied with maize crop to understand the extent of utiliza-tion of nutrients under different water saving irrigation strategies viz., rainfed (simulated by micro sprinkler) and drip irrigation in comparison with conventional surface fertilizer broadcast method and surface irrigation.

Materials and MethodsThe experiment was conducted during November

2006 to March 2007 in the farm of Agricultural College and Research Institute, Madurai, Tamil Nadu, India. The experimental soil (Typic Haplustalf of Madukkur se-ries) was sandy loam in texture, neutral in pH having low organic carbon (0.63 %). The hybrid maize parental line UMI 61 was grown as test crop. In split plot design, the three main and six sub-plot treatments were assigned in two replications. In Main plots, irrigation treatments viz., Surface irrigation, Micro sprinkler irrigation (simulated rainfed condition), and Drip irrigation were imposed. In the Sub plots the methods of fertilizer application tested were: Surface broadcast (100 % Recommended NPK), Nutriseed holder - Open method with 75% N, 100% PK (or) 100% NPK, Nutriseed holder - Closed method with 75% N, 100% PK (or) 100% NPK and Control. The chemical analysis of soil and plant samples and in situ physical measurements were carried out by adopting standard procedures. Based on grain yield, nutrient up-take and nutrient applied the nutrient use efficiency was computed in terms of Apparent Nutrient Recovery and Water Productivity.

Irrigation Surface irrigation was done at weekly intervals

up to tasseling stage and thereafter once in 10 days con-suming 660 mm of water. Micro sprinkler irrigation was done with 4 sprinkler heads laid inside the plot. The wa-ter sprinkled inside the plot as rain droplets simulating rainfall. Each sprinkler delivered water at 70 litres hour-1. The amount of rainfall of 540 mm of North East mon-soon was simulated by adjusting the duration of delivery of water by micro sprinkler. Drip irrigation was given by on-line emitters located near each plot at 10 emit-ters m-2. Each emitter had delivery rate of about 8 litres hour-1. By adjusting the duration of delivery the amount of water admitted was regulated. Altogether during the crop period 360 mm of water was admitted.

Design of Nutriseed HolderDeep placement of fertilizers was done with the

aid of Nutriseed holders made with fertilizer, manure and seed pellets, wrapped in a square butter paper, as a roll (Fig 1). The fertilizer materials needed to supply full N and K and 90 per cent of P as per treatment, for a single maize plant was pressed to a pellet in the pel-leting device. Urea, single super phosphate and Muri-ate of potash were used as nutrient sources. Then the pellet was placed in a small thin polyethylene bag (1 x 1.5 inch), and the mouth was sealed with flame as a water proof pack. The bottom of polyethylene pack was opened using a circular pin to a 5 mm diameter pore in open method, and to a 1 mm diameter pore in closed method. For preparing manure pellet, enriched vermi-compost containing 10 per cent of P as per treatment was used.

When both fertilizer and manure pellets were made ready, they were placed on a 6 × 6 cm perfo-rated butter paper. Two maize seeds were put on top of roll and pressed with moist soil along with bioinoculants (Azospirillum and Phosphobacteria) and placed on top. Now the paper was rolled. The extending paper length was folded inside to protect seed from falling. The roll which contained fertilizer pellet at bottom, manure pellet in the middle and seed with soil and bio-inoculants is called as Nutriseed holder.

Deep PlacementAt the time of sowing Nutriseed holders were

placed vertically down. For this purpose a 6 cm deep hole was made in soil using a 15 mm thick and 15 cm length stick. Implanting was done by slightly placing a Nutriseed holder in the hole and pressing on top of holder vertically down till the top seed portion coincided to the soil surface. When this was done the dissolution surface of fertilizer pellet would have been located at 5 cm depth from the surface.

Results and DiscussionThe yield, water use efficiency and soil physi-

cal conditions varied widely with respect to irrigation regimes and method of fertilizer application. Under sur-face irrigation, deep placement of Nutriseed holder with 100% NPK in open method resulted in 3786 kg ha-1 grain yield (Table 1) which was 55.9 per cent higher than the grain yield of surface broadcast (2429 kg ha-1). Under simulated rainfed condition with micro sprinkler,

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placement of 100% NPK Nutriseed holder in open meth-od recorded 3350 kg ha-1 grain yield, which was 50.8 per cent higher than the surface broadcast (2221 kg ha-1) similar trend was also noted for the Stover yield.

M1 � Surface Broadcast M

2, M

3 � Nutriseed

Holder Open Method at 75 & 100 % N

M4, M

5 � Nutriseed Holder Closed Method at 75

& 100 % N M6 - Control

Significance at 5% level (*) or 1% level (**)

Over the conventional surface broadcast � sur-face irrigation method Grain yield increased due to 100% NPK Nutriseed holder open method to the tune of 55.9 per cent under surface irrigation, 37.9 per cent under micro sprinkler and 14.2 per cent under drip irrigation. Over all, maize stover and grain yields were influenced to greater extent by irrigation treatments in the following order: surface > micro sprinkler > drip.

The positive effect of irrigation was clearly spelt in the dry matter production and yield. This was possi-bly due to high water requirement. Maize requires water of about 650 mm for adequate growth under surface irrigation. In the present study conservative irrigation methods viz, micro sprinkler and drip were used effi-ciently to conserve irrigation water. Hence, according to applied water at 660, 540 and 360 mm under surface, micro sprinkler and drip irrigation respectively, the dry-matter production and grain yield would have resulted proportionately, proving the best performance under surface irrigation. Grain yield increased to the tune of

30.9 per cent for surface irrigation, and 17.4 percent for micro sprinkler (simulated rainfed) irrigation when com-pared to drip irrigation. While evaluating the relation-ship between soil moisture and crop growth Nandal and

Agarwal (1989) reported that water deficit had the direct effect on yield reduction.

The use of micro sprinkler to simulate rainfall and establish rainfed conditions have been successful in the present study. Under water saving situation micro sprinkler irrigation resulted in the considerable grain yield increase. By adjustment of irrigation duration the amount water was irrigated at the same frequency and quantity of rainfall that would occur during monsoon. However, micro sprinkler could not achieve grain yield as that of surface irrigation owing to crop water demand at various stages. Blad et al. (1980) have also success-fully used micro sprinkler for maize cropping.

In regions of water scarcity, drip irrigation has become the necessity. Besides water conservation, it en-ables slow and precise application of water at the rhizo-sphere region. In the present study water admitted for 12 weeks releasing about 360 mm of water has given on an average 2234 kg grain yield. Similar effort of growing maize with drip irrigation was attempted by Phene and Beale (1976).

At all irrigation treatments yield enhancement was realized over the conventional surface irrigation with surface broadcast method of fertilizer application. Maize responding to fertilizer application to appreciable extent in a low fertile soil has been clearly evidenced.

Table 1: Stover and Grain Yield of maize under different irrigation regimes(kg ha-1)

Method of Application Irrigation

Surface Micro Drip Mean Surface Micro Drip Mean Sprinkler Sprinkler

Stover Yield Grain Yield

M1 5493 5285 5085 5288 2429 2221 2008 2219

M2 6665 6225 5642 6177 3447 3099 2557 3034

M3 6831 6453 5801 6362 3786 3350 2773 3303

M4 5937 5648 5178 5588 2868 2539 2134 2514

M5 6242 5925 5387 5851 3173 2827 2336 2779

M6 4917 4821 4640 4793 1840 1697 1598 1712

Mean 6014 5726 5289 2924 2622 2234

SEd CD(P=0.05) SEd CD(P=0.05)

Irrigation 45.2 194.4** 15.3 65.7**

Methods 74.6 159.0** 20.5 43.6**

I at T 129.2 275.4* 35.5 75.6**

T at I 87.2 236.7* 25.5 74.3**

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Also the results indicated that there has been a scope to improve grain yield of maize to >50 per cent over the conventional surface broadcast method, by adopting deep placement using Nutriseed holder.

The promising effect of Nutriseed holder would be attributed to the controlled release of fertilizers which were precisely placed below 5 cm depth, with the com-bination of P enriched manure. The fertilizer pellet posi-tioned at bottom of Nutriseed holder would have allowed only downward movement of N, P and K nutrients, as the pellet was covered by polythene on top and at sides, having exposure area only at bottom. The higher nutri-ent availability and high nutrient uptake resulted under deep placement might have influenced dry matter pro-duction and yield.

In the previous attempts with deep placement, Bhuiyan (1988), Dhane et al. (1995) and Bautista et al. (2000) reported significant increase in yield due to fertilizer N, P and K placement in the root zone. Deiva-nai (2005) reported a yield increase of 63.3 per cent with placement of plastic Nutriseed holder over surface broadcast in soil column study while growing direct seeded rice. The first work carried out on deep place-ment using Nutriseed holder resulted in the grain yield

increase to the tune of 81.8 per cent over surface broad-cast (Asha and Arulmozhiselvan, 2006).

With respect to 100% NPK Nutriseed holder open method, where the grain yield was highest, use ef-ficiency was relatively high (Table 2) to the tune of 45.7, 41.0, 32.7 per cent for N, 28.2, 23.7, 20.0 per cent for P and 44.2, 36.2 and 27.8 per cent for K under surface, micro sprinkler and drip irrigation respectively. Water productivity (g grain / kg water) was high under drip ir-rigation (0.77g / kg) followed by micro sprinkler (0.62 g / kg). Low water productivity was noted for surface irrigation (0.57 g / kg).

M1

� Surface Broadcast M2, M

3 � Nutriseed

Holder Open Method at 75 & 100 % N

M4, M

5 � Nutriseed Holder Closed Method at 75

& 100 % N M6 - Control

In the case of water productivity, the highest yield achievement resulted in 100% NPK Nutriseed holder in open method was associated with low efficiency of 0.57g /kg water under surface irrigation, due to profuse irriga-tion. Water saving irrigations of drip and micro sprinkler achieved high productivity ranging 0.62 to 0.77g / kg water. Use of water under regulated release conditions

Table 2: Nutrient and Water Use Efficiency

Method of Application Nutrient Use efficiency Water productivity [Apparent Nutrient Recovery] (%)

N P K g grain / kg water

Surface Irrigation

M1 24.00 14.99 13.20 0.37

M2 53.23 33.98 52.00 0.52

M3 45.70 28.19 44.20 0.57

M4 40.59 26.52 30.93 0.44

M5 35.48 21.98 30.40 0.48

M6 � � � 0.28

Micro Sprinkler

M1 22.81 12.96 9.60 0.41

M2 49.19 29.31 41.33 0.57

M3 40.96 23.74 36.20 0.62

M4 38.72 21.48 24.00 0.47

M5 32.74 18.46 24.60 0.52

M6 � � � 0.31

Drip

M1 21.26 12.19 10.20 0.56

M2 39.11 23.59 31.73 0.71

M3 32.74 19.97 27.80 0.77

M4 29.73 17.07 16.80 0.59

M5 24.00 15.22 18.80 0.65

M6 � � � 0.44

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reduces water loss, hence always efficient when com-pared to surface irrigation, as evidenced in the study.

Compared to initial soil conditions, a compact-ing effect was noted with surface irrigation and drip ir-rigation at harvest stage (Table 3). Bulk density was 1.53 and 1.67 Mg m-3 under surface irrigation and 1.49 and 1.58 Mg m-3 under drip, when compared to normal bulk density of 1.42 and 1.48 Mg m-3 under micro sprinkler. Surface irrigation increased initial infiltration rate greatly. Hydraulic conductivity and steady infiltration decreased in soil in the order: micro sprinkler > drip > surface ir-rigation.

At the end of experiment the physical param-eters estimated in soil indicated a compaction effect at varying degrees for the irrigation treatments imposed. The measurement was done in the cropped line, in the space between plants. Surface irrigation showed the high bulk density in surface (1.53 Mg m-3) and sub sur-face (1.67 Mg m-3). When compared to micro sprinkler, rapid ponding of water and immediate drainage into soil column under surface irrigation might have broken down aggregates and carried the fine fraction of soil to lower depth leading to compaction. Volume reduction in the surface soil and addition of fine clay to the subsurface soil might have increased the bulk density to a consider-able extent.

*Significant at 5% level

Removal of fine fraction from the surface soil under surface irrigation might be the responsible factor of the very high initial infiltration rate (5.24 cm hr-1). However, due to clay accumulation in lower depth, the

infiltration rate rapidly decreased to a steady state of 0.86 cm hr-1. This effect was also seen with the lowest hydraulic conductivity both in surface (1.95 cm hr-1) and subsurface (1.36 cm hr-1) layers. While simulating rain-fall with micro sprinkler even though soil surface was wetted at faster rate, there was no ponding of water and quick down ward flow. In the case of drip irrigation, soil was wetted at a slow rate, only around the dripper and the resulting downward movement was also slow, hence compaction effect noted for drip irrigation was least. On the whole, based on physical properties estimated, the desirable physical conditions were good in the order: mi-cro sprinkler > drip > surface irrigation.

ConclusionThe improved performance of deep placement

was recorded with the newly designed Nutriseed holder under all irrigation regimes. At the time of sowing, plac-ing fertilizer, enriched manure and seed in a single at-tempt with Nutriseed holder would minimize the labour cost. No further top dressing of nutrients is required as entire NPK dose is placed in the holder with commonly available straight fertilizers. Hence, no specialized tech-nique is required to formulate a different form of fertil-izer. In this study the suitability of Nutriseed holder under surface, micro sprinkler and drip irrigation for maize has been established. When this technology comes to field,

fabrication of Nutriseed holders may be attempted with biodegradable plastic or with slow degradable polymer-reinforced paper. Large-scale industrial manufacture of Nutriseed holders packed with fertilizer, manure and seed will reduce the cost.

Table 3: Physical properties in post harvest soil in maize experiment

Treatment Mg m-3 cm hr-1 cm hr-1

0-15 cm 15-30 cm Initial Steady 0-15 cm 0-15 cm soil depth soil depth rate rate soil depth soil depth

Surface 1.53 1.67 5.24 0.86 1.95 1.36

Micro Sprinkler 1.42 1.48 3.65 1.23 2.86 2.27

Drip 1.49 1.58 2.96 0.97 2.08 1.87

Standard Error

Surface 0.037* 0.092* 0.072* 0.056* 0.059* 0.175*

Micro Sprinkler 0.043* 0.064* 0.114* 0.076* 0.090* 0.228*

Drip 0.021* 0.063* 0.215* 0.097* 0.122* 0.179*

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ReferencesAsha, V.S. 2003. Assessment of contribution of Azolla and deep placed fertilizers in direct seeded rice using 15N

technique. M.Sc.(Ag.) Thesis, Tamil Nadu Agricultural University, Coimbatore.Asha, V.S. and K. Arulmozhiselvan. 2006. 15N Tracer technique for studying efficiency of deep placed fertilizer through

Nutriseed holder in direct seeded rice. J. Nuclear Agric. Biol., 35 (1) : 1-14 Bautista, E.U., D.C. Suministrado and M. Koike. 2000. Mechanical deep placement of fertilizer in puddled soils. J.

Japanese Soc. Agric. Machinery, 62(1) : 146-157Bhuiyan, N.I. 1988. Effect of N source and application method on dry season irrigated rice. IRRN, 13(3) : 28-

29 Deivanai, M. 2005. Dynamics of deep placed fertilizer nutrients in soil column under controlled irrigation for direct

seeded rice. M.Sc.(Ag.) Thesis, Tamil Nadu Agricultural University, Coimbatore.Dhane, S.S., R.R. Khadse and H. K. Pawar. 1995. Integrated effect of deeply placed urea and glyricidia on grain

yield of transplanted rice. IRRN, 23(2): 12-21.Howard, Donald D., Michael E. Essington, and Joanne Logan. 2002. Long-term Broadcast and banded phosphorus

fertilization of corn produced using two tillage Systems. Agron. J., 94 : 51-56Nandal, D.P.S. and S.K. Agarwal. 1989. Response of winter maize to sowing dates irrigation and nitrogen levels in

North West India. Indian J. Agric. Sci., 59 : 629-633Nelson, W.L., W.I. Segars, S.R. Olsen, W. Wallingford, L.F. Welch. 1992. Developing systems for optimum corn

yield. National Corn Handbook NCH -6Phene, C.J. and O.W. Beale. 1976. High-frequency irrigation for water and nutrient management in humid regions.

Soil Sci. Soc. Am. J., 40 : 430-436Purakayastha, T.J. and J.C. Katyal. 1998. In: Fertilizer use situation in India. Nutrient Cycling in Agro

ecosystems, 51 : 107SAI, 2000. Statistical Abstract of India (2000). Central Statistical Organization. Ministry of Statistical and Programme

Implementation. Govt. of India, New Delhi. pp.17-32

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Aerobic Rice for Mitigating Water Scarcity: Physiological

ApproachesC.Vijayalakshmi, N.Sritharan and P.K.Selvaraj

21

IntroductionRice remains the most important staple food on

the planet since it feeds roughly half the population on a daily basis. Approximately, 750 million of the worldÊs poorest people depend on it to survive. According to FAO, the global rice requirement in 2025 will be of the order of 800 million tonnes. The current production is less than 600 million tonnes. The additional 200 million tonnes needed will have to be produced by in-creasing productivity per hectare. Dr. M.S. Swamina-than, The Chairman, National Commission on Farmers, Government of India said that breeding for high yield and feeding for higher productivity should go together and it is important that the crop feeding practices do not lead to the pollution of the ground water as well as soil. Rice grows under a wide range of latitudes and al-titudes and can become the anchor of food security in a world confronted with the challenge of climate change. The decline in soil health and water quality in rice-based systems is a major global issue. The situation is going to be aggravated in the event of possible global warming,

which would have a negative impact on yield and soil fertility. Development of technologies that support mul-tiple uses of water, enhanced water use efficiency and diversification of intensive and upland rice production system is essential.

In India rice is cultivated round the year in one or the other part of the country, in diverse ecologies spread over 44 million hectares with a production of around 90 million tonnes, representing the largest area and the second highest production in the world. Of the 44 mil-lion ha rice production area, 50 per cent is irrigated, 35 per cent is rainfed lowland, 12 per cent is upland and 3 per cent is flood prone or deep-water rice (http:// www.fao.org). In India, during 2004-2005, 87.8 million tonnes of rice was produced from an area of 42.41 mil-lion ha with the productivity of 2.05 t ha-1. In Tamil Nadu, 3.2 million tonnes of rice was produced from 1.4 million ha with the productivity of 2.31 t ha-1 during the year 2003-2004. The area under rice production and productivity declined by 8.0 per cent and 9.9 per cent respectively during the year 2003 and 2004 when com-

150

pared to the previous year due to unpredicted drought during the crop period. It is estimated that demand for rice in 2010 AD will be 100 million tonnes and in 2025 AD, it will be 140 million tonnes (Singh, 2004).

But, the increasing scarcity of fresh water threat-ens the sustainability of the irrigated rice ecosystem ( Tuong and Bouman , 2003). The future rice produc-tion will therefore, depend heavily on developing and adopting strategies and practices that will produce more rice with less and less water to feed the ever increasing population . The increase in water scarcity now made the researchers to look for various ways to decrease wa-ter use in rice production and increase the Water Use Efficiency ( WUE). One of the approaches that lead to a considerable amount of savings in water use by rice is aerobic cultivation, which combines the characteristics of both upland varieties with less water requirements and irrigated rice cultivars with high response to inputs (Bouman et al, 2002). The aerobic rice is defined as  high yielding rice grown in non-puddled and non- flood-ed aerobic soil. Wang et al., 2002 stated that the aerobic cultivation entails the growing of rice in aerobic soil , with the external inputs such as supplementary irriga-tion and fertilizers and aiming at high yields. Bouman et al.,(2002) explained it as a new water saving technology to grow rice aerobically that is in non-puddled and non-flooded soil with irrigation. Improved understanding of the physiological and biochemical control of signaling process that regulates the adoption of rice to aerobic conditions will facilitates the development of successful aerobic cultivars that respond to the environments more like other upland species , which are one of the solutions for looming global water crisis. In India, so far no re-search work is carried out to study the physiological and biochemical responses of rice grown aerobically. In addi-tion, a scientific evaluation on growth and yield potential of aerobic rice using micro-irrigation technology is very much required at present. In the light of these situations the present investigation was carried out.

Materials and MethodsA field experiment was conducted at Agricultur-

al Research Station, Bhavanisagar ( 11o 2‰ N and 76 o 57 „ E with 426.76 m above MSL), TNAU during 2007. The soil of the experiment site is sandy loam. The available soil nitrogen, phosphorus and potassium were 197, 19.1, 220 kg ha-1 respectively (Soil pH 7.2; EC 0.24 dSm-1). The rice cultivar PMK3 was chosen for this study. Different micro irrigation techniques viz.,

micro sprinkler and drip irrigation were imposed and irrigation was based on the evapotranspiration. The surface irrigated plots were maintained to compare the water economy with micro irrigation techniques. Seeds were sown directly with the spacing of 20X10 cm. The experiment was laid out in Randomized Block Design with nine treatments and three replications. The crop management and protection measures were done at the appropriate time as per the recommendations.

The physiological parameters viz., total chloro-phyll content, chlorophyll fluorescence and membrane stability index (MSI) were determined at panicle initiation (PI) and flowering stages of the crop. At maturity, num-ber of productive tillers, grain yield and harvest index (HI) were determined by following the standard meth-ods. Water use efficiency (WUE) was computed based on the total quantity of water used in each treatment.

Results and DiscussionThe photosynthetic pigment chlorophyll content

at PI and flowering stages exhibited higher values under flooded irrigation treatments followed by drip and mi-cro sprinkler irrigation (Table 1). Lafitte and Courtosis (2002) also reported a decline in chlorophyll content un-der micro irrigation. The decline in chlorophyll content is mainly because of increased chlorophyllase activity and thereby limited chlorophyll synthesis under water limited environment. The drip irrigation @ 200 % PE recorded an equal amount of this green pigment compared to surface irrigation T1. The SPAD value is a measure of greenness of the leaf. The treatments showed significant variation among the treatments. The data on the SPAD value recorded by drip irrigation @ 200 % PE is parallel to the surface irrigation. Another important parameter to asses the photosynthetic efficiency is the chlorophyll fluorescence which is measured in terms of Fv/Fm ra-tio., A declining pattern was observed in the case of Fv/Fm ratio under micro-irrigation treatments (Table 1). This decline may be due to photoinhibition which causes damage to a portion of PS II (Cao and Govindjee, 1990), and increase in energy dissipation in the chloro-phyll pigment antennae system that is often observed in plants under water limited environment. Membrane sta-bility index (MSI) is an important physiological trait for water stress tolerance. The data on MSI showed that the drip irrigation T9 had maintained a higher value on par with surface irrigation T1. The leakage of solutes from tissue can be used as a dynamic measure of the damage to membranes incurred by stress experiences. Mainte-

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nance of membrane integrity and function under a given level of dehydration stress has been used as a measure of drought tolerance. All these physiological parameters that reflect the photosynthetic efficiency show that the drip irrigation @ 200% PE was able to maintain photo-synthetic capacity equal to that of surface irrigation T1.

In the present study number of productive til-lers showed significant reduction under micro irrigation comparing to surface irrigation treatments. The grain yield reduced significantly under micro sprinkler treat-ments than drip irrigation (Table 2). This may be due to the amount of water supplied with sprinkler irriga-tion which is not sufficient to saturate the soil during reproductive stage resulting in reduced spikelet fertility, and finally the yield. Scientists have recorded 20 per cent yield reduction in direct seeded rice cultivars under sprinkler irrigation system. In the case of drip irrigation, decline in yield was observed, but the higher level of drip irrigation regime (200% PE) recorded better yield which is close to the yield of surface irrigation (one day af-ter disappearance of ponded water) and superior to the sprinkler irrigation treatments. Drip irrigation treatment showed its performance equal to surface irrigation that saves water effectively.

Pressurized irrigation systems (sprinkler and drip) have the potential to increase irrigation water use ef-ficiency by providing water to match crop requirements, reducing runoff and deep drainage losses, and generally keeping soil drier reducing soil evaporation and increas-ing the capacity to capture rainfall. The data on water

budget showed higher water productivity under micro irrigation technology (Table 3). Even though, the water productivity was higher under micro sprinkler and drip irrigation treatments, the reduction in yield was more in micro sprinkler regimes than drip irrigation. Under the drip irrigation @ 200% PE , grain yield equal to that of surface irrigation ( one day after disappearance of pond-ed water). There are numerous reports of large irrigation water savings when changing from continuously flooded rice to saturated soil culture to alternate wetting and dry-ing, but yields decrease as soil water content declines below saturation (Bouman et al., 2002). The present investigation confirms that the drip irrigation could be exploited for successful rice production under aerobic condition with high WUE.

Aerobic rice could be targeted at water-short ar-eas, where farmers do not have access to water to keep rice fields flooded for a substantial period of time any-more or water shortage encountered in tail end of large scale surface irrigation system. Plant physiologists and breeders have to respond to the challenge of breeding varieties and knowing the physiological mechanism that perform well under aerobic conditions.

T1*

Surface irrigation - 5 cm standing water, one day after disappearance of ponded water (DADPW)

T5 Micro sprinkler irrigation 150 % PE

T2 Surface irrigation - 5 cm standing water, three

DADPW

Treat Total Chlorophyll SPAD Value MSI (%) Fv/Fm ratio Ments* content (mg g-1)

PI Flowering PI Flowering PI Flowering PI Flowering g ng g g T

1 2.124 2.402 32.88 34.60 76.26 79.69 0.805 0.815

T2 1.985 2.311 27.85 29.63 71.51 75.95 0.764 0.775

T3 1.715 1.823 27.20 29.00 67.87 70.90 0.615 0.652

T4 1.589 1.723 27.15 29.70 60.80 64.44 0.713 0.727

T5 1.602 1.811 27.78 31.03 65.35 66.96 0.733 0.752

T6 1.867 1.942 30.43 31.15 67.17 69.39 0.784 0.797

T7 1.875 2.124 30.65 32.13 65.15 71.10 0.747 0.768

T8 2.122 2.294 31.63 34.03 70.09 77.57 0.778 0.791

T9 2.195 2.385 32.25 34.35 74.34 80.30 0.798 0.812

Mean 1.98 2.11 31.19 33.27 72.05 75.35 0.763 0.781 SEd 0.009 0.010 0.088 0.084 0.187 0.228 0.001 0.001 C.D 0.019 0.022 0.186 0.177 0.397 0.485 0.003 0.003 (P=0.05)

Table 1: Total Chlorophyll content, SPAD Value , MSI and Fv/ Fm ratio of PMK 3 at PI and flowering stages under aerobic condition

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T6 Micro sprinkler irrigation 200 % PE

T3 Surface irrigation - 5 cm standing water, five

DADPW

T7 Drip irrigation 100 % PE

T4 Micro sprinkler irrigation 100 % Pan Evapo-

ration Rate (PE)

T8 Drip irrigation 150 % PE

T9 Drip irrigation 200 % PE

Table 2: Productive Tillers, TDMP, Grain Yield and HI of PMK 3 at different stages under aerobic condition

Number of TDMP at Grain yield Treatments productive maturity (g m-2) HI Tillers m-2 ( g m-2 ) T

1 435 1022 409 0.40

T2 400 883 353 0.40

T3 345 795 302 0.38

T4 330 833 300 0.36

T5 340 851 315 0.37

T6 355 894 331 0.37

T7 375 900 342 0.38

T8 390 945 378 0.40

T9 425 1018 407 0.40

Mean 377 904.5 348.5 0.38 SEd 7.04 18.6 6.85 0.002

C.D 16.6 38.9 14.03 0.005 (P=0.05)

Table 3. Water budget for PMK 3 under aerobic cultivation

Treatments Grain yield Total water WUE (kg/ha) used (mm) (kg/ ha)

T1 4089 1143 3.6

T2 3530 926 3.8

T3 3022 785 3.8

T4 3000 589 5.1

T5 3156 748 4.2

T6 3310 907 3.6

T7 3422 589 5.8

T8 3778 748 5.1

T9 4067 907 4.5

ReferencesBouman BAM, Xiaoguang Y, Huaqui W, Zhiming W, Junfang Z, Changgui W and Bin C. 2002. Aerobic rice (Han

Dao): A new way growing rice in water short areas. p.175-181. In: proceedings of the 12th International Soil Conservation Organization Conference, May 26-31.Beijing, China. Tsinghua University Press.

Lafitte HR and Courtois B. 2002. Interpreting cultivar x environment interactions for yield in upland rice: assigning value to drought adaptive traits. Crop Sci. 42:1409-1420

Tuong, T. P and Bouman, B.A.M. 2003. Rice production in water-scarce environments. In: Water productivity in agriculture: Limits and opportunities for improvement. Eds J.W. Kijne, R. Barker, D. Molden, CABI Publishing, UK, pp. 53�67.

Cao J and Govindjee J. 1990. Chlorophyll Âa’ fluorescence transient as an indicator of active and inactive photosystem II in thylakoid membranes. Biochem. Biophys. Acta. 1015: 180-188.

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PMK 3 at Maturity stage

International Symposium on Water Harvesting: Bringing Green Revolution to Rainfed Areas.

Tamil Nadu Agricultural University, Coimbatore, India, 23 -25 June 2008.

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Field view of Aerobic rice at Seedling stage

PMK 3 at Active tillering stage

Experimental Plot View � Micro irrigation

PMK 3 at Panicle Initiation stage

Theme – 4Policies, Institutions, and Socio-economic Aspects

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Socio-Economic Issues in Watershed Development

ProgramsMadar Samad

22

IntroductionWatershed development has been a popular ap-

proach to rural development over recent decades Proj-ects and programs have been implemented across South Asia, Latin America and Africa. In India, watershed de-velopment programs have been implemented for over three decades under an assortment of central and state government schemes and nongovernmental programs. An important aim of these efforts, especially programs implemented under the Drought Prone Areas Program (DPAP), is to protect the population inhabiting frag-ile eco-systems from acute distress caused by recurring droughts (Hanumantha Rao, 2000). This was attempted by implementing programs designed to harmonize the use of water, soil, forest, and pasture resources in a way that conserves these resources while raising agricultural productivity, both by conserving moisture in the ground and increasing irrigation through tank and aquifer-based water harvesting. A watershed is also an area with ad-ministrative and property boundaries, lands that fall under different property regimes, and farmers whose

actions may affect each otherÊs interests. Boundaries defined by humans, however, normally do not match biophysical ones.

The spatial nature of watershed relationships both bio-physical and socio-political, results in exter-nalities and associated problems. Externalities are wide spread in watersheds due to two main reasons: hydrologi-cal linkages between upstream and downstream users of natural resources in the watershed and socio-economic linkages across property boundaries and common lands. Hydrological linkages have been well understood and have been the main areas of focus in watershed develop-ment programs Although, watershed development is rel-atively straightforward from a technical and bio-physical prospective it is extremely complicated from socio-eco-nomic view point Socioeconomic relationships among people in a watershed can complicate efforts to intro-duce seemingly straightforward technical improvements. Addressing the socio-economic externalities is the ma-jor challenge in watershed development programs. This paper outlines some of the key socio-economic factors

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that should be considered in water shed development programs.

Baseline Socio-Economic Conditions Literature suggests there are certain threads

which run through most watershed development pro-grams. These include the physical characteristics of the watershed and technical choices regarding resource de-velopment, the nature of property rights and the social structure and organization of the community (Farrington and Lobo, 1997). Increasingly watershed development efforts are targeted at the poorest societies in the most marginal areas. In India priority for is given to watersheds with an acute shortage of drinking water, there is a high incidence of poverty and low levels of human develop-ment, a preponderance of scheduled castes and tribes, a preponderance of wastelands and common lands and lower than average wages, willingness of the village community to the social infrastructure to enforce regu-lations, equitable distribution of benefits, gender equal-ity and operation and maintenance of assets created, and positive history of womenÊs agency and community action ( MoRD, 2006) These attributes have important implications for the forms of intervention, and the ability of communities to invest in land-based activities through participatory processes. Implicit in the participatory watershed approach is the idea that local level organi-zations usually regulate the use of natural resources ef-fectively for subsistence in the communityÊs collective interest (Farrington and Lobo, 1997). Experiences also indicate the water shed development programs is high in locations where communities are well endowed with stock of social capital - features of social organization such as network, norms and trust that facilitate coordi-nation and cooperation for mutual benefit (Putman, .

A key consideration in the promotion of partici-patory processes in watershed development is a good understanding of the social tensions that prevails within communities. In many instances rural communities are often dominated by local groups that use their powers for patronage rather than broad based equitable change Inadequate attention to community tensions can lead to further replication and legitimization of the hierarchies that exist between sub groups within a community (Car-ney and Farrington, 1996). There is clear evidence to suggest that watershed program are likely to succeed in communities where variations in the socio-economic status are small, especially with regard to the size and ownership of land. Experience indicates that watershed

programs have limited success in communities that tra-ditionally had ineffective and inefficient institutions, sug-gesting that watershed development may not be appro-priate for all communities.

Equity IssuesThere is ample evidence to show that in many

watershed development programs certain social groups have been consistently marginalized. Fernandez (1993) identifies four groups in particular who do not seem to benefit from watershed development; the landless, families in the upper levels of catchments, women and marginalized tribal groups. This is very apparent where development efforts focus on the rehabilitation of com-mon pool resources.

During the early stages, when CPR regimes are first introduced, the poor are affected most adversely. Their greater dependence on what were previously de facto open access resources, means that constraining access during the necessary period of environmental re-cuperation has a disproportionate impact on the poor. At the other end of the process, as the CPR regime matures, the increased value of the resource frequently attracts local (and not so local) commercial and politi-cal interests which also rarely benefit the poor. Where watershed development has the explicit objective of pro-viding greater access for poorer groups, such a shift in power is bound to be contested by those who lose out. The sustainability of such efforts are therefore intricately linked to changes in local institutional and power struc-tures.

The impact of watershed development efforts on women is also a key issue. Pangare and Farrington (1998) note that many of the watershed development projects in India do not empower women as equal part-ners with men. They attribute three reasons for this: womenÊs contribution to the rural economy unrecog-nized; women do have land titles and thereby are pre-cluded from decision making bodies; womenÊs needs are overlooked especially with regard to common property resources. Turton et al (1998) note that access re-strictions imposed on common grazing areas encourage a shift to stall feeding systems. The main bulk of the work of collecting fodder for livestock is undertaken by women, who have to spend extra time cutting and car-rying feeding materials.

In India, in recent years concerted efforts have by many state agencies and NGOse to empower and involve

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women in watershed development primarily through the establishment of self-help groups (Ratna Reddy, et at, 2004) . The recent report of the Technical Committee on Watershed Programs in India proposes several mea-sures to empower women in watershed programs. The proposals include amongst others, the setting up of a separate WomenÊs Watershed Council, reservation of 50% of the membership in the Village Watershed Com-mitteeÊs to women; give women a primary role in the management of common property resources.

Finally, evidence suggests that to ensure even a moderate degree of equity requires high levels of social organization and an ability to articulate their require-ments among women and the poor, together with con-tinuing vigilance to ensure that their rights are not over-ridden.

Upstream-Downstream Linkages When a watershed project is introduced, often

the bulk of the work is done in the upper reaches, while the benefits accrue primarily to those in the lower reach-es.

Many of the upstream development efforts are conservation based. They seek to restore and protect forest cover or promote subsistence oriented, low input, forest-friendly agricultural practices often based on in-digenous cultivation methods in the upper catchments, and confine intensive and commercial oriented intensive agriculture to downstream areas (Walker, 2003). The object is to maintain sustainable water supply for down-stream users. Yet, different individuals and households within a watershed have varying interests in the benefits of watershed development. People who use the upper watershed typically relatively poor people with little or no land, bear the brunt of the costs of watershed devel-opment, which mainly benefits wealthier farmers in the lower watershed. The differing demands for, and abilities to access, water is creating intensified and new linkages between various stakeholders, which are emerging as a major source of tension and conflict amongst various stakeholders and interest groups (Kerr et al 2000, Far-rington et al. 1999, Deshingkar and Start 2003).

Sustainable Rural Livelihoods and Watershed Development

Watershed development has implications for all five types of assets defined in the sustainable livelihood framework:

• Human capital � through capacity build-ing activities; participation in new institutions and pro-cesses;

• Social capital � through the formation of watershed committees, user groups and new or strength-ened institutions;

• Financial capital � through the establish-ment of credit groups, the establishment of a watershed development fund;

• Natural capital � through increases in trees, livestock, irrigated area, more productive land;

• Physical capital � through increase in irri-gation facilities, soil and water conservation structures.

There is a growing awareness of the links be-tween different capital assets. Investments in physical capital such as bunds, check dams and the re-vegeta-tion of common lands for instance are relatively easy to achieve. The returns to physical investments of this type however will rapidly decline if appropriate investments in social and human capital are not also made to develop sustainable and equitable institutions to manage these assets. Similarly the idea of sequencing is important. Some NGOs argue strongly that the local institutions which determine access to natural capital (e.g. common land) need to be regularized before watershed develop-ment activities are undertaken.

Economic LinkagesWhile physical linkages remain the basis for wa-

tershed management interventions, a strategy that also takes advantage of social, economic and institutional linkages between upstream and downstream provides the greatest opportunity for success (Doolette and Mag-arath, 1994).

Upland areas have critical connections with na-tional economies in three significant ways:

• Sources of Raw Materials. Despite diffi-cult conditions, upland areas often possess a compara-tive advantage in the production of certain commodities. In much of the Asia region, timber and grazing represent the primary resources with potential in upland areas.

• Sources and Sinks for Labor. Upland ar-eas in the region were historically, with some exceptions, notably NepalÊs Terai, relatively sparsely populated. Re-cent increases in population pressure in more favored downstream environments has resulted in increased mi-

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gration to the uplands.. Seasonal employment opportu-nities in lowland agriculture and urban areas are increas-ingly important contributors to upland income

• Markets for Downstream Production. Because of low incomes and high transport costs, up-land areas have generally not been major markets for goods produced in lowland areas. Upland areas, how-ever, where incomes have grown and infrastructural in-vestments have reduced transport costs, do constitute significant markets.

• Cost Sharing and Cost Recovery: A corollary of the limited impact of upstream land-use changes on downstream damages is that there is limited justification for schemes to compensate upland farmers and communities for adopting conservation practices. Various subsidies and compensation schemes may be required to bridge the gap between adoption of a conser-vation measure and the realization of a sustainable net return. If so, such compensation should be seen as tran-sitional and not as part of a policy of ongoing subsidy.

Governance and Political LinkagesIt is becoming increasingly apparent that links

between watershed institutions and local political struc-tures are essential for sustaining the new institutions. A central feature of watershed development is that in-stitutional arrangements are characterized by externally organized user groups, overseen by village committees, district authorities and/or local traditional heads. In many cases however, the new regimes fail to build on existing management arrangements. Furthermore, where new regimes assume that common pool resources belong to the watershed community as a whole, they may threaten the traditional users of the resource·raising questions about the equity of the rehabilitation process (Turton et al, 1998a).

The notion of political capital is critical because ÂrightsÊ are claims and assets, These rights are politi-cally defended, how people access these assets depends on their political capital. It is therefore critical to under-stand how rights are constituted at the local level and the dynamic interrelation between political capital, and the other assets (Baumann, 2000).

Watershed associations have become a hunt-ing ground for political parties, partly as a result of the considerable funds at their disposal noted the potential conflict arising as new leaders emerge in the villages and existing systems are challenged.

The situation is usually different in upper water-sheds, in addition to being physically remote, are often politically remote as well. The attention of national poli-cymakers is naturally drawn to the concerns of urban and more affluent lowland agricultural populations. To the extent that developments in upper watersheds are a major item on the national agenda, it is because of their impact, via the physical linkages related to movement of sediment and water, on the well-being of down- stream groups.

Common Pool Resources – An Asset for the Poor

Common pool resources (CPRs) represent a form of natural and social capital that individuals and communities can draw on in pursuit of their livelihood strategies. Jodha (1986) concluded that CPRs make a key contribution to rural livelihoods and are critical for sustainable agricultural production in semi-arid areas They form a part of rural peoplesÊ strategies for adjust-ing to the harsh and stressful environment.

The key question is the extent to which the poor retain access to CPRs after watershed development ef-forts have taken place. To take one example, a crucial el-ement of many watershed projects has been restrictions on the use of common grazing areas during rehabilita-tion and thereafter to permit sustainable off-take. Adolph and Turton (1998) note that such controls in a water-shed project in Andhra Pradesh had different impacts on households of different socio-economic status. Land-owners were able to compensate for the loss of grazing, through the substitution of crop residues, the availability of which had increased due to improved irrigation facili-ties. Landless livestock owners on the otherhand were forced to sell their livestock raised similar concerns (Kerr et al., 1998).

Kerr et al. (1998) report that the landless and nearly landless were the most likely to express dissatis-faction with watershed projects. Problems arise because projects seal off access to common property whilst re-vegetation is under way. Many landless people depend on these lands for their livelihoods, particularly for graz-ing sheep and goats. All projects try to offer employ-ment as compensation. However, most complained that employment created under the project did not adequately compensate for loss of access to common lands or that employment opportunities diminished after the first few years of the project whilst the grazing bans were still in place.

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Concluding RemarksWatershed development is essentially a commu-

nity based development activity. Although hydrological linkages have been well understood and have been the main areas of focus in watershed development programs socioeconomic relationships among people in a wa-tershed can complicate efforts to introduce seemingly straightforward technical improvements. Over the years

the watershed development programs have evolved from being purely technical interventions to programs involv-ing the participation of the people at all stages and ac-tive involvement of non-governmental organizations. Socio-economic conditions of the people inhabiting the watersheds and their aspirations are central to planning any watershed treatments. This paper has highlighted some of the key socio-economic and institutional factors that merit consideration.

References Baumann, Pari. 2000. Sustainable livelihoods and political capital: Arguments and evidence from

decentralization and natural resource management in India, Working Paper 136 Overseas Development Institute,

Carney, D. and Farrington, J. (1997) Institutional change in the natural resources sector. Rural Resources and Poverty Research Programme. Summary of Research 1993-1996. Overseas Development Institute, London.

Deshingkar, P and D.Start. 2003 Seasonal Migration for Livelihoods, Coping, Accumulation and Exclusion. Working Paper No. 220. Overseas Development Institute, London

Doolette, J.B. and McGrath, W.B. (1990). Watershed Development in Asia: Strategies and Technologies, World Bank Technical Paper 27, Washington: World Bank.

Farrington, John and Crispino Lobo (1997). Scaling Up Participatory Watershed Development In India: Lessons From The Indo-German Watershed Development Program, Natural Resources Perspective, Number 17,

Fernandez. A. P. 1993. The MYRADA experience: Alternate management systems for savings and credit of the rural poor. Bangalore: MYRADA.

Hanumantha Rao, C.H. 2000. Watershed Development in India: Recent Experience and Emerging Issues, Economic and Political Weekly November 4,

Jodha, N.S. 1986 Common property resources & the rural poor in dry regions of India. Economic & Political Weekly, No. 54:1169-1182.

Ministry of Rural Development. 2006. Report of the Technical Committee on Watershed Programs in India Department of Land Resources, Ministry of Rural Development., Government of India

Pangare, Vasudha and Farringtion, John. 1999 Strengthening the participation of women in watershed management in Farrington et al,

Farrington, John; Cathryn Turton and A.J. James. 1999. Participatory Watershed Development ; Challenges for the Twenty-First Century, Oxford University Press, New Delhi,

Ratna Reddy, V., M. Gopinath Reddy, S. Galab, John Soussan and Oliver Springate-Baginski. 2004. Participatory Watershed Development in India: Can it Sustain Rural Livelihoods? Development and Change , 35 (2): 297-326.

Turton, Cathryn Michael Warner and Ben Groom 1998.a Scaling Up Participatory Watershed Development In India: A Review Of The Literature Agricultural Research & Extension Network Network Paper No. 86, ODI

Turton, C., J. Coulter, Anil Shah, and J. Farrington. 1998b. Participatory watershed development in India: Impact of the new guidelines. London: Overseas Development Institute,.

Walker, Andew (2003), „Agricultural Trabsformation and Politics of Hydrology in Northern Thailand, Development and Change, 34(5) pp. 941-964.

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Community Resource Management: Much needed strategy in Tank Irrigation

system in IndiaM. Jegadeesan and K. Fujita

23

IntroductionTank irrigation is passing through defining mo-

ment in India today. Tank irrigation contributes signifi-cantly to agricultural production in India in general and particularly in Andhra Pradesh, Tamil Nadu and Kar-nataka. Tank irrigation system is one of a vast network of thousands of water bodies that constituted a distinc-tive landscape which was medieval in origin but still was the basis of livelihood in the dry southern plains (Mosse, 2003). Tank is a small reservoir constructed across the slope of the valley to catch and store water during rainy season. Water is controlled by sluices attached to the tank bank and it is delivered to paddy field by distribut-ing channels. Tank is considered as a common property resource. The National Sample Survey Organization de-fines common property resources as the resources that are accessible to and collectively owned, managed by identifiable community and on which no individual has exclusive property rights (NSSO, 1999). The role of tank is not only providing irrigation water but also it provide biomass, fuel wood, fodder for livestock and other forms of economic livelihood sustenance of villagers (Chopra and Dasgupta, 2008). Tank irrigation get special signifi-

cance as it provides livelihood support to large number of marginal, small farmers and landless agricultural la-bours (Palanisami, 2000). This system then once well maintained by villagers, slowly disintegrated over the pe-riod of time due to various reasons like changes in land holding pattern, development of large scale irrigation project and ground water development and change in preference of livelihood strategies among villagers and so on (Sakthivadivel et al, 2004).

However, based on the presupposition that local population has a greater interest in the sustainable use of resources than does the state or distant corporate manager; that local communities are more cognizant of the intricacies of local socio-ecological process and prac-tices and they are more able to effectively manage those resources through local or traditional forms of access (Brosius, Tsing and Zerner, 1998; Li 2002). In recog-nition of this fact, government and Non Governmental Organizations (NGO) put their effort to motivate farmers to rebuild the institution which was destabilized. Even then things would not happen in the way one would have expected. In this connection, the main focus of this paper is to i) compare effectiveness of traditional irriga-

161

tional institution with government sponsored and NGOs sponsored one. ii) Analyze its functioning style and its efficiency of these institutions at tank system level. iii) Find out possible reason for disintegrating.

MethodologyThe study has been conducted in three tank vil-

lages in Madurai district of Tamil Nadu, India. These study villages has been selected purposefully as they represent different kind of irrigation institution. Consid-ering availability of water is the main motivational factor to organize farmers themselves, care must be taken to identify study villages, which are receiving more or less same amount of rainfall. From the vicinity area, totally three villages were selected, tank village 1 represent tra-ditional institution, tank village 2 represent institution promoted by government, and tank village 3, represent the institution promoted by NGO.

The data has been collected through pre-tested, semi-structured interview schedule paying personal visit to the villages. Simple random sampling was employed

to identify sample respondents (farmers). The data were collected through personal interview; focus group inter-action and discussing with opinion leaders. The study has been conducted during the year 2007.

General Characteristic of The Study Villages

The table 1 presented general characteristics of

the selected study villages. The study villages Kadaneri, Kovalapuram and Menachipuram are located in Peraiyur taluk of Madurai districts. All the selected villages al-most depend on agriculture and allied activities for their livelihood. The fate of agriculture is determined or in-fluenced through rain fed tank irrigation system in the villages. The major crops cultivated are paddy, cotton and pulses. Mostly single season crop and rarely, farm-ers are going for second crop. In the last 10 years there was no intervention on these tanks to improve its perfor-mance. As a result, employment generated through tank irrigated agriculture is in terminal decline. In recognition of this, the government of Tamil Nadu, brought this vil-lages under the National Rural Employment Guarantee Scheme (NREGS) to provide supplementary non-farm employment to assist them (BDO, 2007). Out of three tanks, two tanks are managed by Public Works Depart-ment, and one is coming under Panchayat Union man-agement regime.

Source: Water resource atlas of Madurai district, and Field survey in 2007

Tank water institutionsThe villagers generally have traditional, informal

association other than village panchayat. These associ-ations have a leader who is respected by villagers, some of them by virtue of their age and service rendered in the past and social status, wield considerable influence in village.

Characteristics Tank village 1 Tank Village 2 Tank village 3

Total population 2234 520 440

Command area (Ha) 41.60 62.26 7.94

Management authority Public Works Dept. Public Works Dept. Panchayat Union

Type of Institution Traditional Govt. sponsored NGO Sponsored

Basin Location Vaipar Vaipar Vaipar

Tank capacity (mcft) 14.0 17.66 9.20

Source of water supply Rain fed Rain fed Rain fed

No. of sluices 1 2 1

No. of supply channels 2 2 2

Extent of encroachment (Ha) 0.21 Not available Not available

No. of wells in command area 12 18 1

No. of castes in village 9 5 2

Total No. of households 387 133 110Farming households 214 67 53Landless Agricultural labors 148 43 42Non farming households 25 23 15Major cropping pattern Paddy, pulses Paddy, cotton, pulses Paddy

Tank intervention in last 10 years No No Yes. By NGO (2006)Tank performance (farmerÊs perception) Moderate Poor Moderate

Table 1: General characteristics of study tank villages

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Traditional Irrigation InstitutionTraditional irrigation institution may be referred

to the evolution of principles for collective action of us-ers, for broad spectrum of social responsibilities such as system maintenance, water sharing and conflict resolu-tion (Coward, 1980; Vaidyanathan, 1985 and Janakara-jan, 1993). Even today villagers have traditional institu-tion in many villages to manage the tanks effectively as common property resources. Traditional system of wa-ter distribution was based on their beliefs, customs and the concept of equality. The water allocation ensured smooth sharing to all its members without any default. The performance of these tank irrigation systems de-pends on collective decision they made and keep. These institutions characterized by socio-cultural and contextual arrangement in order to provide services to village com-munity. These institutions have rules and regulation in the form of ethics and norms as it is resultant of complex pattern of behavior of large no of people over protracted period of time (Basu, 2000).

Government Sponsored InstitutionsEffective functioning of tank system is simply

based on how its different components like physical, technical and institutional parameters are managed. In the earlier days, villagers considered tank as system. Over the period of time, when government took over these structures, it is failed to considered as system, con-sequently it is said to be managed by five different depart-ments and acting as separate entity in different direc-tions. After some period, government concentrates only on physical improvements of the tanks. But still they did not yield fruitful result as there are no institutional struc-tures to maintenance. Thus institutional problems crop up and it was hasten by changing social structures, land holding pattern and demographic� population pressure on the lands. After the 1980s when international donor agencies funded for tank modernization, they asked to form water user association at tank level. As a result, the government has shown interest to form institution at tank level as it was stipulated by donor agencies.

NGO Sponsored InstitutionMany NGOs in India are working with rural

people in tank command area, promoting participatory management. They follow different methods to orga-nize farmers and develop institution in the community level in order to provide collective action to tank system management. They employed locally known persons as negotiator to inspire people to participate in the institu-tions.

Field ObservationsThe research demonstrates some specific obser-

vation about the difference in strategy, notion, structure and functioning style among all three institutions in the study villages. Overall aim of all the stakeholders in-volved in this campaign was creating successful local, in-dependent and self-organizing institution at community or village level. But notably, these groups varied tremen-dously in their values, attitudes and beliefs towards the cooperation and the best means to achieve their desired ends. All initiatives look for the active participation of rural people in working out a better livelihood access for themselves. New policies and schemes have been set in the place both by the government and NGOs to facilitate this process of involvement.

Table 2 shows the nature and way of existence of institution in the villages. Institutional arrangement of management of tank resources is carefully constructed and designed to serve specific purpose are at the cross roads now. In all three types of institutions, irrespec-tive of its functioning style, its efficiency and activeness are dramatically low. The most important ingredient for the institutional building is a sense of belonging, mutual trust and empathic cooperation. But unfortunately these ingredients are missing or not given due importance to create it.

Trust building, sense of belonging and social af-filiation towards institutions will come when the villagers perceived that their participation yield good livelihood base for them. Looking at closer view of these institu-

Criteria Traditional Govt. Sponsored NGOs sponsored

Responsibility of organizing villagers Villagers themselves Govt. official in Facilitator appointed by NGO charge of villageSelection of leaders Villagers By election By group opinion & rotationalFunctioning style Informal Formal Semi formalFinancial support Collective contribution Villagers & Govt. Villager, NGO and Govt.Work execution Regular Demand based RegularActiveness Relatively Active Inactive Relatively Active

Table 2: Functioning structure of tank institutions

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tions, it is important to distinguish between different kind of faith or involvement that people pay within their socio-economic and -cultural context such as bonding, bridging and linking with these institutions.

Generally bonding relationship is viewed as strong or thick, while bridging relation is weak or thin (Narayanan, 1999; Onyx and Bullen, 2000; Putnam, 2001; Woolcock, 2001). Thus, bonding relationship is existed in traditional institution, which refers that villag-ers have close relationship with this institution. These people tend to make close relationship as they have similar interest and common affiliation. Ann Dale and Jennie Sparkes (2007) argued that adhesiveness within this network is a sense of deep trust held among mem-bers, which is often highly relational, personalized and thus, has potential for conflict when their trust and com-monalities break down. Once, the tank irrigation sys-tem has been considered as a sole livelihood provider. Almost entire village population depends on it. During the 1980-81, population depended on agriculture in the study villages was 92 percent. But in 2007, it is 67 per-cent. (Block statistics, 2007). Over the period of time, due to changes in government policy and education opens various avenues for villagers. This is aggravated still by frequently failed rainfall. Match box, fire work and cotton industries are coming to exist in nearby towns and they opened opportunity especially for youngsters. They also offered relatively high salary than agriculture. Slowly, youngsters move out from the village to search better opportunity. Consequently, farmers faced with labour shortage as they could not able to attract labour-ers through competitive wages. Most farmers leased out their land or left fallow. They are also looking for non-agricultural employment in the vicinity of the villages and meantime they receive remittance from their son or daughters who are moved out from villages. The govern-ment also announced programs like Sampoorna Grama Rozgar Yojana (SGRY), National Rural Employment Guaranty Scheme (NREGS), Swarna Jayanthi Grama Swarozgar Yojana (SGSY) and Ananithu Grama Anna Marumalarchi Thittam (AGAMT). Basic objectives of all these programs are to give supplementary wage employ-ment to rural labourers. Moreover, upper caste farmers who are enjoyed control over lower caste people, lost their control due to changes in social structure and land holding pattern. Hence, once reason for coming united, common goal is broken, the traditional institutionÊs dis-integration gets started. As our research shows, the role of peopleÊs participation in institution is much dimin-ished now but not entirely forgotten.

In the case of Government sponsored institu-tion, the cohesive force could be termed as „Bridging‰. This relationship characterized by more impersonal and villagers participation is merely perfunctory not intui-tive. It is often viewed as weak and opportunistic tie that facilitate access to resources. „Bridging‰ occurs when someone from the government try to connect with local people through some agenda (Granovetter, 1973). Here, the trust among members are often thin and tend broke when the bridger from the government side left the vil-lage or once his agenda or program completes. This type of institutions tends to provide comprehensive solu-tions that have tried to exorcize the factors which hinder the progress and simply do not work as expected. It is often conceived as designed to provide comic relief but not constant relief. This system failed to understand the fact that villagers are divided into many groups, based on their caste, income status and land holding etc. To connect or bring them into one group as tank command areas farmers, connecting thread is diluted by commu-nal force and widespread social disparity. Government sponsored institution is not concentrated on this aspect. They try to identify all the farmers as tank farmers. They have time limit to implement program and within these time limit, they could not able or not interested to ad-dress this problem.

Regarding NGOs sponsored institutions, the core principle employed is „Linking‰. They try to mo-bilize the farmers themselves and made link with gov-ernment agencies and other financial institutions. The prime objective of this „Linking‰ is to get accustomed to use government program for the benefit of common. It is also considered as opportunistic ties and viewed as the capacity provider for institution to lever resources, ideas and information from the formal institution (Wool-cock, 2001). NGOs showed interest to operate in village only when favorable condition exist or assure to provide. When they find difficulty to operate, they withdraw from these villages and automatically from institution building process. In our experience, in the study village, from 1992-2002, the NGO called ASSEFA (Association of Sarva Seva Farm) came to create sound institutional and regulatory framework as well as enabling environment for peopleÊs participation by providing loans. But after the initial involvement they exhibit, they failed to imbibe a sense of self-help and a sense of sustainable progress. In the long run, villagers attained the mindset that „they will do‰ mentality. Once conducive environment disap-pearing, the NGO also slowly came out from the village.

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There is an argument that NGOs looking for conducive climate to operate on in order to impress their funding agencies. It is easy for the NGOs to operate in new vil-lages rather than operate one village for longer time. Af-ter ASSEFA withdraw, another NGO called DHAN foun-dation came to operate in this village. Considering that relatively small village with single community, the basic platform to launch its program was already initiated by earlier one. This NGO also did its level best to organize the farmers to form tank institution called „Vayalagam‰. They showed substantial and positive improvement in tank performance surpassing initial hurdles. Even then priority between farmers and NGO is differing. This sys-tem also will not yield good result if they fail to under-stand in changes happened in the external environment. Bolding (1994) argued that any external involvement, no matter how well intentioned, can be perceived as med-dling and even be feared. Hence, what they need to do is not bringing expert from outside, but an awakening of the expertise within the villagers.

Functioning Style of InstitutionsTraditional irrigational institution is function-

ing as a two tier system. In the top level, there will be commanding position called „Nattamai‰ (informal vil-lage leader) usually occupied by upper caste people. In the lower level, there will be an executing position as irrigation worker called „Neerkatti‰ (water manager) „Neerpachi‰ (water distributor) and „Thotti‰ (field assis-tant) are employed. These all post usually hired from scheduled caste household on rotation basis. In govern-ment sponsored institution, they will organize water user association with membership of all the ayacut (tank command) farmers. They are expected to elect three po-sitions like president, secretary and treasurer. Based on the number of villages included in association, they will select members also. Apart from this elected body, this system also employs irrigation workers from scheduled caste households. In case of NGO sponsored institution, the NGO appoint one person as negotiator to motivate farmer to join in irrigational institution. The member

farmers elect or select their president, secretary and treasurer. The NGO provide accountant staff to help the farmer to maintain their accounts.

Role ExecutionTraditional tank water institution is existing here

from the time immemorial. Then, these institutions have complete control over the common resources. The way they approach to the problems are perhaps most inci-sive and provide constructive contribution to its better performance. Rules and roles that operate, maintain and manage these systems are strongly shaped by caste hierarchy. These institutions took the responsibility of supply channel maintenance, de-silting tank bed (farm-ers are allowed to remove top fertile layer of silt for their manure need), strengthening of tank bund, maintain-ing of tank physical structure (sluice and surplus weir), water distribution, resolving dispute and conflict reso-lution. However, the present situation is that most of the functions are not executed as external environment explicitly changed. Farmers are not allowed to take silt from the tank as social forestry program implemented by the government. Due to this misplaced priority, regular de-siltation did by farmers are stopped. As a result, ev-ery year about 2 percent of tank capacity is lost due to silt accumulation. Supply channels and catchment area are also encroached and but these institution have no power to deal with them. Thus, at present in majority of the tank water institution have only limited responsibil-ity that too not regularly (Janakarajan, 1993 and Pala-nisami, 2006).

Table 2 delineated that the gap between perceived roles and performed roles is large and illuminating. In government sponsored institution, water user associa-tion was active only during tank rehabilitation program implemented in 1996-1998. After completion of this Eu-ropean Economic Community assisted program, officials responsible for water users association, failed to main-tain its tempo of their members (Palanisami et al, 2007). Farmers also complained that they spent much money

Roles assumed Traditional Govt. Sponsored NGO Sponsored

Supply channel cleaning Occasionally Occasionally YesDe-silting tank bed No No NoStrengthening tank bund No Yes NoSluice and weir maintenance Yes Occasionally YesOutlet channel maintenance Yes No YesWater distribution Yes No NoConflict resolution Yes No No

Table 3: Role execution of Institutions

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on tank structures. The main problem is that its catch-ment and supply channel has been encroached upon, and nothing has been done about it. Farmers are also opined that they are motivated to participate in ongoing process but hardly vested with any power. These kinds of participation are often criticized as tokenist, giving participant with no power (Smith, 1998). It is assumed that people provided with option of passive participa-tion. Certainly, farmers who are expected to participate in institutional building should provide with power to make decision and their priority and choices of invest-ment. If it is not ensured, it is mere sophistry to say that it is participation and institutional success. Pearce and Stiefel (1980) concluded that the promotion of partici-patory institutional building may be regarded as no more than rhetoric unless communities have some degree of power over the services. Smith (1998) also argued that passive participation in the name of consultation is the weakest form of participation in decision making, is of-ten said to be a mean of indoctrinating the public in the values and priorities of the planner to ensure that they obtain public endorsement of their decision, rather than understanding of local needs and priorities.

As we discussed earlier, due to the government policy transfer of land holding is happened from upper caste to lower caste people. It is not simply considered as land transfer but also power transfer. Power sharing is not viewed in right way by upper caste people. They physically accept but are mentally and emotionally much reluctant and not ready to accept that lower caste farm-ers empowered through land. Upper caster people also leased or sold their lands to landless labourers and lower caste farmers. Villagers those who entirely depend on mercy or goodwill of large or upper caste farmers to get employment, became self-employed. In the mean time, the entry of more and more caste based political party into the village system damaged the village cohesiveness and consequently wipes off cooperative attitude within and between farmers and villages. This could be a pos-sible reason for dismantling traditional institutions. Dis-integration of joint family, promotion of education, de-velopment of cottage industry are hastened the process. As Agarwal (2001) rightly put if farmers have earning ac-tivities that are not reliant on common resources, their incentives to the collective management will be reduced. The degree of dependency on small scale irrigation will depend both on farmerÊs capacity to exploit it and on what alternative livelihood options are available to them. Our observation confirmed that farmers are slowly los-

ing their ability to exploit potential benefit from tank irri-gation system because of their weak institutional power. When compare to Government sponsored institution, traditional and NGO sponsored institution showed in-cremental increase in the delivery system.

In these two organizations farmers strives con-tinuously to subjugate impossibility and then try to suc-ceed.

Role Execution of Irrigation Functionaries

An institution, irrespective of its nature or gover-nance, is assisted by a group of irrigation workers called „Neerkatties‰ (water man) who are generally hired from scheduled caste house hold in rotation in the tank village. If a particular tank village does not have that particular schedule caste community, they employed „Neerkatties‰ from nearby villages. The discussion about „Neerkattis‰ becomes important, considering the service they render to tank institution. They are the specialist in water man-agement, having rules to allocate water in the time of scarcity, on the basis of detailed knowledge of the needs of individual wetland fields, thus mitigating usual ten-sion between head and tail-enders (Mosse, 2006) The „Neerkatties‰ are omnipresent who are work almost all the tank villages making their livelihood based on their services like sluice operation, irrigation to the field, pro-tecting tank resources and so on. In the mean time, like any other institution, tank as an institution, has also changed a lot and profiles of these functionaries also changed. In many cases, our field experience showed that, such changes have played havoc with their lives, but still many are thriving by adopting themselves to the changes (Vasimalai, 2003). Among the study villages, two villages have „Neerkatti‰ community and one vil-lage did not have „Neerkatti‰ community. By custom, the „Neerkatties‰ are expected to execute some re-sponsibilities (Table 3). It is clear from the table 3 that mere existence of „Neerkatti‰ family in the village is no guaranty for execution of expected work. During our in-terview with „Neerkatties‰ in the village, they accepted that they are not doing jobs what their father or grand-father as a „Neerkatti‰ did. They spelled out some the reasons for their hesitance.

DependencyIn the past 10 years, because of the uncertainty

and insufficient rainfall tank not received water enough to cater farmers need. Studies showed that only 2 years

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in the last 10 year tank received water its full capac-ity. As a result, most of the farmers ended with crop failure or left fallow. One „Neerkatti‰ needs to work for at least 30 acres of farmersÊ field as water man to get justifiable income. When this falls down, he encountered with insufficient income and struggle to maintain family. Thus, he preferred to go out for other agricultural or non-agricultural jobs.

PaymentUsually after the crop harvest, the „Neerkat-

ties‰ are entitled to have 12 kg of grain per acre. This type of payment is applicable only during normal tank season. When tank fails or partially performed they are not sure about their payment. Again some farmers, even if they are reaped good harvest are reluctant to come forward to pay their due to „Neerkatties‰. This type of problems cropped up day by day. They have often in-volved in quarrel with „Neerkatties‰ about their work execution. These all dissipate the custom of payment to „Neerkatti‰. Hence, they are reluctant to perform their duties as they perceived. Another reason would be as we discussed earlier that disintegration of caste based hierarchy and dismantling of institution. The majority of them were not able to produce enough income through agriculture and start doing or searching on wide array of off-farm activities to supplement the income gap. When they opted out non-agricultural opportunities, they could not fully concentrate on „Neerkatti‰ work as they did earlier.

ConclusionThe thinking of community was of lowest level

of aggregation at which people organize for common efforts; i.e. a small, homogenous, harmonious and ter-ritorially bound unit (Kumar, 2005). Many researches showed that the rural or traditional communities are in harmony with local customs and demonstrate long es-tablished patterns of sustainable and equitable resource

use (Li, 1996). Traditional or institutional approach to common property received wide spread acceptance and resulted successful for quite a long period. It is proved that community can own, manage, sustain and enhance resources such as tank irrigation system (Berkes, 1989 and Ostrom, 1990). But present situation, tank irriga-tion system as an institution fail to deliver what it is ca-pable of. Reasons are multifold and deep rooted as we discussed.

The main flaw in todayÊs approach to tank insti-tution is its fragmented approach and the need is holis-tic approach. Tank irrigation system is involved physical structures, technical aspects and institutional factors. All the attempts made so far to modernize or rehabilitate the tank system fully concentrates only on physical im-provements. That too was not as good as farmers ex-pected. The institutional aspects completely ignored un-til international donor agencies is asked to do so. Even then reports showed that government spent 71 percent of money in physical improvement and 27 percent spent towards administrative purpose. Meager 2 percent was spent on institutional aspects and after maintenance (ADB, 2006). Importantly, the institutional factors and physical factors do not act in isolation; they are so com-plex and often interact with each other. Hence, it is rec-ommended that due importance will be given to address institutional aspects. About 10 percent of the cost could be spent towards institutional and system maintenance.

The farmers asserted that government induced participation is often purely exploitative. They admin-ister some temporary palliatives to address much deep rooted problems. As a result things would not happen in the way one would have expected. The minor irrigation system is to be treated as one integral holistic unit com-prising catchment, water spread, tank structures and tank command. As experience showed that most of the encroachment occurred in catchment and supply chan-nel which is fall in some other village panchayat. So

Assumed Roles Traditional Govt. Sponsored NGO Sponsored

Mobilize village farmer Yes No Yes Watch and ward of tank asset No No No Water management Yes No No Farm management No No No Arranging religious ceremony Yes Yes Yes Sluice operation Yes No Yes Moderator of dispute between farmers Yes No Yes Common fund collector Yes No Yes Announcer Yes Yes Yes Directing Neerpatchi and Thotti No No No

Table 3: Role execution of Neerkatti

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the institution could not exhibit its power on this chronic problem. These institutions are provided with power to evict encroachment and safeguard its resources. In over view, true attempt could be made for revival of tradi-tional irrigation institution with its original vibrant. The policy should underpinned by principles of sustainability and equity. Women are widely encouraged to participate in the institution. Like in the Pudhucherry, women and men from every agricultural household could become member in the institution. It is undeniably true that if we reestablish relationship between farmers and tank institu-tion and reinvent its role as independent arbiter through radically different and inspiring, innovative approach will

strengthen the hopes of farmer who still evidently bank-ing on the tank irrigation as their savior. A sustainable tank irrigated agriculture with all its uncertainties and complexities cannot be envisaged without all the actors being involved with real enthusiasm in all aspects of planning, execution and management process.

AcknowledgementWe would like to express our sincere thanks to

our interviewees for their cooperation and also we sin-cerely thank JSPS, Japan and the Suntory Foundation for their financial assistance.

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169

Indigenous Knowledge use in Dry Lands

P. Balasubramaniam, R. Vijayaraghavan and J. Venkitapirabhu

24

IntroductionTraditionally, a number of practices have been

evolved by farmers to address the problem of risk. These traditional practices are relevant under the changing sce-nario in rain fed agriculture and also to impress upon the need for blending the traditional practices of risk man-agement with modern practices at high production. The knowledge in todayÊs parlance is called local knowledge/traditional knowledge (or) indigenous knowledge. Indig-enous knowledge may also be defined as the sum total of knowledge and practices which are based on peopleÊs accumulated experience in dealing with situations and problems in various aspects of life and suck knowledge and practices are special to a particular culture.

Indigenous knowledge is the knowledge of the people living in certain area, generated by their own and their ancestors experience and including knowledge originating from else where which has been internal-ized by the local people. Farmers have found ways of conserving soil and water, protecting crops and nutrient availability without the use of artificial inputs.

MethodologyThe study was conducted in five villages of Pal-

ladam block of Coimbatore district with a sample size of 120 farmers consisting 50 small farmers and 70 big farmers. The selection of farmers was at random in each village.

Findings and DiscussionThe identified practices were classified to eight

subheads. Therefore 25 indigenous practices identified, and only 18 practices were adopted by majority of dry land farmers. Some of the indigenous practices viz., Summer ploughing, cowdung coating for cotton seeds, soaking sorghum in cow urine, Soaking bengal gram in water, Soaking Sorghum in common salt, cattle pen-ning sorghum raised as mixed crop with lab-lab and crop ploughing were adopted for conservation of soil moisture and to mitigate drought. The advantages and constraints of each indigenous practice were analyzed and suitable strategies formulated to enhance dry land productivity.

Advantages of Indigenous PracticesWhen the farmers continuously practicing indig-

enous knowledge, it will be also relevant to enquire why they do so. In other words, what are the advantages of such practices as perceived by farmers. Understand-ing the rational of such practices from farmers point of

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view, may also help researchers to look into the valid factors while they research to farmers need and help ex-tension workers to select appropriate technologies based on few criteria.

The tables shows the advantages of indigenous practices related to moisture conservation and water harvesting

1. Summer ploughing (SF : Small Farmers, BF : Big Farmers).

Sl.No. Advantages SF BF Total ‘Z’ value

(n=44) (n=66)

1. Conservation of moisture during drought period 100 98.48 90.83 1.007 NS 2. Eradication of weeds 100 100 91.66 NS 3. Control of soil erosion 86.36 100 86.66 2.63 ** 4. Reduction in no. of ploughings at the time of sowing 72.72 87.87 75 1.93NS

Majority of the farmers (75-92 percent) had gone for summer ploughing because it conserves moisture, eradicates needs, consolidates soil erosion and minimizes the number of ploughings at the time of sowing. Percentage of farmers who had convinced about soil erosion control were more among big farmers than among small farmers.2. Cowdung coating for cotton seeds

Sl.No. Advantages SF BF Total ‘Z’ value

(n=45) (%) (n=64) (%)

1. Pest reduction 86.66 100 85.83 2.03** 2. No cost 93.33 85.93 88.33 1.29 NS 3. Easy dibbling of seeds owing to fuzz removal 100 100 90.83 NS 4. Good germination 95.55 92.18 85 0.74 NS

** - Significant at 1% level.

Majority and 100 percent of small and big farmers expressed that due to cowdung coating for cotton seeds, the easy dibbling of seeds to remove fuzz, good germination, no cost and pest-reduction were the advantages.3. Soaking sorghum in cow urine

Sl.No. Advantages SF BF Total ‘Z’ value

(n=39) (%) (n=48) (%)

1. No cost 92.30 83.33 63.33 1.30 NS 2. Drought tolerance 100 100 72.50 NS 3. Easy establishment of seeds with minimum showers 61.53 85.41 54.16 2.56**

** - Significant at 1% level.

In the study sample, 87 farmers used to soak sorghum seeds in cow urine before sowing. About 72 percent had been using the practice, because of drought tolerance. About half of them were of the opinion that the seeds tended to germinate with minimum rain and big farmers attributing this reason numbered more than small farmers. Two-thirds of farmers considered this technology as no cost practice.

4. Soaking Bengal gram in water

Sl.No. Advantages SF BF Total ‘Z’ value

(n=49) (%) (n=42) (%) (%)

1. No cost 15.15 35.17 18.33 2.20* 2. Establishment of seeds with minimum shower 100 100 72.50 NS

** - Significant at 5% level.

As found with the previous practice, 87 farmers had resorted to the practice of soaking bengal gram in water before sowing. The motivating factors appeared to be no cost (18 percent) and with standing water stress (72 percent).5. Soaking Sorghum in common salt

Sl.No. Advantages SF BF Total ‘Z’ value

(n=41) (%) (n=56) (%) (%)

1. Less cost 31.70 17.85 19.16 1.5 NS 2. Good germination even under adverse condition 85.36 94.64 73.33 1.47NS

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The indigenous practice of soaking sorghum in common salt had attracted 97 farmers out of 120 sample farmers. Majority of farmers (73 percent) opined that this practice recorded higher percentage germina-tion even under adverse condition. About one fifth were of the view that no expenditure was involved.

** - Significant at 1% level.A considerably less number of 22 farmers out

of 120 had treated cotton seeds with red soil. Of them, there were 18 big farmers. Half of big farmers stated that this practice facilitate easy dibbling of seeds and however no small farmers were conscious of this reason. All the four small farmers referred to the factor of good germination.

7. Cattle Penning

Of the 120 farmers, 96 families comprising 38 small and 58 big farmers practiced cattle penning and all of them appeared to have fully understand the impo-riuem of soil fertility owing to organic manure.* - Significant at 5% level.

** - Significant at 1% level.Majority of farmers 102 out of 120 raised sor-

ghum mixed with lab-lab. About three-fourths of them mentioned about additional yield owning to mixed crop-ping and about 41 percent cited nitrogen fixation by le-guminous lab-lab. Big and small farmers however differed among themselves in this advantage wise responses.

9. Crop Ploughing

** - Significant at 1% level.

Three fourths of 120 farmers used to have crop ploughing practice and all of them had done so because of weed eradication. About 20 percent farmers hold that labour cost for weeding was considerably reduced com-pared to big farmers, small farmers were more conscious of cost factor.

Constraints in Adopting Indigenous Practices Farmers who had used indigenous practices were asked for not only advantages but also for con-straints if any, normally no farmer would prefer a practice whether it is indigenous (or) modern unless the practice gives more benefit them its constraints.

Knowing the advantages of a practice answers as to why farmers evince keen interest on such prac-tice. At the same time, understanding the constraints will be useful to justify the modification of the practice if needed.

Constraints of indigenous practices (SF : Small Farmers, BF : Big Farmers).

Of 110 farmers, 12.5 percent however felt that summer ploughing costed much to them and all of them happened to be big farmers. No small farmer had thought of this practice as costly affair.

Regarding the practice of cow dung coating for cottong. It had invited many constraints as shown in this table. Of the 108 farmers, about half of them had felt that it would be difficult to follow the practice dur-

Sl.No. Advantages SF BF Total ‘Z’ value

(n=4) (%) (n=15) (%) (%)

1. Easy dibbling of seeds owing to fuzz removal - 01.11 9.16 5.31** 2. Good germination 100 3.83 9.16 3.32**

6. Cotton treated with Red soil

Sl.No. Advantages SF BF Total ‘Z’ value

(n=39) (%) (n=63) (%)

1. Additional yield 79.48 95.23 75.83 2.24* 2. Nitrogen fixation 100 15.87 40.83 1.827**

8. Sorghum Raised as Mixed Crop with Lab-Lab

Sl.No. Advantages SF BF Total ‘Z’ value

(n=30) (%) (n=45) (%) (%)

1. Saving of labour charge 48.64 28.28 25.83 2.71** 2. Weeds eradication 100 100 62.50 NS

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ing rainy season and also treated seeds had taken more time for drying before sowing. about 40 percent farmers considered it to be a time consuming practice. Accord-ing to about 50 percent of 64 big farmers, they treated cotton seeds had to be sown the earliest as it would not last long storage.

Of the 87 farmers who had soaked sorghum in cow urine, one-forth of them opined that crop growth was not uniform. Those who had given such opinion were mostly big farmers.

Of the 87 farmers who had soaked bengal gram in water, a few of them (8 percent) were of the opinion that crop growth was not satisfactory and all of them were big farmers.

Of the 97 farmers who had soaked sorghum in common salt solution, 4 percent of them had observed patches in the crop standing. Those giving such view were all small farmers.

There were 21 farmers who had treated cotton seeds with red soil. About 16 percent of them had ex-perienced that they could not store the treated seeds for long before sowing.

Cattle penning was one of the popular indig-

enous practices for 96 farmers of whom about half of them found it difficult to have goats penning in time. About 21 percent farmers understood that it was pos-sible to have goat penning only during fallow season and 15 percent remarked about the practice to be costly.

In raising a mixed crop of sorghum with lab-lab. Of the 102 farmers. About 10 percent were of the view that the harvest operation of early matured crop had somewhat affected the other crops in maturity stage. This opinion was more prevalent among the small farm-ers as compared to big farmers.

The crop ploughing practice was reported to have two constraints. About 28 percent of the 75 adopt-ers informed that the damage to main crop owing to bullock trampling during crop ploughing was unavoid-able. It was also the view of about 40 percent farmers that complete removal of weeds was not possible. As shown in the table, both small and big farmers differed in their opinion.

ConclusionThe interest in traditional knowledge is gaining

considerable momentum, more so, incase of rainfed ag-riculture where the modern technologies alone is being considered in adequate to overcome the problem. There

Sl.No. Advantages SF BF Total ‘Z’ value

(n=30) (%) (n=45) (%) (%)

1. Summer ploughing SF (n=44) BF (n=66) - 22.75 12.5 4.4** high cost

2. Cowdung coating for cotton seeds SF (n=45) 33.33 50 39.16 1.77NS BF (n=64) time consuming practice

Difficult to follow this practice during rainy season 82.22 23.43 43.33 7.55**

It cannot be utilized along storage - 46.87 25 7.51**

3. Soaking sorghum in cow urine SF (n=45) 25.64 45.83 26.66 2.01* BF (n=48) crop growth was not uniform

4. Soaking bengal gram in water SF (n=45) - 23.8 8.33 3.6** BF (n=42) crop growth not satisfactory

5. Soaking sorghum in common salt SF (n=41) 12.19 - 4.16 2.3* BF (n=56) patches in the crop coverage

6. Cotton treated with red soil SF (n=4) 100 88.88 16.16 1.5NS BF (n=18) it cannot be utilized for long storage

7. Cattle penning SF (n=28) BF (n=58) it is difficult 51.28 60.34 45.83 0.746NS to have cattle penning in time

High cost 76.31 22.41 15 3.84**

8. Sorghum raised as a mixed crop with lab-lab 46.15 4.76 17.5 4.91** SF (n=39) BF (n=63) damage to main crop

9. Crop ploughing SF (n=30) BF (n=45) damage to 66.66 28.88 27.5 3.45** main crop owing to bullock trampling Complete removal of weeds was not possible 86.66 46.66 39.16 4.12**

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is undoubtedly a need to initiate systematic efforts for collecting the traditional practices from different areas. The collection and documentation of the practices is not only the requirement. There is also a need to address the

scientific rationale of each practice, which practice have spread over in larger area, any indigenous practices that has disappeared from the scene and which are the indig-enous practices are comparable with modern practices.

���

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Principles and Policy Perspective of Rain Water

Harvesting P.G.Lavanya and R.K.Haroon

25

Introduction

Water supports all forms of life on this mother earth. The importance of water for the existence of hu-man society cannot be overemphasized. Today, the im-portance of water has been recognised the world over, and greater emphasis is being laid on its economic use and better management. Providing water in the right quantity and quality has been the constant endeavour of all civilizations through the ages. No other natural resource has had such an overwhelming influence on human history. It plays a vital role in agricultural and in-dustrial development and sustaining human life. Rainfall is the only source of water. Rain water harvesting is the deliberate collection of rain water within a catchment and use for the purpose of drinking, irrigation etc. Rain-water storage is generally done in man made tanks, lined pits and small dams or in the sandy beds of seasonal rivers. In several areas of the country including Delhi, parts of Uttar Pradesh, Karnataka, Maharashtra and Tamil Nadu, groundwater levels are dangerously low. There is an urgent need to address the issue of water

management in a sustainable manner. In view of this, rainwater harvesting has become almost like an exhorta-tion - the most sought out refuge to fight this crisis. In fact, the UN during its General Assembly in December 2003 proclaimed the years between 2005 to 2015 as the international decade for ÂWater for LifeÊ.

The per capita availability of water is 1820 m3

which is above the water stress condition threshold val-ue of 1700 m3. However the percapita availability varies from 18417 m3 in Brahamaputra to 380 m3 in some east flowing rivers in Tamil Nadu showing that many ba-sins in the country are already critically starved of water. Due to indiscriminate pumping of groundwater, the wa-ter table has already gone down abnormally and if we do not wake up even now then our future generations may have to face severe crises of water. The rain as impor-tant source of water and if we can harvest rain water, the scarcity of water can be eliminated altogether. There-fore, it is our bound en duty to conserve the rainwater in the form of rainwater harvesting.

Summer comes to Tamil Nadu every year. Along

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with it comes water crisis as well, ponds and taps dry up, women begin to walk the village streets and city roads with pots and pitchers looking for a water-point. Water is becoming a cause for social conflicts. The protests, demonstrations, road-blockades, riots, city-dwellers against farmers, villages against towns, towns against cities, citizens against the government, people against people. Increasingly, these (usually local) conflicts are taking on the general shape of a bitter war for water.

For some time now, the extensive adoption of rainwater harvesting and the revival of traditional water management systems that have gone into decline have been urged by many. In most of the places the duration of rainfall is spread over only for a few months i.e. June to September / October to December in a year. Hence there is a dire need for conserving the rainwater, which occurs in short spells with high intensity, so as to utilize the same during the dry period. If it is not done, the wa-ter will flow rapidly and go waste as run off into the sea, apart from creating water scarcity during non-monsoon period

Demand and Supply GapToday, one billion people in the world � that is,

one sixth of humanity - have inadequate access to clean drinking water. Unless governments and communities begin to effectively tackle this problem, the number of people without clean and sufficient water will rise to 2.5 billion in the next 25 years � that is, nearly one person in three. It is disquieting to know that most of these water-deprived people are and will likely be, in our coun-try. Water requirement in the country is closely related to the population. A population of around 1.6 billion by 2050 would considerably increase the demand for drinking water, food production, non-food agricultural activities, industrial use, energy production, etc. This is likely to put the water availability under enormous stress. Further, the objectives set for improvement in the qual-ity of life and preservation of ecology and environment would result in further increase of the projected per per-son use of water per year. This increased need for water stands in stark contrast to the fundamental truth that water resources are limited and annual replenishments are almost constant over a long time span.

Conservation of Rain Water- for What Purpose

Broadly the rainwater can be harvested for two

purposes i) storing in container/ tank above / below ground for ready use (storage) ii) Charging into the soil for later utilization (groundwater recharge). The question of either storage or recharging of ground water depends mainly on the rainfall pattern of the region, apart from the permeability of the soil. The water collected during the monsoon has to be stored for usage throughout the year, which means huge volumes of storage containers are necessary. Hence, it is feasible to use the rainwater for recharging the groundwater aquifers rather than stor-age. Generally runoff from the paved surfaces only, is used for storage since it is relatively free from bacterial and other contamination. The major part of the rain-water flowing as runoff will be wasted, if not conserved properly.

Methods of Artificial RechargeVarious methods of artificial recharge can be

broadly classified into two viz: a) Surface technique and b) the Sub-surface technique.

� Surface technique group: Contour bunds, Percolation Tanks, Irrigation Tanks and Individual Well recharge.

� Sub-surface technique group: Subsurface dykes, Recharge tube wells, Recharging Trenches, Injec-tion Wells.

In Tamil Nadu ancient people stored rainwater in public places separately one for drinking purpose and another for bathing, and other domestic purposes and called them as Ooranies. They also formed percolation tanks or ponds, for the purpose of recharging irrigation or domestic wells. They periodically cleaned the wa-terways so as to get clean water throughout the year. There are instances in the history that people construct-ed crude rubble bunds across river courses either for di-version of water or for augmenting the ground water.

ImportanceRain water harvesting is essential because:

� Surface water is inadequate to meet our demand and we have to depend on ground water.

� Due to rapid urbanization, infiltration of rain water into the sub-soil has decreased drastically and recharging of ground water has diminished.

� It will provide supplement water for houses, institution and industries. It will enable to re-charge groundwater and prevent water salinity ingress in

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coastal aquifers.

� Need

� To overcome the inadequacy of surface water to meet our demands.

� To arrest decline in groundwater levels.

� To enhance availability of ground water at specific place and time and utilize rainwater for sus-tainable development.

� To increase infiltration of rainwater in the subsoil which has

� decreased drastically in urban areas due to paving of open area

� To improve ground water quality by dilu-tion.

� To increase agriculture production

� To improve ecology of the area by in-crease in vegetation cover etc.

Advantages� The cost of recharge to sub-surface res-

ervoir is lower than surface reservoirs.

� The aquifer serves as a distribution sys-tem also.

� No land is wasted for storage purpose and no population displacement is involved.

� Groundwater is not directly exposed to evaporation and pollution.

� Storing water under ground is environ-ment friendly.

� It increases the productivity of aquifer.

� It reduces flood hazards.

� Effects rise in ground water levels

� Mitigates effects of drought

� Reduces soil erosion.

� Improves moisture content of water in the soil.

Principles Rain Water HarvestingComponents of Rain Water Harvesting

Nature of catchments and space for the storage, depend on the land use pattern. The RWH can be classi-fied as: RWH in urban areas & RWH in rural areas.

RWH IN URBAN AREAS

Roof top Rain Water Harvesting- Storing of Roof Top Water in Tanks/Sumps, Recharge pit/ recharge shaft/bore, Recharge well, Re-charge well with recharge shaft/bore and Re-charge through open dug well

Water harvesting can be taken up in large areas of urban, in public parks, in streets/street corners and in storm water drains

RWH IN RURAL AREAS

Tamil NaduÊs rural areas have already implement-ed rain water harvesting in the form of kulam, kuttai, eri, irrigation tanks, ooranies farm ponds and percolation ponds. RWH in rural areas can be, in general, larger than those in urban areas.

RWH in rural areas have to be commu-nity based for economical reasons and for ef-ficiency. The community has to be organised to go in for collective rainwater harvesting in any one of the forms as tanks, ponds, ooranies and percolation ponds

RWH Structures Suitable in Rural Areas(i) Surface storing

(a) Irrigation tank- It is a reservoir to store water for irrigation constructed using the locally avail-able materials. It is generally located at a place of natural depression. It may be as well along a stream or close to a river course. The major component of tank irrigation is catchments; water spread area and ayacut or com-mand. Irrigation tanks can be classified based on the sources of water viz: - Rain fed tanks, System tanks and Chain tanks

(b) Oorany - It is a pond constructed to store water at an identified suitable place by excavation. It is smaller than an irrigation tank and stored water may be used for drinking or bathing or religious purposes.

(c) Farm Pond- It is small pond excavated at a suitable location of a farm to store water for irriga-tion. The capacity is decided on the basis of its require-ment viz: - for life saving irrigation and for completely irrigating a crop of low water requirement.

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(ii) Sub-surface Storing

Percolation pond - It is a pond constructed at a suitable location to store water for artificial recharge of ground water. It has to be located at place where the infiltration rate is high. It is an effective way of artificially recharging the ground water.

(iii) Retarding the flow

(a) Check dam - It is small wall / brush-wood dam constructed across a stream to retard and to detain the water in stream. It has to allow overflow of water during high rainfall periods and should be suf-ficiently strong enough to withstand the water pressure.

(b) Contour bund- It is bund constructed along an identified contour line of suitable height to hold back the overland flow. It is effective method in con-serve soil moisture in watershed for long duration. It will help to reduce the soil erosion otherwise taking place in the catchment. Spacing between two contour bunds de-pends on the slope of the area as the permeability of the soil. It is suitable on land with moderate slopes without involving terracing i.e. forest catchments and dry farm-ing rural areas.

(c) Gully plug- Gully Plugs are built using local stones, clay and bushes across small gullied and streams running down the hill slopes carrying drainage to tiny catchments during rainy season. Gully plug help in conservation of soil and moisture. The sites for gully plugs may be chosen whenever there is a local break in slop to permit accumulation of adequate water behind the bunds.

ProgrammesThe ground water can be recharged through wa-

tershed development using check dams, contour bund-ing etc., This not only increase availability of water, but also generally lead to more equitable distribution of it. The Eleventh Plan will strengthen the watershed devel-opment programme and also increase the flow of re-sources to these programmes by convergence of other schemes.

Master Plan - The ground water level are de-clining in many parts of the country, artificial recharge of ground water with rainwater is an important strategy to arrest this trend. The Central Ground Water Board have already prepared a master plan to recharge 36 BCM of rainwater into the ground water at a cost of Rs.24,500

crore. Resources under NREGP, BRGF etc., are avail-able for this purpose.

Under the Bharat Nirman Anonymous (2008,b) repair, renovation and restoration of water bodies is being taken up which can expand irrigation capacity in a short period. The states will be assisted to take up such project provided they agree to hand over the water bodies to user groups after renovation so that future maintenance is assured.

Artificial Recharge Schemes with Central Assistance

Central Government has come forward for fund-ing the construction of the artificial structures for aug-menting ground water. A master plan for Tamil Nadu has been prepared by the State Ground and Surface Wa-ter Resources Data Centre for implementation of artifi-cial recharge to ground water through check dams and other suitable structures at a cost of Rs.565 crore over a period of three years from 2008-09.

Scheme for Rain Water Harvesting through Farm Ponds and Rejuvenation of Failed / Unused Wells Anonymous (2008,a)

The ground water potential has been exploited to such an extent that special methods of rainwater har-vesting and ground water recharge are warranted to save the well irrigated areas. Government have provided re-silience to the drought affected agriculture by promoting rain water harvesting. They have sanctioned the con-struction of farm ponds and rejuvenation of failed / un-used / abandoned wells.

A total of 8833 farm ponds were constructed at a total cost of Rs. 2564.29 lakhs and 2093 wells have been rejuvenated at a cost of Rs.264.37 lakhs during 2003-04. This programme will be designed in such a way that the watershed will get the benefit of conver-gence of various watershed development and individual beneficiary oriented programmes. Rain Water Harvest-ing structures such as farm ponds, check dams and re-juvenation of abandoned wells are proposed to be tak-en up during 2005-06, with the NABARD assistance under Rural Infrastructure Development Funds so as to benefit 10,000 farmers. During 2007-08, so far upto Feb.2008, construction of 2532 rainwater harvesting structure have been completed at of Rs.1258 lakh. It is proposed to continue this programme with an outlay of Rs.1800 lakh.

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Tamil Nadu Irrigated Agriculture Modernisation, Water Bodies Restoration and Management Project (IAMWARM)

Tamil Nadu Irrigated Agriculture Modernisation Water Bodies Restoration and Management Project has been formulated with the objective of improving the irri-gation service delivery and productivity of irrigated agri-culture with effective Water Resources Management in a river basin/sub-basin frameworks in Tamil Nadu with the assistance of the World Bank. The Project will be imple-mented in an integrated manner with the participation of line Departments and other institutions. The project is proposed to be implemented in 63 sub basins exclud-ing the areas already covered under Water Resources Consolidation Project and Cauvery basin. The Project cost is Rs.2547 crore. The components of the Project includes Improving Irrigation system performance at the bulk level, i.e., diversion, weirs, anicuts, supply chan-nels, tank storages, tank bunds, spill weirs and sluices, main canals, branch canals, distributaries and minors and Strengthening water sources Management.

In the first year 2007-08, 9 sub basins have been selected for implementation and 14 sub basins are to be implemented in the second year onwards. The Project is in the initial stage and bid documents are being finalized in respect of the 9 sub basins taken up for implementa-tion during the year 2007-08. The anticipated expen-diture for 2007-08 is Rs.127.34 crore and the proposed outlay for 2008-09 is Rs.578.23 crore.

Drought Prone Area ProgrammeThis programme has been in implementation

in parts of Tamil Nadu from 1972-73. Presently 80 notified blocks of 17 districts as drought prone areas. Over the years, the objectives of the programme and the mode of implementation have undergone modifications from infrastructure creation to rainwater harvesting and overall economic development through watershed activi-ties. An area of 3.28 lakh ha is covered (since 1990)as against the 6.14 lakhs ha. at a cost of 180.08 crore.

National Watershed Development Programme for Rainfed areas (NWDPRA)

NWDPRA is implemented in 23 districts of Tamil-nadu except Thanjavur, Nagappattinam, Tiruvarur and Kanyakumari. 763 units of watersheds (1unit=500Ha)

area 381500 Ha for Xth plan have been identified in 23 districts and allocation of funds has been made accord-ingly.

NABARD Assisted Rain Water Harvesting Programme

In order to improve the moisture regime of the watersheds by harvesting rainwater, the rainwater har-vesting programme for ground water recharge with the assistance of NABARD in 249 watersheds of 19 districts at a total outlay of Rs.4781.00 lakhs. Under this pro-gramme, the community works such as construction of percolation ponds and check dams are taken up with 100% grants. So far upto Feb 2008, construction of 3094 rain water harvesting structures have been com-pleted at a cost of Rs.1566 lakhs.

Rehabilitation of tanks identified by MLAs

During the 2007-08, the Government of Tamil Nadu sanctioned rehabilitation of 365 non-system tanks at a cost of Rs.34.81 crore. All these tanks have been identified by the MLAs in 190 rural Assembly Constitu-encies. Some of these works have just commenced and major part will be implemented in 2008-09.

Command Area Development and Water Management Programme

Command Area Development and Water Man-agement Programme is being implemented in the State with an aim to improve the water use efficiency in canal irrigated areas. At present, the programme is implement-ed in Cauvery Command, Tambirabarani River Basin Project, Gadana Ramanadhi Irrigation System, Nam-biyar River Basin System, Patchaiyar River Basin Sys-tem, and Manimuthar Irrigation System. This scheme is implemented with financial assistance from both Centre and State on 50:50 basis. During 2007-08, it is pro-grammed to take up on farm development works in the above project areas at a total cost of Rs.5131.32 lakh.

Pilot Project for Artificial Recharge Structures in existing percolation ponds of Coimbatore and Vellore Districts. (one each)

As a pilot measure, artificial recharge structures like construction of recharge bore well / recharge shaft is proposed to be constructed in the water spread area of the percolation ponds existing in the Vellore and Coim-batore Districts (one each) at a cost of Rs.5 lakh.

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PolicyDepletion of ground water resources, on which

millions of rural families depend for their drinking water needs as well as irrigation, continues unabated. This is made worse by the growing pollution and inefficient use of surface water. Our culture and tradition enjoins upon us to treat our rivers as sacred. Yet, over the past few decades, more rivers are getting more polluted at more places than ever before.

Therefore, the situation is forcing us to recog-nize water security as an overriding national objective · both as an inseparable aspect of food security but also in its own independent right. While we prepare for the challenge ahead, we should critically re-examine the administrative framework and the policies we have actu-ally implemented during the last 55 years for the water resources development.

� The Millennium Development Goals

� National Environment Policy, 2004

� Hariyali guidelines 2003

� National water policy 2002

� Watershed guidelines 1994

� Delhi water amendment bill 2002

� Kerala Government notification on rain water harvesting

� CGWB notifications on rainwater har vesting

� Andhra Pradesh water, land and trees act 2002

� Government order on rainwater harvest ing in Kanpur

� ChennaiÊs groundwater regulation act

� Amendment to Chennai Metropolitan area groundwater act

� Tamil Nadu protection of tanks and evic tion of encroachment act 2007

Himachal Pradesh was the first one in the coun-try to make installation of rooftop rainwater systems mandatory in all new constructions. Over the years, a number of states and cities have promulgated similar or-ders. According to the Tamil Nadu state governmentÊs directions, it is mandatory for every residential and com-

mercial property to harvest rainwater. The Bangalore Mahanagara Palike has also made rainwater harvesting mandatory in new buildings. It also ensures that the cost of implementing this does not exceed one per cent of the total cost of the construction, thus ensuring economic vi-ability. The Brihanmumbai Municipal Corporation had also announced that new buildings constructed on plots measuring more than 1,000 square metres be equipped with rainwater harvesting facilities. The two factors, viz., ÂuseÊ and Âre-useÊ, are stressed upon in achieving water self-sufficiency.

Since water is a state subject, many states in India have regulated policies for rainwater harvesting, such as the Karnataka government, has set up rainwater resources centres in 27 districts. The Delhi government is contemplating a legislation that will make it necessary for all builders to fix rainwater-harvesting systems in all new buildings, offices and apartment complexes in the city. „The Delhi government is giving cash support of Rs 50,000 to each colony that goes in for installing rainwa-ter harvesting projects,‰

Even governments of Madhya Pradesh, Maha-rashtra, Haryana and Tamil Nadu have already initiated follow-up measures. In Tamil Nadu, Kerala rainwater harvesting has been made compulsory. The Mumbai Municipal Corporation has made rainwater harvesting mandatory to properties with plot area over 1,000 sq. metres. This condition will also be made applicable to existing buildings in the near future. BMC will supply 90 lpcd instead of 135 lpcd to ensure RWH will supplement the gap.

The Millennium Development GoalsThe Millennium Development Goals, agreed to

by all 191 United Nations Member States at the Mil-lennium Summit in 2000, set specific targets for reduc-ing poverty, hunger, disease, illiteracy, environmental degradation, focus on water and discrimination against women by 2015. The main targets is to half the number of people without access to safe drinking water. How-ever, all the MDGs adopts on the availability of water in acceptable quality and adequate quantities to meet their target.

The National Environmental Policy 2004

The policy put forth the following strategies: a) promote integrated approach to management of river

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basins b) promote efficient water techniques such as drip and sprinkler c) support practices of contour bunding and revival of traditional methods for enhancing ground water recharge and mandate water harvesting in all new constructions.

The National Water Policy 2002The National water policy 2002, for-

mulated by the GOI incorporates several from the 1987 policy, it recognizes the need for the policy places strong emphasis on non-conventional methods for utilization such as inter-basin transfers, ar-tificial recharge, desalination of brackish or sea water, as well as traditional water conservation practices such as rainwater harvesting, etc to increase utilizable water resources. As in the 1987 policy, the new policy accords top priority to drinking water supply, followed by irri-gation, hydropower, navigation and industrial and other uses.

IndiaÊs National Water Policy emphasizes contin-ued government control over water resources, ignoring plea by environmental groups to involve local communi-ties in order to overcome looming shortages. According to Jain, who has served as vice chairman of the World Commission on Dams, the only solution is for IndiaÊs Water Resources Ministry to be dissolved and for the empowerment of local bodies to embark on a massive rainwater harvesting program. The biggest argument in favor of harvesting rainwater stems from the simple fact that India receives annual precipitation of rain and snow totalling 4,000 cubic km, while the annual poten-tial flow in the rivers, including surface and groundwater, is 1,869 cubic km.

Hariyali Guidelines 2003To involve village communities in the imple-

mentation of watershed projects under all the area de-velopment programmes namely, Integrated Wastelands Development Programme (IWDP), Drought Prone Ar-eas Programme (DPAP) and Desert Development Pro-gramme (DDP), the Guidelines for Watershed Develop-ment were adopted w.e.f.1.4.1995, and subsequently revised in August 2001. To further simplify procedures and involve the Panchayat Raj Institutions (PRIs) more meaningfully in planning, implementation and manage-ment of economic development activities in rural areas, these new Guidelines called Guidelines for Hariyali are being issued.

The major objectives of projects under Hariyali

will be: - Harvesting every drop of rainwater for purpos-es of irrigation to create sustainable sources of income for the village community as well as for drinking water supplies, ensuring overall development of rural areas through the Gram Panchayats and employment genera-tion, poverty alleviation, community empowerment and development of human and other economic resources of the rural areas.

As the Watershed Development Programmes aim at holistic development of watershed areas, the convergence of all other non-land based programmes of Government of India, particularly those of the Min-istry of Rural Development would enhance the ultimate output and lead to sustainable economic development of the village community. The ZP/DRDA, therefore, shall take all possible measures to ensure convergence of other programmes of the Ministry of Rural Development such as the Sampoorna Grameen Rozgar Yojana (SGRY), the Swarnajayanti Gram Swarozgar Yojana (SGSY), the In-dira Awas Yojana (IAY), the Total Sanitation Campaign (TSC) and the Rural Drinking Water Supply Programme in the villages chosen for the implementation of the wa-tershed development projects. It would also be worth-while to converge programmes of similar nature of the other Ministries e.g. Health & Family Welfare, Educa-tion, Social Justice and Empowerment and Agriculture, as also of the State Governments, in these villages.

Tamil Nadu Ground Water Act – 2003

Government of Tamilnadu is committed to en-sure that potable drinking water is available to all habi-tations in next five years. In certain and semi arid and difficult terrain rain water harvesting may be the only techno-economically viable and sustainable solution. There is continuous over-exploitation of ground water in the recent years in Tamil Nadu which leads to alarm-ing lowering of ground water level and deterioration of quality and many existing irrigation and drinking water wells have become dry. This is adversely affecting the small and marginal farmers who mostly depend upon the ground water sources for their livelihood.

To safeguard the small and marginal farmerÊs rights to use the limited Ground Water resources avail-able and also to control and regulate the indiscriminate extraction of ground water, the Government has passed the Tamil Nadu Ground Water (Development & Manage-ment) Act 2003.

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Tamil Nadu Protection of Tanks and Eviction of Encroachment Act 2007

It has become imperative to protect the water bodies from encroachments and disuse. the tanks and their components, if not protected and restored in area of cultivation and thereby food grains production, deple-tion of ground water and environmental degradation. In order to protect the tanks under the control of water Resources Department, an Act entitled „Tamil Nadu Protection Act 2007‰ (TN Act:8 of 2007) was legislat-ed. The Act and Rules have since come into force from 1.10.2007. As a first step for purposeful and effective implementation of this Act, action has been taken for creating awareness among the general public especially at village level about the provision of the Act and Rules and the need to keep the tank in original shape. In the last three months of the year 2007-08, boundary de-lineation works, eviction of encroachment and planting RCC poles along the boundaries have been completed in respect of 316 tanks.

Rain Water Harvesting and Recharging of Ground Water

Rainwater harvesting measures were first initi-ated during 1994 and are being continued. Many type designs have been developed for implementing these in independent houses and multi-storied buildings. Besides creating awareness, Chennai Metropolitan Water Supply and Sewerage Board in association with the Chennai Metropolitan Development Authority has also initiated certain regulatory measures to conserve water. While building plan permissions are given, provisions for rain-water harvesting has been made mandatory.

Initiatives of Metrowater in Promoting Rainwater Harvesting

Considering the importance of Rain Water Har-vesting (RWH) in conserving ground water, the Board has taken the initiative to constitute a fully dedicated ÂRainwater Harvesting CellÊ. The Cell is currently head-ed by the Executive Director assisted by the Senior Hy-drogeologist of CMWSSB as Convenor together with other supporting staff. The main objective of the Cell is to create awareness and to offer technical assistance free of cost to the residents to select and implement suitable cost-effective methods of Rain Water Harvesting in their premises voluntarily. Installation of Rain Water Harvest-ing structures in public places (as models).

Metrowater shall make a concerted effort to install rain water harvesting devices in all its buildings and other Government Buildings. Further, continuing its efforts to popularise rain water harvesting among the citizens, massive awareness campaigns to disseminate information on appropriate rainwater harvesting struc-tured has been undertaken. CMWSSB has initiated a vigorous campaign along with TWAD Board, through training, free technical advise and community partici-pation. A „Rainwater Harvesting Information Centre‰ has also been set up at the TWAD Board Head office, Chennai-5.

Institutions involvedThe International Rainwater Catchments System

Association (IRCSA) is the worldÊs recognised body on the subject, actively promoting the inclusion of rainwater harvesting in border water management strategy. Water harvesting has proved that it not only improves ecology, but also solves water shortage and results in better living standard.

ConclusionWe are, therefore, left with no alternative but to

think radically, and come up with innovative and bold responses to the enormous challenge that India and the citizens are facing. What need is an integrated, multi-disciplinary approach. An approach that covers not only technological aspects but also social, economic, legal and environmental con-cerns.

It is believed that the difference between misman-agement and efficient management of water resources is going to play a crucial role in our fight against pov-erty and in our endeavor to ensure an orderly all-round development of our society. The balance between the water requirement and water availability can be struck only if utmost efficiency is introduced in all types of use of water.

The policy should also recognize that the commu-nity is the rightful custodian of water. Exclusive control by the government machinery, and the resultant mindset among the people that water management is the exclu-sive responsibility of the government, cannot help us to make the paradigm shift that to participative, essentially local management of water resources. Both the Centre and the State governments should, therefore, actively seek the involvement of the community at all levels · from decision-making to monitoring the implementation

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of decisions. Wherever feasible, public-private partner-ships should be encouraged in such a manner that we can attract private investment in the development and management of water resources.

There is also need, through policy measures, to promote the conjunctive use of ground and surface water. Lay special emphasis on localized, decentral-ized harnessing of water resources, which is most cost-effective and which also lends itself to better community participation.

Former Prime Minister Vajpayee, said that Na-tionsÊ catchword should be: “Catch the catchment”. Wherever necessary, our farmers and rural communi-ties should be encouraged to bund every field and bind every rivulet. This will prevent soil erosion and silting of the reservoirs. There is a suggestion that every vil-lage should earmark five percent of its area for creation of community water bodies, much like the community grazing grounds that still exist in many villages. It is a powerful idea whose time has come.

Against a very large potential for drip and sprin-kler irrigation, only a very small fraction has so far been realized. The subsidy scheme for such micro-irrigation systems has not been working too well, mainly due to corruption in its administration. We need to put in place alternative fiscal measures to significantly reduce the price of micro-irrigation systems to the farmer without direct, case-by-case subsidy.

There is a need to make an inventory of best practices, and launch a country-wide program for their replication throughout the country. Some of these models involve economic incentives for conservation and pollution abatements. Some other models may in-volve mutual exchange of rights over water and other resources.

In the ultimate analysis, effective solutions do not lie exclusively in good policies. What is of paramount im-portance is peopleÂs attitude and habits. If we continue to treat, as we have been doing, water as a free or cheap resource that can be wasted, not even the best policies and technologies can help. As in the past, we need to regain the sense of the sacred in the way we relate to water and to our rich water resources.

We have to recognise that just passing a law is not enough. It has to be supported with a massive cam-paign for public awareness and with hard policy actions, which provide incentives and disincentives for its effec-tive implementation. In this case the incentives will have to come in the form of fiscal measures which support households to capture their rain, and the disincentives in the from of pricing of water and supportive urban taxa-tion policies.‰

Construction activity in and around the city is re-sulting in the drying up of water bodies and reclamation of these tanks for conversion into plots for houses. Free flow of storm run off into these tanks and water bodies must be ensured. The storm run off may be diverted into the nearest tanks or depression, which will create ad-ditional recharge.

The situation calls for nothing short of a Nationwide people‘s movement, with the active participation of the governments, the Panchayat Raj Institutions, NGOs, businesses, housing co-operatives and, last but not the least, each and every citizen. No single initiative is adequate to solve the problem of water. We necessarily have to follow di-verse routes and a plurality of programmes to achieve our objective. But, amongst all of them, the one idea that stands out for its simplicity, efficacy and affordability is rain water harvesting.

ReferencesAnonymous (2008,a). Policy Note of the Irrigation and Flood Control, Public Works Department, Government of

Tamil Nadu (2008-2009)Anonymous (2008,b). Policy Note of the Rural Development Department, Government of Tamil Nadu (2008-

2009).���

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Impact Of National Watershed Programme For Rainfed

Agriculture - A Case Study In Tamil Nadu

A.Balakrishnan and T. Selvakumar

26

The watershed management and development include integrated approaches for sustainable agriculture by conserving land and water resources. The devel-opment of watershed is not achieved by individual but through the co-operative movement with support of Government NGO through National Watershed Devel-opment for Rainfed Agriculture (NWDPRA). In Tamil Nadu, 126 watershed areas have been identified and out of this 84 has been selected in seventeen districts for development of watersheds through Tamil Nadu agricul-tural University, Department of Agriculture and Depart-ment of Agricultural Engineering.

Eight watershed areas have been identified in Dindigul district with the following objectives

1. Development of sapota orchards and an-nual morning in watershed areas through rainwater har-vesting for permanent income

2. Recycling of farm waste and organic mulch to increase moisture conservation for increased groundnut yield

3. Selection of suitable drought resistant hardy plant species for life fence

4. Identification of suitable fodder mixture for mixed farming

5. Selection of suitable nursery technique for tree nursery

6. Identification of suitable soil and water conservation measure

7. To study organization, issues related to technology and socio economic in watershed project implementation

8. To study the perception and use of ex-periences of resource persons and farmers in selected watershed areas

9. To compare the existing socio economic issues with post implementations of the projects

Character of Watershed Area• Low and erratic rainfall regions

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• Prone to frequent drought

• Shallow soils, low organic matter

• Poor moisture holding capacity

• Uneven sloppy areas

• Poor illiterate farmers

• Poor socio economic conditions

• Lack of Agricultural technologies

Technologies Adopted1. Soil Conservation on Macro Level

• Contour pits

• Contour stone wall

• Contour grazzy bunds

• Check Dam

• Farm ponds

2. Soil and Water Conservation on Micro Level

• Summer ploughing

• Ploughing across the slope

• Deep ploughing once in 3 years

• Broad bed furrow system

3. Biological Method

• Seed hardening

• Drought resistant crops and varieties

• Intercropping and strip cropping

• Organic manuring

Suggestions for Improvement1. The need for watershed programme and

their advantages to rural people has to be cleared

2. The farmers are in general illiterate and poor, hence the technologies should be indigenous and low cost technologies

3. Training should be given to young farm-ers and progressive farmers through PRA techniques and Audio Visual aids

4. Success stories of watershed programme

has to be exposed to the farmers through field tour

5. Self help group for women and men has to be organized

6. Encourage peopleÊs participation in vil-lage seminars, farmerÊs field visit and local festivals

Impacts of NWDPRA1. Participatory technology development

merged with traditional and modern technology for overall crop productivity.

2. Through macro and micro harvesting of rainwater and soil conservation, the agro eco system has improved

3. The ground water recharge had stabi-lized

4. The integrated farming system concept had been established through SHG

5. Scope for development of dryland horti-culture and agro forestry

6. The gap between the farmers and exten-sion field functionaries were reduced through successful programme

7. The economic advantage

Component B:C ratio

Social forestry 1.70

Dryland Horticulture 7.00

Dryland Agriculture 1.50

Contour bunding 1.70

Combined soil conservation

practices 1.68

Water harvesting techniques 1.80

Social tree nursery 3.40

After the implementation of this project, 80% of watershed area received good amount of rainfall which in turn increase the ground water potential which direct-ly helps for dryland horticulture and integrated farming system. Finally peopleÊs participation in watershed area is important for its effectiveness. The soil and mois-ture conservation measures will be achieved only by the voluntary acceptance of implementation of watershed programme.

185

Finally Government and other N.G.O. should provide fund regularly particularly in event of rainfall fail-ures so that the farmes of watershed areas will maintain their participation forever, in the developed watershed areas.

The transfer of technologies for SHG for pro-moting sustainable agricultural income will be provided for establishing sapota, guava, mango and other tree seedlings. Each member of SHG in that region earned Rs.500 per month as income. Through rearing goats and country poultry birds they earned another Rs.500 per month.

Through watershed development programme, awareness has been created to manage and utilize natu-ral resources and processes to derive more benefits to the society. It involves changes which are slow and gradual and more fundamental.

Capacity building of farmers which bring about a change in his attitude the because of successful water-shed development programme. Farmers continuously learn experience and acquire practical skill and knowl-edge and new information form extension functionaries and through media and training. The welding of tradi-tional and newly acquired skill is helpful for the viability of a farm in a newly developed watershed areas.

The NWDPRA programme may not produce economic returns in some places but it include other benefits like improved soil health, improved groundwater storage, food security and reduced risk of climatic varia-tions. The diversified farming in watershed areas gen-erate diverse benefits and helps in reducing ecological degradation and improved farm management. Through the watershed management programme. Protecting soil

form soil erosion and degradation restore soil health and ensuring productive capacity for future young genera-tion.

Some of the progressive farmers in the water-shed areas converted their farm holding into an integrat-ed and diversified farming through his own experience combined with formal training and acquired skill and knowledge through NWDPRA. The exchange visits and views both from scientists extension functionaries and farmers reinforced the mindset to achieve something in nothing situation in the watershed areas.

The programme has had a number of positive results with negative point also. The farmers are lacking in knowledge but the role of facilitators subside the prob-lems. Being better informed would helps the farmers who visualize the reasons behind the programme and its activities and would allow them to understand their own role. The participatory approaches are needed to motivate the farmers to involve in the programme. Village and agricultural life eco system and social cus-tom has taken a new turn due to this programme. The NWDPRA changes in cropping, farming system, yield, income, socio economic condition, environmental effect, in a under developed society.

Finally through watershed management, agricul-ture has been inseparable from social, cultural and eco-nomic performance of the respective society. Through watershed management, which depends on strong so-cial structure, which permit an improved management of individual or shared local resources, mutual learning improved technology sharing towards achieving a com-mon goal.

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186

Holistic Watershed Development – A Practical Approach for Creating an Enabling Environment to

Promote Water HarvestingM.R.Rajagopalan and S.Gunasekaran

27

IntroductionGandhigram Trust with its six decades of experi-

ence in rural development activities has taken up a ho-listic watershed development project in Dindigul district from 2004 � 2007. This project was sanctioned under Rastriya Sam Vikas Yojana (RSVY) of Union Planning Commission, New Delhi.

This programme comprises of Hariyali based soil and water conservation works and holistic development interventions of the project area viz., Education, Income Generation, Rural Health Care, Agriculture & Animal Husbandry, Water & Sanitation and Medicinal Plants Cultivation. The Physical target of the Project was to treat 2369 hectares of land area with a financial out lay of Rs.2.29 crores. This project is implemented in thirty hamlets of four village Panchayats from 2004 -2007.

Project AreaThe project area is characterized by hot semi arid

eco region with an average annual rainfall of 825.95mm,

46%of which received through northeast monsoon. The soil texture is predominantly loamy with Irugur and pala-vidudhi series having granular and loose structures with a low water holding capacity of 0.20%The project area is selected between Gandhigram and Kodairoad , foot-hill of Sirumalai and sempatti, it is more or less a rain shadow area. More than 60% of the project area is in rain fed condition and in the wet land also the farmers cultivated low water intensive crops.

The total population of the project area is 16937 belong to 4186 households, more than 50% of them are landless labour .The main problems identified in the project area are water level depletion due to scanty rain-fall and excessive use of water which leads to reduction in farm operations and diminishing livelihoods and ulti-mately leading to migration for employment.

GandhigramÊs Intervention in the project area mainly consists of mass awareness, involving people in planning, execution and monitoring, facilitation of group action & conflict resolution, capacity building including social auditing & transparency.

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Water Harvesting MeasuresDuring the project period the Gandhigram Trust

has constructed 35 check dams, 9 percolation ponds, 48 farm ponds, 10 retaining walls and renovated 12 tanks come under the category of Common Property Management (CPM). As private property Management (PPM), ploughing and bunding was carried out in 595 hectares. Some 623 hectares of land area have been covered by afforestation, Horticulture development and medicinal plants.

The structures created are of good quality and cost effective. Locally available resources were mobi-lized. With a combination of farmerÊs technical knowl-edge and experience and with external advice, entire area was treated starting at the ridge.

Recharge of ground water is a major effect of land treatment. Increasing ground water level and conse-quent increase in irrigated area through wells and bore wells was reported in several studies on impact assess-ment. Productivity of land increased substantial wage in-comes during lean season. This has tremendous impact on migration.

Community OrganizationThe trust has been able to involve the people at

various stages of the project. The process of ensuring participation of the people is really a time consuming one. It requires a great deal of efforts on the part of the project holders. They need to establish rapport with the people, organize participatory appraisal, prioritize the problems in consultation with the people, consult them on possible solutions, mobilize people support and ensure participation of people in implementing various activities designed under the project. Implementation of project is not a one-short of affair. It is a continu-ous journey with the people. The Trust has mostly suc-ceeded in undertaking the experiment of traveling with the people.

Holistic Development ProgrammeI. Rural Health Care

Today in spite of advanced technology avail-able in the field of medicine, the fruits of them have not reached the rural masses. They are still deprived of basic amenities in Health care, lack of awareness on proper nutrition, personal Hygiene and sanitation resulting in Health problems, reduced life expectancy and ultimately

fatality. In order to overcome these Lacuna in the rural side this project focused on better health care through establishing better health awareness and care in villages using western and Indian system of medicines.

This project addressed all the Health problems through general health camp, eye camp, Dental camp and awareness on anemia, diabetics, personal hygiene, health camp for combating of vector borne diseases and nutrition.

II. Water & Sanitation

Carce availability of water had strong social and economic effects on the poor. Even the limited quan-tity of available water is not properly used. The main problems identified in the project area are water scarcity, open air defecation, poor maintenance of water supply system and poor hygienic conditions to overcome these problems. The following intervention strategies were ad-opted, Rehabilitation of existing water supply system, Roof top rain water harvesting structures in schools, wa-ter test, awareness building , setting right hand pump repairs , exposure visit and training

Impact of the Programme

• Equitable potable water distribution in 7 villages

• Reduced open Air defecation in 4 vil-lages

• Clean environment � Mass cleaning in 13 villages

• Improved personal Hygiene in schools & Balwadi centres � 10 villages

• Awareness on nitrate content in drinking water � caution board set up in 2 villages.

III. Education

School going children in rural areas are deprived of private tuitions a facility available for children in Ur-ban areas. Keeping this in view, 25 additional coaching centres were started in the project area. This provided joyful learning environment among the children. Edu-cated unemployed women have been provided oppor-tunity as the teachers in these centres on a nominal sti-pend payment. The additional coaching teachers were given training on innovative teaching methods and each centre was provided with teaching aids. The students were given opportunity to have exposure and field class

188

to historical places. They were also given science aware-ness training and participated in a awareness rally and quiz programme.

IV. Agriculture & Animal Husbandry

Agriculture is a major activity in the country. The age old practice has endowed the farmers with a unique wisdom on the subject. Right from sowing to harvest-ing and preservation / storage, traditional agriculture practices in the country still have a sound foot hold. It is also important to stress that different agro climatic zones have their specific product which has a strong bearing on ecosystem and health of human kind. In addition in-discriminate use of inorganic inputs has eroded the soil health and wealth. In turn farmers are burdened with indebtedness. To overcome these problems this project focused on organic cultivation of crops and its dis-semination to farmers to have long term sustainability by organizing Veterinary camp Farmers Forum, Farmers Field School, Exposure visit, FarmerÊs Mela, and Pub-lication

Outcomes

• Awareness on the impact of chemical fertilizer has increased among the farmers.

• Farmers slightly moved towards the or-ganic farming

• Average income of the family has in-creased

• The health of the animals in the water-shed area is good.

V. Medicinal Plants

The medicinal plants are in demand in modern medicine and the Industry is showing special interest in synthesizing natural substances. About 8000 plants

species are used in various systems of medicine in India, out of which 800 species are presently used in the drug formulations. Most of the edicinal plants extensively used in traditional systems of medicines are obtained from wild sources leading to the problems of dwindling of population of numerous plants and insufficient quan-tity for manufacturing genuine medicine. In these cir-cumstances commercial cultivation of medicinal plants has gained importance. Commercial cultivation and processing of medicinal plants by thorough understand-ing and location specific strategies. In this regard, this project addressed medicinal plants promotion through cultivation & processing by means of medicinal tree plantation, medicinal plants cultivation in common land and medicinal plants based enterprise.

VI. Income Generation Programme

The word ÂSHGÊ has brought a renaissance all over the country. It has promoted cooperative action, built confidence and avoided indebtedness. With SHGs running petty shops to cinema theatres, GandhigramÊs intervention has given a fillip to the same cause in the project area.

So far 75 groups have been formed which constitute 58 women groups and 17 men groups total members in the 58 women groups is 870 out of which 345 members belong to SC category, Of the 255 mem-bers in men group, 90 members belong to SC category. The SHGs were given training on various skills, market facilitation training , capacity building training on agro based industries, accounts training and training on utilization of seed money.

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Theme – 5Role of Research,

Extension and Education

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Natures Own Water Harvesting – Groundwater Recharge in

Some Different EnvironmentsGunnar Jacks

28

IntroductionGroundwater is by far the largest fresh water

source on the globe. However, it is not the absolute amount that matters but rather the renewal rate that is what determines the amount we can use. In Sweden we have a renewal rate of about 30 years in our esk-ers, glacial gravel and sand formations that supply many of our middle-sized towns. Globally the turnover rate is about 300 years and the groundwater in the Tertiary strata on the Kerala coast has been found the have ages of 20-30 000 years. While the turnover rate increases exponentially with depth, this is only one of the factors that influence the rate of groundwater renewal. The to-pography, the gradients for flow and the sedimentology, presence of aquicludes and aquitards are other factors of utmost importance.

The turnover rate has not only an implication for the amount of use but it is also of utmost important in case of pollution. Polluting groundwater will very easily be almost for ever. The heterogeneity of aquifers is an-

other factor that turns out to prolong the period of pol-lution. While most of the flow occurs as preferential flow in more permeable sections of the aquifers the pollutant diffuses into less permeable portions. After the end of the pollution the diffusion will be reversed and contribute to prolonged pollution of the bulk groundwater flow.

Assessment of groundwater recharge and turn-over rate is thus a key issue in hydrogeologic investiga-tions. It can be done in quite a number of ways.

use of chloride as a tracer

studies of groundwater level oscillations

use of added radioisotopes like tritium

use of natural stable isotopes like 18O in water

use of pollutants like fluorocarbons

dating with radioisotopes like 14C and 36Cl

with a very good water budget and geometry of the aquifer

The most commonly used method is probably

192

the use of chloride as a tracer. It tends to give the best re-sults in semi-arid areas where the deposition of chloride is increased several-fold by evapotranspiration (Allison & Hughes, 1983).

A few examples of the different methods will be cited below illustrating the enormous spread in ground-water recharge and turnover rates.

Use of Chloride as Tracer Sahel

Quite a number of assessments have been done in the Sahel region south of Sahara in Africa motivated by an often precarious water situation (Bromley et al, 1997; Edmunds & Gaye, 1997). The situation is similar to that in the Thar desert in Rajasthan. The rainfall in Timbuktu is 225 mm with large inter-annual differences. The chloride in rainwater in the region is 0.5 mg/l (Bro-mley et al., 1997). In view of the sparse vegetation the dry deposition can be neglected. The recharge has been assessed to 3-4 mm/year by studying the accumulation in groundwater as compared to that in the precipitation (Jacks & Traoré, 2000). Similar results were obtained by looking at soil moisture. The groundwater recharge turned out to be concentrated to low points in the ter-rain. Crusts formed on the slopes of the sand-dunes cre-ated a runoff-runon regime (Gaze et al., 1997).

The crust formation forms a special pattern of vegetation where the rainfall is more abundant, the so called „tiger bush vegetation‰, strips of vegetation along the slopes collecting and using the runoff water (Issa et al., 1999). The sparse vegetation was considered to use 15 mm for its evapotranspiration (Nizinski et al., 1994) while the rest of the rainfall was lost in evaporation.

Noyil basin, Coimbatore district, S. India

In areas more vegetated, it is necessary to as-sess the dry deposition. This can be done by knowing the content of chloride in the air and applying a de-position factor. Deposition factor can be found in the literature (Gustafsson & Franzén, 2000). Alternately the deposition can be assessed by some kind of net which is exposed to the wind and washed at periods. Another complication in a rather densely populated area is the addition of chloride from the use of common salt by the population. The latter can be fairly well assessed as the use of salt is astonishingly uniform around the world, irrespective of climate and region, amounting to about 10 g NaCl per person and day (Intersalt Group, 1988).

It seems that the use of salt is rather a matter of taste than need, the latter being only about 2-3 g NaCl per person and day.

Groundwater Oscillations and Tritium Addition

There is an excellent comparison done with these two methods done by Rangarajan & Athavale (2000) and Raju (1998). The two articles report groundwater recharge for the whole of India on the basis of a large number of individual observations. The groundwater os-cillation method gives 130 mm (Raju, 1998) and 148 mm (Rangarajan & Athavale, 2000). The results thus differ by a little more than 10 % which is really impress-ing and convincing of very good assessments.

Use of Stable IsotopesThe isotopic ratios of D and 18O in precipitation

varies over the year depending on fractionation during evaporation from sea water. This can be traced in a soil profile and by analyzing the isotopic ratios in soil water and assessing the amount of soil moisture the amount of recharge can be assessed for a year. The fractionation of the oxygen isotopes in the precipitation varies over the year being less in summer time. This can be traced in the soil water as kind of a sinus curve (Fig. 3).

Groundwater Turnover in The Kerala Coastal Plain

Tahe Kerala coast is underlain by Quaternary and Tertiary sediments on the top ofthe Precambrian basement. The thickness of the Tertiary is up to 300 m in the section near Alapuscha. In the Tertiary sediments three aquifers can be distinguished, The Warkala, the Quilon and the Vaikom aquifers.

14C dating of 10 groundwater samples from the Tertiary aquifers indicate that recharge occurred from 23 000 to 33 000 years before present, during a period of low seawater level. During the period of recharge the sea water level ranged from below about 80 m to close to 120 m below the present level. Thus there was a good gradient for flow and recharge. Much of the Ter-tiary groundwater has a Na-HCO

3 compostion which

indicates flushing out of former saline water. There is a gradient along the Kerala coast from Ca-HCO

3 via

Na-HCO3 to a brackish water from south to north. The

recharge seemed to have been interrupted by an arid period as per the paleoclimatology.

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Water BudgetsWith a good water budget it is possible to assess

groundwater recharge and turnover. The Salalah Plain aquifer in southern Oman is vulnerable to sea water in-trusion and this has warranted detailed investigation into the groundwater turnover (Shammas & Jacks, 2007). The main recharge comes from the mountains behind the plain which receives 230-450 mm rainfall per year. A thorough study shows that the major portion of this is fog collection on the mountain forest (Hildebrandt et al., 2007). This fact has forced authorities to initiate forest plantation and decimation of a large browsing popula-

tion of camels. Further artificial recharge of treated sew-age water has been introduced. Still the aquifer has a negative water budget and further actions are needed to safeguard it (Shammas, 2007).

Water Harvesting and Groundwater Quality

The mode of groundwater recharge can affect the water quality. In semi-arid climates, a rapid onset of rainfall after the dry season may cause flushing of nitrate into the groundwater (Tredoux & du Plessis, 1992; Ed-munds & Gaye, 1997; Jacks & Traoré, 2000).

Water harvesting may be useful not only to in-crease groundwater recharge but also to affect the water quality. While fluoride removal is possible by using filters or chemical treatment it has generally not been success-ful in India due to problems in exchange of filters or maintenance of larger plants for the chemical treatment. Water harvesting has on the other hand been proven to be a cheap and reliable method for lowering fluoride con-centrations (Reddy & Raj, 1997; Jacks et al., 2005).

Similarly arsenic remediation should be possible in the case of reducing groundwater containing iron ac-companied by arsenic. By introducing aerated recharge water, iron could be precipitated in situ co-precipitating the arsenic. In Bangladesh this is generally not feasible as there is a clay cover on the top of the aquifers. Then some kind of well recharge is needed.

ConclusionsAssessment of groundwater recharge is useful in

stating the safe extraction level. The previous examples show that the recharge and turnover rates can vary by many orders of magnitude. This is useful also when con-sidering efforts to increase the recharge. Pollution of the groundwater can be more or less extended depending on the turnover rate. Over-pumping of the Kerala Ter-tiary aquifers may not give a very early warning signal, but once a sea water intrusion occurs it may be almost everlasting. On the other hand aquifers in the peninsular India in hard rock areas react fast both to over-pumping and to increased recharge for instance as an effect of water harvesting.

Fig. 3.d 18-O in s soil profile under Nordic conditions (after Saxena, 1987). The higher levels of d18-O represents summertime with less fractionation

in the precipitation.

Fig. 4. Seawater level in the Arabian Sea and recharge period as per 14C-dating of groundwater

from the Tertiary aquifers in The Kerala Coastal Plain.

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ReferencesAllison, G. B. & Hughes, M. W. 1983. Use of natural tracers as indicators of soil-water movement in a temparate

semi-arid region. Journal of Hydrology 60:157-173.Bromley, J., Edmunds, W. M., Fellman, E., Brouwer, J. Gaze, S. R., Sudlow, J. & Taupin, J-D. (1997). Estimation

of rainfall input and direct recharge to the deep unsaturated zone of southern Niger using the chloride profile method. Journal of Hydrology 188-189:139-154.

Edmunds, W. M. & Gaye, C. B. 1997. Naturally high nitrate concentrations in groundwaters from the Sahel. Journal of Environmental Quality 26:1231-1239.

Gaze, S. R., Simmonds, L. P., Brouwer, J. & Bouma, J. 1997. Measurement of surface redistribution of rainfall and modelling its effect on water balance calculations for a millet field on sandy soil in Niger. Journal of Hydrology 188-189:267-284.

Gustafsson, M. E. R. & Franzén, L. G. (2000) Inland transport of aerosols in southern Sweden. Atmospheric Environment 34(2): 313-325.

Hildebrandt, A., Al Aufi, M., Ameerjeed, M., Shammas, M. & Eltahir, E. A. B. (20079 Ecohyrology of a seasonal cloud forest in Dhofar. Water Resources Research 43(10).

Intersalt Cooperative Study Group (1988) Intersalt, an international study of electrolyte excretion and blood pressure. Results from 24 hour urinary sodium and potassium excretion. Br. Med. J. 287: 319-328.

Issa, O. M., Coute, A., Valentin, C., Trichet, J. & Défarge, C. 1999. Morphology and microstructure of microbiotic crusts on a tiger bush sequence (Niger, Sahel). Catena 37:175-196.

Jacks, G. & Traoré, M. (2000) Mechanisms and rates of recharge at Tombouctou, Republic of Mali. Journal of African Earth Sciences 30: 41-42.

Jacks, G., Bhattacharya, P., Chaudhary, V. & Singh, K. P. (2005) Controls on the genesis of some high-fluoride grondwaters in India. Applied Geochemistry 20: 221-228.

Nizinski, J., Morand, D. & Fournier, C. 1994. Actual evapotranspiration of a thorn scrub with Acacia tortilis and Balanites aegyptiaca (North Senegal). Agricultural and Forest Meteorology 72: 93-111.

Raju, K. C. B. (1998) Importance of recharging depleted aquifers. State of the art of artificial recharge in India. J. Geol. Survey Soc. India 51(4): 429-454.

Rangarajan, R. & Athavale, R. N. (2000) annual replenishable ground water potential of India � based on injected tritium stidies. J. Hydrol. 234(1-2): 38-53.

Reddy, T. N. & Raj, P. (1997) Hydrogeological conditions and optimum well discharges in granitic terrain in parts of Nalgonda district, Andhra Pradesh, India. J. Geol. Soc India 49: 61-74.

Saxena, R. K. (1987) Oxygen-18 fractionation in nature and estimation of groundwater recharge. Ph D. thesis. Dept. of Phys. Geography, Uppsala University, Sweden. 152 pp.

Shammas M & Jacks G (2007) Seawater intrusion in the Salalah plain aquifer, Oman. Environ. Geol. 53(3): 575-587.

Shammas, M. (2007) Sustainable management of the Salalah coastal aquifer, Oman using an integrated approach. Ph D thesis, Royal Inst. of Technology, Stockholm, Sweden.

Tredoux, G. & du Plessis, H. M. 1992. Situation appraisal of nitrate in groundwater in South Africa. Water Supply 10:7-16.

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195

WATER HARVESTING -A Look at the Past and Vision for the

FutureR.Thangamani

29

IntroductionWater harvesting is not a new technique to the

Indian sub-continent. Like in many other fields, India is one of the pioneer in the water harvesting technolo-gies also. The practices and policies adopted varies from region to region within the Indian sub-continent, owing to the specific topography and socio- cultural aspects. By keeping the essence of this knowledge, the water harvesting technology has seen many phases of devel-opment from traditional water harvesting to the artificial recharge of acquifiers. Due to the increased pressure on the available water in the recent years and the necessity to harness the major portion of annual rainfall which just concentrates in 100 hours, has forced us to update the technologies and policies adopted again and again. Rain captured from 1 to 2% of IndiaÊs land can provide as much as 100 lpcd for the entire population of India

Policies Adopted In India for Traditional Water Harvesting

Archeological evidences reveals that several rain

water conservation structures were existing during the Indus valley settlement (3000- 1500 B.C). The kautilyaÊs Arthashastra gives detailed account of the irrigation and water conservation structures built during the period of Mauryan Empire. Different types of taxes were collected from the cultivators depending upon the nature of irriga-tion. The rate of tax was 25% of the produce in respect of water drawn from natural sources like rivers, tanks and springs. For water drawn from storages built by King, the tax structure varied according to the method of drawing water. It was 20% of the produce for water drawn manually, 25% for water drawn by bullocks and 33% for that diverted through channels. Tax exemptions were given for building/improving irrigation facilities. The period of tax exemption was 5 years for new tanks, 4 years for renovating old tanks and 3 years for cleaning the works over-grown with weeds.

Apart from the tax collection and tax holiday for new construction, severe punishments were also given for violating the water laws. This includes from debarr-ing from community to death sentences.

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During the Chola dynasties, south India wit-nessed construction large number of water construction structures like tanks and Eris.(tanks) The great event dur-ing their period was the construction of Grand Anicut across river Cauvery. About one-third of the irrigated area of Tamil Nadu is watered by Eris (tanks) . Till the British rule, these Eris were maintained by local com-munities. About 4-5 percent of gross produce of each village was allocated to maintain eris and other irrigation structures. Assignments of revenue free lands, called manyams were made to support the maintenance and management of eris. These allocations ensured eris up-keep through regular desilting and maintenance of sluic-es, inlets and irrigation channels.

Throughout India, different traditional water con-servation methods and policies were adopted to suit the local conditions. In Himachal Pradesh, a traditional sys-tem called Kuhls were constructed and maintained by the village community. Any person refusing to participate in construction and repair activities without any valid rea-son, would be denied water for that season. Since denial of water was a religious punishment, it ensured commu-nity participation and solidarity.

Rain Water Harvesting and Policy Measures For Improvements

The awareness towards rainwater harvesting and the policies of the Union and state Govt. towards achieving this goal is a welcome one. However, certain issues are worth revisiting and reviewing for further im-provement.

Integrated Approach and Scientific Implementation

The roof-top rain water harvesting being adopted at present needs to be expanded and implemented in an integrated manner. The rain water harvesting schemes should be planned and executed on scientific principles taking in to consideration of the hydrological, hydrogeo-logical and geophysical aspects. More attention needs to be given to the areas of potential acquifier system as these will have higher water retention capacity.

Mass Awareness and Involvement of NGOs

For taking the technology closer to the people, mass awareness programmes at grass roots levels needs to be undertaken by Govt. agencies with the active in-volvement of NGOs. In the urban areas, the services of the Resident Welfare Associations also may be utilised. By involving all the stake holders, this shall be made as a peopleÊs movement.

Concession for Adopting Rainwater Harvesting

A good water conservation policy shall find a place to accommodate education, regulation, incentives and disincentives. The roof water harvesting regulations/guidelines adopted so far provides for disincentives for non-compliance in the form of penalty, disconnection of water supply, electricity etc but has not given much emphasis for the incentives part. Incentives in the form of tax holiday or reduction of property taxes for compli-ance of roof water harvesting, subsidy for the materials used etc needs to be provided which will encourage the people.

Periodical Maintenance and Effective Monitoring System

For the effective functioning of the rain water harvesting system, proper maintenance is needed which is lagging in the present scenario. Further, an effective monitoring mechanism also needs to be in place for as-sessing the impact of rain water harvesting both qualita-tively and quantitatively.

ConclusionThe facts mentioned above indicates that a

proper rain water harvesting policy shall accommodate both disincentive for non-compliance and incentive for compliance. Apart from that Scientific implementation, proper maintenance and monitoring mechanism and participation of all stakeholders will no doubt increase the efficiency of this most sought after system.

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197

Water Resource Management and Sustainability of Drinking

Water Sources – TWAD Experience

T. P. Natesan

30

IntroductionWater as a resource is indivisible; rainfall, rivers,

ponds, lakes and groundwater are all part of one sys-tem, the larger ecological System. Growth process and the expansion of economic activities inevitably lead to increasing demands of water for the diverse purposes: domestic, industrial, agricultural, hydropower, thermal power, navigation, recreation, etc.,

Water scarcity is not a general phenomenon but a regionally, locally and seasonally specific problem. It is imperative that water as a scarce and precious national and natural resources should be planned, developed, conserved and managed on environmentally sound basis keeping in view the socio- economic aspects and needs at sub national and local levels.

General StatusWater is essential for life. Yet many millions of

people around the world face water shortages and a daily struggle to secure safe water for their basic needs.

The International decade for Action 2005-2015, „ Wa-ter for Life‰ aims to provide access to water which is also fundamental for achieving the Millennium Devel-opment Goals, such as alleviating poverty, hunger and malnutrition, reducing child mortality, increasing gender equality, providing more opportunity for education and ensuring the environmental sustainability.(source www.unesco.org)

Global Water ResourcesThe total water resource of the planet Earth is

estimated to be 1400 million cubic kilometer. According to the report of Global Environment Outlook (Geo-2000 of UNEP), the global fresh water consumption has risen six fold from 1900 to 1995 which is more than twice the rate of population growth.

One third of the worldÊs population is already living in countries with moderate to high water stress, where the water consumption is more than 10 percent of the renewable fresh water supply.

198

The overview of water availability shows dispari-ties across the continents and in particular the pressure faced in Asia, which supports more than half of the worldÊs population with only 36 percent of global water resources (Source 97% of the WorldÊs utilisable fresh wa-ter exists in Groundwater Aquifers and nearly 80 % of the WorldÊs Rural Population depends on Groundwater for Safe Water Supplies. Over pumping of groundwa-ter by the WorldÊs farmers, industries, etc., exceeds the natural replenishment by at least 160 Billion Cubic Me-ters a year.

Global water situation will get worse over next 30 years if major improvements in the way water is al-located and used, are not introduced. Share of worldÊs population undergoing moderate or high water stress could rise to two- thirds by 2025.

Indian Water ResourcesIndia, which has 16% of the worldÊs population,

has roughly only 4 % of the worldÊs water resources and 2.45 % of the worldÊs land area. The distribution of the water resources within the country is highly uneven over time and space. Water Resources of India presents two contrasting Scenario - One harmful plenty in form of devastating floods in few regions and the other acute scarcity of water resulting in severe drought conditions in some other regions.

The National Commission for Integrated Water resource Development Plan (IWRS, 1999) reviewed the grouping of the river basin divisions made by Central Water Commission and divided the country into 24 river basins. Estimate of water resources has been made ba-sin wise since the river basin are the natural hydrologic units.

The total water potential of India is computed as 1953 cubic kilometer of which only 1086 cubic ki-lometer can be utilised (690 KM3 of Surface water and 396 km3 of groundwater) of this quantity 600 km3 has already been put into use.

Taking into consideration of the population as in 1991 census, only 7 out of the 24 river basins are above the water stress zone. Expecting the population to be doubled by 2050, all the basins except Brahmaputra will come under the water stress zone and most of the basins will become water scarce by middle of the current century. (IWRS, 1999)

Tamilnadu GeologyTamilnadu is predominantly a shield area with

73% of the area covered under hard crystalline forma-tions while the remaining 27% comprises of unconsoli-dated sedimentary formations. As far as ground water resource is concerned scarcity is the major problem in hard rock environment while salinity is the problem in sedimentary areas.

RainfallTamil Nadu is a state with limited water resourc-

es and the rainfall in the state is seasonal. The annual average rainfall in the state is 977 mm. Approximately 33 % of this is from the southwest monsoon and 48 % from the northeast monsoon.

The annual rainfall distribution is as follows:The rainfall pattern recorded for the past 30

years i.e. from 1971 to 2003 is highly varying and shows a deficit rainfall from the year 1985 onwards (except for the years 1993,1996 and 1997 where the annual rain-fall is slightly above normal).

The rainfall pattern over space and time as indi-cated below , clearly portrays a cycle of good monsoon for a period of 3 to 4 years followed by the successive drought / deficit cycle during the next years which war-rants advance planning and preventive action that should be taken during the years of excessive rains to tackle the calamity conditions in the years to follow.

Surface Water PotentialThe total surface water potential of the river

basins of Tamilnadu is assessed as 24160 MCM (853 TMC).

The details of the break up of the potential is as under:

� 39000 tanks with a storage capacity 347 TMC� 79 reservoirs with a storage capacity 243 TMC� Contribution from the other States 261 TMC

Season Month Average rainfall mm Percentage

Winter rains Jan � Feb 47 4.82 %

Summer rains May 138 14.12 %

Southwest monsoon Jun � Sept 322 32.96 %

Northeast monsoon Oct - Dec 470 48.10 %

977

199

� Other Storages 2 TMC The average Run off (surplus flow) to the sea

from the 17 Basins of Tamilnadu State is computed as 177.12 TMC.

Groundwater PotentialThe Estimation Committee constituted for the

evaluation of Ground Water potential has assessed that the utilisable ground water potential in the State to be in the order of 734 TMC(20763 MCM) and the net draft is 622 TMC(17226 MCM) thereby leaving a balance of only 112 TMC(3303 MCM).

The committee further reported that out of total 385 blocks of Tamilnadu

State, 138 blocks as over exploited, 37 blocks as critical, 105 blocks as semi critical, 97 blocks as safe and 8 blocks as saline

It is seen that about 45% area of the State has already been categorised as over exploited and critical where the grounds water potential has already been util-ised more than the natural renewal limits.

IssuesRural water supply in India is the largest sup-

ply chain of its kind in the World and significant prog-ress is achieved with the sustained efforts of the Central and State Governments. Adequate drinking water (i.e. 40 litres per capita per day) has been made available to about 90 % of the habitations in the Country. This sig-nificant coverage is not without any environmental crisis. Heavy dependence on groundwater for drinking water supply as well as irrigation coupled with ineffective con-junctive use of water resources and the neglect of tradi-tional practices and systems including rainwater harvest-ing have resulted in the depletion of water levels.

The Tamilnadu State, like India, is facing three major challenges in water sector:

� Slippage of the Covered habitations

� Water quality problems and

� Sustainability of sources and systems

ResurveyThe status of rural habitations in Tamilnadu

State is being reviewed and resurvey works to assess the status of water supply position in terms of coverage of water supply is being taken up by TWAD. TWAD

Board studies the coverage of watersupply under three categories namely

� Fully covered � the entire population has access to safe assured drinking water of the prescribed service through out the year

� Partially covered - includes all the other habitations with service level upto 40 lpcd

� Not Covered � Habitations having no safe and perennial sources (no potable supply)

The details are presented in the Table:

Sectoral Water Demand and GapAgriculture is a major sector of the StateÊs econ-

omy. Besides meeting the growing demand for food, it is the sector from which the majority of the people earn their livelihood. Of the net area sown (5580786 hect-ares) only 46% of the area is under irrigation. The rest of the area depends only on rainfall. Productive land is be-ing continually lost on the urban periphery due to urban development and industrialisation. Because of the rapid urbanisation and high settlement densities, the choice of expanding the irrigated area is reducing rapidly. The next but important constraint is WATER.

Water availability is a pre - requisite for food se-curity and water now is becoming a scarce commodity. The other sectors like industries, hydro - power, domes-tic, livestock and environment need increasing share of water. The demand from the various sectors as assessed by the Institute of Water Studies, Government of Tamil-nadu is presented in the table below.

Category of Habitations 1992 1997 2001 Resurvey Resurvey Resurvey

Fully Covered 20375 37155 35727Partially Covered 44829 29476 36777Not Covered 1427 ··· 9283

Total 66631 66631 81787

S.No Sectors Annual water demand in TMC

1 Drinking Water sector Corporation 13.80 TMC Municipalities 9.60 TMC Town Panchayat 10.00 TMC Rural 18.00 TMC 51.40 2 Irrigation Sector 1766.00 3 Industries 54.90 4 Power 4.20 5 Live stock 18.30

Total demand 1894.80

200

Supply and Demand GapThe following table depicts the gap between the

demand vs availability

The challenge is how best this gap could be bridged by reducing the demand or by efficient water management.

Population ExplosionTamilnadu is the 6 th most populous State in India

with a total population of 62.41 million as per census 2001.Tamilnadu is also one of the most urbanized State in India with 27.48 million people living in urban areas.

The comparison of the population of the State and All India in rural and urban areas for the past two decades is presented in the Table.

Source: Census of India – 1981, 1991, 2001The decadal growth rate of the rural population

of the State was 16.86 percent during 1961-71, which decreased to 12.78 percent during 1981-91. It is inter-esting to observe that the decadal growth rate of rural population was in negative i.e. 5 percent during 1991-2001.

Populations and Drinking Water Demand Projection

The population projection has been made for the years 2011, 2021, 2031, 2041 and 2051 for both rural and urban population with 2001 population taken as the base year. The drinking water demand for the population for the projected years has been worked out and presented in the table below.

Energisation of wellsAgriculture is the single largest consumer of wa-

ter in the State consuming nearly 805% of the StateÊs water resources. The agriculture demand as of now is 1765 TMC (49978MCM) and it is likely to be at the same level at the present rate of overall irrigation effi-ciency. With improved efficiency it can be brought down to 1593TMC(45098MCM) in a phased manner and the State is striving to achieve higher efficiency.

All along, the vagaries of the monsoons and the erratic flow of the water in the river systems were par-tially countered through sinking of wells. The number of wells shows a sharp rise from 16.7 lakh wells in 1980-81 to 18.3 lakh wells during 1999-2000. The number of energised wells which stood at 9.2 lakh in 1980-81 rose to 16.2 lakh wells in 1999-2000.l

The predominance of the well irrigation in the State is seen from the shares of the three modes of ir-rigation in the total land area being irrigated. Availability of the free power to the farmers was also providing a helping hand to the increased adoption of well irrigation which now at present accounts for about 54 % of the to-

tal irrigated area followed by the canal irrigation of 26% and tank irrigation of 20%

Irrigation PracticesIn the face of shrinking water resources and ever

increasing demand for larger food and agricultural pro-duction, intensification of agriculture is the main course of future growth of the agriculture.

Crop diversification from low value to high value crops, from water loving to water saving crops, from sin-gle crop to multiple/ mixed crops and from crop alone to crop with crop- livestock-fish �apiculture and from ag-riculture production to production with processing and value addition.

There is an urgent need to arrest this decline

Description Supply/Demand in TMC

Total Assessed water Resources 1587.00 TMC (853 +734)Drinking water demand 51.40 TMCIrrigation demand 1766 TMCIndustries, Power, Live stock 77.40 TMCTotal Demand 1894.80 TMC

Gap (Demand – Availability) 307.80 TMC

Type 1991 2002

Tamilnadu India Tamilnadu India

Rural (million) 36.78 628.70 34.92 742.49 Urban (million) 19.08 217.61 27.48 286.12 Total 55.86 846.31 62.40 1028.61 Growth rate (Rural) 13.17 19.59 -5.06 18.10 Growth rate (urban) 19.25 36.43 44.03 31.48 Growth rate (Total) 15.18 23.51 11.71 21.54

201

trend, with focus on drought resistant and less water consuming crop.

It is time to critically redesign alternative crop-ping pattern based on the agro climatic zone and this must be demonstrated in the farmers holding in order to effectively utilise the natural resources and also to stabi-lize the production and profitability.

Depletion of Water ResourcesThe deterioration in ground water levels can be

attributed to a variety of reasons: the failure of mon-soons, over-withdrawal of water and lack of rainwater harvesting. The average water levels of Tamilnadu as ob-served through the select network of observation wells established by TWAD Board indicate that the decline in water level is evident since 1999. The water level in 1999, stood at 13.5 metre, which has now depleted to 26.3m in the year 2003. ground water users;

The cycle of aquifer depletion has a series of serious consequences for all

� Direct aquifer depletion effects (such as falling well yields) and indirect consequences such as ex-cessive well drilling depths and cost of well drilling

� Drying up of most of the traditional large diameter irrigation wells early in the dry season, imply-ing that the traditional irrigation infrastructure is essen-tially unproductive

� An Explosion of deep drilling to depths of 150 m to 300 m for agricultural irrigation and to less-er degree for industrial water supply.

The task of obtaining acceptable service-level, security and sustainability for rural drinking water supply is this made all the more difficult.

Extent of Recharge FocusTWAD Board since inception has played a role

in exploitation to provide protected water supply to the populace of the State. With ever increasing demand on water resources, the focus has been switched over to the conservation mechanism in unison with the exploitation activities by the various water user Organisations.

TWAD Board in coordination with the Insti-tute of Remote Sensing Anna University has taken up a project on „Identification of Recharge Structures using Remote Sensing and GIS‰ during 1999- 2001 and the Outcome of the project was the generation of Zonation maps Block wise for the entire State of Tamilnadu which has been made available to all the user departments for use in implementation.

TWAD Board since 2001-2002 to 2007-2008 has implemented 3666 recharge structures spread over the various districts under various programme at a fi-nancial outlay of Rs.114.00 Crores. The detail of the recharge structures implemented by TWAD board is presented as under.

The impact assessment of the recharge struc-tures so far implemented monitored through select net-work of monitoring wells have indicated and appreciable rise in water levels from 1 m to 2.5 m in the vicinity of the structures that have been implemented by TWAD Board. Further impact assessment studies are under-way.

Need for Ground Water Demand Management

The groundwater extraction has already attained varying degrees of intensity. The rate of drawal has far exceeded the capacity to recoup; and recharge. This is due to a large number of wells and depth and quantity of withdrawal by mechanical and electrical pump sets and the limitations of aquifer recharge due to adverse climatic conditions.

Even though various initiatives for aquifer re-

Population Projection in Lakhs

Category Year

2011 2021 2031 2041 2051Urban 308.1 346.1 387.0 430.9 487.3Rural 362.6 376.9 391.4 406.2 421.3Population Projection 670.7 723.0 778.4 837.1 908.6Drinking water Demand in MCMUrban 1124.6 1263.3 1412.6 1572.8 1745.8Rural 529.4 550.3 571.4 593.1 615.1Drinking water demand 1654.0 1813.5 1984.0 2165.8 2360.9

202

charge measures are ongoing using various techniques, with out action on agriculture demand management sus-tainability of drinking water sources cannot be assured. In this context, it has been decided to explore a partici-patory approach to address this problem by mobilizing the local community to find ways in which ground water supply and demand can be balanced, through a combi-nation of enhancing aquifer recharge and constraining consumptive usage in agricultural irrigation.

The water Balance for the 135 Pilot Village Panchayat were Prepared by collection of field Data and the status of each Village Panchayat were evalu-ated (Habitation wise) based on the various parameters like Geology, Water level fluctuation, Drinking Water demand against availability, Categorization of Blocks as per Ground Water Estimation Committee.

ConclusionsThough Government of Tamil Nadu (GoTN) has

been attempting to provide access to safe water supply to the rural people of the State, full coverage in pro-vision of water supply in terms of level of supply still remains elusive. The cause of the water crisis lies in over-exploitation of surface as well as sub surface waters

for the multifaceted developmental activity, environmen-tal degradation, water quality degradation and pollution. The situation has become complex and as such no water body is left without the man made pollution through let-ting out of the hazardous wastes being let off into the watercourses.

Notwithstanding the numerous programmes implemented by the Government in the rural water sup-ply sector, water scarcity remains a perennial problem. Since the water bodies are dependant on rain, the failure of successive monsoons has resulted in inadequate flows in the river courses. Surface water gets contaminated, particularly in areas close to the seacoast, through in-gress of the saline underground water.

The need of the hour is to take a holistic ap-proach on Water Management with a coordinated effort by all the stakeholders and to involve the Village Com-munity in conservation of water and Demand Manage-ment.

Refrenceswww.unesco.org

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WATER HARVESTINGBrining Green Revolution to Rainfed Areas

Proceedings of the International SymposiumHeld on 23 to 25 June 2008

at the Tamil Nadu Agricultural University

EditorsDr. Arumugam KandiahVisiting Professor, TNAU

Dr. K. RamaswamyProfessor, TNAU

Regional Programme Specialist, UNESCOand

A. SampathrajanDean, Agricultural Engineering College and Research Institute, TNAU

Volume – II

Published Jointly byTamil Nadu Agricultural University, Coimbatore

andUnited Nations Educational, Scientific and Cultural Organization,

New Delhi Office, New Delhi

July 2008

ISBN : 978-81-89218-41-6First Impression : 2011Published by : UNESCO, New DelhiPrinted at : Bal Vikas Prakashan Pvt. Ltd.

This book is a sole subject, to the condition that shall not be away of trade or otherwise, be lent, resold, hired out, or otherwise circulated without the publisherÊs prior written consent, in any form of binding or cover, other than that, in which it is published, and without a similar condition including being imposed on the subsequent purchaser and without limiting the right under copyright, reserved above, no part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise), without the prior written permission of, both the copyright owner, and the publisher of this book.

Copyright © : UNESCO Tamil Nadu Agricultural University, Coimbatore

PREFACE

With a global withdrawal rate of 600 � 700 km3/year, groundwater is the worldÊs most extracted raw

material. Particularly in rural areas of developing countries, in arid and semi arid regions and in the inlands,

groundwater is the most important source of drinking water. Irrigation systems in many parts of the world

strongly depend on groundwater resources. Groundwater is also a reliable resource for industry. However,

managerial control over groundwater resources development and protection is often lacking and that has

led to uncontrolled aquifer exploitation and pollution. Intensive aquifer use affects springs, stream base-flow,

groundwater table, piezometric level, groundwater storage, surface water - groundwater interface, wetlands

and land subsidence. Groundwater vulnerability to the human impacts is therefore recognized as a serious

worldwide social, economic and environmental problem.

It has been estimated that about 80 countries, constituting 40% of the worldÊs population, are suffering

from serious water shortages and that within 25 years two thirds of the worldÊs population will be living

in water-stressed countries. Although long been seen as the only option to improve crop productivity and

thus the quality of life of millions of people, development of irrigation is not always possible because of the

inherent climatic constraints in the arid and semi-arid regions of the world. It is now a well understood fact

that expansion of irrigation, although technically possible, is not always cost-effective or environmentally

friendly. Thus development of rainfed agriculture is not only necessary to improve the food security but also

is a necessary prerequisite for the sustainable development of the world.

UNESCO is working to create the conditions for genuine dialogue based upon respect for shared values

and the dignity of each civilization and culture. The world urgently requires global visions of sustainable

development based upon observance of human rights, mutual respect and the alleviation of poverty, all of

which lie at the heart of UNESCOÊs mission and activities. UNESCO has a mandate to advance hydrological

sciences and their application for improving water security. UNESCO is therefore uniquely placed to work

with other concerned partners to popularize and better study water harvesting technologies. Through its

International Hydrological Programme (IHP), and especially through its Water and Development Information

for Arid and Semi-Arid Areas (GWADI) initiative, UNESCO remains committed to sharing its know-how,

cooperating with others and building new partnerships. In its VIIth Phase, IHP is extensively working in the

field of rainwater harvesting, not only to consolidate existing knowledge, but also to develop cheaper and

more appropriate technologies for water harvesting.

I am confident that this set of proceedings of the International Symposium on „Water Harvesting - bringing

green revolution to rainfed areas‰ will serve as good reference to those who are genuinely committed to bring

green revolution to rainfed areas.

Parsuramen⁄

Armoogum Parsuramen

Director and UNESCO Representative to Bhutan, India, Maldives and Sri Lanka

List of Poster Paper Contributors

1. Anilkumar, A.S., Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram, Pin : 695522

2. Balasubramanian.R, Department of Agronomy, Agricultural College & Research Institute, Madurai-625 104

3. Baskar.K, Associate Professor (Soil Science) Assoicate Professor, Agricultural Research Station, Kovilpatti.

4. Damodharan.T, Assoc. Professor(Agrl Extension), KVK,Needamangalam

5. Dhayamalar.D, Scientist-B, Central Ground Water Board, Rajaji Bhavan, Besant Nagar, Chennai

6. Ganesamurthy.K,Department of Millets, Tamilnadu Agricultural University, Coimbatore � 3

7. Ganesaraja.V, Department of Agronomy, Agricultural College and Research Institute, Madurai,Tamil Nadu, India.

8. Jansirani.P, Professor, Horticultural College and Research Institute, TNAU, Coimbatore-3.

9. Jegadeesan.M ,Center for Southeast Asian Studies, Kyoto University, Japan.

10. Nayak.N.C, Scientist ÂCÊ, Central Ground Water Board (SER), Ministry of Water Resources, Govt. of India

11. Nirmala Kumari.A, Professor, Department of Millets,Center for Plant Breeding and Genetics,Tamil Nadu Agricul-tural University, Coimbatore 641 003, India.

12. Paramaguru.P,Horticultural College & Research Institute, TNAU, Coimbatore � 3

13. Paulpandi.V.K,Department of Agronomy Agricultural College and Research Institute,Madurai, Tamil Nadu, India

14. Porpavai.S, Soil and Water, Management Research Institute,Kattuthottam, Thanjavur.

15. Radhamani.S, Department of Agronomy,Tamil Nadu Agricultural University, Coimbatore-3, Tamil Nadu

16. Ragavan.T, Agricultural Research Station, Kovilpatti, Tamil Nadu.

17. Rajeswari. M , Associate Professor (SWC), Agricultural Research Station, Kovilpatti

18. Ravi.A, Scientist-B, Central Ground Water Board, SECR, Rajaji Bhavan, Besant Nagar, Chennai

19. Rawat.S.S,Indian Institute of Technology- Roorkee, Uttarakhand, India

20. Samanta.S.K ,Government of India, Central Ground Water Board, Ministry of Water Resources,North Eastern Region, Tarun Nagar, Bye Lane-1, Guwahati, Assam.

21. Shantha Sheela.M, *Assistant Professor,** Director of CARDS, TNAU, Coimbatore-3

22. Sivakumar.M , Scientist-C, Central Ground Water Board, SECR, Chennai

23. Subramanian.V, Professor& Head (Soil Science) and 2Associate Professor (Soil Science), Agricultural Research Station, Kovilpatti.3rincipal Scientist (Agricultural Statistics), CRIDA, Santoshnagar, Hyderabad.

24. Suresh.S, Tamil Nadu Agricultural University, Pechiparai � 629 161 Tamil Nadu

List of Student Forum Contributors

1. Amudha.K,Department Of Rice, Centre for Plant Breeding and Genetics,Tamil Nadu Agricultural University,Coimbatore- 641 003, Tamil Nadu.

2. Anitta Fanish.S,Tamil Nadu Agricultural University, Coimbatore � 641 003

3. Govindaraj.M, Centre for Plant Breeding and Genetics, 2Centre for Plant Molecular Biology,Tamil Nadu Agricultural University, Coimbatore-3, INDIA.

4. Janapriya.S, Senior Research Fellow (SWCE),2. Professor(SWCE), 3.Director(WTC),Tamil Nadu Agricultural Uni-versity, Coimbatore-3, INDIA.

5. Maheshwara Babu.B, Research Scholars , Dept. of Soil and Water Conservation Engineering,Agricultural Engi-neering College and Research Institute, TNAU, Coimbatore

6. Manikandan.M, Senior Research Fellow, WTC, TNAU, Coimbatore, manik_meag@rediff.com

7. Neelakanth J.K.,PhD Scholars, Department of Soil & Water Conservation Engineering,Agricultural Engineering College and Research Institute, Tamil Nadu Agricultural University, Coimbatore � 641 003, India

8. Prabhu.T,Department of Soil and Water Conservation,AEC&RI, TNAU, Coimbatore

9. Prasad S.Kulkarni, Department of Soil & Water Conservation Engineering, Agricultural Engineering College and Research Institute,Tamil Nadu Agricultural University, Coimbatore � 641 003, India

10. Sahoo.D.C., Research Scholars,Department of soil and Water Conservation Engineering,Agricultural Engineering College and Research Institute, TNAU.

11. Salunkhe.S.S,Agricultural Engineering College and Research Institute, Tamil Nadu Agricultural University, Coim-batore � 641 003, India; e-mail of corresponding author: sagar_tnau@yahoo.co.in

12. Senkuttuvan.P, Department of Geography, Presidency College, Chennai.Govt. Arts College, Karur

13. Silvas Jebakumar Prince.K, Department of Plant Molecular Biology & Biotechnology.Centre for Plant Molecular Biology,TNAU, Coimbatore.

14. Sudhalakshmi.C,Department of Soil Science and Agricultural Chemistry,TNAU,Coimbatore, Email : soilsudha@yahoo.co.in,K.

15. Thangaraja.K,PhD Scholar (Agrl. Extension), DAE &RS, TNAU, Coimbatore -3

16. Vijayakumar.G,Ph.D Scholar, Dept. of Soil and Water Conservation, TNAU, Coimbatore-3,

CONTENTS

S.No. Chapter Name Page No.

Theme 1: Water Harvesting at the Farm Level — 1-46

1. Effect of insitu moisture conservation methods and integrated nutrient

management practices on the productivity of rainfed maize

(Zea mays L.) in vertisols · 3-8

2. Sustainable Yield Index of rainfed Sorghum under different rainfall

situation in Vertisols of South Tamil Nadu · 9-15

3. Modeling organic Carbon Status under Permanent Manurial

Experiment in rainfed Vertisols of Semi-arid region of

South Tamil Nadu — 16-18

4. Land configuration and rain water management for higher

cotton productivity in rainfed deep vertisol — 19-21

5. Studies on the effect of insitu moisture conservation methods and

integrated nutrient management practices on the productivity of

sunflower (Helianthus annus L.) in rainfed vertisols — 22-27

6. Study on the insitu-moisture conservation practices over rain fed

cotton in vertisols of southern region of Tamil Nadu · 28-31

7. Influence of Tillage, Land Treatment and Organic Residue

Management on Soil Health and Yield of Cotton in

A Vertisol Under Dry Farming — 32-34

8. Effect of In-Situ Moisture Conservation and Nitrogen Management

In Dry Land Agroforestry Systems. · 35-39

9. Effect of Moisture Conservation and Watering on Growth of

Tree Seedlings Under Drylands · 40-43

10. Land Management Practices for in-situ water harvesting in drylands. · 44-46

Theme 2: Water Harvesting at Micro-watershed Level — 47-52

11. Harvesting of Surface Runoff for Ground Water

Recharge - A Case Study of Koilmalai Watershed — 49-52

Theme 3: Enhancing Water Productivity in Rainfed Areas — 53-85

12. Irrigation scheduling in long pepper (Piper longum) under partial shade. · 55-58

13. Changes In Irrigation Management System Among Cauvery Old Delta Farmers · 59-62

14. Characterization of Sorghum Germplasm for Drought Tolerance · 63-66

15. Effect of Mulching, Irrigation and Growth Regulants on Growth and

Yield of Curry Leaf In Winter · 67-69

16. Horticultural Technologies for Watershed Development · 70-76

17. Production Potential and Water Use Efficiency of Various Cropping Systems · 77-78

18. Inter row and Inter plant water harvesting systems on the productivity of

rain fed pearl millet under vertisol of semi- arid region · 79-81

19. Effect of rainfall on changes in Soil Organic Carbon in Continuous

manorial fields of rainfed black cotton soils of Sourth Tamil Nadu · 82-85

Theme 4: Policies, Institutions, and Socio-economic Aspects — 86-110

20. Choice of Genotypes in Fingermillet to Enhance Water

Productivity in Rainfed Areas. · 87-96

21. Community Resource Management: Much needed strategy in

Tank Irrigation System in India · 97-105

22. Rethinking the Strategic Approach including Adaptation

of Rainwater Harvesting for Landscape Irrigation and

Agricultural Use-A Review · 106-110

Theme 5: Role of Research, Extension and Education — 111-242

23. Participatory Irrigation Management � Need of an Hour · 113-119

24. Augmentation Of Ground Water Resources By Rain Water

Harvesting Case study from Chennai City, Tamil Nadu, India · 120-128

25. Plan for augmentation of Ground water Resources in Critical

Cumbum Block, Theni district, Tamil Nadu · 129-133

26. Development of Natural springs for Sustainable Drinking Water

Supply in Himalayan Region of India. · 134-138

27. Validation of Length of Growing Period Developed Through Models for

Minimising the Climatic Risk under Dryland · 139-145

28. Identification of Promising Rice Hybrids for Aerobic Condition

Based on Physiological Traits · 146-149

29. Aerobic Rice - A new tool for water scarcity management · 150-154

30. Standardization of Fertigation for Cucumber underPolyhouse using Soilless Media · 155-158

31. A Review of the Water Harvesting Programmes in Dryland Watersheds · 159-165

32. Impact Of Rainwater Harvesting On Water Budgeting And Irrigation

Potential At Orchard And Eastern Farm In Tnau Campus · 166-168

33. Roof Top Rain Water Harvesting and its potential in TNAU campus · 169-178

34. Traditional Water Harvesting Systems In India · 179-186

35. Effect of Fertigation on Biochemical, Yield and Economics of

Paprika (Capsicum Annuum Var.Longum) · 187-192

36. Water Harvesting for Agriculture in Drylands Of India · 193-202

37. The Emerging Water Crisis in India and Possible Solutions to

Address through Water Harvesting · 203-207

38. Rainfall Probability Analysis For Efficient Water Harvesting And

Crop Planning In Nilgiris · 208-212

39. Time Series Modeling of Groundwater Level of Western

Noyyal River Basin of Tamil Nadu · 213-220

40. Geographical Information System for Evaluation of Groundwater

Potential Zones in Marudaiyar Basin of Tamilnadu · 221-226

41. Engineering of photorespiration mechanism in crop plants for

higher productivity in drought prone areas · 227-229

42. Water Efficient Rice Cultivation Strategy · 230-233

43. A Study on Adoption Behaviour of Dry Land Farmers · 234-237

44. Effect of Crop Geometry Cropping System in Bhendi Under Drip Fertigation · 238-242

Theme – 1Water Harvesting at

the Farm Level

3

Effect of Insitu Moisture Conservation Methods and

Integrated Nutrient Management Practices on The Productivity of Rainfed Maize (Zea mays L.) in

VertisolsR. Balasubramanian, P. Senthilkumar, V. K. Paulpandi and V. Ganesaraja, Department of Agronomy, Agricultural College & Research Institute, Madurai-625 104

1

IntroductionMaize (Zea mays L.) is one of the most important

staple food crops and it ranks third after wheat and rice in the world scenario because of its production potential and adaptability to wide range of environments. The major constraint for low production of crops in rainfed situation is the inadequacy of soil moisture and poor fertility status of the soil. Research information available also shows sufficient evidence in favour of positive interaction between soil moisture and nutrient availability. Management of rainfed soils have to play a vital role to store maximum rain water in the profiles to supply moisture to meet the daily ET of the crop. In view of increased moisture holding capacity, vertisols offer scope for raising crops in kharif and rabi seasons in many states of India whereas in Tamil Nadu rainfed crop is raised only during North East monsoon season (rabi season).

Materials and MethodsField experiments were conducted during rainfed

season of 2001-02 and 2002-03 with maize cv. Co l at Regional Research Station, Aruppukottai, Tamil Nadu to study the effect of insitu moisture conservation methods, time of sowing and integrated nutrient management practices on the productivity of rainfed maize in vertisols. The experiments were laid out in Split Plot design replicated thrice. Pre monsoon sowing and monsoon sowing in flat bed, compartmental bunding and broad bed and furrow were assigned to main plots. INM practices like RDF @ 40:20:0 kg NPK ha-1 through inorganic fertilizers, 75% inorganic N + 25% N as FYM + Azophos, 50% inorganic N + 50% N as FYM + Azophos, FYM 12.5 tonnes ha-1 alone were assigned to sub plots. A common dose of 20 kg P

2O

5 ha-1 and all manures

and fertilizers as per treatments were applied as basal. The biometric observations were recorded on plant

4

height, LAI, DMP, root length, total number of grains cob-1 and shelling percentage and grain and stover yield. The economics were worked out. Soil moisture content at 30-45 cm depth and RUE were also recorded for all treatments.

Results and DiscussionVarious insitu moisture conservation methods

had been practiced for conserving rain water to build up soil moisture for better growth and development of crops under rainfed condition as reported by Singh et al. (1990). The pre-monsoon sown crop received higher quantum of rainfall during growth stages than monsoon sown crop which reflected in soil moisture status. The increased availability of soil moisture promoted plant growth in pre-monsoon sown crop was reported by Senthivel (1996). The different land configuration of insitu moisture conservation methods tried in the present study revealed a substantial increase in plant height, LAI, root length and DMP under broad bed and furrow followed by compartmental bunding method (Table 1). The favourable moisture situation created in broad bed and furrow method might have helped to increase the uptake of nutrients by maize crop with increased root growth for obtaining increased plant height. The increased soil moisture level in broad bed and furrow and its favourable effect on growth characters of cereal crops was reported by Tumbare and Bhoite (2000). The increased leaf area index observed in broad bed and furrow method helped the crop to have more assimilating area available for appreciable quantum of source to sink. The favourable moisture status created in broad bed and furrow method might have increased the water and nutrients uptake by the crop for producing more LAI. This is in agreement with the findings of Patil et al. (1991). The greater influence of broad bed and furrow method in increasing DMP of maize was due to favourable moisture status in soil under broad bed and furrow method. The insitu moisture conservation methods such as broad bed and furrow and compartmental bunding influenced the development of more extensive root system. This might be due to proper air and water relationship maintained in broad bed and furrow method which helped the crop to develop a better root system (Wani et al., 1997). The pre-monsoon and monsoon sown crops greatly influenced the yield attributes (Table 2) based on the quantum of rainfall received during crop periods. The yield attributes namely total number of grains cob-1 and shelling percentage were influenced by the quantum of rainfall received particularly during flowering and maturity stages

of crop growth. In the first year, pre-monsoon sown crop received 284.0 mm and 76.0 mm of rainfall at flowering and maturity phases but the monsoon sown crop received rainfall of only 239.0 mm and 22.2 mm at flowering and maturity stages. The increased quantum of rainfall in the above critical stages helped to provide adequate soil moisture for pre-monsoon sown crop to increase the yield attributes over monsoon sown crop. Favourable yield characters associated with adequate moisture status in the soil might be due to better accumulation and translocation of assimilates coupled with favourable grain filling obtained in broad bed and furrow over flat bed method. This was confirmed by Baskaran et al. (2001). Regarding time of sowing, pre-monsoon sowing crop recorded 3.1 to 25.0 per cent increased grain yield over monsoon sown crop. This was mainly due to more rainy days, well distribution of rainfall and availability of required soil moisture throughout the cropping period compared to monsoon sown crop. However in 2002-03, the pre-monsoon sown crop recorded more or less similar grain yield of monsoon sown crop. Similar result was obtained by Senthivel (1996) who reported that the grain yield of maize in pre-monsoon and monsoon sown crops was due to variation in quantity and distribution of rainfall during different growth stages of crop growth. The increase of 43.3 to 43.4 per cent of stover yield was recorded under broad bed and furrow over flat bed method. Because of low rainfall received during cropping period of 2002-03 compared to 2001-02, the rainfall use efficiency was higher in 2002-03. The low RUE was reflected in comparatively poor growth and yield of maize. Regarding time of sowing, pre-monsoon sown crop recorded higher percentage of RUE over monsoon sown crop (Table 2). In case of insitu moisture conservation method of broad bed and furrow recorded higher percentage of RUE. This might be due to higher grain yield obtained in broad bed and furrow method.

The promising INM practice of application of 75% N through inorganic fertilizers + 25% N through FYM + Azophos had significant influence on plant height, LAI, root length and DMP (Table 1). The reason might be due to better availability of moisture in the soil with the application of FYM which in turn enhanced the release of nutrients from the soil complex with help of increased activity of beneficial microorganisms. Azophos played a very significant role in improving soil fertility by fixing atmospheric nitrogen, both in association with plant roots and in a free living status, solubilized insoluble soil phosphates and produced plant growth substances in

5

soil. This resulted in more uptake of nutrients by maize crop for its normal metabolic activities. The improved soil moisture status and increased nutrients uptake were the base for quick crop growth which resulted to get taller plants, LAI and DMP which in turn increased yield attributes and grain yield of maize under above promising INM practice. The benefits of INM practice in improving LAI were observed by Dodamani (1997) and increased DMP by Kavitha and Swarajya Lakshmi (2002). The application of organic manure along with recommended dose of fertilizers helped maize crop to get increased growth and yield as pointed out by Nanjundappa et al. (2001). This is in agreement with present study. The yield attributing characters such as total number grains cob-1 and shelling percentage were increased due to INM practice of 75% N through inorganic fertilizers + 25% N through FYM + Azophos (Table 2). The combined effect of organic, inorganic and biofertilizer application on the yield attributes was reported by Nanjundappa et al. (2001). The favourable maintenance of soil moisture status and nutrients availability by incorporation of FYM in addition to biofertilizer and inorganic fertilizers application contributed in increasing plant height, LAI and DMP. The above appreciable increase in growth parameters was reflected in increasing yield attributing characters. This helped to retain more rain water in the soil to a greater possible extent and produced more grain yield of 47.0 to 47.1 per cent over organic manure application alone under favourable soil moisture status. This finding is in conformity with the results of Kavitha and Swarajya Lakshmi (2002). The yield increase achieved in the above promising INM practice was a

cumulative effect of increased growth parameters such as taller plants, LAI and DMP. Similarly, stover yield was also increased under this INM practice.

Pre-monsoon sowing in broad bed and furrow method with application of promising INM practice registered more grain and stover yield of maize (Table 3). The favourable physiological functions carried out in plant system might have helped the crop for better uptake of water and nutrients under the above combined effect of pre-monsoon sowing in broad bed and furrow with application of promising INM practice. The combination of insitu moisture conservation methods with time of sowing and INM practice registered more grain and stover yield of sorghum as reported by Hebbi (2000).

The improved agronomic practice of pre-monsoon sowing in broad bed and furrow combined with INM practice of application of 75% N through inorganic fertilizers + 25% N through FYM + Azophos resulted in producing maximum grain yield which in turn produced higher net return (Rs 7175 to 15031) and B:C ratio (1.76 to 2.60) (Table 3).

The adoption of pre monsoon sowing in broad bed and furrow combined with application of 75% N through inorganic fertilizers + 25% N through FYM + Azophos registered higher grain yield of maize (3754 kg ha-1 and 2345 kg ha-1), net return (Rs.15031 and Rs.7175 ha-1) and B:C ratio (2.60 and 1.76) during 2001-02 and 2002-03, respectively. Hence, this combination can be practiced for getting higher productivity and economic returns.

6

ReferencesBaskaran, R, Solaimalai, A., Joseph, M., Sudhakar, P. and S.E. Naina Mohammed. 2001. Land configuration measures

for insitu water harvesting in rainfed sorghum. National seminar on Technology option for dryland Agriculture held at AC & RI, Madurai during Nov.20-22.

Dodamani,S.V. 1997. INM in sunflower. M.Sc.(Ag.) Thesis, AC&RI., University of Agricultural Sciences, Bangalore, Karnataka.

Hebbi. 2000. Influence of insitu moisture conservation practices in sunhemp green manuring and levels of N on rabi sorghum. M.Sc.(Ag.) Thesis, University of Agric. Sci., Bangalore.

Kavitha, P and G. Swarajya Lakshmi. 2002. Effect of different sources of nitrogen on yield and quality of sunflower (Helianthus annuus L.). J. Oilseeds Res. 19(2): 250-251.

Nanjundappa,G., Shivaraj,B., Janarjuna,S. and S.Sridharan. 2001. Effect of organic and inorganic source of nutrients applied alone or in combination on growth and yield of sunflower. Helia, 24(34): 115-120.

Patil,S.N., Mazumdar,G.K. and D.B.Pore. 1991. Effect of moisture conservation measures on growth and yield of sorghum-pigeonpea intercropping in watershed area. Indian J. Soil Conservation, 19(1-2): 6-11.

Senthilvel, T. 1996. Studies on dry seeding and configuration and phosphorus management on the productivity of rainfed maize (Zea mays L.) in vertisols with residual effect of phosphorus on blackgram. Ph.D Thesis, Tamil Nadu Agrl. Uniuersity, Madurai..

Singh,R.P., Das,S.K., Bhaskar Rao,V.M. and M.Narayana Reddy. 1990. Towards sustainable dryland agricultural practices. Central Research Institute for Dryland Agriculture, Hyderabad.

Tumbare,A.D. and S.V.Bhoite. 2000. Effect of moisture conservation techniques on growth and yield of pearlmillet-gram sequence in watershed. Indian J. Dryland Agric. Res. & Dev., 15(2): 94-95.

Wani,A.G., Tumbare., A.D., Bhale,T.M. and S.H. Shinde. 1997. Response of pearl millet to N and moisture conservation practices under rainfed conditions. Indian J. Dryalnd Agric. Res. & Dev., 12(2): 130-132.

7

Table 1. Effect of insitu moisture conservation methods, time of sowing and INM practices on growth characters of maize

Table 2. Effect of insitu moisture conservation methods, time of sowing and INM practices on yield attributes and RUE and soil moisture content in maize

Treatments Plant height at LAI at 60 DAS Root length at Dry matter harvest (cm) harvest (cm) production at harvest (kg/ha)

2002 2003 2002 2003 2002 2003 2002 2003

Insitu moisture conservation methods with time of sowing

M1 137.4 97.6 4.10 2.76 21.0 17.0 12785 8924

M2 109.4 96.7 3.15 2.72 19.5 16.6 10228 8834

M3 176.6 124.3 5.32 3.57 26.4 18.9 17048 11864

M4 142.9 123.0 4.10 3.53 21.9 18.5 13637 11745

M5 189.4 131.6 5.72 3.90 28.6 22.9 18331 12758

M6 151.3 130.3 4.50 3.80 23.5 22.5 14664 12629

SEd 4.09 2.45 0.13 0.06 0.49 0.31 419.5 255.2

CD (0.05) 9.12 5.47 0.29 0.15 1.09 0.85 934.9 568.6

INM practices

S1 152.6 117.5 4.50 3.37 24.0 19.7 14639 11263

S2 175.0 134.9 5.23 3.92 27.5 22.7 16805 12930

S3 154.9 119.6 4.56 3.42 24.4 20.0 14788 11378

S4 122.2 93.7 3.66 2.64 19.1 15.7 11564 8931

SEd 2.17 1.30 0.06 0.03 0.25 0.21 222.6 135.9

CD (0.05) 4.56 2.75 0.14 0.07 0.54 0.42 467.5 285.4

Treatments No. of Shelling RUE Soil moisture grains/cob percentage content at 30-45 cm depth at harvest

2002 2003 2002 2003 2002 2003 2002 2003 Insitu moisture conservation methods with time of sowing

M1 212 149 71.3 60.7 21.0 17.0 11.1 8.1

M2 172 146 69.8 60.5 19.5 16.6 9.3 7.9

M3 279 193 72.7 61.2 26.4 18.9 13.2 10.5

M4 222 166 70.8 60.0 21.9 18.5 14.2 10.3

M5 303 208 74.1 62.6 28.6 22.9 13.9 10.8

M6 240 205 72.2 62.4 23.5 22.5 12.2 10.6

SEd 6.74 3.96 0.21 0.13 0.49 0.31 0.26 0.20

CD (0.05) 15.03 8.83 0.48 0.30 1.09 0.85 0.59 0.42

INM practices

S1 240 183 72.4 60.8 24.0 19.7 7.3 7.8

S2 275 194 73.3 62.9 27.5 22.7 8.4 9.0

S3 243 186 72.5 61.9 24.4 20.0 9.6 10.2

S4 195 149 70.0 59.0 19.1 15.7 11.1 11.7

SEd 3.57 2.10 0.11 0.07 0.25 0.21 0.10 0.11

CD (0.05) 7.51 4.41 0.24 0.16 0.54 0.42 0.20 0.22

8

Table 3. Effect of insitu moisture conservation methods, time of sowing and INM practices on grain yield, stover yield, net return and BC ratio

Treatments Grain yield Stover yield Net return BC ratio (kg/ha) (kg/ha) (Rs/ha)

2002 2003 2002 2003 2002 2003 2002 2003

Insitu moisture conservation methods with time of sowing

M1 2351 1599 4513 3876 3558 1863 1.74 1.21

M2 1881 1550 3609 2789 3490 3158 1.40 1.18

M3 2977 2021 6061 3834 3890 3850 2.06 1.41

M4 2381 1960 4813 3719 5978 3469 1.64 1.37

M5 3201 2178 6470 4124 11240 4812 2.19 1.51

M6 2560 2113 5175 4000 7035 4390 1.74 1.46

SEd 68 54 150 134 - - - -

CD (0.05) 150 120 330 296 - - - -

INM practices

S1 2583 1919 5167 3616 7891 3569 1.58 1.40

S2 3000 2232 5931 4247 10337 5301 2.12 1.57

S3 2610 1945 5219 3652 7540 3211 1.79 1.34

S4 2040 1517 4081 2712 3691 1226 1.37 1.12

SEd 39 29 77 69 - - - -

CD (0.05) 83 62 162 146 - - - -

Treatment combination

M1S

1 2374 1615 4467 2924 6905 1966 1.81 1.23

M1S

2 2758 1875 5248 3435 9131 3379 2.04 1.38

M1S

3 2398 1632 4513 2953 6536 1550 1.72 1.17

M1S

4 1874 1275 3350 2193 3660 557 1.38 1.05

M2S

1 1900 1566 3440 2836 3805 1650 1.45 1.19

M2S

2 2206 1817 4041 3331 5517 3005 1.63 1.34

M2S

3 1920 1583 3475 2864 3408 1234 1.37 1.13

M2S

4 1501 1236 2580 2127 1230 426 1.13 1.04

M3S

1 3006 2034 5957 3898 10530 4183 2.17 1.46

M3S

2 3491 2373 6998 4579 13426 5913 2.44 1.63

M3S

3 3037 2064 6018 3938 10206 3848 2.07 1.40

M3S

4 2374 1614 4467 2924 5399 1454 1.54 1.14

M4S

1 2404 1972 4587 3781 6575 3783 1.73 1.42

M4S

2 2792 2301 5388 4441 8830 5647 1.95 1.60

M4S

3 2429 2002 4634 3819 6212 3446 1.65 1.36

M4S

4 1899 1565 3440 2836 2293 998 1.23 1.10

M5S

1 3232 2197 6407 4194 11893 5130 2.30 1.56

M5S

2 3754 2553 7525 4924 15031 7175 2.60 1.76

M5S

3 3265 2230 6427 4235 11583 4813 2.20 1.50

M5S

4 2553 1735 4805 3146 6453 2130 1.64 1.21

M6S

1 2585 2131 4935 4068 7643 4703 1.83 1.51

M6S

2 3003 2478 5794 4776 10092 6688 2.07 1.71

M6S

3 2612 2163 4983 4107 7292 4379 1.75 1.45

M6S

4 2042 1682 3702 3051 3111 1788 1.30 1.17

SEd 84 53 176 115 - - - -

CD (0.05) 180 113 382 245 - - - -

9

Sustainable Yield Index of Rainfed Sorghum under

different Rainfall Situation in Vertisols of South Tamil Nadu

K. Baskar1, V.Subramanian2 and G. Maruthi Sankar3, 1Associate Professor (Soil Science) and 4Professor & Head (Soil Science), Agricultural Research Station, Kovilpatti. 3rincipal Scientist (Agricultural Statistics), CRIDA, Santoshnagar, Hyderabad�500059.

2

Introduction Sorghum (Sorghum bicolor L.) is an important

cereal crop grown under rainfed conditions in several states of India. In Tamil Nadu, since the North-East monsoon occurs during October to January, this crop is grown during this period as rainfed crop. Among different input variables, effect of fertilizer is greatly influenced by soil moisture available at the time of sowing and during crop growth period, while the soil moisture content, retention and supply are directly influenced by amount and distribution of rainfall under rainfed conditions. Mathur (1997) studied long term effects of fertilizer on yield and soil fertility under cotton�wheat rotation in arid soils of North�West Rajasthan. Prihar and Gajri (1988) examined usefulness of fertilizer application to rainfed crops and described strategies for rationalizing the application in relation to seasonal water supply and available soil fertility. Precise information on sustainable treatments and optimum fertilizer requirement at varying soil test values and rainfall situations is lacking for rainfed crops. An attempt is made in this paper to assess the

effects of soil and fertilizer nutrients on sorghum yield in different rainfall situations using regression models and optimize fertilizer doses at varying soil test values for attaining sustainable yield in a semi-arid vertisols.

Materials and MethodsFifteen trials on sorghum (Sorghum bicolor

L.) were conducted in a fixed site during North-East monsoon season of 1982 to 2005 in a semi-arid vertic inceptisol at Agricultural Research Station, Kovilpatti. The research center is located at a latitude of 9.12� North, longitude of 77.53� East and altitude of 166.42 m above mean sea level. Nine fertilizer treatments of N through urea, farmyard manure (FYM) and crop residue in combination with single super phosphate (SSP) were tested in each season. The treatments were (i) Control; (ii) 40 kg N (urea) + 20 kg P/ha (SSP); (iii) 20 kg N (urea) + 10 kg P/ha (SSP); (iv) 20 kg N (crop residue)/ha; (v) 20 kg N (FYM)/ha; (vi) 20 kg N (crop residue) + 20 kg N (urea) + 10 kg P/ha (SSP); (vii) 20 kg N (FYM) + 20 kg N (urea) + 10 kg P/ha (SSP); (viii) 40 kg N (urea) + 20 kg P (SSP) + ZnSO

4 @ 25 kg/ha; and (ix) FYM @ 5 t/ha.

10

The crop residue and FYM contained 0.53 and 0.50% N; 0.07 and 0.16% P; 0.80 and 0.43% K respectively on dry weight basis. The trials were conducted in a net plot size of 7.5 m x 3.6 m with row x plant spacing of 45 cm x 15 cm in a Randomized Block Design with 3 replications. Initial soil samples were collected in each plot from a depth of 0�30 cm and analyzed for alkaline permanganate N (Subbaiah and Asija, 1956), OlsenÊs P (Olsen et al., 1954) and ammonium acetate K (Jackson, 1973). The site of the experiment is a Typic Chromustert with clay texture, pH of 8.2, Electrical conductivity of 0.5 dS/m, organic carbon of 4.3 g/kg, available soil N of 80 kg/ha, P of 10 kg/ha and K of 586 kg/ha. The soil depth varied from 110 to 150 cm with an infiltration rate of 0.9 cm/hr. The soil has 46.4 to 61.2% clay, 10.0 to 17.5% silt and 12.6 to 24.5% coarse sand. The bulk density varied from 1.23 to 1.32 kg/m3 with field capacity of 35% and permanent wilting point of 14%.

Rainfall and its distribution during crop growing period

The earliest date of sowing of sorghum was on 29th September (1995), while the latest was on 27th October (1984 and 1985). The earliest date of harvest of the crop was on 7th January (2004), while the latest was on 25th February (1986). Out of 15 years, crop seasonal rainfall was < 250 mm from 11 rainy days

in 2 years, 250�500 mm from 21 rainy days in 10 years and 500�750 mm from 30 rainy days in 3 years. Under < 250 mm rainfall, sorghum had a duration of 104 (1995) to 122 days (1985) with a mean of 113 days and coefficient of variation of 11.3%. The duration ranged from 88 (1983) to 138 days (2005) with a mean of 112 days and variation of 14.8% in 250�500 mm compared to 103 (1987) to 114 days (1997) with a mean of 109 days and variation of 5.1% in 500�750 mm situation. A mean rainfall of 117.1 mm with variation of 24.9%, 361.6 mm with variation of 21.2% and 618.2 mm with variation of 4.5% occurred in <250, 250�500 and 500�750 mm situations respectively. The crop growing period, rainy days, crop seasonal rainfall, date of sowing and harvest in different years are given in Table 1.

Results and DiscussionAnalysis of variance of soil nutrients and yield

in different rainfall situations ANOVA indicated no significant difference between treatments for their effect on yield and soil nutrients in <250 mm rainfall, while the differences were significant for both yield and soil N, P and K in 250�500 mm and only yield, soil N and P in 500�750 mm rainfall situation (Table 2). The treatments gave a mean yield of 384 kg/ha with variation of 21.4%, 1063 kg/ha with variation of 20.1% and 854 kg/ha with variation of 19.8% in <250, 250�500 and 500�750 mm rainfall respectively. All the treatments gave

Year Variety DOS DOH CGP RD CRF Rainfall: < 250 mm 1985 K Tall 27�Oct 25�Feb 122 14 137.7 1995 K-8 29�Sep 10�Jan 104 8 96.4 Mean 113 11 117.1 CV (%) 11.3 38.6 24.9 Rainfall : 250–500 mm 1982 CSH-6 16�Oct 31�Jan 108 25 385.4 1983 CSH-6 18�Oct 13�Jan 88 28 484.8 1984 CO-25 27�Oct 9�Feb 106 14 357.6 1986 K Tall 2�Oct 4�Feb 126 15 307.3 1991 K-8 30�Sep 12�Feb 136 22 265.5 1993 K-8 14�Oct 24�Jan 103 27 426.8 1999 K-8 13�Oct 25�Jan 105 18 292.0 2001 K-8 1�Oct 26�Jan 118 13 310.6 2003 K-8 4�Oct 7�Jan 96 19 317.5 2005 K-8 1�Oct 15�Feb 138 24 468.8 Mean 112 21 361.6 CV (%) 14.8 26.7 21.2 Rainfall : 500–750 mm 1987 K Tall 1�Oct 11�Jan 103 29 634.2 1989 K Tall 5�Oct 22�Jan 110 21 634.6 1997 K-8 10�Oct 31�Jan 114 39 585.7 Mean 109 30 618.2 CV (%) 5.1 30.4 4.5

Table 1. Date of sowing and harvest of sorghum and crop seasonal rainfall at Kovilpatti

11

Values in parentheses are coefficient of variation (%) T1 : Control T2 : 40 kg N (urea) + 20 kg P/ha T4 : 20 kg N/ha (crop residue) T6 : 20 kg N (crop residue) + 20 kg N (urea) + 10 kg P/haT7 : 20 kg N (FYM) + 20 kg N (urea) + 10 kg P/haT8 : 40 kg N (urea) + 20 kg P + ZnSO

4 @ 25 kg/ha

LSD: Least significant difference (p<0.05)T3 : 20 kg N (urea) + 10 kg P/haT5 : 20 kg N/ha (FYM) T9 : FYM @ 5 t/ha a significantly higher yield but with a relatively higher variation in 250�500 mm, followed by 500�750 and <250 mm rainfall situation.

The treatments gave a mean soil N of 115 kg/ha with variation of 18.2% in <250 mm, followed by 110 kg/ha with variation of 10.8% in 500�750 mm and 105 kg/ha with variation of 12.9% in 250�500 mm rainfall. A mean soil P of 9.5 kg/ha was observed with variation of 15.7 and 14.1% in <250 and 250�500 mm respectively, compared to 8.7 kg/ha with variation of 6.2% in 500�750 mm rainfall. A mean soil K of 496

kg/ha with variation of 6.4% was observed in 250�500 mm, compared to 358 kg/ha with variation of 7.4% in <250 mm and 328 kg/ha with variation of 7.9% in 500�750 mm rainfall.

Superiority of Fertilizer Treatments in Different Rainfall Situations

The treatments were compared based on LSD criteria and superior treatments for yield and soil nutrients in 250�500 and 500�750 mm rainfall situations were identified (Table 3). Application of 40 kg N (urea) + 20 kg P + ZnSO

4 @ 25 kg/ha gave significantly higher yield

of 1339 kg/ha in 250�500 mm and 1168 kg/ha in 500�750 rainfall. However, 20 kg N (FYM) + 20 kg N (urea) + 10 kg P/ha in 250�500 mm and 40 kg N (urea) + 20 kg P/ha in 500�750 mm rainfall maintained significantly higher soil N of 117 and 134 kg/ha and soil P of 10.7 and 9.9 kg/ha respectively, while 20 kg N (crop residue) + 20 kg N (urea) + 10 kg P/ha maintained soil K of 533 kg/ha in 250�500 mm rainfall.

It is observed that 20 kg N (FYM) + 20 kg N (urea) + 10 kg P/ha and 40 kg N (urea) + 20 kg P + ZnSO

4 @

25 kg/ha were superior in 250�500 mm, while 40 kg N (urea) + 20 kg P/ha and 40 kg N (urea) + 20 kg P +

Variable T1 T2 T3 T4 T5 T6 T7 T8 T9 Mean LSD Rainfall : < 250 mm (1985 & 1995)Yield 250 488 448 354 290 317 394 480 436 384 NS (19.0) (21.0) (34.0) (23.2) (2.9) (4.7) (24.8) (40.6) (36.9) (21.4) Soil N 112 125 124 123 99 123 120 113 97 115 NS (42.5) (11.9) (18.2) (4.0) (15.1) (21.8) (3.0) (10.7) (19.0) (18.2) Soil P 8.7 9.1 8.6 9.7 10.6 10.0 10.5 9.8 9.1 9.5 NS (39.0) (28.0) (26.3) (5.1) (7.4) (23.5) (2.7) (8.0) (3.1) (15.7) Soil K 323 367 338 349 360 402 367 353 366 358 NS (15.1) (27.4) (17.6) (19.7) (27.7) (31.2) (27.6) (14.8) (25.5) (7.4) Rainfall : 250–500 mm (1982, 1983, 1984, 1986, 1991, 1993, 1999, 2001, 2003 & 2005)Yield 785 1195 965 879 923 1102 1246 1339 1136 1063 190 (59.2) (45.7) (49.8) (60.9) (55.9) (69.3) (52.2) (48.4) (66.3) (20.1) Soil N 95 112 100 102 97 116 117 115 91 105 12.1 (20.6) (16.6) (19.9) (19.4) (14.4) (17.3) (17.2) (21.3) (11.8) (12.9) Soil P 8.3 10.0 9.1 8.7 9.1 9.9 10.7 10.5 9.4 9.5 1.2 (40.0) (14.6) (36.2) (26.7) (28.0) (24.1) (22.6) (31.2) (32.7) (14.1) Soil K 456 485 482 483 507 533 512 496 515 496 (43.8) (29.9) (38.3) (35.2) (34.9) (31.3) (33.6) (33.7) (33.5) (6.4) 28.5 Rainfall : 500–750 mm (1987, 1989 & 1997)Yield 493 997 765 870 756 944 1072 1168 619 854 292 (40.6) (16.5) (28.6) (51.6) (31.7) (32.1) (29.2) (16.4) (42.5) (19.8) Soil N 93 134 117 106 100 118 107 113 102 110 20.6 (10.9) (13.5) (5.6) (9.1) (14.4) (1.7) (10.6) (1.0) (20.1) (10.8) Soil P 6.8 9.9 8.6 8.6 8.7 9.5 9.1 9.8 7.7 8.7 0.9 (18.4) (8.2) (14.1) (9.5) (10.8) (9.5) (15.3) (11.0) (29.7) (6.2) Soil K 301 315 335 313 332 319 311 361 363 328 NS (13.2) (12.8) (20.7) (21.3) (16.3) (22.5) (22.6) (4.3) (8.3) (7.9)

Table 2. Mean and variation of yield and soil nutrients in different rainfall situations

12

T1 : Control,T2 : 40 kg N (urea) + 20 kg P/ha, T3 : 20 kg N (urea) + 10 kg P/ha T4 : 20 kg N/ha (crop residue),T5 : 20 kg N/ha (FYM), T6 : 20 kg N (crop residue) + 20 kg N (urea) + 10 kg P/ha T7 : 20 kg N (FYM) + 20 kg N (urea) + 10 kg P/ha, T8 : 40 kg N (urea) + 20 kg P + ZnSO

4 @ 25 kg/ha,

T9 : FYM @ 5 t/ha

ZnSO4 @ 25 kg/ha were superior in 500�750 mm

rainfall in a maximum number of treatment comparisons. Prihar and Gajri (1988) recorded usefulness of fertilizer application to rainfed crops and described strategies for rationalizing the application in relation to seasonal water supply and available soil fertility.

Application of 40 kg N (urea) + 20 kg P + ZnSO4

@ 25 kg/ha for yield and soil N; 20 kg N (FYM) + 20 kg N (urea) + 10 kg P/ha for soil P and 20 kg N (crop residue) + 20 kg N (urea) + 10 kg P/ha for soil K were superior in 250�500 mm rainfall. Similarly, 40 kg N (urea) + 20 kg P + ZnSO

4 @ 25 kg/ha for yield and

soil P; and 40 kg N (urea) + 20 kg P/ha for soil N were superior in 500�750 mm rainfall.

Correlation of yield with crop seasonal rainfall, soil and fertilizer nutrients

The sorghum yield had a significant positive correlation of 0.48 with soil N, 0.73 with soil P and 0.47 with soil K and 0.39 with fertilizer P in 500�750 mm, while it had a significant positive correlation of 0.23 with fertilizer P and negative correlation of �0.22 with soil N and �0.28 with soil K in 250�500 mm rainfall. In <250 mm, it had a significant positive correlation of 0.47 with soil K, 0.55 with fertilizer N and 0.65 with fertilizer P. Significant negative correlation of �0.52, �0.38 and �0.38 was found between yield and rainfall in <250, 250�500 and 500�750 mm rainfall respectively. Soil N and P had a significant correlation of 0.57 in <250 mm, 0.41 in 250�500 mm and 0.68 in 500�750 mm. Soil N had a significant correlation of 0.38 with soil K and 0.24 with organic N in 250�500 mm; and 0.38 with fertilizer N in 500�750 mm rainfall. Soil P had a significant correlation of 0.71 in 250�500 mm and 0.49 in 500�750 mm with soil K and 0.41 with fertilizer P in 500�750 mm rainfall. Soil nutrients had a significant correlation among themselves in 250�500 mm, compared to soil and fertilizer nutrients in 500�750 mm rainfall.

Superior 250–500 mm 500–750 mmtreatment Yield SN SP SK Total Yield SN SP Total

T2 > T1, T3, T1, T3, T1, T4 T1 11 T1, T9 T1, T4, T1, T3, 13 T4, T5 T5, T9 T5, T7, T4, T5, T8, T9 T9

T3 > T7, T8 2 T1 T1, T9 3

T4 > T1 T1, T9 3

T5 > T1 1 T1, T9 2

T6 > T1, T4 T1, T3, T1, T4 T1, T2, 14 T1, T9 T1 T1, T3, 7 T4, T5, T3, T4, T4, T9 T9 T8

T7 > T1, T3, T1, T3, T1, T4, T1, T3, 16 T1, T3, T1, T9 6 T4, T5 T4, T5, T5, T9 T4 T5, T9 T9

T8 > T1, T3, T1, T3, T1, T4, T1 15 T1, T3, T1 T1, T3, 11 T4, T5, T4 T5, T5 T4, T5, T4, T5, T6, T9 T9 T9 T9

T9 > T1, T4, T1, T2, 7 T1 1 T5 T3, T4

Total 19 19 13 15 66 14 9 23 46

Table 3. Superiority of fertilizer treatments for sorghum yield and soil nutrients at Kovilpatti

13

* and ** indicate significance at p < 0.05 and p < 0.01 level respectively R2 : Coefficient of determinationΦ : Prediction error (kg/ha)η : Sustainable yield indexY : Yield (kg/ha) SN : Soil N (kg/ha)SP: Soil P (kg/ha) SK : Soil K (kg/ha) FN : Fertilizer N (kg/ha) ON : Organic N (kg/ha) FP: Fertilizer P (kg/ha) ZN : Zinc sulphate (kg/ha)Sustainable yield index of fertilizer treatments

Using mean yield of a treatment over years, maximum yield of 617 (1995), 2451 (1999) and 1342 kg/ha (1989) attained by 40 kg N (urea) + 20 kg P + ZnSO

4 @ 25 kg/ha and prediction error of 66, 196 and

230 kg/ha based on regression model of yield under <250, 250�500 and 500�750 mm rainfall respectively, sustainable yield index of treatments was derived using (2). The index values are graphically plotted against soil N, P and K and variation of yield in Fig. It is observed that a mean yield of 384, 1063 and 854 kg/ha could be attained with a sustainable yield index of 51.5, 35.4 and 46.5% in <250, 500�750 and 250�500 mm rainfall respectively. The treatments had a sustainability of 35�75% for yield variation of 25% in <250 mm compared to 35�55% with yield variation of 50�75% in 250�500 mm and 35�75% for yield variation of 25�50% in 500�750 mm rainfall. Application of 40 kg N (urea) + 20 kg P/ha was efficient in <250 mm with sustainability of 68.4%, while 40 kg N (urea) + 20 kg P + ZnSO

4 @ 25

kg/ha was efficient in 250�500 and 500�750 mm with sustainability of 46.6 and 69.9% respectively.

Optimization of fertilizer doses at vary-ing soil test values

Using fertilizer equations given in Table 4, optimum fertilizer doses were derived at varying soil test values for attaining sustainable sorghum yield in different rainfall situations. At a soil N of 110 kg/ha, fertilizer N of 22 kg/ha was optimum in <250 mm compared to 24 kg/ha in 250�500 mm and 32 kg/ha in 500�750 mm rainfall. At same soil N, organic N of 8, 11 and 16 kg/ha was optimum in the respective rainfall situations. Similarly, at a soil P of 11 kg/ha, fertilizer P of 3, 12 and 27 kg/ha was optimum in <250, 250�500 and 500�750 mm rainfall respectively. Fertilizer N was not required beyond soil N of 130 kg/ha in <250 mm, 150 kg/ha in 250�500 mm and 170 kg/ha in 500�750 mm rainfall. Fertilizer P was not required beyond soil P of 13 kg/ha in <250 mm, while 8 and 22 kg/ha was required at a soil P of 17 kg/ha in 250�500 and 500�750 mm rainfall situations respectively. Dalal and Mayer (1986) revealed long term trends in soil properties of nutrients when cereal crops were grown continuously over years in Southern Queensland.

Based on soil N, the treatments had a sustainability of 35�75% at 115�135 kg/ha in <250 mm, 15�55% at 85�115 kg/ha in 250�500 mm and 35�75% at 95�115 kg/ha in 500�750 mm rainfall. Based on soil P, the treatments had a sustainability of 35�75% in <250 mm and 15�35% in 250�500 mm at 8�11 kg/ha compared to 15�55% at 6.5�9.5 kg/ha in 500�750

Rainfall (mm) Regression model R2 Φ η Fertilizer equation

< 250 Y = � 613 � 9.95 (SN) + 173.05 * (SP) 0.91* 66 51.5 FN = 159 � 1.25 SN + 1.44 ** (SK) + 25.41 (FN) � 0.08 (FN2) ON = 13 � 0.05 SN + 23.85 (FP) � 0.35 (FP2) + 22.01 (ON) FP = 34 � 2.79 SP � 0.85 (ON2) � 4.26 (ZN) � 0.20 (FN) (SN) � 1.95 (FP) (SP) � 0.08 (ON) (SN)

250�500 Y = � 2347 ** � 20.16 ** (SN) + 87.09 ** 0.74** 196 35.4 FN = 106 � 0.75 SN (SP) � 0.59 * (SK) + 29.55 * (FN) ON = 35 � 0.22 SN � 0.14 (FN2) + 30.81 * (FP) � 0.79 (FP2) FP = 20 � 0.69 SP + 21.18 (ON) � 0.30 (ON2) � 9.33 (ZN) � 0.21 * (FN) (SN) � 1.09 * (FP) (SP) � 0.13 (ON) (SN)

500�750 Y = � 1719 + 32.99 * (SN) � 241.23 * 0.70* 230 46.5 FN = 105 � 0.66 SN (SP) + 2.54 * (SK) + 39.85 * (FN) ON = 42 � 0.24 SN � 0.19 (FN2) + 63.86 * (FP) � 0.89 (FP2) FP = 36 � 0.85 SP + 26.34 (ON) � 0.31 (ON2) � 7.63 (ZN) � 0.25 (FN) (SN) � 1.52 (FP) (SP) � 0.15 (ON) (SN)

Table 4. Regression models of yield through soil and fertilizer nutrients in different rainfall situations

14

mm rainfall. Based on soil K, the treatments had a sustainability of 15�55% at 450�550 kg/ha in 250�500 mm compared to 35�75% at 300�400 kg/ha in <250 and 500�750 mm rainfall.Similar result was observed by Prasad and Goswami (1992)

Based on long term trials conducted for 15 years in a fixed site in a semi-arid vertic inceptisol at Kovilpatti, efficient fertilizer treatments which provided significantly higher sorghum yield and maintained maximum soil N, P and K were identified. Based on regression analysis of yield through soil and fertilizer nutrients, optimum fertilizer N and P were derived for varying soil test values in <250, 250�500 and 500�750 mm rainfall. Based on ANOVA, 40 kg N (urea) + 20 kg P + ZnSO

4 @ 25 kg/

ha and 40 kg N (urea) + 20 kg P/ha were superior in 250�500 and 500�750 mm rainfall. Application of 40 kg N (urea) + 20 kg P/ha gave maximum sustainable yield index of 68.4% in <250 mm, while 40 kg N (urea) + 20 kg P + ZnSO

4 @ 25 kg/ha gave maximum of 46.6%

in 250�500 mm and 69.9% in 500�750 mm rainfall. Fertilizer N of 22 kg/ha and organic N of 8 kg/ha was optimum when rainfall was <250 mm compared to 24 and 11 kg/ha in 250�500 mm and 32 and 16 kg/ha in 500�750 mm at soil N of 110 kg/ha. Fertilizer P of 3, 12 and 27 kg/ha was optimum at a soil P of 11 kg/ha in the three respective rainfall situations. The study indicated that application of optimum fertilizer doses based on soil tests would provide sustainable sorghum yield in different rainfall situations in a semi-arid vertisols.

Fig. Sustainability of treatments at different soil test values and variation in sorghum yield.

15

ReferencesDalal, R.C. and Mayer, R.J. (1986). Long term trends in fertility of soils under continuous cultivation and cereal

cropping in Southern Queensland : In Overall changes in soil properties and trends in winter cereal yields. Australian Journal of Soil Research, 24 : 265�279.

Mathur, G.M. (1997). Effects of long term application of fertilizers and manures on soil properties under cotton�wheat rotation in North West Rajasthan. Journal of Indian Society of Soil Science, 42 (2) : 288�292.

Prasad, R. and Goswami, N.N. (1992). Soil fertility restoration and management for sustainable agriculture in South Asia. Advances in Soil Science, 17 : 37�77.

Prihar, S.S. and Gajri, P.R. (1988). Fertilization of dryland crops. Indian Journal of Dryland Agricultural Research and Development, 3 (1): 1�33.

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16

Modeling Organic Carbon Status under Permanent

Manurial Experiment in Rainfed Vertisols of Semi-arid Region of

South Tamil NaduK.Baskar1,V.Subramanian2 and G.Maruthi Sankar3, 1Associate Professor (Soil Science) and 4Professor & Head (Soil Science), Agricultural Research Station, Kovilpatti. 3rincipal Scientist (Agricultural Statistics), CRIDA, Santoshnagar, Hyderabad.

3

IntroductionSoils are a major carbon pool and are estimated

to contain 1220 to1550 Pg C in organic form and almost half in inorganic form. Amongst different soil orders Histosols contain maximum and Vertisols contain minimum carbon. In general, Inorganic C in soils is generally very stable but SOC is very reactive and a large quantity can be lost through changes in land use especially from ploughing and erosion. Most of the good lands in tropics are already under intensive cultivation leading to depletion of soil organic carbon (Datta et al. 2001). The present investigation is to know the modeling of changes in soil organic carbon through soil temperature, rainfall and evaporation under dryland vertisol tract of Tamil Nadu.

Materials and MethodsPermanent Manurial experiment (PME) on pearl

millet � sorghum rotation was conducted at Agricultural Research Station, Kovilpatti under semi-arid vertisol

during 1995 to 2005. The study was conducted to assess the changes in soil organic carbon as influenced by different climatic variables over a period of time. The PME were conducted with a set of 9 fertilizer treatments viz., Control, 40 kg N + 20 kg P/ha (RDF),20 kg N + 10 kg P/ha, 20 kg N/ha (Farm residue), 20 kg N/ha (FYM), 20 kg N (Farm residue) + 20 kg N (urea) + 10 ka P/ha, 20 kg N (FYM) + 20 kg N (urea) + 10 kg P/ha, 40 kg N (urea) + 20 kg P + 25 kg ZnSO

4/ha and

FYM @ 5 t/ha (farmerÊs practice).

Results and DiscussionThe soil organic carbon (%) was observed in each

plot of the 9 fertilizer treatments under PME during the eleven year study. The organic carbon ranged from a minimum of 0.26% under control to a maximum of 0.62% under 20 kg N/ha (FYM) over years. The control had a minimum mean organic carbon of 0.34% with a coefficient of variation of 24%, while FYM @ 5 t/ha (farmerÊs practice) had a maximum mean of 0.48% with a lower variation of 17.3% over years. However,

17

the treatment of 20 kg N (Farm residue) + 20 kg N (urea) + 10 kg P/ha had the lowest variation of 15.4% over years in the study. It is observed that the soil had a maximum organic carbon of 0.54% in 1995 and 1996 with a variation of 11.4 and 7.3% respectively, while it depleted to a minimum of 0.36% in 1999 and 2005 with a variation of 15.1% and 18.8% respectively over 9 treatments of fertilizer examined in the study. The

changes in soil organic carbon in different treatments during 1995 to 2005 under PME are also depicted in Fig.1.

The Regression model of changes in organic carbon through climatic variables under PME was worked out. Treatment-wise regression models to predict changes in soil organic carbon through soil temperature observed at 7.28 PM and 2.20 PM in 5�7.5, 10�15 and 20�30 cm depth, rainfall and evaporation during

September to February were calibrated with the pooled data observed under PME during 1995 to 2005. The estimates of regression coefficients of soil temperature, rainfall and evaporation, along with coefficient of determination (R2) and sustainable index of treatments for organic carbon build-up in the soil are given in Table 1. The model of T4 was having a maximum and significant organic carbon predictability of 0.48, while T8 had minimum predictability of 0.39. However, T6 gave a minimum prediction error of 0.054%, while T4 and T9 had a maximum prediction error of 0.067% based on the models. The sustainable index of organic carbon was found to be maximum of 66.6% for T9, followed by T7 with 66.5%, T5 with 64.5% and T6 with 63.9%, and while control had a minimum sustainability of 44.8% based on the trials conducted under PME.

* & ** indicate significance at 5 & 1% level. Values in parentheses are ranks assigned to treatments Based on the regression models, the soil temperature observed under 5�7.5, 10�15 and 20�30 cm depth at 7.28 AM was having a significant influence on soil organic carbon

compared to the soil temperature observed at 2.20 PM. The soil temperature in 5�7.5 and 20�30 cm depth was found to have a significant negative influence, while the soil temperature in 10�15 cm depth had a significant positive influence on the soil organic carbon based on the models of all the 9 treatments examined in the study. The soil temperature observed in 5�7.5 cm at 2.20 PM had a negative influence, while the temperature in 10�15 and 20�30 cm had a positive influence on soil organic

Table 1. Regression models of organic carbon through soil temperature, rainfall and evaporationunder PME at Kovilpatti

Treatment Regression model R2 Φ η T1 OC = 0.30 � 0.044 ** (ST1) + 0.081 ** (ST2) � 0.038 ** (ST3) 0.45** 0.062 44.8

� 0.002 (ST4) + 0.001 (ST5) + 0.005 (ST6) + 0.001 * (RF) + 0.001 (EV) (4) (6) (9) T2 OC = 0.24 � 0.032 ** (ST1) + 0.063 ** (ST2) � 0.029 ** (ST3) 0.40** 0.056 55.5

� 0.003 (ST4) + 0.002 (ST5) + 0.005 (ST6) + 0.001 (RF) + 0.001 (EV) (8) (2) (7) T3 OC = 0.30 � 0.036 ** (ST1) + 0.081 ** (ST2) � 0.044 ** (ST3) 0.47** 0.065 54.0

� 0.002 (ST4) + 0.002 (ST5) + 0.003 (ST6) + 0.001 (RF) + 0.001 (EV) (2) (7) (8) T4 OC = 0.31 � 0.033 ** (ST1) + 0.083 ** (ST2) � 0.048 ** (ST3) 0.48** 0.067 58.5

� 0.003 (ST4) + 0.003 (ST5) + 0.004 (ST6) + 0.001 (RF) + 0.001 (EV) (1) (9) (5) T5 OC = 0.39** � 0.021 * (ST1) + 0.061 ** (ST2) � 0.04 ** (ST3) 0.46** 0.060 64.5

� 0.003 (ST4) + 0.004 (ST5) + 0.003 (ST6) + 0.001 (RF) + 0.001 (EV) (3) (5) (3) T6 OC = 0.34** � 0.023 ** (ST1) + 0.062 ** (ST2) � 0.035 ** (ST3) 0.44** 0.054 63.9

� 0.002 (ST4) + 0.002 (ST5) + 0.002 (ST6) + 0.001 (RF) + 0.001 (EV) (6) (1) (4) T7 OC = 0.35** � 0.032 ** (ST1) + 0.071 ** (ST2) � 0.038 ** (ST3) 0.44** 0.058 66.5

� 0.001 (ST4) + 0.001 (ST5) + 0.003 (ST6) + 0.001 (RF) + 0.001 (EV) (5) (3) (2) T8 OC = 0.31* � 0.029 ** (ST1) + 0.066 ** (ST2) � 0.035 ** (ST3) 0.39** 0.059 58.2

� 0.001 (ST4) + 0.001 (ST5) + 0.002 (ST6) + 0.001 (RF) + 0.001 (EV) (9) (4) (6) T9 OC = 0.38* � 0.033 ** (ST1) + 0.075 ** (ST2) � 0.039 ** (ST3) 0.40** 0.067 66.6

� 0.002 (ST4) + 0.003 (ST5) + 0.001 (ST6) + 0.001 (RF) + 0.001 (EV) (7) (8) (1)

Fig.1. Performance of treatments for soil organic carbon under PME during 1995 to 2005 at Kovilpatti.

18

carbon, but was not significant based on the models. A positive effect of rainfall and evaporation on soil carbon were observed under all fertilizer treatments, however, rainfall had a significant effect only under control (Lal et al. 2001).

Ranking and Selection of Superior Fertilizer Treatments for Sustainable Organic Carbon

Ranks were assigned to treatments for the performance based on soil organic carbon build-up or depletion in different years under PME during 1995 to 2005 (table 2) and rank sum Âl1Ê was derived. Ranks were also assigned to treatments for the mean organic carbon, coefficient of determination, prediction error and sustainable index based on regression models calibrated for the pooled data over years and rank sum (l2) was derived. Based on the pooled rank sum of l1 and l2, a superior fertilizer treatment was selected. A graphical plot of rank sums Âl1Ê and Âl2Ê derived for fertilizer treatments tested under PME is given in Fig.2. The study has clearly indicated that T9 was superior with a minimum rank sum of 22 and 17 under PME for soil organic carbon observed in individual years (l1) during 1995 to 2005,

and mean, coefficient of determination, prediction error and sustainable index (l2) over years at Kovilpatti under semi-arid vertisols.

Based on a detailed regression and rank analysis of fertilizer treatments, the study has clearly indicated that T9 was superior with a minimum rank sum of 22 and 17 in PME for soil organic carbon observed in individual years (rank sum 1) during 1995 to 2005, and mean, coefficient of determination, prediction error and sustainable index (rank sum 2) over years in the study.

Treatment PME

λ1 λ2 Rank sum Rank

T1 96 28 124 9

T2 74 24 98 7

T3 82 25 107 8

T4 57 20 77 5

T5 38 14 52 4

T6 33 15 48 3

T7 33 12 45 2

T8 63 25 88 6

T9 22 17 39 1

Table 2. Ranking of treatments for organic carbon status in individual years, mean, coefficient of determination, prediction error and sustainable index over years at Kovilpatti

Fig.2. Performance of treatments for soil organic carbon under PME during 1995 to 2005 at Kovilpatti.

ReferencesDatta, M., Bhattacharya, B.K. and Saikh (2001). J.Indian Soc.Soil Sci.49, 104.Lal,R., Kimble, J. and Follet ,R. (1998). In Management Of Carbon Sequestration in Soil (Lal,R., Kimble, J.M., Follet,

R.E. & Stewart, B.A. eds.) CRC Boca Raton,pp 1-10.Aggarwal,R.K., Praveen-Kumar & Power, J.F. (1997). Soil Tillage Res.41, 43.

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19

Land configuration and rain water management for higher cotton productivity in rainfed

deep vertisolDr. V. Ganesaraja, Dr. S. Senthivel, Dr. V. K. Paulpandi, Dr. R. Balasubramanian and M. P. Kavitha Department of Agronomy, Agricultural College and Research Institute, Madurai � India.

4

IntroductionThe Kovilpatti taluk of Thoothukudi district in

Southern Tamil Nadu is one of the rain shadow areas where rainfall is erratic and undependable. The deep vertisol in these areas has the potential for holding maximum possible quantity of water received from rainfall for crop production. Sorghum, cotton and pulses are the important mandate crops under rainfed cultivation in the region besides having some area under chillies and other millets.

Rainfed agriculture in this zone is facing many problems associated with the vagaries of monsoon especially during North East Monsoon season when the commencement of rains may be quite early or considerably delayed (Ganesaraja, et al., 2001). This condition of uncertainty warrants efficient use of rainwater which will pave the way for getting successful crop production.

Materials and MethodsField experiments were conducted at Agricultural

Research Station, Kovilpatti to study the effect of land configuration and rain water management on cotton productivity during North East Monsoon Season of 1999 and 2000.

The experiments were laid out in split plot design with three replications. The cotton variety MCU 10 was sown as dry sowing after treating the seeds with 2 % KCl solution and cow dung slurry as per treatment. The seeds were sown at 45X 15 cm spacing. The recommended weed and fertilizer management practices were taken. The observed data on growth, yield attributing characters and cotton yield were statistically scrutinized. The soil moisture content at three different depths in 0-15, 15-30 and 30-45 cm were taken.

20

Results and DiscussionThe mean of two years data revealed that

among the land configuration methods, Compartmental bunding recorded higher plant height (89.1 cm), LAI (5.09) and dry matter production (4245 kg / ha). This treatment recorded higher Boll weight (2.73 g) and seed cotton yield of 675 kg/ha and was closely followed by broad bed furrow system (672 kg/ha). Mulching with

farm wastes recorded improved growth characteristics and there by higher seed cotton yield of 623 kg/ha and it was on par with dust mulching (610 kg/ha). This could be due to higher soil moisture content resulted in better growth and yield attributes and thereby yield (Selvaraju et al.,1999).The different methods of seed treatments did not exhibit any significant influence on seed cotton yield. Regarding

the soil moisture content, compartmental bunding recorded higher soil moisture content of 26, 43, 31.01 and 33.66% at 0-15, 15-30 and 30-45 cm respectively. The farm waste mulching recorded higher soil moisture content of 24.75, 26.12 and 27.18% at 0-15, 15-30 and 30-45 cm respectively. The lower soil moisture content of 20.01, 21.01 and 22.75 % were noticed with control.

References1.Ganesaraja, V., M.Raveendran, A.Gurusamy, S.Subbiah, T.N.Balasubrmanian and Y.S. Ramakrishna. 2001. Climate

probability estimates of Kovilpatti taluk of Southern Tamil Nadu. pp.14-15.2..Selvaraju, R., P.Subbian, A.Balasubramanian and R.Lal.1999. Land configuration and soil nutrient management options for

sustainable crop production on alfisols and vertisols of southern peninsular India. Soil and Tillage Research 52(3&4): 203-216.

Land configurations MulchingM

1- Control S

1-Control

M2- Compartmental bunding S

2- Mulching with farm wastes

M3- Ridges and furrows S

3-Dust mulching

M4-Tied ridging Sub Plot Seed treatment

M5-Broadbed and furrows SS

1-Seed treatment with cowdung slurry

SS2- Seed treatment with 2 % KCl

Treatment Details Main plot:

21

Growth Characteristics at 120 DAS Boll Seed cotton

Treatment details Plant Height LAI DMP weight yield (cm) (kg / ha) (g) (kg / ha)Land configurations

M1- Control 83.1 3.65 3147 2.49 522

M2- Compartmental bunding 89.1 5.09 4245 2.73 675

M3- Ridges and furrows 85.6 4.67 3346 2.52 573

M4-Tied ridging 86.0 4.85 3548 2.62 592

M5-Broadbed and furrows 86.9 4.95 3946 2.67 672

SEd 0.44 0.66 55.50 0.015 22

CD(P=0.05) 0.90 0.14 113.69 0.030 50

Mulching

S1-Control 82.3 4.58 3425 2.54 588

S2- Mulching with farm wastes 88.7 4.71 3856 2.69 623

S3-Dust mulching 87.4 4.63 3658 2.59 610

SEd 0.34 0.05 42.99 0.011 13

CD(P=0.05) 0.69 0.11 88.06 0.023 27

Seed treatment

SS1-Seed treatment with cowdung slurry 85.9 4.61 3568 2.60 605

SS2- Seed treatment with 2% KCl 86.3 4.67 3724 2.61 609

SEd 0.03 0.003 6.58 0.004 NS

CD (P=0.05) 0.06 0.006 13.44 0.008

Table 2. Soil moisture content Treatment details Soil moisture content (%)

0-15 cm 15-30 cm 30-45 cmLand configurations

M1- Control 20.01 21.01 22.75

M2- Compartmental bunding 26.43 31.01 33.66

M3- Ridges and furrows 22.65 24.75 25.71

M4-Tied ridging 22.05 24.92 25.85

M5-Broadbed and furrows 24.01 25.09 26.08

Mulching

S1-Control 21.03 24.32 26.25

S2- Mulching with farm wastes 24.75 26.12 27.18

S3-Dust mulching 23.32 25.60 27.05

Seed treatment

SS1-Seed treatment with cowdung slurry 23.01 25.31 26.71

SS2- Seed treatment with 2 % KCl 23.07 25.38 26.92

���

Table 1. Effect of land management practices and mulching on growth characteristics and

22

Studies on The Effect of Insitu Moisture Conservation Methods

and Integrated Nutrient Management Practices on

The Productivity of Sunflower (Helianthus Annus L.) in

Rainfed VertisolsDr.V.K.Paulpandi, Dr.V.Ganesaraja, Dr. R. Balasubramanian and M. P. KavithaDepartment of Agronomy Agricultural College and Research Institute Madurai , India

5

IntroductionIndia occupies a premier position in global

scenario accounting for 19 per cent area and 9 per cent production which has undergone a dramatic change in recent years, wherein the oil seed sector becomes a net foreign exchange earner leading to yellow revolution.

Among the oil seeds, sunflower gained importance due to its special features such as short duration, photoperiod insensitivity, drought evidence, and fast recovery for drought stress, adaptability to wide range of soil climatic conditions, lower seed rate and high seed multiplication ratio. The sunflower seeds have a high oil content (40 -50 per cent), which is a high quality cooking oil because of low saturated and high polyunsaturated fatty acids in lowering down the level of harmful serum cholesterol property (Giriraj,1988).

The major constraint for lower productivity of crops in dry land is the inadequacy of the soil moisture and poor fertility status of the soil. The land configurations are site specific and lead to a yield advantage of about 20

+ 5 per cent over control at any given level of productivity (Venkateswarlu, 1987). Appropriate land configurations such as broad bed and furrow and compartmental bunding hold great promise for insitu conservation of soil, water and plant nutrients.

The combination of organic waste like composted coirpith and chemical fertilizers plays a key role in modern dryland agriculture in increasing the productivity of crops and sustained management of soil fertility and inturn soil health.

Materials and MethodsThe field experiments were conducted at

Tamil Nadu Agricultural University, Regional Research Station (RRS), Aruppukottai, Tamil Nadu during North East monsoon season of 2001-2002 and 2002-2003 under rainfed condition. The soils of the experimental fields were medium deep, well drained, vertisol (Typic Chromusterts) with a pH of 8.5 in both the seasons. The soil was low in available N (192.5 and 171.5 kg ha-1), low in available P (7.32 and 9.0 kg ha-1) and high in

23

available K (358.7 and 300.0 kg ha-1) during 2001-2002 and 2002-2003 respectively. Sunflower variety Co 4, released by the Tamil Nadu Agricultural University was selected for this study. The experiments were laidout in split plot design with three replications.

Main plot consisted of three treatments viz,. M1-

Flat bed, M2- Compartmental bunding and M

3- Broad

bed furrow. The subplot consisted of eight treatments viz., S

1 - Recommended dose of nutrients (RDN) @

40:20:20 kg N, P2O

5 and K

2O ha-1 through inorganic

fertilizers, S2 - 100% N through composted coirpith

(CCP), S3 - Recommended dose of nutrients (RDN) as

inorganic fertilizers + 0.2% boron foliar spray at ray floret stage and 10 days after first spray, S

4 - 100% N

through CCP + 0.2% boron foliar spray at ray floret stage and 10 days after first spray, S

5 - 75% N through

inorganic fertilizer + 25% N through CCP + Azophos (seed and soil application), S

6 - 75% N through inorganic

fertilizers + 25% N through CCP + Azophos (seed and soil application) + 0.2% boron foliar spray at ray floret stage and 10 days after first spray, S

7 - 50% N through

inorganic fertilizer + 50% N through CCP + Azophos (seed and soil application) and S

8 - 50% N through

inorganic + 50% N through CCP + Azophos (seed + soil application) + 0.2% boron foliar spray at ray floret stage and 10 days after first spray.

Land management methods (insitu moisture conservation methods) were carried out in respective plots as per the treatment schedule. The plot size of 6.0 x 4.5 m was uniformly adopted for all insitu moisture conservation methods. The CCP was incorporated basally after forming land management methods but before levelling of the field. Coirpith was decomposed at RRS, Aruppukottai farm by adopting the methodology given by Nagarajan et al. (1987).

Organic manure (CCP) to substitute 100 or 50 or 25 per cent nitrogen was worked out based on N content for individual application as per treatment schedule. Recommended dose of inorganic fertilizers such as 40 kg N as urea, 20 kg P as single super phosphate and 20 kg K as muriate of potash ha-1 were applied as basal manure. Calculated quantity of organic manure to substitute 100 or 50 or 25 per cent of recommended N along with inorganic source of fertilizers as per the treatment schedule was also applied as basal. All the treatments received a uniform dose of 20 kg P

2O

5 and

20 kg K20 ha-1 as basal through inorganic fertilizers.

Azophos @ 2 kg ha-1 was mixed with 50 kg fine sand

and applied near the base of the sunflower plants at 30 DAS as per the treatment schedule. Solubor (Na

2 B

4

O7 5H

2O + Na

2 B

10 O

16. 10 H

2O) was used as boron

source. It contains 20 to 21 per cent boron. As per the treatment schedule 0.2 per cent boron was sprayed at ray floret stage and the second spray on 10 days after first spray.

Observations on all the growth and yield attributes were taken. The capitulum of border plants on all the sides of the plot were harvested first and then net plots were harvested separately and dried. Threshing of the capitulum was done manually and seeds were separated, sun dried and the yield was recorded. Data on soil moisture content was estimated by gravimetric method at 25, 45, 65 DAS and at harvest in 0-15, 15-30 and 30-45 cm depth during both the years of study.

Results and DiscussionGrowth Attributes

All the treatments exerted a distinct effect on growth attributes of sunflower (Table 1). Among insitu moisture conservation methods, sowing on broad bed and furrow (BBF) treatment (M

3) recorded the higher

plant height (156.1 cm), maximum LAI (4.27) and maximum DMP (5393 kg ha -1) at harvesting stage. (Table 1). The favourable moisture situation created in BBF might have increased more moisture and nutrient uptake by the sunflower crop with the help of increased root growth resulted in increased plant height as reported by Tumbare and Bhoite (2000). The BBF method of insitu moisture conservation could produce more DMP of 15 to 26 per cent increase over flat bed method. The reason for obtaining more DMP in BBF might be due to the availability of required moisture status.

Among integrated nutrient management practices (INM), application of 75% N through inorganic + 25% N through CCP + Azophos + 0.2% boron spray (S

6)

recorded higher plant height (155.9 cm), maximum LAI (4.45) and maximum DMP (5962 kg ha-1 ) at harvesting stage. The reason might be due to better availability of moisture with the help of CCP application which retained more quantum of moisture in the soil. The above treatment combination of inorganic and organic source with biofertilizer had a greater effect in enhancing the release of nutrients from the soil complex with the help of increased activity of beneficial microorganisms resulted in more uptake of nutrients by sunflower crop for its normal metabolic activities.

24

Soil moisture Content

Data on soil moisture content was estimated at 25, 45, 65 DAS and at harvest in 0-15, 15-30 and 30-45 cm depth during both the years of study. In general, soil moisture content increased with increase in soil depth. Among insitu moisture conservation methods, at 45 cm soil depth, BBF method (M

3) registered higher

soil moisture content of 34.2, 23.1, 16.3 and 15.1 per cent at 25, 45, 65 DAS and at harvest. (Table 2) This might be attributed due to the better collection of rain water in the furrows and absorption of rain water in the broad bed and furrow with the help of horizontal movement of water from furrow to the inner layer of broad bed and furrow during dry spell period. This type of enrichment of moisture could help to maintain the soil moisture content for better crop growth and yield in BBF. (Anon, 1981).

Regarding the nutrient management practices, 100 % N substitution (S

2) registered higher soil moisture

content of 34.5, 23.2, 16.3, 15.4 per cent at 25, 45, 65 DAS and at harvest. CCP applied at 100% N substitution recorded higher percentage of soil moisture content followed by INM practice of 50% N through inorganic + 50% N through CCP + Azophos. This might be due to higher moisture holding capacity of coirpith as reported by Ramaswami and Sree Ramulu (1983). The higher moisture retention capacity of coirpith might be due to its high carbonaceous nature (Mayalagu et al., 1983).

Yield and economics: Regarding the yield parameters and seed yield, the BBF method (M

3) resulted

in higher head diameter (14.5 cm) , increased number of filled seeds head-1 (428), seed yield (983 kg ha-1) and stalk yield (3388 kg ha-1) . (Table 3). Favourable yield attributing characters obtained in BBF was due to unrestricted moisture status in the soil for better accumulation and

translocation of assimilates from stem and leaves to sunflower head coupled with required nutrient uptake by the crop. Among different INM practices tried, application of 75% N through inorganic + 25% N through CCP + Azophos + 0.2% boron spray (S

6) registered higher head

diameter (14.9 cm) , increased number of filled seeds head-1 (446) ,seed yield (1082 kg ha-1 ) and stalk yield ( 3493 kg ha-1). In the present study the inclusion of CCP in the promising INM of 75% N through inorganic + 25% N through CCP + Azophos + 0.2% boron spray combination helped to retain more rain water in the soil to a greater extent possible and produced more seed yield of 22.1 to 26.4 per cent over RDN as inorganic fertilizer application. This finding is in conformity with the results of Kavitha and Swarajya Lakshmi (2002). An interaction effect of broad bed and furrow combined with INM practice of 75% N through inorganic + 25% N through CCP + Azophos + 0.2% boron spray registered higher seed yield of 1193 kg ha-1. The favourable maintenance of soil moisture status and nutrient availability by the incorporation of CCP in addition to biofertilizers and inorganic fertilizers application contributed to the appreciable increase in growth parameters reflected in increasing yield attributing characters. (Sivamurugan, 1998).

Higher net return (Rs.4827) and BCR (1.74) were obtained in BBF method (M

3).The net returns and

BCR were found higher under INM practices of 75% N through inorganic + 25% N through CCP + Azophos + 0.2% boron spray (S

6) which recorded the net return of

Rs 6312 and BCR of 1.87 . Profound influence of insitu moisture conservation methods for better crop growth and yield could result in improving the net returns and benefit cost ratio under BBF over compartmental bunding and flat bed methods. The results are in conformity with the findings of Senthivel (1996)

25

References1. Anonymous. (1981). Annual Report of International crop Research Institute for the Semi-Arid Tropics. Patancheru,

Hyderabad. 2. Giriraj, K., (1988). In: National Seminar on „Strategies for Making India Self reliant in Vegetable Oils‰, September

5-9, 1998. Hyderabad.3. Kavitha, P and Swarajya Lakshmi. G. 2002. J. Oilseeds Res. 19(2): 250-251.4. Mayalagu, K., et al., (1983). In: Proc. of National seminar on utilization of organic wastes. Tamil Nadu Agrl.

University, AC&RI., Madurai, 110-1165. Nagarajan, R., et al., (1987). Coirwaste in Crop Production. Bulletin unpublished, Centre for Soil and Crop

Management Studies, Tamil Nadu Agricultural University, Coimbatore and Central Coir Research Institute, Coir Board, Kalavoor.

6. Ramaswami, P.P. and Sree Ramulu.U.S. (1983). In: Proc. National Seminar on utilisation of organic wastes. (Ed.) U.S.Sree Ramulu, March 24-25 Tamil Nadu Agricultural University, Coimbatore. pp.101-103.

7. Senthivel, T. 1996. Studies on Dry seeding, Land configuration and phosphorus management on the productivity of rainfed maize in vertisol with residual effect of phosphorus on blackgram. Ph.D Thesis, TNAU, Coimbatore.

8. Sivamurugan. (1998). M.Sc.(Ag.) Thesis, Tamil Nadu Agricultural University, Coimbatore.9. Tumbare,A.D. and S.V.Bhotie. (2000). Indian J. Dryland Agric. Res. & Dev., 15: 94-95.10. Venkateswarlu, J. (1987). Adv. Soil Sci., 7: 165-221.

26

Table 1. Effect of insitu moisture conservation methods and INM practices on growth attributes of sunflower at harvesting stage (pooled data of two years)

Treatments Plant height Leaf Area Dry matter (cm) Index production (kg ha -1) Insitu moisture conservation methodsM

1 � Flat bed 139.3 3.26 4403

M2 � CB 149.7 3.97 5051

M3 � BBF 156.1 4.27 5393

SEd 3.2 0.10 91CD (P=0.05) 9.0 0.27 252INM practices

S1 � 100% RDN 147.0 3.85 4805

S2 � CCP at 100% N 135.0 3.04 3854

S3 � 100% RDN + 0.2% B 148.1 3.91 5261

S4 � CCP at 100% N + 0.2% B 135.7 3.03 4166

S5 � 75% N inorg. + 25% N CCP + Azophos 154.6 4.41 5400

S6 � 75% N inorg. + 25% N CCP + Azophos + 0.2% B 155.9 4.45 5962

S7 � 50% N inorg. + 50% N CCP + Azophos 151.0 3.99 4852

S8 � 50% N inorg. + 50% N CCP + Azophos + 0.2% B 152.1 4.02 5295

SEd 3.2 0.06 67CD (P=0.05) 6.4 0.13 136

Table 2. Effect of insitu moisture conservation methods and INM practices on soil moisture content (%) at 45 cm depth of sunflower (pooled data of two years)

Treatments 25 DAS 45 DAS 65 DAS Harvest Insitu moisture conservation methods M

1 � Flat bed 31.5 19.8 14.6 13.8

M2 � CB 33.9 22.4 16.0 14.9

M3 � BBF 34.2 23.1 16.3 15.1

SEd 0.4 0.2 0.1 0.1 CD (P=0.05) 1.2 0.7 0.3 0.3 INM practices S

1 � 100% RDN 32.1 20.2 15.0 13.9

S2 � CCP at 100% N 34.5 23.2 16.3 15.4

S3 � 100% RDN + 0.2% B 31.8 20.2 15.0 13.8

S4 � CCP at 100% N + 0.2% B 34.4 23.3 16.3 15.3

S5 � 75% N inorg. + 25% N CCP + Azophos 32.5 21.3 15.4 14.4

S6 � 75% N inorg. + 25% N CCP + Azophos + 0.2% B 33.0 21.4 15.6 14.3

S7 � 50% N inorg. + 50% N CCP + Azophos 33.5 22.3 15.8 14.9

S8 � 50% N inorg. + 50% N CCP + Azophos + 0.2% B 33.9 22.4 15.9 15.1

SEd 0.5 0.1 0.04 0.05 CD (P=0.05) 1.0 0.2 0.08 0.10

27

Table 3. Effect of insitu moisture conservation methods and INM practices on yieldattributes,yield and economics of sunflower (pooled data of two years)

Treatments Head Number Seed Stalk Net Benefit diameter of filled yield yield return cost (cm) seeds head–1 kg ha-1 kg ha-1 (Rs ha-1) ratio

M1 � Flat bed 11.2 282 772 2397 2850 1.43

M2 � CB 13.6 413 922 3173 4163 1.58

M3 � BBF 14.5 428 983 3388 4827 1.74

SEd 0.2 5 17 76 - -

CD (P=0.05) 0.6 14 46 211 - -

INM practices

S1 � 100% RDN 12.9 369 856 3122 4473 1.71

S2 � CCP at 100% N 10.9 265 685 2570 822 1.11

S3 � 100% RDN + 0.2% B 13.5 418 948 3155 5178 1.77

S4 � CCP at 100% N + 0.2% B 11.4 297 752 2599 1197 1.14

S5 � 75% N inorg. + 25% N CCP + Azophos 14.5 391 974 3451 5395 1.79

S6 � 75% N inorg. + 25% N CCP + Azophos + 0.2% B 14.9 446 1082 3493 6312 1.87

S7 � 50% N inorg. + 50% N CCP + Azophos 13.2 382 875 3182 3745 1.52

S8 � 50% N inorg. + 50% N CCP + Azophos + 0.2% B 13.6 429 967 3206 4454 1.58

SEd 0.1 3.0 10 53 - -

CD (P=0.05) 0.2 6.0 20 108 - -

28

Study on The Insitu- Moisture Conservation Practices Over

Rain Fed Cotton in Vertisols of Southern Region of Tamil Nadu

T. Ragavan, N. S. Venkataraman, T. Saravanan and S. SomasundaramAgricultural Research Station, Kovilpatti, Tamil Nadu-628 501.

6

IntroductionDry farming is the practice of crop production

entirely with rain water received during crop season or on conserved soil moisture in low rainfall areas. In-situ moisture conservation practices not only reduce the run-off, soil and nutrient losses but also improve soil physical properties, nutrient status and moisture content, there by improving and sustaining the crop yields. Adequate availability of conserved moisture through various in situ moisture conservation practices helps in improving the crop growth and productivity. Cotton is an important commercial crop grown under black cotton soils under semi arid region in Tamil Nadu. For upholding the productivity of rainfed crops sowing time is an important parameter under rainfed condition, where in crop growth is decided by the environment. Even under optimum conditions small variations in temperature influenced the growth and development of crops (Bishnoi, 2002). There is limited information on the effect of insitu moisture conservation practices under varied sowing windows under rainfed vertisol condition.

Hence an experiment was conducted to study the sowing time, land management and cultivars interaction under rainfed vertisol condition.

Materials and MethodsThe Field experiment was conducted at

Agricultural Research Station, Kovilpatti under rainfed vertisol condition for the two consecutive years from 2003 and 2004 at during North East Monsoon season. The study was aimed to determine the effect of in-situ moisture conservation practices under varied time for sowings with different cultivars on the yield components and yield of rainfed cotton. The soil of the experimental site was vertisol (Typic Chromusterts) with PH of 8.1. The soil is low in available N and P, high in K. The soil organic content of the soil was 0.37. The soil texture is clayey having the bulk density of 1.27 kg/m3 with field capacity of 35 per cent and permanent wilting point of 14 per cent. In the experiment, in situ moisture conservation practices viz., flat beds of size 8x5 m and the broad bed and furrows at 150 cm were formed with

29

bund former and tractor drawn broad bed and furrow former respectively. The different dates of sowing

namely, pre monsoon (39th standard week), monsoon (41st standard week) and late monsoon (43rd standard week) period with cotton cultivars KC 2, SVPR 2 and K11 were tried. The sowing was taken by the hand dibbling method and the recommended fertilizers @ 40:20:0 kg NPK ha-1 was applied as basal with adequate soil moisture. The experiment was laid out in split-split plot design with three replications. The recommended package of management technologies were followed for the crop. The rain fed region of this tract experiences with annual rainfall of 721 mm and seasonal rainfall during North East Monsoon of 385 mm received in 27 rainy days. The rainfall during the crop growing season was 317.5 mm and 458.5 mm during NEM season of 2003 and 2004 respectively.

Results and DiscussionEffect of Sowing Dates

The cotton crop sown under different dates of sowing exerted significant variation in the growth, yield attributes and kapas yield of cotton (Table.1). The plant height, number of sympodial branches, bolls per plant and kapas yield of cotton was significantly higher at pre monsoon sown crop followed by monsoon sown. The late monsoon sown crop registered lesser values of these attributes. The boll weight was higher at premonsoon sown cotton and it was comparable with monsoon sown crop and significantly superior to the late sown. The higher yield attributes and kapas yield under premonsoon crop might be due to the crop utilized the entire rainfall of 336.5 and 458.5 mm during crop growth period respectively of 2003 and 2004 received during 39th std week to 8th std week. More over the premonsoon shower with subsequent rainfall favoured the better establishment, initial vigour of the crop and good growth development of the crop. Where as the monsoon and late monsoon sown crops utilized the rainfall of 271.7, 225 mm and 363.9, 267.7mm respectively of 2003 and 2004. The delayed sowing reduced the plant growth and yield attributes due to lesser biomass accumulation. This is in conformity with the findings of Raj Singh et al (2002).

Effect of Moisture Conservation Practices

The insitu-moisture conservation practices in rainfed vertisols exerted significant influence on the growth, yield attributes and kapas yield of cotton. In the pooled data, the kapas yield of cotton was increased significantly by 62.2 per cent with the formation of flat bed and further yield was doubled with broad bed and furrow compared with control (5.38 Q/ha). Insitu-moisture conservation measures improved soil moisture in 0-15, 15-30 and 30-60 cm soil depths from sowing to till harvest, especially with broad bed and furrow system causing the difference in yield in the present study (Table 2). Patil and Sheelavantar (2000) observed that the increase of crop yields due to the formation of insitu moisture conservation practices viz, broad bed and furrow and flat bed over the control. The reason for increased yield was mainly due to the higher availability of moisture (Fig.1). Higher number of sympodial branches, boll numbers (10.4) and boll weight (3.89) were significantly higher with broad bed and furrow compared to flat bed system of moisture conservation. Higher yields with adoption of insitu moisture conservation measures are also reported by Velayudam et al (1997).

Effect of Cultivars

The performance of different cultivars under moisture conservation practices in rainfed vertisols showed that the cultivar KC 3 and SVPR 2 were performed significantly better than the K11. This might be due to the genetic potentiality of the cultivars tried under moisture conservation practices. More over, KC 2 and SVPR 2 were derivative from the Combodia type of cotton, and K11 is the derivative of Hirsutum type. The hirsutum type of cultivar is desi cotton type with prolified root system, highly resistant to drought and comparatively less yielder than the combodia type. However the moisture conservation practices with pre monsoon sowing favoured the better development of growth, yield attributes and kapas yield of cotton.

From the experimental results it was concluded that the premonsoon sowing of combodia type of cotton cultivars with insitu moisture conservation practices of broad bed and furrow system under vertisol condition was found to give higher kapas yield of rainfed cotton.

30

References1. Bishnoi, O .P, 2002 .Impact of meteorological variables on the growth and development of wheat varieties. J. of

Agrometeorology.4(1):9-15.2. Patil,S.L. and M.N. Sheelavantar.2000. Yield and yield components of rabi sorghum as influenced by insitu moisture

conservation practices and integrated nutrient management in vertisols of semi-arid tropics of Indian. Indian J.of Agronomy, 45(1): 132-137.

3. Raj Singh,V.U.M.Rao and Diwan Singh.2002. Biomass partionting in Brassica as affected by sowing dates. J. of Agrometeorology.4(1):59-63.

4. Velayudham, K.,Rajendran.P and S.Krishnaswamy.1997. Field evaluation of insitu moisture conservation practice. Madras Agric.Journal, 84(2):80-82.

31

Table 1. Effect of in-situ moisture conservation practices underdifferent time of sowing in rain fed vertisol condition.

Treatments Plant No. of No. of Boll Kapas height sympodial bolls / weight yield (cm) branches plant (cm) (kg/ha)Premonsoon sown 84.5 9.2 12.4 3.93 8.59

Monsoon sown 76.4 8.4 10.6 3.72 6.28

Late monsoon sown 64.2 5.4 6.8 2.54 3.76

SEd 2.71 0.35 0.47 0.28 0.84

CD(0.05) 5.60 0.72 0.96 0.55 1.72

Flat bed 77.8 8.4 9.2 3.56 6.68

BBF 72.1 9.3 10.4 3.89 8.27

Control 61.5 6.1 6.8 3.14 4.38

SEd 1.72 0.26 0.34 0.09 0.46

CD(0.05) 3.58 0.54 0.86 0.18 0.91

KC 2 76.4 9.7 11.2 3.98 7.79

SVPR 2 81.3 10.2 14.4 4.21 8.82

K 11 113.8 11.7 8.3 2.43 3.54

SEd 2.08 0.32 0.67 0.15 0.54

CD(0.05) 4.22 0.66 1.18 0.32 1.05

Table.2.Effect of insitu moisture conservation practices on the soil moisture contentat different depths under rainfed vertisol condition.

Soil depth (cm) 0-15 15-30 30-60

Growth stages Flat bed BBF Flat bed BBF Flat bed BBF

Germination 29.7 32.98 29.4 31.9 28.53 30.35

Vegetative 29.4 35.04 31.1 35.02 33.5 35.73

Flowering 23.24 30.46 25.94 30.4 31.2 30.64

Maturity 15.05 17.12 18.53 19.32 21.08 19.78

Mean 24.35 28.9 26.24 29.16 28.58 29.13

Fig. 1. Effect of insitu moisture conservation practices on the soilmoisture content under rainfed vertisol condition.

���

32

Influence of Tillage, Land Treatment and Organic Residue Management on Soil Health and

Yield of Cotton in a Vertisol under Dry Farming

S. Suresh and D. Jawahar*Krishi Vigyan Kendra, Tamil Nadu Agricultural University, Pechiparai � 629 161 Tamil Nadu

7

IntroductionIn southern Tamil Nadu more than 70% of the

area is rainfed. The Kovilpatti region is a representative of typical dryland and cotton is grown in Vertisols. The climate of the region is semi-arid with uneven and erratic distribution of rainfall. The mean annual

*AC&RI, Tamil Nadu Agricultural University, Killikulam rainfall is less 700 mm. Cotton area and productivity have been shrinking over years mainly due to soil degradation (Muthuvel et. al., 1989). Management practices for improving soil health are required for sustaining the cotton productivity of the region.

Materials and MethodsField experiments were conducted during Rabi

(October to February) season of 2001-2002 and 2003-2004 with the following treatments to assess the tillage requirement and land configuration in order to improve the soil health and productivity of cotton under dry farming in a Vertisol. The initial soil characteristics were pH-8.1, EC-0.8 dS/m, available KMnO

4-N 121 kg/ha,

available Olsens- P 8.6 kg/ha and available N NH4OAc-K

423 kg/ha. The treatment details are as follows.

Treatment Details

Tr. No. Treatment Details

T1 Conventional Tillage (CT)

T2 CT+Broad Bed Furrow System (BBF)

T3 Reduced Tillage(RT)+BBF +Green Manure(GM)

T4 RT+BBF +GM+ ZnSO

4

CT- Conventional tillage, RT- Reduced Tillage, BBF- Broad Bed Furrow and GM- Green Manure

In CT - one disc ploughing and two tiller ploughing, RT - one disc ploughing and one tiller ploughing with application of pre-emergence herbicide viz., fluchloralin @ 3.3 l /ha. The BBF was made as 100 cm wide flat bed and 50 cm wide furrows. The green manure crop cowpea (C 152) was grown between two rows of cotton and incorporated at 35-40 days after sowing. The Recommended Dose of Fertilizer namely 40:20:0 kg/ha of N: P: K was applied as common dose

33

for all the treatments.The ZnSO4 was applied @ 25

kg/ha. The test crop Cotton variety KC2 was raised. The experiment was conducted in Randomized Block Design in10 farm holdings as the replications. The crop was protected from pest and diseases by adopting need based plant protection measures.

ResultsYield of seed cotton

The pooled analysis results revealed that the reduced tillage combined with BBF system and ZnSO

4 @

25 kg/ha along with cow pea green manure incorporation recorded the highest plant height (53.8 cm), number of branches/plant (11.6), number of bolls/plant (7.7), number of squares/plant (6.1) and seed cotton yield (754 kg/ha) (table 1). The favourable effect of green manure application on the improvement in the nutrients availability, physical properties and root establishment was reported by Anon, 2000. Further the soil is inherently deficient in DTPA-extractable zinc. The calcareous nature further induced more Zn deficiency in the soil. Therefore

extraneous application of zinc further enhanced the yield of cotton. The reduced tillage and the broad bed furrow system favoured moisture conservation by way of water harvesting and build up of the soil structure as stated by Muthuvel et. al. (1989).The incorporation of green manure increased the soil organic carbon content (0.58 per cent) to a marginal extent and the porosity of the soil (49.1 per cent) to a marginal extent.

Residual Soil Characteristics

Reduced tillage combined with BBF system and ZnSO

4 @ 25 kg/ha along with cow pea green manure

incorporation recorded highest residual soil KMnO4-N

(140 kg/ha), highest residual soil Olsens- P (9.4 kg/ha) and highest residual soil NNH

4OAc- K (444 kg/ha)

than other treatments. This highlighted the favourable influence of these treatments in sustaining the soil fertility status.

ConclusionFrom the above study, it can be concluded

that the reduced tillage of one disc followed by tiller ploughing combined with BBF system and application of recommended dose of fertilizers along with ZnSO

4

@ 25 kg/ha and green manure incorporation recorded highest plant height, number of branches/plant, number of bolls/ plant and seed cotton yield. The above treatment sustained soil health and fertility and also recorded higher B:C ratio. Therefore the reduced tillage of one disc followed by tiller ploughing combined with BBF system and application of recommended dose of fertilizers along with ZnSO

4 @ 25 kg/ha and green

manure incorporation imperative for sustaining the soil health and yield of cotton under dry farming.

Table 1. Effect of treatments on the biometric characteristics, yield of cotton and soil properties

Treat- ments Plant Branch/ Bolls/ Squares/ Seed KMnO4N Olsen-P NN Org. B:C

height plant plant plant cotton kg/ha NH4OAc- C ratio

(cm) yield K (%) (kg/ha)

CT 48.2 9.5 5.9 4.2 606 123 8.2 425 0.55 1.32

CT+BBF 52.5 6.3 6.9 5.3 685 128 8.5 429 0.55 1.47

RT+BBF +GM 53.3 11.5 7.3 5.9 737 137 9.2 437 0.58 1.50

RT+BBF +GM+ ZnSO4 53.8 11.6 7.7 6.1 754 140 9.4 444 0.58 1.48

SEd 0.47 0.2 0.1 0.1 6.3 1.2 0.1 1.4 0.003

CD (0.05) 0.95 0.4 0.2 0.2 13 2.3 0.2 2.8 0.006

34

ReferencesAnonymous 2000 Annual Report of All India Coordinated Research Project, CRIDA, Hyderabad.Muthuvel, P., Pallikondaperumal, R.K, Sivasamy, R., Subramanian, V and Sree Ramulu, U.S. 1989. Soil fertility under

continuous cropping of cotton- pearl millet in dryland vertisol. Madras Agric. J 76 (4): 189-191.

���

35

Effect of In-Situ Moisture Conservation and Nitrogen Management in Dry Land

Agroforestry SystemsS. Radhamani and P. Subbian, Department of Agronomy Tamil Nadu Agricultural University

8

IntroductionRainfall is the major deciding factor for the

success of crop production in dry lands. Even the rainfall is fairly high, it is often wasted as runoff, percolation and evaporation. It is necessary to maximize its retention in soil and consumed by the crops. The major focus should be to improve the surface infiltration and retention of soil moisture within the root zone. Present farming systems under dry lands are characterised by low and unpredictable yield due to inefficient use of rainfall, rare use of fertilizers, non inclusion of high yielding varieties and lack of improved soil conservation (Pathak and Laryea, 1995). Efficient resource management including insitu conservation of moisture, crop production technologies, nutrient management and alternate land use systems are the key issues to increase the productivity of the dryland areas. In drylands, agroforestry is an important option to enhance the productivity by utilizing the off-season rainfall and as an alternate land use system adopted to replace or modify the traditional land use (Singh and Osman, 1995). For providing stability and sustainability

to the farming system, combining perennial trees with seasonal crops would be more appropriate. A study was hence carried out to identify the efficiency of this system for the rainfed agro-ecosystem of Tamil Nadu.

Maerials and MethodsField experiments were conducted at Research

Farm, Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore during North East monsoon seasons of 1999 and 2000. The soil of the experimental site was vertisol having low available nitrogen (147 kg ha-1), medium available phosphorus (137 kg ha-1 ) and high available potassium (432 kg ha-1). The pH of the soil was 7.9 with an EC of 0.37 d Sm-1. Amount of rainfall received during the North East Monsoon seasons of the years 1999 and 2000 were 422.6 and 291.2 mm, respectively. The cropping systems studied were grain sorghum (CO 26) + cowpea (CO 4), fodder sorghum (CO 27) + cowpea (CO 4) and Cenchrus glaucus. The experiment was laid out in split plot design with three replications. The main plot treatments comprised of tree

36

species viz., Ailanthus excelsa(T1), Ceiba pen tandra (T

2)

and Emblica officinalis (T3) and moisture conservation

practices viz., Tied ridges(M1) and Flat bed (M

2). Sub

plot treatments consisted of nutrient management practices viz:,100 per cent N through fertilizer(N

1)

and 50 per cent N through fertilizer + 50 per cent N through goat manure(N

2). Tree seedlings were planted

well in advance during the North East Monsoon of 1998 for establishment. Crops were grown as intercrops in between the tree seedlings during North East Monsoon seasons of 1999 and 2000. Tied ridges were formed at third week after germination of the seeds as per the treatments. Recommended fertilizer schedule of 40 : 20 kg N and P ha-1 was adopted. Goat manure was applied basally on equal N basis and incorporated as per the treatments assigned. Productivity in terms of grain and fodder yields were recorded and converted into sorghum fodder equivalent yield and expressed as tones per ha.

RESULTS AND DISCUSSIONSoil Moisture Status

Higher soil moisture content was recorded with E.officinalis than other tree species in all the cropping systems. This might be due to less competition among the plants and E.officinalis for moisture. Lower available soil moisture was recorded with C.pentandra which might have utilized more moisture for its growth and produced higher basal diameter with compact crown. Odhiambo et al. (1999) reported that 60 and 55 per cent of the root biomass of Gliricidia and Grevillea was within the top 30 cm of soil.

Soil moisture content was higher under tied ridges than flatbed sowing during first year. Less runoff and more opportunity time for infiltration might have favoured the better infiltration of water into the deeper soil layers which in turn increased the soil moisture status under this treatment. During the second year, due to non receipt of adequate rainfall after the formation of tied ridges, not much variation between the moisture conservation practices was recorded. Kolekar et al. (1998) also reported that tied ridges recorded higher moisture content and increased the crop yield. Application of goat manure along with inorganic fertilizer conserved higher soil moisture throughout the crop period due to high water holding capacity of soil which caused increase in absorption and retention of rain water. This might have reduced the bulk density of soil and increased infiltration rate and hydraulic conductivity, and hence improving water holding capacity of the soil (Sugandaraj,1990).

Crop and Soil Nutrient Studies

The increased total nutrient uptake of the crops with E.officinalis might be attributed to less competition between the tree and crop component as compared to other tree species. Higher total nutrient uptake in sorghum + cowpea cropping systems was recorded with tied ridges than flat sowing during first year. The possible reason might be the availability of higher moisture during all the growth stages which in turn increased the uptake of nutrients by sorghum and cowpea. Shaikh et al. (1995) reported that total N and P uptake were higher with ridges and furrow sowing as compared to normal sowing in rainfed pearl millet. Bhan et al. (1998) also reported that ridging and furrowing increased the N uptake of rainfed sorghum. Non receipt of rainfall after the formation of tied ridges and also inadequate soil moisture at critical growth stages of the crop might have reduced the uptake of nutrients which in turn reduced total nutrient uptake during second year.

The nutrient uptake was increased with application of 50 per cent N through fertilizer and 50 per cent N through goat manure. Higher nutrient uptake might be due to continuous and steady availability of nutrients due to chelation effect of organic acids released during decomposition of organic matter (Tomar et al., 1984). The addition of basal dose of N along with goat manure could have narrowed down the C:N ratio and increased the N availability as reported by Hofman et al. (1986). Higher P uptake might be due to availability of moisture and better root growth created by application of goat manure. Increased P uptake coupled with N uptake in sorghum plant was already reported by Roy and Wright (1974). Increased P uptake was attributed to the increased solubilisation of insoluble P fraction during humification and reduced P fixation in the soil particles due to the protective action of manure by releasing organic acids during the decomposition. Increased uptake of N and P might have helped to extract more K from the soil resulting in higher K uptake under the application of goat manure.

Higher post harvest soil available nutrients with E.officinalis as compared to other tree species might be due to less removal of nutrients with this tree component. Inclusion of cowpea with sorghum recorded higher available N, P and K content of the soil which might be due to the legume which fixes atmospheric nitrogen in the soil. Improvement in the soil N and K status was observed with the combined application of

37

organic and inorganic sources. The magnitude of loss of P was lowered with the application of goat manure to supply 50 per cent of the recommended N as compared to 100 per cent N through inorganic fertilizer alone. Less gain under inorganic source might be due to loss of N by volatilization.

Productivity of The Cropping Systems

The total drymatter production (DMP) and sorghum fodder equivalent yield of the grain sorghum + cowpea and fodder sorghum + cowpea systems were higher with E. officinalis with tied ridges and application of 50 per cent N through inorganic fertilizer and 50 per cent N through goat manure in both the years (Table 1). The tree species and moisture conservation practices had no significant influence on the total DMP and sorghum fodder equivalent yield of C. glaucus in both the years. Among the N management practices, application of 50 per cent N through inorganic fertilizer and 50 per cent N through goat manure recorded the highest total DMP and sorghum fodder equivalent yield of C. glaucus in both the years.

Among the three systems tried, higher sorghum fodder equivalent yield was recorded with grain sorghum + cowpea as compared to fodder sorghum + cowpea and C. glaucus . This was due to higher market value for grain than the fodder. Due to adequate supply of moisture through rainfall sorghum fodder equivalent yield was higher during 1999. Crops grown with E. officinalis recorded higher sorghum fodder equivalent yield. The possible reason might be due to less competition posed by E. officinalis than other trees. Similarly higher sorghum fodder equivalent yield recorded under tied ridges and application of 50 per cent through inorganic N and 50 per cent N through goat manure which might be due to adequate moisture and nutrient supply. Arya

et al. (2000) also reported that higher sorghum grain equivalent yield was obtained with combined application of both organic and inorganic source of nutrients.

Economic Analysis

The highest net return (Rs.7385) and B:C ratio (2.18) were obtained under grain sorghum with cowpea intercropped under tied ridges with application of 50 per cent N through fertilizer and 50 per cent N through goat manure during the year 1999. Similar results were earlier reported by Balasubramanian et al. (1982) who reported that sorghum intercropped with two rows of cowpea under paired row system gave the highest net return. This was followed by fodder sorghum + cowpea, which produced higher net return (Rs.1554) and B : C ratio (1.40) with the above treatment. Whereas during the year 2000, due to inadequate rainfall and soil moisture during reproductive and maturity phases the grain yield was reduced in the grain sorghum + cowpea system which in turn reduced the net return and B: C ratio (Table 2). With less amount of rainfall the grass system produced higher yield and net return during the year 2000.

From the above study it could be inferred that less competition posed by Emblica officinalis and improved moisture status of the soil under tied ridges along with combined application of organic manure and inorganic fertilizer under grain sorghum + cowpea system which utilized the resources in a better way and produced higher grain yield during first year, which in turn increased the gross return, net return and B: C ratio. Even with less rainfall, grass produced substantial yield and also due to less cost of cultivation the Cenchrus glaucus system recorded higher gross return, net return and B: C ratio during second year as compared to grain or fodder sorghum with cowpea as an intercrop.

38

References1. Arya, R.L., K.P.Niranjan, A.Singh and J.B.Singh. 2000. Production potential and sustainability of food-fodder alley

cropping system under rainfed conditions. Indian J. Agric. Sci., 70(2): 73-76.2. Balasubramanian, A., K.V.Selvaraj, M.N.Prasad and O.Thangavelu. 1982. Intercropping studies in dryland sorghum.

Sorghum Newsletter, 25: 45. 3. Bhan, S., S.K.Uttam and Radhey Shyam. 1998. Effect of moisture conservation practices and nitrogen levels on

jowar (Sorghum bicolor L.) under rainfed condition. Bhartiya Krishi Anusandhan Partrika, 13(3/4) : 93-99.4. Hofman, G., C.Ossemerct, G.Ide and M.Vanruymbeke. 1986. Nitrogen study from soil types with various organic

matter treatments. Plant and Soil, 91(3) : 411-415.5. Kolekar, P.T., N.K.Umrani and D.V.Indi. 1998. Effect of moisture conservation techniques and nitrogen on growth

and yield of rainfed rabi sorghum. J. Maharashtra Agric. Univ., 23(1): 26-28.6. Odhiambo,H.O., C.K.Ong, J.Wilson, J.D.Deans, J.Broadhead and C.Black. 1999. Tree crop interactions for below

ground resources in drylands: Root structure and function. Ann. Arid Zone, 38 (3) : 221-237.7. Pathak, P. and K.B.Laryea. 1995. Soil and water conservation in the Indian SAT; Principles and improved practices.

In: Sustainable development of dryland agriculture in India. (Ed.) R.P.Singh, Scientific Publishers, Jodhpur, p. 83-92.

8. Roy, R.N. and B.C.Wright. 1974. Sorghum growth and nutrient uptake in relation to soil fertility and NPK uptake pattern by various plant parts. Agron. J., 66(1) : 5-10.

9. Shaikh, A.A., A.S.Jadhav and M.J.Wallamwar. 1995. Effects of planting methods, mulching and fertilizers on yield and uptake of rainfed millet. J.Maharashtra Agri. Univ., 20(1) : 146-147.

10. Singh, R.P. and M. Osman. 1995. Alternative land use systems for drylands. In: Sustainable development of dryland agriculture in India. (Ed.) R.P.Singh, Scientific Publishers, Jodhpur, p.375-398.

11. Sugandaraj, S. 1990. Evaluation of sorghum based cropping system and its nutrient requirement for rainfed vertisols. M.Sc (Ag.) Thesis, Tamil Nadu Agri. Univ., Coimbatore.

12. Tomar, N.K., S.S.Khanna and A.P.Gupta. 1984. Evaluation of rock phosphate � superphosphate mixtures by incubation in orgnaic matter for efficient use in wheat. Fert. News, 29(5) : 37-38.

39

Table 2. Economic analysis (Rs ha-1) of the cropping systems (1999 and 2000)

Treatment 1999 2000 Sorghum + cowpea Sorghum + cowpea Cenchrus glaucus Sorghum + cowpea Sorghum + cowpea Cenchrus glaucus (grain) (fodder) (grain) (fodder)

Net B:C Net B:C Net B:C Net B:C Net B:C Net B:C return ratio return ratio return ratio return ratio return ratio return ratio

T1M

1N

1 4442 1.69 904 1.22 687 1.18 -2539 0.61 -1026 0.75 759 1.26

M1N

2 6900 2.10 1216 1.31 1163 1.32 -2037 0.67 -694 0.82 1217 1.43

M2N

1 3891 1.62 858 1.22 933 1.27 -2296 0.63 -849 0.78 941 1.35

M2N

2 5778 1.94 1152 1.31 1392 1.41 -1775 0.70 -473 0.87 1448 1.57

T2M

1N

1 3495 1.54 529 1.13 676 1.18 -2307 0.64 -1037 0.75 744 1.26

M1N

2 5593 1.89 1294 1.33 1160 1.32 -1933 0.69 -767 0.80 1183 1.43

M2N

1 2712 1.44 549 1.14 870 1.25 -2070 0.67 -829 0.79 948 1.35

M2N

2 4110 1.68 735 1.20 1356 1.40 -1634 0.73 -514 0.86 1406 1.55

T3M

1N

1 4276 1.66 757 1.18 647 1.17 -1804 0.72 -540 0.87 721 1.25

M1N

2 7385 2.18 1554 1.40 1156 1.32 -1485 0.76 -167 0.96 1270 1.46

M2N

1 4125 1.66 456 1.12 864 1.25 -1531 0.75 -329 0.92 957 1.36

M2N

2 5253 1.87 1005 1.27 1363 1.40 -1651 0.73 -297 0.92 1411 1.55

Table 1. Sorghum fodder equivalent yield (t ha-1) of the cropping systems

Treatment Sorghum + cowpea Sorghum + cowpea Cenchrus glaucus (grain) (fodder)

1999 2000 1999 2000 1999 2000

T1 27.3 9.7 11.8 7.5 11.0 9.1

T2 24.3 10.1 11.2 7.5 10.9 9.1

T3 27.3 11.4 11.6 8.7 10.9 9.1

CD at 5% 1.76 0.53 NS 0.40 NS NS

M1 27.8 10.4 12.1 7.9 10.9 9.1

M2 24.8 10.4 10.9 7.9 10.9 9.1

CD at 5% 1.40 NS 0.75 NS NS NS

N1 24.2 10.1 11.2 7.7 10.5 8.7

N2 28.5 10.7 11.9 8.1 11.4 9.5

CD at 5% 1.59 0.48 0.61 0.31 0.59 0.26

40

Effect of Moisture Conservation and Watering On Growth of

Tree Seedlings under Drylands S. Radhamani and P. Subbian , Department of Agronomy, TNAU, Coimbatore.

9

IntroductionAgro forestry is a part of alternate land use

system which encompasses all techniques that attempt to establish or maintain trees and agricultural production on the same piece of land. For providing stability and sustainability to the farming system, tree cum crop farming will be the most appropriate one. Deficiency of moisture and extremes of temperature in arid and semiarid condition adversely affect the early growth and establishment of trees. The percolated water during the rainy season is not used by the trees in their early establishment. Application of mulching material on the soil surface increases the moisture availability and growth of tree seedlings (Shukla, 1998). Coir pith, a waste from the coir industry, having less economic value and high water holding capacity, can be used as a mulching martial. Pitcher irrigation is a technique of growing plants using small amount of water with earthern pots buried in the soil. According to Chauhan et al (1999), the water loss was found negligible in pitcher method of irrigation. Hence, a study was carried out to evaluate

the practices to increase the moisture availability and for checking evaporation losses for efficient utilization of moisture for the establishment of tree seedlings under dry land.

Materials and MethodsField experiments were conducted at

Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore during 1999 and 2000 to evaluate techniques suitable for the establishment and growth of tree seedlings under drylands. The soil of the experimental site was vertisol having low available nitrogen (147 kg ha-1), medium available phosphorus (137 kg ha�1 ) and high available potassium (432 kg ha-1). The pH of the soil was 7.9 with an EC of 0.37 d Sm�1. The experiment was laid out in split plot design with nine replications. The main plot treatments consisted of tree species viz., Ailanthus excelsa (T

1), Ceiba pentandra

(T2) and Emblica officinalis (T

3) and sub plot treatments

consisted of mulching viz., mulching with coir pith (M

1) and without mulching (M

2) and watering methods

41

viz., pitcher irrigation (P1) and control (P

2). One year

old tree seedlings were planted during the North East Monsoon season of 1998. The total rainfall received during 1999 and 2000 were 536.4 and 557.7mm, respectively. Among the total rainfall, 54.3 and 20.0 mm of rainfall was received during summer 1999 and 2000, respectively. During the Summer, weeding was done around the trees and the treatments were imposed. Pitcher pots having 5 lit capacity were installed as per the treatments, 15 cm from the base of the seedlings in the first year of establishment during Summer. Coir pith was applied 50 cm diameter around the trees at the rate of 5 kg as per the treatments assigned. The pitcher pots were filled after draining the entire water once in a week. A common watering was done to all the seedlings once in 15 days in order to maintain the population. Soil moisture content was estimated gravimetrically and soil temperature was recorded at 15 and 30cm depth before filling the pots.

Results and DiscussionSoil Moisture

The soil moisture content was varying among the tree species. E. officinalis recorded higher soil moisture content than A. excelsa and C. pentandra . Mulching with coir pith recorded higher soil moisture content than without mulching in both the seasons. With regard to watering, soil moisture content was higher in pitcher as compared to without pitcher irrigation. Among the different depths, the soil moisture content was higher in 15-30 cm depth than 0-15 cm depth in both the seasons(Table 1). According to Subramanian and George (1998) soil moisture in the coir pith mulched plot remained higher than control and the fall in moisture per cent was also gradual in mulched plots.

Soil Temperature

There was noticeable difference in the soil temperature between coirpith mulched and unmulched treatments. Coirpith mulching recorded lesser soil temperature than without mulching. The soil temperature was less in 30cm depth as compared to 15cm depth.

Reduction in soil temperature through the application of coir pith was also reported by Singh and Prasad (1993), who recorded 0.5oC to 6oC reduction in soil temperature in coir pith mulching. With regard to watering, pitcher irrigation recorded lesser soil temperature than control.

Growth of Tree Seedlings

The growth of trees was better with moisture conservation and pitcher irrigation as compared to control during Summer. Among the trees, the E. officinalis recorded greater increment in height as compared to C. pentandra and A. excelsa in all the seasons. With coir pith mulching and pitcher irrigation, the increment in height as well as basal diameter was greater with E. officinalis than other tree species during Summer(Table 2). This indicated the better response of E. officinalis for the mulching and pitcher irrigation. Results are in accordance with the findings of Solanki et al. (1999) who reported better growth of E. officinalis with various in situ moisture conservation techniques.

Increased height and basal diameter with pitcher irrigation might be due to higher moisture availability at the root zone which in turn helped in efficient utilization of the applied water by reduced water loss through evaporation. Similar views were also reported by Chauhan et al. (1999). Narvane and Desai (1989) also reported that the plant height, stem girth and leaf area of mango saplings were highest with sub soil irrigation though pitcher. The highest tree seedling height and basal diameter with application of coir pith mulching might be due to higher soil moisture content and lower soil temperature which would have created favorable environment in the root zone, in turn increasing the growth of the tree seedlings.

From the above study it could be inferred that coirpith mulching with pitcher irrigation produced better growth of tree seedlings and among the trees E. officinalis had better response to mulching and pitcher irrigation than C. pentandra and A. excelsa under dryland situation.

42

References1. Chauhan, V., R.A.Singhania, S.K.Singh and Ashok Kumar. 1999. Impact of saline water by pitcher method on

chillies production � A study. Indian J. Agric. Res., 33(1): 62-66.2. Narvane, S.M. and U.T.Desai. 1989. Influence of irrigation methods and mulching on the establishment of mango

saplings. J. Maharashtra Agric. Univ., 14(3) : 381-383.3. Shukla, S.K. 1998. Tips to grow aonla in red soil. The Hindu, 10-12-98.4. Singh, S.B. and K.G.Prasad.1993. Use of mulches in dryland afforestation programme. In: Afforestation of arid

lands. (Eds.) A.P.Dwivedi and G.N. Gupta. Scientific Publishers, Jodhpur,P.181-190.5. Solanki, K.R., R. Newaj, S.K.Shukla, A.K.Bisaria, A.K.Handa, Ajit and Anil Kumar. 1999. Performance of Aonla

in agroforestry with application of root management and moisture conservation technique. Annual Report, NRCA, p.47-48.

6. Subramanian, V. and M.George. 1998. Retain soil moisture with coir pith. The Hindu, 11-06-1998.

43

Table 1. Effect of treatments on soil moisture content (per cent) (Summer 1999 and 2000)

Treatment Summer 1999 Summer 2000

0-15cm 15-30 cm 0-15cm 15-30 cm

March April May March April May March April May March April May

T1M

1P

1 13.32 16.91 14.32 18.80 17.25 18.61 15.63 11.08 11.38 15.80 11.27 11.45

P2 11.94 12.39 11.42 16.90 16.51 16.32 13.10 10.86 10.96 13.52 10.94 10.99

M2P

1 12.15 16.70 13.14 18.08 17.32 18.44 14.81 11.05 11.18 14.91 11.17 11.24

P2 10.43 10.50 10.33 16.89 16.40 16.41 11.52 10.53 10.38 12.31 10.61 10.43

T2M

1P

1 13.80 15.00 14.70 19.52 18.94 20.01 15.13 11.02 11.85 15.33 11.69 12.32

P2 10.73 11.00 11.35 15.91 15.75 16.14 12.82 10.88 10.73 12.90 11.37 12.14

M2P

1 11.61 12.43 12.11 17.90 17.03 19.72 14.54 10.96 11.60 14.91 11.65 12.31

P2 10.62 10.91 10.83 15.92 15.81 15.90 11.30 10.67 10.52 11.42 10.91 10.74

T3M

1P

1 14.95 16.34 16.02 18.80 19.23 20.00 15.83 13.90 11.96 16.11 18.99 12.58

P2 11.50 10.81 10.90 16.01 16.16 16.03 13.22 12.59 10.40 14.02 13.83 11.89

M2P

1 12.09 13.72 12.81 17.14 18.42 19.60 14.71 13.71 11.58 14.15 13.92 12.29

P2 10.91 10.63 10.83 15.92 15.85 15.90 11.44 10.70 10.01 11.52 11.50 10.80

Table 2. Effect of treatments on height (cm) and basal diameter (cm) of tree seedlings (Summer 1999 and 2000)

Height (cm) Basal diameter (cm)

Summer 1999 Summer 2000 Summer 1999 Summer 2000

Treatment 7 months 9 months Increase 19 months 21 months Increase 7 months 9 months Increase 19 months 21 months Increase after after in height after after in height after after in dia after after in dia planting planting (cm) planting planting (cm) planting planting (cm) planting planting (cm)

T1 33.2 40.7 7.5 78.5 85.3 6.8 1.60 1.83 0.23 3.58 3.87 0.29

T2 46.3 54.2 7.9 129.3 137.8 8.5 1.57 1.72 0.15 4.83 5.06 0.23

T3 72.2 88.8 16.6 211.8 227.0 15.2 1.10 1.62 0.52 3.56 3.96 0.40

SEd 0.29 0.34 0.32 0.51 0.02 0.02 0.02 0.02

CD (P=0.05) 0.61 0.72 0.68 1.09 0.04 0.03 0.05 0.04

M1 51.1 61.9 11.3 148.8 163.6 14.8 1.47 1.80 0.37 4.38 4.75 0.37

M2 50.0 60.5 10.0 130.9 136.4 5.5 1.37 1.65 0.24 3.60 3.85 0.25

SEd 0.22 0.26 0.32 0.25 0.01 0.01 0.02 0.02

CD (P=0.05) 0.43 0.52 0.64 0.49 0.02 0.03 0.04 0.04

P1 49.6 62.9 12.5 158.9 172.8 13.9 1.43 1.72 0.31 4.56 4.95 0.39

P2 51.5 59.5 8.8 120.8 127.3 6.5 1.41 1.73 0.30 3.42 3.65 0.23

SEd 0.22 0.26 0.32 0.25 0.01 0.01 0.02 0.02

CD (P=0.05) 0.43 0.52 0.64 0.49 0.02 NS 0.04 0.04

44

Land Management Practices for In-Situ Water Harvesting in

DrylandsRajeswari. M*, I Seegan Paul** and V. Subramanian***

10

IntroductionVertisols constitute 23.1 per cent of rainfed lands

in the country and possess great production potential. These soils are poor in organic matter and structure and suffer from higher expansion and shrinkage. These soils disperse easily resulting in low infiltration rate and high runoff which eventually leads to poor soil moisture storage and low yield. These constraints can be alleviated by adopting in-situ moisture conservation practices which help to slow down the runoff and increase infiltration ultimately resulting in improved soil moisture storage.

Materials and MethodsField experiments were conducted in vertisols

at Agricultural Research Station, Kovilpatti. Four land treatments viz., Broad bed (1.5 m width) and furrow (30 cm width), compartmental bunding of size 8x5 m, planting of vettiver across the slope at 25 m interval and farmers practice of ploughing across the slope were evaluated in non-replicated plots of 100 x 30

m dimension. Since the sequential cropping system followed in these area is a cash crop followed by cereal crop, Cotton intercropped with blackgram followed by sorghum crop was chosen as the crop rotation. The runoff was recorded using H-Flumes and stage level recorders. The soil moisture was estimated by gravimetric method.

Results and DiscussionEffect of Land Treatments on Runoff

The runoff as percentage of rainfall recorded from different land treatments is presented in Table 1.

The mean values of runoff for 4 years revealed that compartmental bunding was superior to other treatments since only 11.82 per cent of the seasonal rainfall was lost as runoff when compared to the farmers practice which registered 30 per cent of runoff. The percentage reduction in runoff due to the land treatments was 60, 48.3 and 27.0 per cent in compartmental bunding, vettiver and broad bed and furrows respectively.

45

Effect of Land Treatments on Soil Moisture Storage

The mean soil moisture content in (0-45 cm) depth of the soil during the months of October, November and December were estimated by gravimetric method and compared to assess the effectiveness of the land treatments (Table 2).

The soil moisture stored in the land treatments was found to be non significant. However compartmental bunding has recorded numerically higher values of moisture content. Channappa (1974) has reported that compartmental bunding is the best in-situ moisture conservation practice.

Influence of Land Treatments on Yield of Crops

The yield data of cotton + black gram and sorghum crops raised in rotation is furnished in Table 3.

The effect of the land treatments on yield over years was compared by converting the cotton and blackgram yield into sorghum equivalent yield and statistical analysis was done treating the yield of different years as replications (Table 4).

Among the land treatments, compartmental bunding has recorded the highest sorghum equivalent yield (1982 kg/ha) which was 25.4 per cent higher than control with a mean B: C ratio of 1.40. The results

confirm with the findings of Robinson et.al (1986). Radder et.al.,(1991) reported that yield increase of 24 and 56 per cent could be obtained with compartmental bunds of 4.5 × 4.5 m and 3 m × 3 m respectively in deep black soils.

Tr. No. Treatment Runoff as percentage of rainfall

2000-01 2001-02 2002-03 2004-05 Mean

T1 Farmers practice (Control) 13.37 32.56 36.09 36.62 29.66

T2 Compartmental bunding 2.50 9.50 20.66 14.60 11.82

T3 Broadbed and furrows 11.14 20.78 31.29 23.41 21.66

T4 Vettiver 6.77 13.90 22.83 17.82 15.33

Table 1. Runoff as percentage of rainfall for different land treatments

Tr. No. Treatment Grain (kg/ha)

2000-01 2001-02 2002-03 2004-05

Sorghum Cotton Blackgram Sorghum Sorghum

T1 Farmers practice (Control) 1115 476 178 1166 2078

T2 Compartmental bunding 1577 608 231 1332 2501

T3 Broadbed and furrows 1305 512 189 1232 2313

T4 Vettiver 1017 551 207 1265 2306

S. No. Treatment Mean soil moisture content (%db)

1. Farmers Practice 23.38 24.95 21.43 25.24

2. Compartmental bunding 25.33 24.50 23.24 30.93

3. Broad bed and furrow 24.14 24.65 22.11 29.45

4. Vettiver 24.30 24.87 23.30 31.00

Rainfall (mm) 289.4 306.2 289.2 317.5

Table 2. Mean soil moisture content (% dry basis)

Table. 3 Yield of crops due to different land treatments

46

Conclusion

For semi - arid vertisols, having a land slope of one per cent and an annual rainfall of 600-700 mm, the land treatment, compartmental bunding (8m x 5m) formed across the slope helps in reducing runoff to the tune of 60 percent resulting in 25 per cent yield increase in sorghum with a B:C ratio of 1.40.

References Channappa, T.C. (1974). In-situ moisture conservation in arid and semi-arid tropics. Indian J. Soil conservation, 22

: 1-2.Radder, G.D., C.J. Itnal, B.M. Birdar and V.S. Surkod (1991). Compartmental bunding an effective in-situ moisture

conservation practice on medium deep black soils. Indian J. Soil conservation, 51 : 1-2.

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Tr. No. Treatment Grain (kg ha-1) Mean Benefit/ 2000-01 2001-02 2002-03 2004-05 Mean cost ratio of all products

T1 Farmers practice (Control) 1115 1962 1166 2078 1580 1.18

T2 Compartmental bunding 1577 2517 1332 2501 1982 1.40

T3 Broadbed and furrows 1305 2103 1232 2313 1738 1.24

T4 Vettiver 1017 2274 1265 2306 1716 1.22

CD 0.05 187

Table 4. Yield of crops in sorghum equivalent for different land treatments

Theme – 2Water Harvesting at

Micro-Watershed Level

49

Harvesting Of Surface Runoff for Ground Water Recharge - A Case Study of Koilmalai

WatershedM. Sivakumar , Scientist-C, Central Ground Water Board, SECR, Chennai

11

About Koilmalai WatershedThe watersheds/ river basins referred as

hydrologic units (HUs) are independent of territorial boundaries. Parts of blocks namely Anaicut, Madhanur and Alangayam of Vellore district and Jawadhu hills and Pudupalayam of Thiruvannamalai district forms the total area of koilmalai watershed. The details of location and administrative set up of Koilmalai watershed are shown in fig- 1. The koilmalai water shed is having an area of 200.83 Sq. km and lie between north latitudes 12.56� and 12.75� and east longitudes 78.79� and 78.95. About 60% of water shed area is falling within administrative boundary of Vellore district and remaining area falling within administrative boundary of Thiruvannamalai district. Topographically, about 58.6 Sq.km area of watershed is having plain to undulating topography and 142.23 Sq.km areas are covered with hills and dense forest. In general, most part of watershed is having steep slope due to many hills ranges, which is responsible for generation of sudden overland flow even for small shower. Plain to undulating topography exists mostly in the downstream side of watershed and valley and plateaus of hilly regions.

Drainage PatternThe Koilmalai watershed area drained by a

stream called „Koilmalai Ar‰. The two major tributaries of Koilmalai Ar are „Mamarattur Ar‰ and „Periya Ar‰. The stream „Mamarattur Ar‰ originates near Nayakkanur village in Alangayam block of Vellore district at an elevation of 710 m amsl and flow northwards across Alangayam Reserve forest. The stream „Periya Ar‰ originate near Melmarattur village in Jawadhu hills block of Thiruvannamalai district at an elevation of 900 m amsl and flow towards SW direction across virappanur reserved forest. These two streams join together at an elevation of 510 m amsl in the dense Jawadhu hills of virappanur reserve forest and flow towards NE direction with the name „Koilmalai Ar‰. The total length of stream is of 28.33 km. The stream traverse 20.6 km within hilly terrain from the elevation of 710 m amsl at Nayakkanur village to 410 m amsl at Melarasmpattu village and rest in plain further down to 330 m amsl at china cheripadi village, which is the mouth of the watershed. The stream is 5th order stream and the total no of stream segments of all order within the watershed is 865 nos., which include 669 first order, 148 second

50

order, 38 third order and 9 forth order streams. The drainage pattern of Koilmalai watershed is shown in fig-2. Morphometrically, the shape of the watershed is strongly elongated in nature and having very high relief and steep slopes. Moderately high drainage density and less value of length of overland flow are indicative that the regions of weak or impermeable sub surface materials sparse vegetation and mountainous relief facilitate poor groundwater recharge.

Soils & Infiltration StudyThe soils of Koilmalai watershed can be classified

broadly into types namely clayey and loamy. The distribution of important soil types in the watershed, based on the map prepared by the National Bureau of Soil Survey and Land Use Planning (ICAR) in cooperation with Department of Agriculture, Tamil Nadu (1996). Moderately deep, somewhat excessively drained, gravely clay soils occur on moderately sloping high hills and hill ranges. Shallow, somewhat excessively drained, gravely loamy soils are found on moderately sloping foot slopes. Moderately deep, somewhat excessively drained, gravely loam soils occur on high hills. The soils are either red

or black in colours and or mixture of both at some places. The loamy structure of soil or the intermixture of fine and thick particles make it suitable for cultivation of large variety of crops than black soils. The areal distribution of soils in Koilmalai watershed is depicted in fig-3. Infiltration capacity of soils is one of the important factors controlling the recharge of water into the aquifer systems. In the field, soil infiltration test were conducted at 8 sites. The tests were conducted for durations ranging from 280 to 420 minutes. The locations of soil infiltration tests conducted in the field are shown in fig-3. The infiltration test conducted on sandy soil / gravelly soil have shown higher rate of infiltration, which are classified under „Rapid Infiltration‰. The infiltration rate of loamy clay and silty clay are in the range of 1.2 � 3.1 mm/hr. In general, the infiltration rate in the majority of cases is moderate to rapid.

RainfallThe rainfall data collected from the gudiyatham

rain gauge station over the period of 100 years is considered for analysis. Based on the statistical analysis of 100-years annual rainfall data, the annual normal rainfall of watershed is worked out as 900.97 mm, of which 768.87 mm received during monsoon periods. Based on the probability analysis of annual normal rainfall data, the average annual rainfall at 50% and 75% dependability work out as 861 mm, 733 mm respectively and average monsoon rainfall at 50% and 75% dependability work out as 621.5 mm and 739 mm respectively. The rainfall occurring during non-monsoon seasons do not produce significant quantity of surface run off and even some time negligible. Hence, monsoon rainfall at 75% dependability i.e. 621.5 mm is considered for the computation of surface runoff of Koilmalai watershed.

Estimation of Surface RunoffKoilmalai watershed is an un-gauged one and

runoff of the basin can be computed using empirical / rational methods. A number of formulae and tables are available for different types of catchments in India (Dhir et al., 1955). The most commonly used ones being those developed by Strange, Inglis, Lacey and Khosla (Dhir et.al., 1955). All these methods have been used in the present study to assess the monsoon runoff generated in the watershed.

The computation of surface runoff of koilmalai watershed using Ingles and KhoslaÊs formula is much

51

higher i.e. the runoff co-efficient which is defined as the ratio of runoff to precipitation, is about 36% and 78% respectively. But in case of strange curves, LaceyÊs formulae and BarlowÊs methods, the computed runoff values are more less equal and within agreeable limit. In these methods, the runoff coefficient is in the range of 14% to 20%, which is considered to near realistic value. Hence, in order to eliminate the over estimation of runoff of watershed, the lowest value of 18.07 MCM obtained using Strange table is taken as the total surface water available in the watershed.

Committed StorageDams/ Reservoirs and tanks/ponds are the

important surface water bodies constructed across river/ stream to store surface flow for various purposes. Theses structures were built traditionally for domestic and irrigational uses. As on today, there are no major/ medium level dams/ reservoirs constructed in the watershed except some traditional water bodies like tanks and ponds. There are about 16 tanks and ponds in the watershed. The total water spread area of all tanks is about 0.556 Sq.km. It is assumed that the height of tank bunds are of 1 m above the bed level and these tanks were get filled twice in a year. Hence the total surface runoff harvested in tanks is the committed storage of watershed, which is 1.112 MCM per year. The water impounded in the check dams and percolation ponds constructed across a few minor streams in the watershed has not been included in the computations as it is considered negligible.

Computation of Non-Committed Sur-face Water Resources

The quantum of non-committed surface water resources available in the watershed is the difference between the annual runoff in the entire watershed and the committed water supply required for filling up the surface water bodies. Based on the computations shown above, the non-committed surface water resource available in Koilmalai watershed is of the order of 16.958 MCM. This could be effectively utilized for creating additional irrigation potential in the plains of the watershed as well as for augmentation of ground water resources through scientifically designed artificial recharge structures constructed at suitable locations.

Assessment of Ground Water ResourcesThe assessment of ground water is needed to

meet the water requirements of domestic, irrigation and industrial sectors. The Central Ground Water Board, SECR, Chennai in co-ordination with state has done block wise assessment of ground water resources for Tamil Nadu using GEC-97 methodology and published during 2004. The parts of Anaicut, Madhanur and Alangayam blocks of Vellore district and parts of Jawadh hills and pudhupalayam blocks of Thiruvannamalai district form the total area of Koilmalai Watershed. The net ground water resource of these blocks, stage of ground water development and draft were extracted from the above said report. Out of these, four blocks namely Anaicut, Madhanur, Alangayam and Pudhupalayam are categorised as over-exploited blocks, where the stage of ground water development is more than 100%. In case of Jawadhu hills block, the stage of groundwater development is 99% and is categorised as critical.

In case of Koilmalai watershed, about 70% of watershed area covered by hills and forest ranges having slope more than 20% are identified and deleted, as these areas are not likely to contribute groundwater recharge. However, the areas of valley and plateau and plain to undulating topography having slope less than 20% is considered for recharge computation. Hence, the ground water resources of kolimalai watershed is computed on prorate basis. Accordingly, the net ground water available within the watershed for all uses is computed as 6.411 MCM.

Results and DiscussionsThe Koilmalai water shed is having an area of

200.83 Sq. km and lie between north latitudes 12.56� and 12.75� and east longitudes 78.79� and 78.95�. About 70% of the watershed area is covered by hills & reserved forests and remaining area has a plain to undulating topography. A stream called „Koilmalai Ar‰ drains the entire watershed. The stream is a 5th order one and ephemeral in nature and traverse for a distance of 28.33 km within the watershed. The total no of stream segments of all order within the watershed is about 865 nos, of which 669 first order streams, 148 second order streams, 38 third order streams and 9 forth order streams. The soils of Koilmalai watershed can be broadly

52

classified as clayey and loamy types. Sandy soil / gravely soil have shown higher rate of infiltration, which are classified under „Rapid Infiltration‰. The infiltration rate of loamy clay and silty clay are in the range of 1.2 � 3.1 mm/hr and are classified under „moderate type‰.

Morphometrically, the shape of the watershed is strongly elongated in nature and having very high relief and steep slopes. Moderately high drainage density and less value of length of overland flow are indicative that the regions of weak or impermeable sub surface materials sparse vegetation and mountainous relief and poor groundwater recharge.

Based on the statistical analysis of 100-years annual rainfall data, the annual normal rainfall of watershed is worked out as 900.97 mm, of which 768.87 mm received during monsoon periods. The estimated surface runoff of Koilmalai watershed is about 18.07 MCM, of which the committed storage of watershed for the existing 16 nos. of tanks and ponds were worked out as 1.112 MCM. The net ground water available within the watershed for all uses is 6.411 MCM. The non-committed surface water resource available in the Koilmalai watershed is of the order of 16.958 MCM.

Since the high relief of morphology present in the watershed favours good generation surface runoff but the presence of clayey and loamy soils not conducive for good ground water recharge. In spite of

the sufficient surface flow available in the watershed, so far no irrigation project was done to meet the domestic/ irrigation demands. Hence almost the entire demands are meet through ground water only. The block wise computation of resources have already been shown that all the blocks falling in watershed are classified under overexploited blocks, which means the annual ground water extraction is more than the annual recharge. However, the non-committed surface water resource of 16.958 MCM can be utilized scientifically and integrated manner. All the tanks in the watershed must be revitalized and their bunds and allied structure are strengthened to augment the surface storage and the remaining flow can be utilized for ground water recharge. The detailed study on integrated surface and groundwater management could be done to effectively utilized surplus runoff for creating additional irrigation potential in the plains of the watershed as well as for augmentation of ground water resources through scientifically designed artificial recharge structures constructed at suitable locations.

AcknowledgementThe author is very much thankful to Sh. B.M.Jha,

Chairman, Central ground Water Board, Faridabad and Dr.N.Varadaraj, Regional Director, Central Ground Water Board, SECR, Chennai for their encouragement and permission to participate in the International Seminar.

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Theme – 3Enhancing Water Productivity

in Rainfed Areas

55

Irrigation Scheduling in Long Pepper (Piper Longum) under

Partial ShadeAnilkumar, A. S., Suharban, M, Hajilal, M. S., Sherief, A. K. and Harikrishnan Nair, K

12

IntroductionPiper longum is popularly known as thippali

or long pepper. It is a slender aromatic climber with perennial woody roots. Dried spike is the economic part commonly used in ayurvedic and unani medicines. It is a major constituent of the ayurvedic drugs prescribed for increasing immunity against AIDS virus and it acts as immunostimulant. It is an integral component of ÂTrikaduÊ an ayurvedic formulation, prescribed against several respiratory complaints. Regulation of soil moisture is beneficial for improving the growth, productivity and quality of long pepper. It also helps for optimum utilization of irrigation water besides extending the area under irrigation. Organic matter content of the soil is intimately related to its productivity because it acts as a store house for nutrients, increases exchange capacity, provides energy for microbial activity, increases water holding capacity, improves soil structure, reduces crusting and increases infiltration and buffers the soil against changes in acidity, alkalinity and salinity (Tisdale,

et al., 1993). With this background an experiment was conducted to find out the effect of irrigation interval and organic manure on the productivity and quality of long pepper intercropped in coconut gardens.

Materials and MethodsThe field experiment was conducted during

2004- 06 at the College of Agriculture, Vellayani in the interspaces of a thirty to forty year old coconut garden. The treatments consisted of combinations of nine levels of irrigation intervals, viz, irrigation at canopy � air temperature difference of 0oC, 1oC, 2oC and irrigation at 5 mm, 10 mm, 15 mm, 20 mm, 25 mm and 30 mm of CPE (cumulative pan evaporation) and two levels of organic manure, viz, FYM @ 20 t ha-1 and control. The experiment was laid out in split plot design. Viswam variety of long pepper was planted in the interspaces of a coconut garden at a spacing of 60 cm x 60 cm. Uniform dozes of FYM @ 20 t ha-1 year-1 and NPK @ 60: 60: 120 kg ha-1 year-1 were given. The crop attained stability in yield after one year of establishment and the

56

treatments were imposed during the second year of crop growth. Infra red thermometer and vapour pressure osmometer were used for the measurement of canopy temperature and osmotic potential respectively.

Results and DiscussionData on biometric characters, spike number

and spike yield of long pepper are presented in Table 1. Biometric characters, yield attributes and yield were significantly influenced by treatment effects. Irrigation scheduling at CPE 15 mm combined with FYM application @ 20 t ha-1 year-1 improved vine length, leaf number and number of spikes. Irrigation scheduling at canopy-air temperature difference of 10C and irrigation scheduling at CPE of 15 mm were found beneficial for increasing both fresh and dry spike production, spike number and crude extract. FYM enhanced spike production and crude extract per cent compared to the control.

Interaction effects of irrigation interval and levels of organic manure on biometric characters, spike number and spike yield are furnished in Table 3. Interaction effects showed significant variation with respect to on biometric characters, spike number and spike yield. Integration of irrigation scheduling at canopy-air temperature difference of 10C and irrigation scheduling at CPE of 15 mm along with incorporation of FYM @ 20 t ha-1 is beneficial for improving both quantity and quality of the officinal part. This might be due to better growth of plants associated with favourable soil moisture regimes. Long pepper responds very well to nutrient application. Nutritional disorders are common in long pepper because being a perennial it occupies the same impoverished soil year after year (Krishnan, 2003). Frequent harvest of long pepper spikes results in depletion of soil fertility at a

faster rate. Hence, application of FYM @ 20 t ha-1 might have benefited the growth.

Quality parameters, viz, osmotic potential, crude extract and alkaloid content were estimated and the results indicated the superior performance of irrigation scheduling at canopy � air temperature difference of 10C and irrigation scheduling at CPE 15 mm. Application of organic manure @ 20 t ha-1 was beneficial for significant improvement in osmotic potential, crude extract per cent and alkaloid content. Irrigation scheduling at 15 mm CPE resulted in maximum benefit cost ratio of 1.76 followed by irrigation scheduling at canopy � air temperature difference of 10C. Although the effect of organic manure was not significant, incorporation of FYM @ 20 t ha-1 increased benefit cost ratio compared to control.

Management practices adopted for increasing the productivity of the intercrop, ie, long pepper also influenced the productivity of the main crop. The indirect influence of irrigation interval and FYM on the productivity of the main crop, ie coconut was remarkable. The highest nut yield of 153 nos palm-1 year-1 was observed when irrigation was scheduled at 15 mm CPE followed by scheduling irrigation at 10 mm CPE. Similarly, manuring the intercrop, ie, long pepper with FYM @ 20 t ha-1 resulted in enhancing the productivity of the main crop from 131 to 142 nos palm-1 year-1. Coconut is a crop which produces nuts round the year. Therefore, year round availability of soil moisture is essential for its unhindered growth Moisture stress leads to stunted growth, drooping of leaves, immature nut fall and decreased yield (Peter, 2002). Soil fertility management is also equally important in boosting coconut yields. Inter row zone management of intercrops favourably influenced the growth and productivity of the predominant crop,ie, coconut.

References1. Krishnan, B. 2003. Rhizosphere modulation for higher productivity in long pepper (Piper longum Linn.). M.Sc

(Ag) thesis submitted to Kerala Agricultural University, Vellanikkara2. Peter, K.V. 2002. Plantation crops. National Book Trust, India, p. 3323. Tisdale, S.L., Nelson, W.C., Beatson,J.D. and Havlin,J.L. 1993. Soil fertility and fertilizers. Prentice Hall of India.

Pvt. Ltd. New Delhi, p.613

57

Table 1. Performance of long pepper as influenced by irrigation intervals and levels of organic manure.

Treatments Vine Leaf Spike Spike yield (t ha-1) Benefit cost length number number ratio (cm) Fresh Dry

Irrigation intervals

CT-AT = 0 69 9 6.75 2.70 0.54 1.54

CT-AT=10C 81 10 8.0 3.05 0.61 1.74

CT-AT=20C 72 10 6.75 2.53 1.51 1.44

CPE 5 mm 60 8 5.5 2.78 1.56 1.60

CPE 10 mm 53 7 5.25 2.61 1.52 1.48

CPE 15 mm 83 12 8.75 3.08 1.62 1.76

CPE 20 mm 52 7 5.25 1.49 1.30 0.84

CPE 25 mm 43 7 4.75 1.32 1.26 0.75

CPE 30 mm 62 9 7.5 0.85 1.17 0.48

CD (0.05) 13.5 1.8 1.38 0.25 4.91 0.41

Levels of organic manure

FYM 66 10 7.06 2.55 0.51 1.39

Control 55 7 5.94 1.99 0.40 1.19

CD (0.05) 5.1 0.8 0.64 0.13 2.65 NS

Table 2. Quality parameters of long pepper and productivity of coconut as influencedby irrigation intervals and levels of organic manure

Treatments Osmotic Crude Alkaloid Productivity of potential extract (%) coconuts (nut (m mole kg-1) (%) palm-1 year-1)

Irrigation intervals

CT-AT = 0 718 8.69 5.5 135

CT-AT=10C 840 9.76 5.8 144

CT-AT=20C 650 8.56 5.2 128

CPE 5 mm 720 9.44 5.6 145

CPE 10 mm 625 8.37 5.4 150

CPE 15 mm 810 9.69 5.8 153

CPE 20 mm 630 8.31 5.2 142

CPE 25 mm 568 7.75 4.9 119

CPE 30 mm 565 8.31 4.8 112

CD (0.05) 77.3 - 0.62 15.4

Levels of organic manure

FYM 734 9.21 5.6 142

Control 627 8.32 5.2 131

CD (0.05) 51.3 NS 0.36 9.2

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Table 3. Performance of long pepper as influenced by the interactioneffects of irrigation intervals and levels of organic manure

Treatments Vine Leaf Spike Spike yield (t ha-1) Crude length number number extract (cm) Fresh Dry (%)

W1 F1 78 10.0 7.0 3.08 0.62 9.38

W1 F2 61 8.0 6.5 2.31 0.46 8.0

W2 F1 84 11.5 8.5 3.36 0.67 10.13

W2 F2 78 8.5 7.5 2.75 0.55 9.38

W3 F1 77 11.5 7.0 2.70 0.54 8.88

W3 F2 68 9.0 6.5 2.37 0.47 8.25

W4 F1 67 10.5 6.5 3.03 0.61 9.88

W4 F2 54 6.5 4.5 2.53 0.51 9.0

W5 F1 56 8.0 6.0 2.97 0.59 9.13

W5 F2 50 6.0 4.5 2.26 0.45 7.63

W6 F1 89 12.5 9.0 3.25 0.65 10.25

W6 F2 77 11.5 8.5 2.92 0.58 9.13

W7 F1 57 7.0 5.5 1.82 0.36 9.13

W7 F2 47 7.5 5.0 1.16 0.23 7.5

W8 F1 55 8.5 5.5 1.71 0.34 8.13

W8 F2 31 6.5 4.0 0.94 0.19 7.38

W9 F1 36 11.5 8.5 1.05 0.21 8.0

W9 F2 28 8.0 6.5 0.66 0.13 8.63

SE m 4.8 0.77 0.6 0.12 2.49 -

CD (0.05) 15.4 2.47 1.92 0.40 7.96 -

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59

Changes in Irrigation Management System among Cauvery Old Delta Farmers

T. Damodharan*, M. Asokhan**, G. Ranganathan*** & I. Md. Iqbal****

13

IntroductionWater is one of the most important essential

inputs for agriculture. Plants require it continuously during their life and in large quantities. water is the basic component. In rice cultivation whether rainfed, lowland, upland, deep-water, flood-prone or irrigated, water is intimately linked to it. Intensive or extensive cultivation of land depends mainly on the availability of water. Water can create, preserve and destroy the life on the earth and therefore, water must be used in a precise way with due care and caution as lack of it may create dryness, deluge; both may cause lives and properties on earth. Cauvery is one of the major rivers of the Indian Peninsula and it is the most important river of Tamil Nadu. This is held in high esteem by the people of Tamil Nadu as the natureÊs precious boon. The study has been designed to assess the irrigation management changes among Cauvery old delta farmers.In Tamil Nadu, Cauvery is the most important river basin system providing irrigation to the delta districts and accounting for maximum area under rice. Changes in irrigation management system before 2001 and there after in the

succeeding years was studied The Cauvery and Vennar rivers systems together contributed 77.12 percentage of the total area under the old ayacut. A sample size of 180 farmers and 75 Extension personnel were interviewed with structured schedule. The flooding type of irrigation method , alternate wetting and drying , field to field irrigation , individual field channel irrigation , providing drainage structures , adjusting period of raising nursery , practicing summer ploughing and application of organic manures (100.00 to 33.89%) were majorchanges in irrigation management system among Cauvery old delta farmers

MethodologyIn Tamil Nadu, Cauvery is the most important

river basin system providing irrigation to the delta districts and accounting for maximum area under rice. The year 2001-02 was taken into consideration as base year since the date of release of water for irrigation has coincided the date contemplated normally for the release of water for irrigation purposes in the old delta system. The irrigation management changes before this year and there after in the succeeding years was studied .Old

60

delta districts was purposively selected. . The Cauvery and Vennar rivers systems together contributed 77.12 percentage of the total area under the old ayacut.. There were 114 numbers of ÂAÊ class channels in the Cauvery river basin and 97 numbers of ÂAÊ class channels in Vennar river basin . These ÂAÊclass channels were taken into consideration and classified under head, mid and tail end regions Six ÂAÊ class channels were selected in each river basin using random sampling, A sample size of 180 farmers was fixed for the study which was equally chosen from Cauvery and Vennar river basin systems. 75 Extension personnel from Thanjavur, Thiruvarur and Nagapattinam districts. Interview schedule was used for the collection of data from the respondents.

Irrigation water conveyanceField to Field Irrigation

It could be observed from Table 38 that the conveyance of the irrigation water through field to field had decreased from 78.89 to 50.56 per cent in Cauvery old delta. Among the three categories, in head reach (20.00 to 11.67 %), mid reach (30.56 to 20.00 %) and tail end also (28.33 to 18.89 %) there was a decrease on field to field irrigation which was a very good sign.This referred to the sprouted seeds used for for sowing followed by ash application 3.4.6.11. Planting under water logged conditionsThis referred to the use of aged seedlings for planting 3.4.6.12 Flood damaged crop maintenanceThis referred to the practices like gap filling or replanting to maintain the plant population.3.4.6.13 Drainage management. This referred to the providing drainage structures to drain the stagnated water.

The highest percentage of decrease in field to field irrigation was noticed in Vennar river basin (28.89%) followed by Cauvery river basin (27.78 %). Among the reaches the mid had ranked first (10.56 %) followed by tail end (9.44 %) and head (8.33 %). Considerable quantities of water which could be used for irrigation are lost during irrigation water conveyance by field to field irrigation. Provision of separate channels for irrigation and drainage will go a long way for increased water use efficiency. Awareness on the advantages of individual field channel irrigation might be the reason for the decreased change

Individual Field Channel Irrigation

It could be observed form Table 39 that the percentage of respondents irrigationg their field through

individual channel had increased from 21.11 to 49.44 per cent in the study area. River wise analysis revealed 25.55 to 53.33 per cent and 16.67 to 45.55 per cent of increased changes in Cauvery and Vennar river basins respectively. Among the three categories, in head reach (9.44 to 17.78%), mid reach (6.67 to 17.22%) and tail end (5.00 to 14.44%) also it had increased in individual field channel irrigation. It implied that there were increased changes in irrigation water conveyance through individual field channel. Under limited water availability, awareness on importance of individual field channel irrigation had changed the farmers for taking the water through separate field channels („Kannivaikkal‰). Use of either pipelines or hose for conveying the bore well water to nursery and main field was also observed in the study area. This finding is in line with Kavitha (2001) and Balasubramaniam. (2005).

Excess wThis referred to the practices reommndated to cultivate crop during late release of mettur water ater management

Providing Drainage Structures

This referred to the sprouted seeds used for for sowing followed by ash application

3.4.6.11. Planting under water logged conditions

This referred to the use of aged seedlings for planting

3.4.6.12 Flood damaged crop maintenance

This referred to the practices like gap filling or replanting

to maintain the plant population.

3.4.6.13 Drainage managementThis referred to the providing drainage structures to drain the stagnated water.

It could be observed from the Table 40 the percentages of respondents providing drainage structures had increased from 52.78 to 75.01 per cent in Cauvery old delta. River wise analysis revealed 52.23 to 75.56 per cent and 53.33 to 74.44 per cent of changes in Cauvery and Vennar river basins respectively. Among the three categories, in head reach (17.78 to 21.67%), mid reach (22.22 to 30.56%) and also in tail end (12.78 to 22.78%) it had increased. Under prevailed water logged situation, the farmers were providing drainage structures („Thondukal‰) on temporary basis. For proper irrigation and drainage the farmers were providing a slope in the head portion of the field for facilitating quick drainage in their field portion.

61

Adjusting The Period of Raising Nursery

It could be observed from Table 41 that the percentage of changes in adjusting period of raising nursery had decreased from 47.23 to 25.01 per cent in Cauvery old delta. River wise analysis revealed 47.78 to 24.45 per cent and 46.67 to 25.56 per cent in Cauvery and Vennar river basins respectively. Among the three categories, in head (11.67 to 7.78%), mid reach (15.00 to 6.67%) and also in tail end (20.56 to 10.56%) it had decreased. In areas prone for water logging in the North East Monsoon period, farmers earlier had the practice of growing either early planting or delayed planting to tide over the ill effects of the heavy down pour resulting in total loss of crop. But now farmers could not adopt this practice fully since the canal water supply was not definite due to poor storage position in the Mettur reservoir. As such the farmers during these uncertain periods got flood and crop losses by taking the cultivation without advance planning. Farmers with supplemental irrigation could have raised nursery as planned. But majority of farmers, who were solely dependent on canal water, were forced to take up nursery at the time of canal water released. This had resulted in uncertain floods and crop loses. This was observed mostly in single crop wetland areas.

Soil moisture conservationSummer Ploughing

It could be observed from Table 42 that the percentage of respondents practicing summer ploughing had increased from 34.45 to 53.89 per cent in Cauvery old delta. River wise analysis revealed 28.90 to 47.78 per cent and 40.00 to 60.00 per cent in Cauvery and Vennar river basins respectively practiced summer ploughing. Among the three categories, in head reach (7.78 to 13.89 %), mid reach (10.56 to 15.56 %) and also in tail end (16.11 to 24.44 %) there had been an increase in summer ploughing. This referred to the sprouted seeds used for for sowing followed by ash application 3.4.6.11. Planting under water logged conditionsThis referred to the use of aged seedlings for planting 3.4.6.12 Flood damaged crop maintenanceThis referred to the practices like gap filling or replanting to maintain the plant population.3.4.6.13 Drainage management This referred to the providing drainage structures to drain the stagnated water.

The analysis further revealed that overall 19.44 per cent of the respondents practiced summer

ploughing in Cauvery old delta. The highest percentage of practicing summer ploughing was noticed in Vennar river basin (20.01 %) followed by Cauvery river basin (18.89 %). Among the reaches the tail end had ranked first (8.33 %) followed by head (6.11 %) and mid (5.00 %). In the study area, due to the delayed receipt of water, the farmers were practicing summer ploughing for availing the benefits of summer rains as well as to start the cultivation operations without any delay and getting the canal water. This might be the reason for increased change. However, there is a felt need to motivate all the farmers for summer ploughing which is very essential in order to conserve moisture. This finding is in line with Kavitha (2001) and Balasubramaniam (2005).

Organic Manures Application

It could be observed from Table 43 that the application of organic manures had decreased from 100.00 to 33.89 per cent in Cauvery old delta. River wise analysis revealed 100.00 to 30.01 per cent and 100.00 to 37.78 per cent in Cauvery and Vennar river basins respectively. Among the three categories, in head reach (29.44 to 7.22%), mid reach (37.22 to 12.78 %) and also in tail end (33.33 to 13.89 %) the application of organic manures application was on the declining trend. This referred to the sprouted seeds used for for sowing followed by ash application 3.4.6.11. Planting under water logged conditionsThis referred to the use of aged seedlings for planting 3.4.6.12 Flood damaged crop maintenanceThis referred to the practices like gap filling or replanting to maintain the plant population.3.4.6.13 Drainage management

This referred to the providing drainage structures to drain the stagnated water. The highest percentage of decrease in organic manures application was noticed in Cauvery river basin (70.00 %) followed by Vennar river basin (62.23 %). Among the reaches the mid had ranked first (24.44 %) followed by head (22.22 %) and tail end (19.44 %). Since the farmers could not accumulate sufficient quantity of farm yard manure for want of cattle population, the results are justified.

Analysis of variance on irrigation management changes among Cauvery old delta farmers.

Analysis of variance was worked out to find out significant differences among the farmers from each of the two river basins on irrigation management. The results are presented in Table 44.

It could be observed from the Table 44 that

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there existed a significant difference among the farmers in Cauvery and Vennar river basins with regard to irrigation management. This was confirmed by a significant ÂFÊ value at one per cent level. The farmers in Cauvery and Vennar river basins were differed in the following aspects. Compare to Vennar river basin (14.45%), Cauvery river basin (33.33%) farmers had higher percentage of supplemental irrigation source. Vennar river basin farmers were Table 44. Analysis of variance on irrigation management changes among Cauvery old delta farmers blessed with good irrigation structures (62.23%).

** : Significant at 0.01% level

Compare to Vennar river basin (36.67%), Cauvery river basin farmers had higher percentage of favourable response towards continued rice cultivation (58.89%). The data in Figure 19. shows that there was higher percentages of increased changes on use of cage wheel (18.89%), use of land leveller (84.45%) semi dry sowing (13.33%), individual field channel irrigation (28.89%) and summer ploughing (20.01%) were observed among Vennar river basin farmers. The higher percentage of increased changes among Cauvery river basin farmers were strengthening of field bunds (46.67%), contingent cropping (37.77%), alternate wetting and drying method of irrigation (32.22%) and providing drainage structures (23.34%).

The decreased changes on trimming of field bunds (35.56%) and field to field irrigation (28.89%) were higher in Vennar river basin. There was a declined in raising nursery nearer to water source (18.89%), preference of long duration rice varieties (34.44%), flooding method of irrigation (20.01%), adjusting the period of raising nursery during prevailed rainy season (23.34%) and organic manures application (70..00%) among Cauvery river basin farmers. There was no difference between Cauvery (22.22%) and Vennar (22.23%) river basin farmers on preference of short duration rice varieties.

Based on the findings it may be concluded that the changes had been taken in the irrigation management among Cauvery old delta farmers.

ConclusionThe flooding type of irrigation method had

decreased from100.00 to 82.22 per cent , alternate wetting and drying had increased to 27.22 per cent, field to field irrigation had decreased from 78.89 to 50.56 per cent, individual field channel irrigation had increased from 21.11 to 49.44 per cent. percentage of respondents providing drainage structures had increased from 52.78 to 75.00 per cent, adjusting period of raising nursery had decreased from 47.21 to 25.00 per cent, percentages of respondents practicing summer ploughing (34.45 to 53.89%) and application of organic manures (100.00 to 33.89%) had decreased were major changes in irrigation management system among Cauvery old delta farmers.

Groups Degrees of freedom Sum of squares Mean square ‘F’

Between groups 14 319.500 22.821 10.083

Within groups 165 373.450 2.263

Total 179 692.950

RefrencesKavitha, S. 2001. Integrated Water Management - An Ex-post Facto Study on Differential Knowledge And Adoption

Behaviour of Rice Growers. Unpub. M.Sc. (Ag.) Thesis, TNAU, Coimbatore.Balasubramaniam, P. 2005. Developing TOT Strategy for Water Management in Canal Command Area of Lower

Bhavani Project, Unpub. Ph.D. Thesis, TNAU, Coimbatore.

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63

Characterization of Sorghum Germplasm for Drought

ToleranceK. Ganesamurthy*, D. Punitha , A. R. Muthiah and T. S. Raveendran

14

Introduction Sorghum is one of the most important crops

grown for food and feed. In Tamil Nadu it is cultivated over an area of 3.5 lakh hectares with an annual production of 3.46 lakh tonnes with a productivity of 984 kg/ha of grain. It is a dual purpose crop and is valued both for its grain as well as for its excellent fodder. It forms the major source of staple food among the rural population in the state. It is the crop suited to hot and dry ecologies where it is difficult to grow other food grains. Owing to its drought tolerance capacity, its cultivation in drought prone areas is effectively providing food and fodder through on sustainable basis. (kong et al., 2000). The potential of this low input demanding crop for diverse uses such as feed and biofuel crop besides as a supplier of raw materials for other industrial uses is anticipated to bring significant benefits to the farmers in the years to come. Hence, to meet out the need of sorghum based industries and to cater the basic requirement of the farming community, identification of genotypes with high, stable yields with drought tolerance capacity

is essential .Based on the importance, a total of 100 sorghum accessions was screened for drought tolerance using drought tolerance indices.

Genetic improvement mainly depends upon the amount of genetic variability present in the population. In the present investigation, an attempt was made to study the genetic variability in germplasm accessions for biometrical traits in order to gather knowledge of yield and yield component characters towards drought tolerance in sorghum crop

Materials and MethodsIn the present investigation comprised of 100

accessions of sorghum, which include local land races, adapted to different agroclimatic zones of Tamil Nadu. The trial was laid out in a randomized block design (RBD) with two replications under two different situations at Department of millets, Tamil Nadu Agricultural University, Coimbatore during 2006-2007. The first set was under irrigation and another set was treated as drought imposed. Water stress was imposed by with

64

holding irrigation at anthesis stage and continued till maturity. One set of treatments with normal irrigations from planting to maturity served as control. The drought indices like drought susceptibility index, relative yield, yield stability ratio were recorded for characterizing the drought tolerant genotypes. Observations on metric traits like plant height, days to 50% flowering, earhead length, leaf area index, relative water content, SPAD chlorophyll reading, root length, root volume, root dry weight, earhead weight, 1000 grain weight, biological weight, stay green score, harvest index and grain yield were recorded on single plant basis for five randomly selected competitive plants in each genotype from replication of each set separately. The genetic information has been sought through analysis of genetic variability, heritability in broad sense and genetic advance as per cent of mean was estimated according to Allard (1960). Phenotypic and genotypic co-efficient variation was estimated as per Burton (1991). Genetic advance as % of mean was estimated according to Johnson et al., (1955).

Results and Discussion The mean, phenotypic (ó2p) and genotypic

variances, the co-efficient of phenotypic and genotypic

variation, heritability and expected genetic advance are given in table 1 and 2. The results furnished hereunder only for the stress condition. The analysis of variance for the various component traits of drought tolerance revealed significant differences among genotypes under study. Based the mean performance, the genotypes such as CO 21, CO 22, Tenkasi 1, AS 2059, AS 2752, AS 5078, AS 5057, AS 8021, AS 4289, AS 8038, AS6616, K 3, MS 7819, MS 7837, Murungapatti local, Uppam cholam, VS 1564, VS 1560, CO 24 and CO 1 recorded good performance and had high mean values for relative water content, SPAD chlorophyll reading, root length, root volume, root dry weight, ear head weight, 1000 grain weight, harvest index, grain yielding and had low score for stay green when compared to other genotypes under stress and they have been reported on par with the drought resistant check B 35. Earlier findings of Nour and Weible (1978), Yadav et al., 2002, Blum et al.,(1989) Jordan and Miller (1890), Xu et al., (2000), Dale et al (1980) on phenotypic and physiological traits for drought resistance were in agreement with the present investigation.

CHARACTERS Grand Range VP V

g PCV% GCV% Genetic

mean advance

Plant height (cm) S 231.31 109.20 - 2718.94 2714.58 22.54 22.52 107.24 347.70 I 238.41 114.5-358 2794.09 2789.74 22.17 22.15 108.72Days to 50% flowering S 66.35 58-74 9.53 8.68 4.65 4.44 5.79 I 63.2 54-72 10.09 9.16 5.04 4.80 5.94Ear head length (cm) S 23.43 8.70-35 17.51 16.17 17.86 17.16 7.96 I 27.03 13.5-37 14.27 12.75 13.98 13.21 6.95Leaf area index S 2.46 1-4.60 0.62 0.61 32.05 31.71 1.59 I 3.04 1.3-5.3 0.69 0.68 27.46 27.19 1.69Relative water content% S 65.3 46.20-79 61.60 59.42 12.02 11.80 15.60SPAD Chlorophyll reading S 31.02 11-48.30 105.37 103.15 33.09 32.74 20.70 I 45.06 30-58 43.38 41.68 14.61 14.32 13.03Root length (cm) S 24.91 9-39.0 31.39 28.76 22.49 21.52 10.57 I 29.61 16.4-42.6 23.72 21.58 16.45 15.68 9.13Root volume (cc) S 21.61 8.40-37 47.63 45.28 31.93 31.13 13.51 I 25.85 11.3-38 39.09 37.11 24.18 23.56 12.22Root dry weight (g) S 24 10.00-36 30.61 28.63 23.05 22.29 10.66 I 25.82 12.4 -38 18.69 16.72 16.74 15.83 7.97Ear head weight (g) S 25.47 9.60-42.80 36.05 34.07 23.57 22.91 11.69 I 32.36 17.3-45.0 24.62 22.50 15.33 14.65 9.331000 grain weight (g) S 26 9.20-41 43.40 41.29 25.33 24.71 12.91 I 29.06 16.1-42.6 27.48 25.38 18.03 17.33 9.97Biological yield (g) S 131.72 80-205.40 538.83 534.44 17.62 17.55 47.42 I 141.97 91.3-218.6 563.35 556.94 16.72 16.62 48.33Stay green S 3.4 1.60-5 0.90 0.88 28.00 27.54 1.90 I 2.32 1.3-4.3 0.54 0.52 31.84 30.96 1.44Harvest index S 0.24 0.09-0.43 0.004 0.004 28.06 27.67 0.14 I 0.29 0.2-0.5 0.003 0.003 21.35 20.74 0.12Grain yield (g) S 31.02 16-46 54.00 51.89 23.69 23.22 14.54 I 40.43 26.6-56.1 38.13 34.90 15.27 14.61 11.64

Table 1. Grand Mean, Range ,Genetic parameters for the drought tolerant component traits. ( I- Irrigated, S-Stress )

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Selection for drought tolerance involves evaluating genotypes for either high yield potential or stable performance under varying degrees of water stress. Drought susceptibility index (DSI) and relative yield (RY) values were used to describe the yield stability and yield potential. Promising drought Tolerant Genotypes identified through drought tolerance indices are given in Table 2.

These genotypes had the low drought susceptibility index (<1) and high relative yield (> mean RY). These results are similar to the findings of Ahmed et al. (2003) where they selected the drought tolerant genotypes based on the low drought susceptibility index and high relative yield and showed that the genotypes with high relative yield performed relatively well under drought.

In general, the estimate of phenotypic co-efficient of variation was higher than those of genotypic co-efficient of variation for all the traits indicating the influence of environment on the expression of these character (Table 1). The data further indicated that characters like stay green, root volume, leaf area index, plant height and harvest index showed high value for phenotypic and genotypic co-efficient of variation. High values of GCV for these characters suggest better scope of improvement by selection. Days to 50% flowering showed the lowest co-efficient of variation at phenotypic and genotypic levels. Similar results were reported for theses traits with respect to PCV and GCV Geleta and Daba (2005).

However it is not possible to determine the amount of heritable variation with the help of genotypic co-efficient variation alone. Burton (1952) suggested that the study of genotypic co-efficient of variation along with heritability estimates is needed to obtain the best results on the extent of heritable variation. Heritability estimate for all the traits for stress condition

was depicted in graph 1. Swarup and chaugle (1982)) reported that heritability estimates along with genetic gain are usually more efficient than heritability values alone in predicting the final out come of selection. In this study, the characters such as stay green, leaf area index, root volume, plant height and harvest index sowed high heritability estimates associated with high genetic advance indicating the presence of additive gene effect. High heritability accompanied by high genetic gain is

an indication of the additive genetic effects (Panse and Suthatme, 1987). Thus selection of these traits is likely to accumulate more additive genes leading to further improvement in their performance and these traits can be used as selection criteria in sorghum drought tolerance improvement programme.All the characters under study exhibited high heritability and expected genetic advance. Among the characters studied, high estimates of heritability (>80%) and genetic advance expected (>40%) were obtained for stay green, leaf area index, plant height, root volume and harvest index. These characters exhibited high heritability along with high genotypic co-efficient of variation indicating importance of additive genetic variance for these characters.

The character days to 50% flowering recorded the lowest heritability estimate indicating larger influence of environmental conditions on these characters.

Based on above discussion, it is suggested that due weightage should be given to stay green, leaf area index, root volume, plant height and harvest index for selection of drought tolerance in sorghum. The genotypes such as B35, CO21, CO22, AS5078 ,K3 ,Murungapatti local ,VS1564, VS1560 , AS6616 , AS8038 , Tenkasi1, MS7819 ,AS2059 AS8021 AS4289, CO24 ,AS2752 ,CO1 were found to be promising for drought and can be used as the parents for future breeding programmes, where the sorghum varietal improvement for drought conditions could be achieved.

S.No. Genotypes DSI RY S.No. Genotypes DSI RY

1 B35 0.48 0.91 10 AS8038 0.58 0.94

2 CO21 0.44 0.95 11 Tenkasi1 0.64 1.00

3 CO22 0.40 0.92 12 MS7819 0.62 0.96

4 AS5078 0.40 0.97 13 AS2059 0.87 0.93

5 K3 0.94 0.96 14 AS8021 0.55 0.94

6 Murungapatti local 0.81 0.93 15 AS4289 0.21 0.93

7 VS1564 0.42 0.96 16 CO24 0.78 1.00

8 VS1560 0.92 0.94 17 AS2752 0.49 0.95

9 AS6616 0.66 0.91 18 CO1 0.72 0.82

Table 2. Promising Drought Tolerant Genotypes

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References1. Allard , R.W.(1960).Principles of plant breeding, pp. 89 � 98 ,John Wiley and Sons, Inc.New York2. Blum, A., J. Mayer and G. Golan. 1989. Agronomic and physiological assessments of genotypic variation for

drought resistance in sorghum. Aust. J. Agric. Res., 40: 49-61.3. Burton, G. W. 1952. Quantitative inheritance in grasses. Proc. 6th int. Grassland Cong., 1: 24 - 84.4. Dale, R. F., D. T. Coelho and K. P. Gallo.1980. Prediction of daily green leaf area index for corn. Agron. J., 72:

999-1005. 5. Geleta, N. and C. Daba. 2005. Inter relationships among quantitative traits in sorghum (Sorghum bicolor (L.)

Moench) landraces from Northern Ethiopia. Crop Res., 30(3): 432-438.6. Johnson, H.W., H.F. Robinson and R.E. Comstock. 1955. Estimates of genetic and environmental variability in

soybean. Agron. J., 47: 314-318.7. Jordan, W.R. and F.R. Miller. 1980. Genetic variability in sorghum root systems: implications for drought tolerance.

In „ Adaptation of plants to water and high temperature stress‰.N.C. Turner and P.J. Kramer (Eds.). John wiley, Newyork, pp. 383-399.

8. Nour, A.E.M. and D.L. Weibel. 1978. Evaluation of root characteristics in grain sorghum. Agron. J., 70: 217-218.

9. Panse, U. G. and P. V. Sukhatme. 1961. Statistical method for Agricultural workers. ICAR, New Delhi. pp.381.10. Swarup , V. and Chaugle,D.S.(1982). Studies on genetic variability in sorghum 1. Phenotypic variation and its

heritable componet in some important quantitative characters contributing towards yield. Indian J. Gene. 22 : 31 � 36.

11. Xu, W., D.T. Rosenow and H.T. Nguyen. 2000a. Stay green trait in grain sorghum: Relation ship between visual rating and leaf chlorophyll concentration. Plant Breed., 119: 365-367.

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67

Effect of Mulching, Irrigation and Growth Regulants on

Growth and Yield of Curry Leaf In Winter

P. Jansirani*, R. Subha**, D. Durgadevi*** and K. Rajamani*

15

IntroductionCarry leaf (Murraya Koeingii) is an important

herbal spice crop grown for its aromatic leaves. An essential volatile oil extracted from its fresh leaves is commercially exploited. Both of its fresh leaves and essential oil has got export value curry leaf has greater use as antioxidant and anticarcinogenic potential properties. Though Tarai region (Uttar Pradesh) is considered as the probable origin curry leaf is cultivated commercially in few southern states of India. The annual growth pattern of curry leaf showed that it has peaks in monsoon and summer and its growth is limited during winter season. However, the demand for fresh curry leaf is ever growing throughout the year. The market price analysis indicated a high returns with poor crop during winter i.e. during the months of November, December and January. Proper cultivation and management practices of this commercially important crop is to be analyzed to fetch continuous and the maximum returns throughout the year.

Earlier reports are available on manipulation of crop growth through some agronomic practices and application of chemicals etc. in many horticultural crops viz., annual moringa (Vijayakumar, 2001), Okra (Maheskumar and Sen, 2005). With this back ground in view, an investigation was carried out to study the effect of mulching application of nutrients, growth regulants on growth, yield and quality of curry leaf during winter.

Materials and MethodsThe investigation was carried out to study of

different mulches and efficacy of growth regulants on growth and yield of curry leaf during winter season. The field experiment was conducted from October 2006 to January 2007 in a farmerÊs field at Karamadai in Mettupalayam block of Coimbatore district of South India. A local collection of curry leaf viz., Senkaampu of 5 years old plants is utilized for the study. The crop is grown under organic manures mainly. However, little amount of inorganic fertilizers are applied at the rate of 100 g of NPK per plant after pruning of every crop.

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Regular cultural operations were followed as per the standardized package of practices to curry leaf.

The experiment was laid out in randomized block design with eleven treatments and replicated thrice. The treatments were, mulching with block polythene sheet (200 microns) (T1), mulching with coir pith (T2), irrigation (T3), water spray (T4), foliar spray of Panchagavya (three percent) (T5), foliar spray of GA at 50 ppm (T6) urea at 0.5, percent (T7), Humic acid 0.2 percent, (T8), Salicylic acid 100 ppm (T9), Salicylic acid 200 ppm (T10) and control (T11). Water spray and surface irrigation in the early morning hours were given once in 15 days.

The plant biometrical traits, viz., plant height number of secondary branches per plant, number of leaves per rachis, fresh leaf weight per rachis (without petiole) fresh leaf yield per plant, shelf life and essential oil content were recorded and analyzed statisfically (Panse and Sukhatme, 1985).

Results and DiscussionFresh curry leaf was harvested during January

2007 after four months of treatments application. The results of the study revealed (Table 1) that the mean performance of plant height in all the treatments ranged from 81-91 cm in control (T11) to 99-91 cm in T5 (Foliar spray of panchagavya three percent) followed by T8 (foliar spray of (Humic acid 0.2 percent) as 98.62 cm. The number of secondary branches per plant and number of leaves per rachis were also found to he the highest inT5 (the plants sprayed with panchagavya three percent) as 22.23and 18.25 respectively. The possible reason for the acceleration of growth by the application of panchagavya might be due to presence of more of nitrogen, the chief constituent of protein essential for the formation of protoplasm which led to cell division and cell enlargement (Balkey, 1974). During winter season, increase in number of laterals by the application of panchagavya might be due to increase in osmotic effects and uptake of nutrients as confirmed by Sridhar (2003) in Solanum nigrum. The increased number of leaves per rachis was due to the increased meristammatic activity in the plant and enhanced supply of photosynthates (Khandif, 1998).

The fresh leaf weight without petiole and fresh leaf yield per plant was observed to be the highest in plants sprayed with panchagavya three percent and similar results were observed by Sivakumar (2004) in Solanum.

Among the treatments of the present study to increase the fresh curry leaf yield per plant, application of three percent panchagavya (T5) was found to record the highest fresh leaf yield of 450.65 g per plant. It was also noticed that the treatments T8 � humic acid 0.2 percent spray (438.74 g) and T2-mulchingwith coir pith (435.65g), were also found to record a considerable yield increase next to the best treatment (T5).

The quality traits viz., shelf life of fresh leaves under ambient temperature (4.0 days) in poly bags with five percent vent and essential oil content (0.187 per cent) were also observed to be the highest in plants sprayed with panchagavya three percent. Similar influence of panchagavya on quality improvement as enhancement in essential oil content was reported in advance by Krishnamoorthy (1985), Arularasu (1995) in ocimum sanctum.

At farmerÊs point of view cost economics plays a vital rate in adopting any new crop production practice. The ultimate goal is to help the grower to get more profit with lesser input cost.

The best treatment identified as foliar spray of three percent panchagavya is recorded the highest cost : Benefit ratio of 1:5.77 during winter season of curry leaf production. It was also observed that curry leaf plants supplied with simple irrigation in the early morning (T3) hours once in 15 days during winter months was also observed to improve the fresh curry leaf yield considerably which is expressed in terms of higher best benefit ratio of 1:5.00 (except with 0.2 percent humic acid spray.(T8)).

Hence, it could be concluded that the simple irrigation in early morning hours in winter months to curry leaf is a cost effective technology to increase the fresh curry leaf yield next to foliar spray of panchgavya three percent.

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Reference

1. Arularsu,P. (1995). Effect of graded doses of nitrogen and spacing on growth and yield of herbage and oil in Tulsi (Ocimum sanctum L.) M.Sc. (Hort.), Thesis, TNAU,Coimbatore.

2. Balkly, S.A. (1974). Effect of fertilization treatments on the yield of Chrysler Imperial rose plants. Agri Res. Rev. 52 (9) : 95-99.

3. Khandait, H.M. 1991.Standardizationof nitrogen, phosphorus and potato levels for flower production of annual chrysanthemum cv. Yellow. M.Sc. Thesis Dr. Punjab Deshmukh Krishi, Vidyapeeth (PDKV), Akola, Maharashtra, India.

4. Krishnamoorthy, R., 1985. Studies on the effect of nitrogen, phosphorus and potassium on growth, her bage yield and essential oil production in Davana (Artemosia pallens wall.) M.Sc.(Hort.). Thesis, U.A.S. Bangalore, India.

5. Mahesh Kumar and N.L.Sen, 2005. Effect of zinc, Boton and gibberellie acid on growth and yield of okra. The Orissa Journal of Horticulture, Vol. 33(2) : 46-48.

6. Panse, V.G. and P.V. Sukhatme (1985). Statistical methods for agricultural wowrks. IVth Edn., ICAR, New Delhi.

7. Sivakumar, V. 2004. Studies on standardization of protocol for maximization of growth, yield and alkaloid content in Black nightshade (Solanum nigrum L.) M.Sc. (Hort.). Thesis. Tamil Nadu Agricultural University, Coimbatore, India.

8. Sridhar, T. 2003. Effect of bioregulators on Black nightshade (Solanum nigrum L.),M.Sc. (Ag.), Thesis, Tamil Nadu Agricultural University,Coimbatore-3,India.

9. Vijayakumar,R.M. (2001, Studies on influence of months of sowing and growth regulation on Annual Moringa, Ph.D. Thesis, HC&RI, TNAU,Coimbatore-3.

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Table : Effect of mulching, irrigation and growth regulants on growth and yield of Curry leaf during winter season

Treatments Plant No. of Leaf Fresh Fresh Shelf Essential C:B height Secondary number leaf leaf life oil ratio (cm) branches per weight yield (day) content rachis without per (percent) petiole plant (g) (g)

T1 93.69 20.12 17.18 1.099 395.87 2.92 0.134 1:3.69

T2 91.53 19.02 16.43 1.265 435.65 2.85 0.136 1:4.80

T3 92.44 19.01 15.56 1.024 405.27 2.50 0.121 1:5.00

T4 92.72 17.08 15.23 1.012 380.34 2.00 0.137 1:4.69

T5 99.91 22.23 18.25 1.275 450.65 4.00 0.187 1:5.77

T6 91.62 20.18 14.49 1.124 350.56 3.50 0.126 1:4.64

T7 85.21 18.34 15.89 1.157 340.71 3.00 0.165 1:4.50

T8 98.62 21.28 17.34 1.196 438.74 3.96 0.171 1:5.73

T9 90.52 17.45 16.49 1.024 310.73 2.56 0.119 1:4.09

T10

85.27 18.42 15.68 1.101 330.54 3.00 0.117 1:4.33

T11

81.91 14.25 13.83 0.960 305.63 2.00 0.122 1:4.10

Mean 91.22 18.85 16.03 1.107 376.79 2.935 0.139

CD at 5% 93.03 2.168 1.866 0.128 42.566 0.281 0.014

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Horticultural Technologies for Watershed Development

P. Paramaguru1 P. S. Kavitha2 and M. Velmurugan3

16

IntroductionAsia emerges as the hot spot for poverty,

malnutrition and also for severe land degradation in the world. In India, the situation is similar as out of 8.52 million poor, 2.21 million are in India and 108.6 Mha are degraded. There is an urgent need to break the unholy nexus between drought, land degradation and poverty using community watersheds to manage the natural resources such as water and land sustainably for improving livelihoods. Watershed approach is adopted by Government of India as a growth engine for development of rainfed areas.

Watershed The watershed is a continuous area whose runoff

water drains to a common point, so that it facilitates water harvesting and moisture concentration.

The main principles of watershed management are :

Utilizing land according to its capacity and putting adequate vegetal cover on the soil.

Conserving as much rainwater as possible at the place where it falls both at farmlands and common property resources.

Draining out excess water with a safe velocity and diverting it to storage ponds and storing it for future use.

Avoiding gully formation and putting checks at suitable intervals to control soil erosion and recharge ground water.

Maximizing productivity per unit of area, per unit of time, and per unit of water.

Increasing cropping intensity and land equivalent ratio through intercropping and sequence cropping.

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Safe productive utilization of marginal lands through alternate land use system.

Ensuring sustainability of the eco-systems benefiting the man-animal-plant-land-water-complex in the watershed.

Maximizing the combined income from the interrelated and dynamic crop-livestock-tree-labour-complex over the years.

Stabilizing the total income and cut down risks during aberrant weather situation.

Improving infrastructural facilities like storage, transportation and marketing.

Arid & Semi Arid ZonesArid and semi-arid regions occupy large part

of geographical area of India. The arid region receives less than 450 mm annual rainfall against 450-850 mm rainfall in semi-arid region. The evapotranspiration is 4-5 fold higher than that of rainfall in the arid region, while it is only two times higher in the semi-arid region. Natural resource base is quite fragile in the arid zone. The hot arid zone is characterized by extremes of temperature (-2 to 480 C), high solar radiation incidence (450 to 500 cal per sq. cm/day) and high wind velocity. The scare low rainfall (100-400 m) is also spread over in 9-21 spells. The soil is generally light textured with 60-90per cent sand and therefore water holding capacity of the soil is very poor.

The importance of weather assumes a greater significance in rain fed regions. The elements of weather that characterize the agro climatic environment act as a natural resource influencing the cropping are rainfall, temperature, sunshine, wind regime, humidity, and radiation. The choice of cropping system is mostly governed by the length of the growing period. The weather during cropping season strongly influences the crop growth and it accounts for 2/3rd (67%) of the variation in productivity, while other factors including soil and nutrient management accounts for 1/3rd (33%) of the productivity. Considering the above points it is advisable to plan the crops in the watersheds viz fruit crops, Vegetables, Medicinal plants, Multipurpose trees.

Selection of Crops Horticulture based land use is being increasingly

considered in developmental plans both in arid and semi-

arid regions. The climatic conditions are conducive for production of quality fruits and vegetables. The marked fluctuations in night and day temperature and low RH helps in development of sweetness and attractive colour in fruits and disease-insect incidences are comparatively low in such climatic situations.

Abiotic stresses owing to scanty rainfall, high summer temperature, high solar radiation, high wind velocity, high salinity in irrigation water is also associated with crop failures. In arid environment, monoculture system is risk prone as well as less productive.

An integrated approach to develop the farming systems, and promote horticulture-based land use systems which have already found to be viable and suitable for different terrains is to be followed. Following strategy is proposed:

(a) Identification of potential areas for expansion under rainfed, full and partially irrigated horticulture enterprises, using satellite data, Digital Image Processing Technique and GIS, followed by delineating potential areas for specific crops on cluster basis in a given location.

(b) Emphasis should be on commercially important crops such as follows:

a. Fruits : Ao n l a , C a s he w, Ber, Bael, custard apple, Tamar ind, pomegranate, date palm, fig, Karonda etc.,

b. Vegetables : Brinjal, Muskmelon, watermelon, Round melon, Chilli, tomato, m o r i n g a , c u r r y leaf, chekurmanis, Vegetable cowpea, cluster bean,

c. Spices : Cumin, fenugreek, anardana, garlic and chillies

d. Ornamentals : Rose (Rosa damascena) for essence

e. Medicinal plants : S e n n a , C o l e u s , periwinkle. Gloriosa, Aloe vera etc.,

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Multipurpose Tree CropsThe multi purpose Tree Species (MPTS) can

also be grown in these areas. The trees grown in dry lands take 5-8 years to cover the inter space and suitable intercrops with rain fed annual crops can be grown.

Selection of suitable VarietiesAonla : NA7, Krishna, Kanchan and BSR 1

Bael : NB 5, NB 9

Ber : Umran & Kaithali

Custard apple : Balanagar, mammoth

Mango : Neelam, Banganapalli, Alphonso, Kalepad

Pomegranate : Jothi, Ganesh

Sapota : PKM 1, PKM 4 & PKM 5

Tamarind : PKM 1 & Urigam

Land use systemsMixed Planting of Fruit Trees

An approach to optimize resource use by systematic arrangement of diverse plant canopies with varying growth habits. Alignment of plants of slow and fast growing types and those with early or late fruit bearing habits in different formations is the mainstay of the proposed land use. The key principle is to combine plants of slow and fast growing types, early and late bearing fruit plants. Fruiting of drumstick and custard

apple started from the third year. A few encouraging mixed planting systems are given below:

(i) Ber/guava + Tamarind/mango in 4: I ratio

(ii) Pomegranate + Sapota/aonla in 4: I ratio

(iii) Drumstick + Tamarind/wood apple in 4: I ratio

(iv) Custard apple + jamun in alternate pits/rows

(v) Pomegranate/phalsa + Sapota/aonla in alternate

pits/rows

(vi) Mango/sapota + papaya in alternate pits/rows

Hortipastoral System

A combination of fruit trees and pasture species commonly known as „hortipastoral system‰ is one of the several ways to satisfy human needs and alleviate cattle hunger. A hortipastoral system comprising of hardy fruit trees is advocated for land capability class (LCC) III and IV. Two fruit species, viz., guava and custard apple with 6 m × 6 m spacing and interspaces utilized for raising stylo or Cellchrus by dividing each fruit block into three.

Silvipastoral System

Marginal dry lands are usually shallow and poor in nutrients. Yield of arable crops from these lands are low, uncertain and often not remunerative. The returns from these lands may improve if they are put to an

Table 1: Crops suitable for dry lands

S.No Category Common name Scientific name

1. Fruit crops Mango Mangifera indica Red soil with minimum irrigation Guava Psidium guijava Sapota Achras sapota Pomegranate punica granatum

Rain fed regions Ber Ziziphus mauritiana Cashew Anacardium occidentale Tamarind Tamarinds indica Anona Annona squamosa Aonla phyllanthus emblica

2. Multi purpose tree Albizia Albizia lebbeck Semi arid red soils Leucaena Leucaena leucocephala Acacia Acacia auriculiformis Karuvel Acacia nilotica Semi arid black cotton soils Acacia Acacia procera Acha Hardwichia binata Sesbania Sesbania spp. Neem Azadirachta indica

Saline & alkaline soils Acacia Acacia nilotica Dalbergia Dalbergia sisoo Pongam Pongamia pinnata Albizia Albizia procera

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alternate land use like silvipasture. Silvipasture system apart from yielding fuel wood and fodder, improves the soil fertility. After one rotation with silvipasture system say, 6-8 years arable crops can be grown on the built up soil fertility, without fertilizer application.

Cropping System No. of fruit trees

Guava+ no pasture 90

Guava + stylo 63

Guava+ Cenchrus 38

Custard apple+ no pasture 73

Custard apple+ stylo 73

Custard apple+ Cenchrus 73

Horticulture techniques

Mulching Mulching minimizes water losses from soil surface

as a result of solar radiation and wind action and by suppressing weed growth. Mulch also prevents erosion and adds organic matter to the soil and keeps it cool. Materials such as hay, straw, cutgrass, dry leaves, weed materials and polythene can been used for mulching.

Crop Suitable mulching materials 1. Banana black polythene2. Ber black polythene3. Citrus dry leaves / grasses 4. Mango black polythene 5. Pomegranate Sugarcane trash / paddy husk

Vegetative BarriersVegetative barriers with Vettiver/cenchrus can

be planted in zigzag manner to conserved soil moisture and it will bind the soil particles thereby preventing soil erosion.

Use of Anti-transpirantsAnti- transpirants are the substances which

reduces water loss in the dry region crop plants.

1. Film forming type eg., wax/plastic emulsion spray.

2. Reflectant type eg., White wash @ 2% or Kaolinite clay @ 3%.

Selection of Planting Materials The planting materials are of prime importance

in the fruit orchards. They should be originated from quality scion materials and proper grafting should be done in the growth phase and union of graft should be proper and uniform. Pre sowing hardening / pelleting of seeds is one of the methods which results in modifying the physiological and biochemical nature of seeds so as to get the features that are favourable for drought tolerance. Some of the chemicals used are CCC, NaCl, CaCl

2, ZnSO

4 and MnSO

4.

Establishment in FieldPlanting time and planting spot (microsite) is a

pre-requisite for success of any perennial plants on dry lands. This should be coupled with timely planting (with onset of monsoon), so that the saplings establish well before cessation of rains and become hardy enough to pass through the first summer.

Establishment in the field can be achieved by timely planting. In Tamil Nadu June � July is the time suitable for planting in western districts where the rains from South West monsoon are received. The planting time for other districts are September � October, where the rains are received due to North East monsoon during this months. Staking and tieing the grafted plant with 8 type of knot will make the plant to have more anchorage and withstand the heavy winds. Protecting the young plant (saplings) from the sunlight has also to be done. The leaves of coconut or Palmyrah may be staked both in Eastern and Western side to protect the plants from sunlight.

Hardening of planting materials viz, layers, grafts and budlings are necessary to get increase in success rate. Partial and slow exposure to sunlight will allow the plants to suit to the filed conditions and there by the success rate is increased.

Water Harvesting TechniquesIn arid and wasteland water is a major constraint.

The ground water potential is low and the available water may also be saline or alkaline. Hence, the available rainfall should be harvested in an effective way. Following are some of the successful rain water harvesting techniques that can be adopted in arid and waste lands.

74

Farm PondsFarm ponds are small tanks constructed to collect

surface run off. Some ponds get water from surface run off and some from ground water seeping into the pit. The water stored can be used directly for irrigation, for the cattle, fish production etc.

Percolation Ponds

Percolation ponds are small water harvesting structures constructed across small natural streams and water courses to collect and impound the surface run off, during monsoons.

Drainage Line TreatmentsThe soil gets eroded through rain splash in

the form of sheet, rill and gully erosion. Unattended development of rills leads to formation of gullies. The best way to control the gullies is to vegetate the surface of the gully to protect it from further development. Temporary gully control structures like brush wood dam, loose rock dam, wire woven dam etc, made of cheap and locally available materials can be established.

Effective Water UtilizationThe fruit crops in arid and wasteland can be

grown under drip system of irrigation for the effective utilization of available water. Drip / micro irrigation has emerged as an ideal technology, through which the required amount of water is applied to the root zone of the crop by means of a network of pipes in the form of drippers. The efficacy under micro irrigation is as high as 80 � 90 percent. The system permits the use of fertilizers, pesticides and other water soluble chemicals along with the irrigation water at optimum levels.

Soil ConservationNature takes about 110 years to form 1 cm thick

top soil and it could be brought down to 11 years by intensive cultivation practices. In arid and wastelands, the soils are not productive. They are less in nutrients and are affected by wind erosion. Saline and alkaline conditions are more prevalent. This necessitates soil conservation in these areas. The following soil conservation approaches have to be followed (Shanmugasundaram, 2005).

Contour BundingThe construction of small bunds across the slope

of the land on a contour is contour bunding. The long slope is cut into a series of small ones and each contour bund acts as a barrier to the flow of water. Contour bunds are constructed in relatively low rainfall areas, having an annual rainfall less than 600mm, particularly in areas having high textured soils.

Graded BundsGraded bunds are constructed in medium high

rainfall areas having an annual rainfall of 600 mm and above and in the lands having slopes between 2% and 6%. These bunds are provided with a channel if necessary.

Contour TrenchesContour trenching is excavated trenches along

a uniform level across the slope of the land in the top portion of catchments. Bunds are formed down stream along the trenches. The main idea is to create more favorable moisture conditions and thus accelerate the growth of planted trees.

Staggered TrenchesStaggered trenching is excavating trenching of

shorter lengths in a row along the contour with interspace between them. In Tamil Nadu, contour and staggered trenches are adopted in high rainfall hilly areas of lands with slopes steeper than 3%.

Bench TerraceBench terracing is one of the most popular

structural soil conservation practices adopted by the farmers of India and other countries for ages on sloping and undulating lands. Intensive farming can be adopted in these bench terraces.

Contour Stone WallIn this cut stones of size around 20 � 30 cm are

dry packed across the hill slope to form a regular shape of random rubble masonry without mortar.

Canopy ManagementManagement of canopy of fruit trees by training

& pruning is an important horticultural practice where in the trees will be able to overcome the drought situations and sturdy ness to with stand the wind and to increase flowering.

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Integrated Nutrient ManagementThe arid and wastelands are poor in nutrition.

The nutrient status is aggravated due to frequent drought as well as run off. The critical soil fertility related issues in drylands are runoff, poor organic matter, poor physical properties and management practices. To grow fruit crops in this region it is essential to manure organically. The constraints of nutrient management can be overcome by integrated nutrient management with application of FYM, Green manures, biofertilizers, Neem cake, vermicompost and application of fertilizers when moisture is available can be practiced in water sheds.

Strategies for Development of Watersheds

1. Diversified and sustainable production systems through practices such as crop diversification, integrated nutrient management, integrated pest management efficient in of harvested rainwater, tree bound farming like agro-forestry, crop rotation, intercropping and contingent crop planning to meet weather aberration can be promoted.

2. Suitable farming system models involving Agriculture, Horticulture, Forestry, Dairy, Poultry, Sericulture, Bee keeping, Fisheries etc., suitable for a given location to achieve more income and more yields per ha of land per unit time can be adopted.

3. Water saving agronomic practices, pressurized systems viz., sprinkler, drip, trickle irrigation which have already have been accepted needs further support and funding.

4. In the crop improvement programmes too, development of varieties suitable to rainfed agriculture or assumes greater importance. The important crops are sorghum, maize, pearl millet, millets, groundnut, sunflower, pigeonpea, greengram and blackgram.

5. Indigenous technical know how of farmers and technologies are being documented and evaluated. These technologies need be popularized through the farmer � to farmer, innovative research and adoption programmes.

6. For dryland zone, dry land horticultural corps like mango, sapota, guava, ber, jack, lime, pomegranate, grapes, coconut, banana, cocoa, coffee, areca etc., in place of irrigated crops may be considered with a backstop on marketing.

7. Efficient management of marginal and shallow lands through alternate land use systems. Multipurpose trees like Subabul, Pongamia, Gliricidia, Sesbania etc. may be promoted.

8. Improve in livestock through improved availability of fodder and better nutritional status and strengthen livestock support services.

Conclusion Shifting of low value crops to high value

commodities like fruits, vegetables and medicinal crops under watershed programme will generate more income in drylands and also will provide more employment

Fruit crops Canopy management

Mango � Overlapping, intercrossing, diseased, dried and weak branches have to be pruned during august-September, once in three years.

� Root stock sprouts have to be removed Guava � Pruning of past season terminal growth to a length of 10 to 15 cm is to be done during Sep-Oct and Feb-March � Erect growing branches are to be bent by tying on to pegs. Sapota � Root stock sprouts, water shoots, criss cross and lower branches has to be removed Pomegranate � The past season shoot has to be pruned by removing 1/3rd of the length Ber � Root stock sprout has to be removed and a straight stem up to 75 cm from the ground level has to be trained � Pruning in Feb-March to remove crowded branches Aonla � Main branches should be allowed to appear at a height of 0.75 to 1.0m above the ground level � Plants are trained to modified central leader system � During March-April pruning and thinning of crowded branches may be done Cashew � Trunk is developed to a height of 1m by removing low lying branches Tamarind � Root stock sprouts are to be removed � Dry and diseased parts are to be removed

Table 1. Canopy management in fruit crops

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opportunities for the rural poor. Further, watersheds have to be linked with markets and proper infrastructure facilities have to be created for storage, transportation and processing, since all fresh horticultural produces are highly perishable.

In the context of changing global policy environment due to WTO, it is necessary to adhere

to the international quality standards by following the hazard analysis and critical control point (HACCP) guidelines, Codex standards. India should not loose site of advantages of dry climatic conditions of arid/semi-arid regions for enhancing export promotion of selected horticultural crops.

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77

Production Potential and Water Use Efficiency of Various

Cropping SystemsS. Porpavai, P. Devasenapthy, T. Jayaraj and K. Sathiyabama

17

IntroductionRice followed by rice is the cropping system

prevailing in Thanjavur district. Recent past the farmers are unable to cultivate rice crop in time due to delayed release of water from Mettur Dam. Considering water availability, labour demand and economics of cultivation, it is felt that rice based alternate cropping system with inclusion of pulses, vegetables and oil seeds to suit our existing situation is necessary to save water, to improve the soil health and economic status of the farmers. Hence the present experiment was conducted to find out the possibility of raising crops other than rice in Kuruvai and Summer seasons and to find out the production potential and WUE.

Materials and Methods Field experiments were undertaken during

2000 � 2005 at Soil and Water Management Research Institute, Kattuthottam, Thanjavur under All � India Co�ordinated Research Project on cropping systems,

to identify the appropriate alternative, need based and profitable cropping systems for Cauvery new delta zone of Tamilnadu. Treatments comprised of ten rice based cropping systems, viz., rice � rice � black gram , rice � rice � sesame, rice � rice � bhendi, Lab-Lab � rice � maize, onion � rice � blackgram, rice�rice � onion, bhendi � rice � radish, maize � rice � sesame , groundnut � rice � blackgram and rice � rice·greengram were evaluated for their production potential and economics in randomized block design with four replications. The crops were raised under irrigated condition with recommended package of practices. Production � efficiency values in terms of kg / ha / day was calculated by total productivity and net monetary returns of the rotation divided by total duration of the crop in that rotation (Tomer and Tiwari, 1990).

Results and DiscussionProduction efficiency

The production efficiency was the maximum in onion � rice � blackgram (79.5 kg / ha / day) followed by

78

bhendi � rice � radish (71.3 kg / ha / day) sequence due to higher yield and net returns. The lowest production efficiency (38.9 kg / ha / day) was noted in the Lab-Lab � rice � maize system. This was obviously due to less production.

Production Efficiency and Water Use Efficiency in Different Cropping Systems

Water Use Efficiency (WUE)In kharif season the highest WUE was obtained

in bhendi followed by onion and maize. Both bhendi and onion being a vegetable crop recorded higher yield and WUE. In rabi season, no appreciable difference in WUE was observed where rice was grown in all the treatments. During summer season radish recorded the highest WUE followed by bhendi and maize.

Among the ten cropping sequences, maximum WUE was obtained in the bhendi � rice � radish cropping sequence followed by rice � rice � bhendi and onion �

rice � blackgram. This may be due to higher system productivity.

Treatments Crop sequence Production WUE kg/ha/cm efficiency (kg/ha/day) Kharif Rabi Summer Total

T1 Rice - rice - blackgram 53.5 65.03 60.93 50.56 176.52

T2 Rice - rice - sesame 47.7 65.82 60.80 30.72 157.34

T3 Rice - rice - bhendi 59.2 65.72 61.11 134.00 260.83

T4 Lab lab - rice - maize 38.9 41.45 61.20 100.14 202.79

T5 Onion - rice - blackgram 79.5 128.56 63.44 51.60 243.60

T6 Rice - rice - onion 61.0 65.16 60.63 78.80 204.60

T7 Bhendi - rice - radish 71.3 150.75 59.14 162.70 372.60

T8 Maize - rice - sesame 42.7 102.56 58.50 31.00 192.06

T9 Groundnut - rice - blackgram 50.7 57.00 61.20 53.00 171.20

T10 Rice - rice - greengram 53.7 64.10 59.63 53.56 177.30

CD (P = 0.05) 3.12 NS 2.35 8.05

References1. Tomar, S. S and Tiwari A. S 1990. Production potential and economics of different crop sequences. Indian Journal

of Agronomy 35 (1 and 2): 30 � 35.

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79

Inter Row and Inter Plant Water Harvesting Systems on The

Productivity of Rain Fed Pearl Millet Under Vertisol of Semi-

Arid RegionT. Ragavan, N. S. Venkataraman, T. Saravanan and S. Somasundaram

18

IntroductionPearl millet (Pennisetum glaucum L.) is one of

the most important cereal crop grown in India, especially under dry land conditions, Because of its potential for high grain and dry matter production under water deficit and high temperature conditions it has made a mark in drought prone areas. Rainfed pearl millet occupies 1.52 lakh hectare in Tamil Nadu with average productivity of 1121 kg ha-1. More over, in the event of delayed on set of North East Monsoon rainfall considerable sorghum and cotton area under rainfed will be occupied by pearl millet. In this context, enhancement of individual farm productivity will be useful to increase over all production of pearl millet in southern zone of Tamil Nadu during Rabi season with average rainfall of 415 mm, distribute in 23-28 days. Because of low and erratic distribution of rainfall the total production and productivity per unit area from these areas are very low. One way of improving the productivity in rainfed lands is to adopt moisture conserving techniques to make available and best use of rain water. Moisture conservation has long been recognized as a kind of managemental insurance

against risks under aberrant rainfall behaviour of dry land environment. In addition, equalizing nutrient harvest and its addition is a pre requisite in sustaining productivity goals. Further an abated up rise in the use of fertilizers can inflict irreparable damage to land and environment. An integrated nutrient management aims at sustainable productivity with minimum deleterious effect of chemical fertilizers (Abrol and Katyal, 1990). Hence an attempt has been made to evolve suitable moisture conservation techniques with integrated nutrient management for increasing the productivity of pearl millet under rainfed vertisol condition.

Materials and MethodsA field experiment was conducted at Agricultural

Research Station, Kovilpatti during North East Monsoon season of 2002 and 2003. The experiment was conducted in split plot design and replicated thrice. The soil at experimental site was black soil classified under the family of Typic chromusterts with low in available N, P and medium in available K and soil PH was 8.1. The soil texture is clayey with the bulk density of 1.27 kg/ m3 with a field capacity of 35 per cent and permanent

80

wilting point of 14 per cent. The pearl millet cultivar ICMV 221 was used as a test crop. The water harvesting and conserving practices constituted the main plot treatments viz., sowing across the slope (M

1), ridges

and furrows with tide ridging (M2), paired row sowing

30/60 cm and opening wider row at 35 DAS(M3),

intercropping with short duration cowpea (C.152) in 2:1 ratio (M

4) and farmers practice (M

5). The sub plot

constituted with 100% RDF (N1), 50% RDF + FYM 2.5

t ha-1 (N2), 50% RDF + Bio-fertilizer (N

3), 50% RDF +

FYM+ Bio- fertilizer (N4). The soil of the experimental

site was vertisol (Typic Chromusterts) with PH of 8.1. The rain fed region of this tract experiences with annual rainfall of 721 mm and seasonal rainfall during North East Monsoon of 385 mm received in 27 rainy days. Further, this region is having intermittent dry spells during the growth season with unpredictable frequency. The crop was sown with a spacing of 45x15 cm during 41st standard week by dibbling. The recommended dose of fertilizers 40kg N +20 kg P

2O

5 ha-1 was applied as per

the treatments. The bio-fertilizer (Azospirillum) as soil application @ 2 kg ha-1 was applied immediately after sowing.

Results and Discussion

Effect of Water Harvesting SystemsAmong the inter row and inter plant water

harvesting systems, the ridges and furrows with tied ridging(M

2) recorded significantly higher grain yield of

pearl millet (1982 kg ha-1) as well as gross monetary returns (Rs.11892) over rest of the insitu moisture harvesting and conserving techniques. The net returns (Rs. 6523) and B: C ratio (2.21) was also higher with this treatment. The ridges and furrows with tied ridging method of moisture conservation prevent runoff of water and enhance entry of rain water in to the soil profile. Thus ensuring higher soil profile moisture content favourable

for better plant growth and development. This is in conformity with the findings of Thumbare and Bhoite (2003). Sowing of Pearl millet in paired row 30/60x15 cm with opening of furrow in wide space at 35 DAS (M

3)

was found to be best next to the M2 in terms of higher

grain yield and B: C ratio. (Table.1)

Effect of Nutrient Management SystemIn the nutrient management system, application

of 50 per cent recommended dose of fertilizers along with 2.5 t ha-1 of farm yard manure and bio fertilizer ( Azospirillum @ 2 kg ha-1)as seed and soil application registered significant increase in the grain yield (1954 kg ha-1) with net return and B:C ratio (1.98). Adequate availability of nutrients with conserved moisture through various measures helps in improving the crop growth and productivity. The integrated nutrient management system not only helps for the better growth and development under rain fed lands but also improves the soil health, especially water holding capacity and organic carbon content and ultimately resulted with higher productivity of crops. These results are in agreement with the finding of Wani et al (1997) and CRIDA (2002).

Soil Moisture ContentThe soil moisture content at different stages

of the crop growth due to water harvesting systems revealed that the soil moisture content at all the stages was higher where moisture conservation practices were followed which has helped in better utilization of applied fertilizers ultimately resulted with higher yield (Fig.1). This in agreement with the findings of Reddy et.al(2005). The higher soil moisture content was comparatively higher at ridges and furrows with tied ridging method of moisture conservation (M

2) followed by (M

3). The inter row and

intra row water harvesting systems maintained slightly higher moisture at all the growth stages of pearl millet compared to the farmers practice.

ReferencesCRIDA, 2002. Annual Progress Report. Central Research Institute for Dry land Agriculture,Hyderabad.Reddy, B.N., C.V. Raghavaiah, M. Padmaiah and P.Murali Arthanari.2005. Performance

of Castor (Ricinus communis L.) cultivars under moisture and nutrient constraints in alfisols of semi- arid tropics.

Thumbare,A.D and S.U.Bhoite,2003. Effect of moisture conservation techniques on growth and yield of pearl millet -chick pea cropping sequence in a water shed, Indian J.Dry land Agric. Res. And Dev., 18(2):149-151.Wani, A.G.,A.D.Tumbare. T.M.Bhale and S.H.Shinde. 1997. Response of pearl millet to N and moisture conservation

practices under rain fed conditions. Indian J. Dry land Agric. Res. And Dev., 12(2):130-132.

81

Fig. 1. Soil moisture content (%) under different inter row and inter plant water harvesting systems.

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Table 1. Effect of different inter row and interplot water harvesting and nutrient Management systems on the grain yield and economics of pearl millet.

Treatments Grain yield (kg ha-1) Gross income Net income B:C ratio

M1 1492 8952 4089 1.84

M2 1982 11892 6523 2.21

M3 1825 10950 5587 2.04

M4 1628 11580 6000 1.97

SEd 43.5 - - -

CD (0.05) 92.7 - - -

N1 1562 9372 4399 1.88

N2 1730 10380 4807 1.86

N3 1681 10086 4468 1.80

N4 1954 11724 5831 1.98

SEd 43.8 - - -

CD (0.05) 87.6 - - -

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Effect of Rainfall on Changes in Soil Organic Carbon in

Continuous Manorial Fields of Rainfed Black Cotton Soils of

Sourth Tamil NaduV. Subramanian,1 K. Baskar2, and G. Maruthi Sankar3

19

IntroductionIn general, the increasing plant biomass is the only

option to increase carbon in soils. Aggarwal et al.(1997) have reported that incorporation of crop residue and fertilizer N increased soil organic carbon (SOC) content as well as crop yield. The present investigation is to know the modeling of changes in soil organic carbon through soil temperature, rainfall and evaporation under Long Term Manurial Experiment in Dry land Vertisols of Tamil Nadu.

Materials and MethodsLong Term Manurial (LTM) experiments on

cotton + black gram and sorghum + cowpea were conducted at Kovilpatti under semi-arid vertisols during 1995 to 2005. The LTM experiments were conducted with a set of 13 fertilizer treatments viz., Control, 20 kg N/ha (urea), 40 kg N/ha (urea), 20 kg N/ha (urea) + SSP at 10 kg P/ha, 40 kg N (urea) + 20 kg P/ha (SSP), 20 kg N/ha (FYM), 40 kg N/ha (FYM), 20 kg N (FYM) + 10 kg P/ha (SSP), 40 kg N (FYM) + 20 kg P/ha (SSP),

10 kg N (urea) + 10 kg N/ha (FYM), 20 kg N (urea) + 20 kg N/ha (FYM), 10 kg N (urea) + 10 kg N/ha (FYM) + 10 kg P/ha (SSP) and 20 kg N (urea) + 20 kg N (FYM) + 20 kg P/ha (SSP).

Results and DiscussionThe soil organic carbon (%) was observed in

each plot of the 13 fertilizer treatments during the 11 year study under LTM experiments. The organic carbon ranged from a minimum of 0.20% under control to a maximum of 0.65% under 40 kg N/ha (FYM) over years. The control had a minimum mean organic carbon of 0.32% with a coefficient of variation of 28.2%, while 40 kg N/ha (FYM) and 20 kg N (urea) + 20 kg N (FYM) + 20 kg P/ha had a maximum mean of 0.44% with a variation of 22.9% and 19.0% variation respectively over years. However, the treatment of 40 kg N (urea) + 20 kg P/ha had a minimum variation of 15.8%, while 10 kg N (urea) + 10 kg N/ha (FYM) + 10 kg P/ha had a maximum variation of 30.6% over years in the study. It is observed that the soil had a maximum organic carbon of 0.55%

83

in 1995 with a variation of 12.0, while it depleted to a minimum of 0.29% in 1999 with a variation of 17.3% over 9 treatments of fertilizer examined in the study. The soil carbon improved to a mean of 0.35% with a variation of 10.5% over treatments during 2005 in the study. The changes in soil organic carbon in different treatments during 1995 to 2005 under LTM are also depicted in Fig. 1.

The Regression model of changes in organic carbon through climatic variables under LTM was worked out (table 1). The model of T9 was having a maximum and significant organic carbon predictability of 0.53, while T5 had minimum predictability of 0.42. However, T5 gave a minimum prediction error of 0.049%, while T12 had a maximum prediction error of 0.089% based on the models. The sustainable index of organic carbon was found to be maximum of 57.8% for T13, followed by T9 with 57.1%, T7 with 56.5% and T11 with 54.0%, while control had a minimum sustainability of 38.6% based on the trials conducted under LTM.

Based on the regression models, the soil temperature observed under 5�7.5, 10�15 and 20�30 cm depth at 7.28 AM was having a significant influence on soil organic carbon compared to the soil temperature observed at 2.20 PM under all the 13 fertilizer treatments. The soil temperature in 5�7.5 and 20�30 cm depth was found to have a significant negative influence, while the soil temperature in 10�15 cm depth had a significant positive influence on the soil organic carbon based on the models of all the treatments examined in the study.

Fig. 1. Performance of treatments for soil organic carbon under LTM during 1995 to 2005 at Kovilpatti

Treatment Regression model R2 Φ η T1 OC = 0.22 � 0.054 ** (ST1) + 0.089 ** (ST2) � 0.038 ** (ST3) � 0.44** 0.069 38.6 0.003 (ST4) + 0.001 (ST5) + 0.008 (ST6) + 0.001 * (RF) + 0.001 (EV) (11) (8) (13) T2 OC = 0.25 � 0.048 * (ST1) + 0.096 ** (ST2) � 0.05 ** (ST3) � 0.46** 0.077 40.5 0.002 (ST4) + 0.001 (ST5) + 0.007 (ST6) + 0.001 (RF) + 0.001 (EV) (9) (11) (12) T3 OC = 0.28 * � 0.04 ** (ST1) + 0.073 ** (ST2) � 0.036 ** (ST3) � 0.47** 0.056 46.8 0.001 (ST4) + 0.001 (ST5) + 0.006 (ST6) + 0.001 * (RF) + 0.001 (EV) (6) (3) (9) T4 OC = 0.29 * � 0.041 ** (ST1) + 0.072 ** (ST2) � 0.035 ** (ST3) � 0.50** 0.054 48.6 0.002 (ST4) + 0.001 (ST5) + 0.007 (ST6) + 0.001 * (RF) + 0.001 (EV) (5) (2) (7) T5 OC = 0.24 * � 0.036 ** (ST1) + 0.054 ** (ST2) � 0.021 ** (ST3) � 0.42** 0.049 52.5 0.001 (ST4) + 0.004 (ST5) + 0.007 * (ST6) + 0.001 * (RF) + 0.001 (EV) (13) (1) (5) T6 OC = 0.29 � 0.049 ** (ST1) + 0.097 ** (ST2) � 0.053 ** (ST3) � 0.46** 0.082 47.4 0.003 (ST4) + 0.002 (ST5) + 0.009 (ST6) + 0.001 (RF) + 0.001 (EV) (8) (12) (8) T7 OC = 0.34 � 0.036 ** (ST1) + 0.082 ** (ST2) � 0.05 ** (ST3) � 0.52** 0.073 56.5 0.004 (ST4) + 0.004 (ST5) + 0.008 (ST6) + 0.001 (RF) + 0.001 (EV) (2) (9) (3) T8 OC = 0.25* � 0.039 ** (ST1) + 0.08 ** (ST2) � 0.045 ** (ST3) � 0.51** 0.069 50.9 0.003 (ST4) + 0.003 * (ST5) + 0.01 * (ST6) + 0.001 (RF) + 0.001 (EV) (3) (7) (6) T9 OC = 0.31 * � 0.035 ** (ST1) + 0.075 ** (ST2) � 0.042 ** (ST3) � 0.53** 0.059 57.1 0.002 (ST4) + 0.002 (ST5) + 0.007 (ST6) + 0.001 (RF) + 0.001 (EV) (1) (4) (2) T10 OC = 0.26 � 0.056 ** (ST1) + 0.099 ** (ST2) � 0.047 ** (ST3) � 0.47** 0.077 46.6 0.002 (ST4) + 0.001 (ST5) + 0.010 * (ST6) + 0.001 * (RF) + 0.001 (EV) (7) (10) (10) T11 OC = 0.30 � 0.036 ** (ST1) + 0.078 ** (ST2) � 0.046 ** (ST3) � 0.50** 0.069 54.0 0.002 (ST4) + 0.002 (ST5) + 0.010 * (ST6) + 0.001 * (RF) + 0.001 (EV) (4) (6) (4) T12 OC = 0.28 � 0.053 ** (ST1) + 0.101 ** (ST2) � 0.054 ** (ST3) � 0.44** 0.089 44.8 0.002 (ST4) + 0.001 (ST5) + 0.011 * (ST6) + 0.001 * (RF) + 0.001 (EV) (10) (13) (11) T13 OC = 0.32 * � 0.046 ** (ST1) + 0.068 ** (ST2) � 0.030 ** (ST3) � 0.43** 0.064 57.8 0.002 (ST4) + 0.001 (ST5) + 0.013 ** (ST6) + 0.001 * (RF) + 0.001 (EV) (12) (5) (1)

Table 1. Regression models of organic carbon through soil temperature, rainfall and evaporation under LTM at Kovilpatti

* & ** indicate significance at 5 & 1% level Values in parentheses are ranks assigned to treatments

84

The soil temperature observed in 20�30 cm at 2.20 PM had a significant positive influence on soil organic carbon under T5, T8, T10, T11, T12 and T13 treatments, while it was not significant in other treatments. The soil temperature observed in 5�7.5 cm at 2.20 PM had a negative influence, while the temperature in 10�15 cm had a positive influence on soil organic carbon, but was not significant based on the model of any treatment. A positive effect of rainfall and evaporation on soil carbon were observed under all fertilizer treatments, however, rainfall had a significant effect on soil organic carbon under control, T3, T4, T5, T10, T11, T12 and T13 based on the regression models calibrated for the treatments under LTM study.

Ranking and Selection of Superior Fertilizer Treatments for Sustainable Organic Carbon

Ranks were assigned to treatments for the performance based on soil organic carbon build-up or depletion in different years under LTM experiments during 1995 to 2005 (table 2) and rank sum Âl1Ê was derived. Ranks were also assigned to treatments for the mean organic carbon, coefficient of determination, prediction error and sustainable index based on regression models calibrated for the pooled data over years and rank sum (l2) was derived. Based on the pooled rank sum of l1 and l2, a superior fertilizer treatment was selected. A graphical plot of rank sums Âl1Ê and Âl2Ê derived for fertilizer treatments tested under LTM is given in Fig.2. The study

has clearly indicated T7 was superior under LTM with 30 and 16 for soil organic carbon observed in individual years (l1) during 1995 to 2005, and mean, coefficient of determination, prediction error and sustainable index (l2) over years at Kovilpatti under semi-arid vertisols (Solanki et al.1999).

Based on field experiments conducted under LTM during 1995 to 2005 at Kovilpatti under semi-arid vetisols, the soil temperature observed under different soil depths at 7.28 AM was found to have a significant influence on the changes in soil organic carbon, apart from rainfall under LTM experiment. Based on a regression and rank analysis of fertilizer treatments, the study has clearly indicated that T7 was superior under LTM with 30 and 16 for soil organic carbon observed in individual years (rank sum 1) during 1995 to 2005, and mean, coefficient of determination, prediction error and sustainable index (rank sum 2) over years in the study.

Treatment LTM

l1 l2 Rank sum Rank

T1 136 45 181 13

T2 125 44 169 12

T3 105 28 133 11

T4 95 24 119 8

T5 70 25 95 6

T6 85 35 120 9

T7 30 16 46 1

T8 65 21 86 5

T9 37 10 47 2

T10 81 35 116 7

T11 49 18 67 4

T12 88 43 131 10

T13 35 19 54 3

Table 2. Ranking of treatments for organic carbon status in individual years, mean, coefficient of determination,

prediction error and sustainable index over years at Kovilpatti

Fig. 2. Rank sum of treatments for soil organic carbon in individual years (Rank sum 1) and mean, coefficient of determination, prediction error and sustainable index over years (Rank sum 2) under LTM during 1995 to 2005 at

Kovilpatti.

85

ReferencesAggarwal,R.K., Praveen-Kumar & Power, J.F. (1997). Soil Tillage Res.41, 43.Solanki,K.R., Bisaria, A.K. & Handa, A.K. (1999). In Sustainable Rehabilitation of Degraded Lands through

Agroforestry. National Research Centre for Agroforestry, Jhansi.���

Theme – 4Policies, Institutions, and Socio-economic Aspects

87

Choice of Genotypes in Fingermillet to Enhance Water Productivity in Rainfed Areas

Dr. A. Nirmala Kumari,

20

IntroductionRagi or fingermillet (Eleusine coracana (L.) Gaertn)

occupies a primer position in area and productivity among various small millets. Ragi is estimated to comprise 8 per cent of the area and 11 per cent of the production of all millets in the world. Perhaps 4.5 million tonnes of grain are produced annually on as much as 5.0 million hectares throughout the world; almost the entire production is confined to Africa and Asia. India alone produces 45 per cent of the total world production.. Fingermillet ranks third in importance among millets in India after sorghum and pearlmillet. The area under this crop is around 2 million hectares which 7.5 per cent of the total millets area, but its contribution (2.5 million tonnes) to total millet production is around 13 per cent. In India, Karnataka ranks first with more than 40 per cent area, accounting a little over 50 per cent production in the country. The other important Ragi-growing states are Tamil Nadu, Andhra Pradesh, Orissa, Maharashtra, Bihar, Uttar Pradesh and Gujarat. The productivity is the highest in Tamil Nadu (1900 Kg/ha) followed by

Karnataka (1436 Kg/ha). Productivity of this crop has been gradually increasing inspite of its cultivation under diverse agro-climatic and ecological conditions. This has been mainly possible through development of improved cultivars through breeding (Seetharam, 1989).

Effective Soil and Moisture Conservation for Sustained Production

Fingermillet is predominantly a rainfed crop. The minimal moisture for successful growing of the crop is around 35-40 cm per season, up to about 75 or 80 cm. One of the striking features of fingermillet is its resilience and ability to adjust to different agro- climates in terms of soil, rainfall and weather parameters. Conservation of moisture is critical for realising predicted higher harvests. Soil and moisture conservation measures including bunding across the slope, land smoothening, early tillage, sowing and intercultivation on contour and opening furrows at suitable interval help in mitigating drought effects. It is noteworthy that fingermillet has vast untapped yield potential in areas where other crops have less chance of adaptation.

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Physiological Basis of Productivity Under Dryland Farming

In any crop, increase in the productivity under dryland condition requires understanding of the physiological constraints and also the ways and means of overcoming them have to be designed. Fingermillet, a C

4 plant, has a production potential of 4000-5000

Kg/ha under optimum conditions. However, the yield levels achieved are far below its actual potential because fingermillet is predominately grown under rainfed conditions (Udaya Kumar et al., 1989). Drought stress severely limits the yield of fingermillet although it is reputedly one of the most resistant crops to drought.

However, recently significant progress has been made in understanding the nature of stress injury and the adaptive mechanisms associated with growth and survival. Field evaluation programmes have been refined and several quick screening techniques developed for rapid screening of a large number of germplasm materials to identify specific characters associated with higher productivity under moisture stress.

At first, it is necessary to assess (i) the time, magnitude and duration of stress effect in a particular season, (ii) the effect of drought stress on growth of the plant as a constraint for productivity, (iii) identifying the adaptive strategies of the plant for higher productivity under drought conditions and (iv) the optimum growth period of the crop for maximum utilization of precipitation. Analysis of the constraints in growth and productivity suggests that the following are the major factors.

(i) Stress after sowing� Effect on seedling emergence and crop establishment.

(ii) Early season stress � Effect on early crop growth rate.

(iii) Mid � season stress � Effect on sink number and sink development.

Germination and Seedling SurvivalStress during germination and seedling

establishment drastically affects crop stand and is often a major constraint especially in small seeded fingermillet with limited seed reserves. Germination and establishment are often affected under semi-arid conditions, where the soil moisture is inadequate and the rate of evaporation is high. In such circumstances, the seedling must compete

with the process of atmospheric drying, for the rapidly diminishing moisture of the surface layers. Often, these layers dry out too rapidly for the seed to germinate or for the germinated seedling to extend its roots down into the deeper layers where available moisture can be found. As a result, the seedling may fail to survive even though the overall ecological conditions may be favourable for a mature plant. This problem is further compounded by the formation of crust, the extent and severity of which predominantly depends on soil characteristics. Significant species variation and also variation amongst genotypes within a species do exist in relative germination rates under these situations (Udaya Kumar et al., 1989).

Apart from the pre-sowing moisture conservation measures generally adopted and the intrinsic water holding capacities of soils, seed characteristics associated with seedling vigour may determine the final crop stand. One of them is the intrinsic ability of the seedling itself to maintain higher growth rates which is a good reflection of its vigour. This would directly encourage survival by faster emergence before severe defection of soil moisture occurred or indirectly by better osmotic adjustment by accumulation of osmotically active solutes. High seedling growth rates under stress are also favoured by higher rate of imbibition and the metabolic activity of the seeds. The latter facilitates uptake of water especially under low soil water potentials. The survival of the germinated seed during the stress period and its regrowth on stress alleviation is another important factor which determines seedling establishment. Hydration and dehydration tolerance of the germinated seeds by osmotic adjustment, better endogenous hormonal regulation and utilization of seed reserves is important.

Differences in solute potential of the seeds had been observed depending on the prevailing conditions during earhead development. Seeds developed from a dryland crop which had experienced stress, showed higher germinability and seedling vigour when osmotic stress was imposed during germination. This may possibly related to the higher solute content in the seeds particularly sucrose. Such induced variability could be exploited. Though significant genotypic variations had been reported (Udaya Kumar et al., 1989) in several of these characteristics associated with seedling establishment, a breeding programme to incorporate these parameters is difficult and time consuming. It is worth while to develop agronomical techniques which can induce tolerance or facilitate stress avoidance thereby enhancing seedling vigour.

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Moisture Stress as The Limiting Factor for Growth and Productivity

Based on stress situation, the mechanisms adapted by plants to drought stress are different. There are specific escape, avoidance and tolerance mechanisms (Levitt, 1980). These mechanisms either favour survival under stress situation or help in maintaining good productivity under stress situations.

Adaptive Mechanisms and Their Relationship with Productivity Under Drought StressStrategies for Higher Productivity with Drought Avoidance Mechanism

(a) Maintenance of water uptake (i) Root characters

(b) Water utilization efficiency

(i) Characters associated with low transpiration quotient

(c) Higher partitioning efficiency

(i) Higher harvest index

(ii) Remobilization of reserve carbohydrates

Strategies for Less Reduction in Productivity with Drought Escape Mechanism

(a) Developmental plasticity

(i) Postponement of flowering

(ii) Plasticity of tillering

Strategies for Less Reduction in Productivity with Drought Tolerance Mechanism

(a) High crop growth rates under stress and on alleviation of stress

Characters at the organ level:(i) Higher growth rate with low tissue water

potential

(ii) Higher leaf expansion on alleviation of stress

(iii) Higher partitioning on stress alleviation

Characters at the cellular level:

(i) Osmoregulation

(ii) Chloroplast integrity

(iii) Hormonal factors

(iv) Membrane integrity

Strategies Resulting in Possible Reduction in Productivity with Drought Avoidance Characters

(i) Increase in stomatal and cuticular resistance

(ii) Reduction in radiation load

(iii) Reduction in evaporative surface

It is more important for a drought resistant crop to have the following adaptive characteristics associated with maximizing productivity under stress conditions rather than to ensure mere survival.

Higher Water Harvesting and Utilization Efficiency(a) Water conservation mechanism (Agronomical)

(b) Water harvesting by roots.

(c) Efficient water utilization (TQ)

Developmental Plasticity Under StressSurvival and growth under stress

Higher crop growth rate after alleviation from stress.

Partitioning and effective remobilization of reserves.

The best strategy for drought management is increasing the water harvesting and its utilization efficiency. The total productivity of any crop depends on the evapotranspiration, water use efficiency and the harvest index. Agronomical approaches to enhance moisture conservation and a few strategies to minimize water loss like mulching and practising optimum date of sowing will definitely give nice dividends for enhancing productivity of dryland fingermillet. Apart from these practices two other physiological processes associated with water harvesting and conservation are (1) root factors and (2) transpiration quotient.

Root factors: An important feature of a drought resistant plant could be its deep root system. The relevance of root volume, spread and depth, relative energy allocation to roots and the vertical conductances of the root system had been reviewed by Passioura (1981). As soil water potential in the surface layers

90

decreases, water retained in the deeper layers makes a larger contribution to ET.Often in many shallow rooted crops like finger millet, when most of the moisture from the upper layers is exhausted, the plant is unable to extract water to satisfy the ET demand even though the soil water available in the deeper layer is still high. Under these conditions a deeper root system will definitely have an advantage. Genotypic differences in root density especially in deeper soil layers are well documented in rice (Yoshigwa and Hasegawa, 1982). To develop a suitable programme to identify fingermillet genotypes with high water extraction capabilities will investigate the following aspects further.

(i) Rapid and accurate measurement of root depth, spread, volume and activity.

(ii) Duration of the functional root system during the crop growth period.

(iii) The characteristics associated with hydraulic conductivity of root system.

(iv) The relative allocation of carbohydrates to root systems and its significance.

Plant processes associated with high water use efficiency: The physiological and biochemical factors associated with a low transpiration quotient and high water use efficiency are other important adaptive strategies of the plants for higher productivity under stress conditions. Though the total evapotranspiration always shows a relationship with biomass production and productivity, Yield =Total ET x WUE x HI, the differences in productivity amongst the genotypes at a given level of evapotranspiration are mainly attributed to variations in TQ or WUE. The high WUE achieved by some genotypes is often attributed to increased assimilation rate per unit water transpired (Bierhuzien, 1976).

Stomatal and mesophyll characteristics are basically responsible for the variation in TQ. However, under field conditions canopy characteristic have to be considered in terms of the relative rates of water loss and assimilation. The canopy conductance, a product of the stomatal conductance and Leaf Area Index, is an important determinant of productivity under field conditions. In this context, the total number of stomata is a more useful parameter as it takes into account the variability in both stomatal frequency and leaf area. A higher number of stomata per plant would increase the total transpirational water loss concurrently. For crops

grown under dryland conditions, genotypes with low canopy transpiration rates are desirable (Jones, 1977). This can be achieved by identifying genotypes with low conductances or alternatively with genetically low leaf area and low number of stomata per plant but without sacrificing the ability to produce higher drymatter, since drymatter production is highly correlated with grain yield in fingermillet (Sastry et al., 1982).

Field experiments were conducted with seventy medium duration genotypes during monsoon and summer seasons to investigate the possibility of identifying genotypes with genetically low leaf area, leaf area index, leaf area duration, stomatal number per plant, yet harvesting good grain yield and biomass. In these genotypes the canopy water loss is likely to be relatively lower than in genotypes with larger leaf area (Fig 1, 2). The biological yield was used as the primary selection criteria to screen genotypes. Among these genotypes there were some distinct genotypes with high leaf area, high dry matter and high harvest index and some others with low leaf area, high dry matter and high harvest index (Table1). Successive field experiments conducted in selected high and low leaf area types with high biomass and high harvest index had shown the possibility of identifying genotypes with low and high stomatal number (Table 2, 3). It is logical to assume that total canopy water loss would be low in genotypes with low leaf area or low stomatal number. Since fingermillet is predominantly a dryland crop, low canopy water loss assumes greater importance. If the total biological yield is still high in these genotypes despite a reduction in assimilation leaf area, then the carbon exchange ratio (CER) should be high leading to high grain productivity. High CER could be mainly due to high mesophyll conductances and also the significance of these factors in maintaining low TQ had been emphasized earlier (Bierhuzien, 1976).

The genotypes identified with low stomatal number and high drymatter were tested for the relative drought tolerance by subjecting them to different moisture stress conditions. Genotypes with low stomatal number and biomass (Table 4) showed less reduction of biomass and yield when subjected to intermittent moisture stress compared to genotypes with high stomatal number and high biomass. Similar results were obtained for land races of pearlmillet adapted to different ecological conditions showing smaller leaf area associated with high carbon exchange rates (Blum and Sullivan, 1986). Precise gravimetric techniques were used to assess the

91

differences in TQ amongst the genotypes (Malathi et al., 1986; Udaya kumar et al., 1989).

By determining the cumulative water transpired and the dry matter accumulated during the crop growth period, genotypes differing distinctly in TQ were identified. The major factors contributing for low TQ were high NAR and low transpiration rate per unit leaf area. Genotypes belonging to high CWU and low TQ and low CWU and low TQ are better for dryland conditions. Genotypes with high CWU and low TQ types have an advantage when moisture available in the deeper layers can be harvested. In this type high CWU is possibly associated with greater stomatal conductances resulting in high water demand. However, if moisture is severely limited it is imperative to select types with a low CWU associated with a low TQ. Again in these types the low CWU may presumably be a consequence of lower canopy conductances. In general, the small leaf area types showed low TQ associated with low CWU and genotypes with moderate or larger leaf area associated with high NAR and high transpiration showed high CWU with low TQ. The following are the desirable morphological and physiological characters associated with low TQ with moderate or high CWU and high dry matter production.

(i) Low leaf area (small leaf size or less number of leaves)

(ii) High dry matter production

(iii) High NAR/ Photosynthetic rate (High mesophyll conductances)

(iv) Low canopy transpiration and

(v) High partitioning efficiency.

Biomass production is predominantly dependent on canopy photosynthesis. Though, both leaf area and photosynthesis contribute to biomass production, increasing the photosynthetic efficiency is advantageous especially for dry land crops. Genotypes with high photosynthetic rate may still produce high biomass with small leaf area. Such type will have a low transpiration leaf area, and could be expected to have a low transpiration quotient and high water use efficiency. The concept of low leaf area, high photosynthetic efficiency and high biomass types of fingermillet having an advantage under dry land farming had been already established (Gurumurthy, 1982; Sastry et al., 1982).

The genotypic differences in photosynthetic efficiency (PE) are often arrived at by measuring PE in a single leaf. The mean photosynthetic rate over crop growth period can be calculated by leaf area duration / dry matter ratio. Higher the value, lesser the photosynthetic rate and vice versa. This concept of LAD / DM can be extended and widely adopted as a preliminary screening technique for determining the canopy photosynthetic rate in different genotypes. Differences in PE of different leaves of canopy, diurnal fluctuations in PE and problems associated with plant architecture like mutual shading are taken care of by determining LAD / DM ratios. The genotypes selected for high biomass and low leaf area were shown to have high PE in fingermillet (Sashidhar et al., 1984). Significant genotypic variation exists in the photosynthetic rate in fingermillet genotypes. Several plant characteristics were shown to be associated with high PE and high in translocation efficiency of photosynthates.The leaf vein frequency, the ratio of veinal width to leaf width, the mean veinal width and mean inter veinal width showed significant relationship with PE and also translocation of photosynthates. Some of these characteristics had been shown to have high heritability value and genetic advance (Perumal, 1982) and could be used in the breeding programme to improve photosynthetic traits.

Developmental PlasticityIn spite of inbuilt mechanism for low transpiration

quotient in finger millet, the crop experiences severe moisture stress during early stages of growth even with a good degree of soil moisture conservation practices. Stress induced plasticity in postponing the flowering and development of new tillers on stress alleviation are often suggested as adaptive mechanisms under dryland conditions. Medium duration cultivars have better plasticity both in terms of postponement of flowering during stress and production of new tillers on stress alleviation as compared to early cultivars.

Plasticity in TilleringMid-season drought stress effect on overall

productivity is less in tillering genotypes with ability for tiller development on alleviation of stress (Alagarswamy, 1981). In many genotypes of fingermillet, the productivity of successive tillers reduces drastically and the late formed tillers and nodal tillers formed after stress alleviation contribute very little to grain weight. In fingermillet, a relationship exists between productivity and mean ear weight, but not ear number per plant.

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Thus, in recently developed genotypes, the higher yield potential is the result of enhanced mean ear weight.

High crop growth rate on alleviation of stress: The differences in productivity under dryland situations are often attributed to differences in crop growth rates on alleviation of stress. The functional leaf at the end of stress period and resumption of leaf growth and its activity on alleviation of stress determines the CGR. The leaf expansion even at low tissue water potential under stress is generally marginal and very little genetic variation exists in this character. In fingermillet as leaf water potential decreased, there was a rapid cessation of leaf elongation indicating that it is a very sensitive character to moisture stress. However, in fingermillet, there is resumption in leaf elongation on stress alleviation and in some genotypes the leaf elongation rates exceed that of the control (Vishwanatha, 1977). The resumption of leaf expansion and the NAR depends on the intrinsic dehydration tolerance mechanisms like osmo-regulation, maintenance of membrane integrity, reduced photo-inhibition and photo-oxidation properties and hormonal aspects.

Remobilization of Reserve Carbohydrates and Contribution to Grain Yield

One major adaptive mechanism for enhancing productivity when stress occurs during later stages of crop growth is relative utilization efficiency of stem reserves for the grain development, as well as higher ear photosynthesis. Significant variation exists in partitioning of photosynthesis under stress to the developing ear. In fingermillet, ear photosynthesis constitutes nearly 5 to 30 per cent to the grain dry weight (Perumal, 1982). Under stress condition, the reduction in photo-synthetic rate of the ear is relatively very less compared to leaves. The advantage of high glume size for higher ear photosynthesis and grain development by virtue of greater translocation had been shown in some collections of fingermillet from Malawi (Sashidhar et al., 1984).

Crop Duration and ProductivityThe productivity of a genotype is often dependent

on full exploitation of favourable growth period in an agroclimatic region. This led to the identification of location specific duration groups with desirable adaptive mechanisms suitable for each region. Duration of a genotype in different environments is controlled by its relative photoperiodic response, to a certain extent to

thermoperiodic response and to much lesser degree to the stress induced postponement or hastening of growth periods. In this regard, the response of fingermillet to thermo-periodism seems to be very high, as seen from the distinct variation recorded when a single genotype was grown at different locations (Anonymous, 1986). Although the mean growth duration of a particular group of genotypes may remain constant over locations is markedly different. In Fingermillet, there is always a direct relationship between growth duration and biomass productivity.

One of the approaches to exploit the entire crop growth period is to identify suitable quantitative photosensitive types. Under dryland condition, the rainfall in the beginning of the season may be erratic, unpredictable and often gets delayed. With a photoinsensitive type flexibility is not possible because the early sown crop matures early without exploiting the complete growth period and the late sown crop would fill the grains under moisture stress. Also many high yielding genotypes evolved are photoinsensitive and maturity period depends on the sowing dates. Therefore, it is necessary to use different genotypes which suit the different sowing date. Photosensitive genotypes are best suited and adjust to the flexibility in sowing dates. However, photosensitive genotypes possess limited range of adaptations and low partitioning factors.

The quantitative short day plants have on advantage particularly when precipitation in an agroclimatic zone is bimodal. Such a situation occurs in some regions where premonsoon showers are adequate enough to support plant establishment and growth. However, premonsoon showers are followed by a rainfree period of 4 to 6 weeks before the monsoon sets in. An already established crop, if it survives the stress period, in this situation would have higher crop growth rate on stress alleviation during monsoon period and therefore these genotypes would be more productive. Under such situations, the desirable characteristics of the genotype would be:

(i) Establishment of the crop during premonsoon period.

(ii) Tolerance to moisture stress for a period of 4 to 6 weeks.

(iii) Higher crop growth rate on stress alleviation

(iv) Photosensitive nature of the genotype.

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The genotypes which had deeper root system were able to withstand the water limiting conditions and they were also found to perform well in the transport of

S.No. Characters Mean Range Significance

CD(P=0.01) CV (%)

1. Total dry matter accumulation at harvest (g/ m row length)* 148 97 - 195 10.2 9.3

2. Leaf area on 85th DAS (cm2/ m row length) 4230 2134 -6208 93.7 11.4

3. Straw weight (g/m row length) 303 201- 914 36.2 6.2

4. Grain yield (g/m row length) 267 161-396 31.0 7.8

5. Harvest index 0.37 0.22- 0.53 0.09 10.0

6. Net assimilation rate (g/dm2 LA during 65 � 85 DAS) 0.15 0.06- 0.27 0.01 5.2

assimilates to the developing grains as compared to the genotypes which have shallow root system. Genotypes TNAU 1005 and Karipoottai conform to this pattern.

Fig. 1. Low canopy transpiration and high productivity genotypes identification (High biomass always associated

with high yield)

Fig. 2. Screening of fingermillet genotypes for low canopy transpiration and high biomass.

Table 1. Mean values for major physiological characters in 70 fingermillet genotypes (kharif, 2004)

* Ten plants per m row length.

Table 2. Genotypes variation in growth characters and stomatal number in low and high leaf area types

Genotypes Stomatal Total LA ** LAI LAD NAR DM at Grain HI frequency Stomatal (cm2/ (days) (g/dm2 harvest yield (No. mm2) number/ Plant) LA/ (g/m (g/m Plant days) row Row (x105)* length)*** length) Category I : High LA, high DM and high HI

TNAU 946 258 24.3 484.2 3.88 201 0.15 403.5 149.3 0.37

TNAU 995 263 27.2 513.4 4.23 207 0.17 490.3 171.6 0.35

TNAU 1003 248 23.7 492.0 3.67 216 0.12 398.4 135.5 0.34

TNAU 1018 272 26.9 507.3 4.44 213 0.09 365.2 131.5 0.36

CO 10 280 27.4 550.1 4.52 210 0.13 418.6 163.3 0.39

Mean 264.2 21.1 509.4 4.15 209.4 0.13 415.2 150.2 0.36

Category II : Low LA, high DM and high HI

TNAU 1005 190 10.0 198.9 1.88 109 0.25 455.2 218.5 0.48

CO 8 198 12.4 210.4 2.03 110 0.24 438.3 206.0 0.47

CO 7 210 13.1 231.8 2.41 116 0.23 424.4 191.0 0.45

Karipoottai 207 11.3 220.2 2.78 121 0.19 419.7 209.9 0.50

IE 349 205 11.9 218.7 2.65 133 0.20 400.5 172.2 0.43

Mean 202.0 11.7 216.0 2.35 117.8 0.22 427.6 199.5 0.47

CD (P= 0.05) 28.2 4.7 30.5 0.97 59.7 0.06 40.2 23.5 0.01

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* Mean stomatal frequency x 2 x LA per plant for upper and lower surfaces of leaf. ** LA on 85th DAS*** Ten plants / m row length

Details Range and mean stomatal frequency Mean Range and Mean in relation to leaf position frequency mean stomatal No. (number / mm2) (85 DAS) per plant (x 105) Top (flag Middle Bottom leaf) (L

4) (L

8)

High LA genotypes 3680 � 5960 96.4 (4555)

Adaxial surface 123 � 167 91 � 166 103 � 173 128 ( 32) (129) (124)

Abaxial surface 86 � 148 96 � 153 100 � 166 107 (109) (106) (110)

Mean 120.5 117.5 117.0 117.8

Low LA genotypes 2119 � 3819 65.0 (2343)

Adaxial surface 135 � 241 110 � 184 117-191 141 (163) (135) (138)

Abaxial surface 104 � 197 98 � 145 100 � 152 118 (121) (112) (115)

Mean 142.0 123.5 126.5 129.5

Table.3. Variations in stomatal frequency in leaves at different canopy positions and the total number of stomata per plant in high and low leaf area finger millet genotypes

Details Genotypes LA (cm2/ plant ) LAD (days) Grain yield Total DM at (85 DAS) (g/pl) harvest (g/pl)

Control Stress Control Stress Control Stress Control Stress

High stomatal TNAU 995 50.4 35.9 208 153 13.6 11.3 12.1 9.5number and high DM CO 10 54.2 40.3 212. 163 12.4 10.70 11.3 8.7genotypes Mean 52.3 38.1 210 158.0 13.0 11.0 11.7

Reduction due to stress (27.2) (24.8) (15.4) (22.2)

Low stomatal TNAU 1005 20.4 18.5 107 98.4 13.0 12.9 44.2 48.7number andhigh DM Karipoottai 22.0 19.7 118 100.5 11.8 10.6 39.8 33.9genotypes Mean 21.2 19.1 112.5 99.5 12.4 11.8 42.0 36.3

Reduction due to stress (9.9) (11.6) (4.8) (13.6)

Control: Non �stressed block which was given with two protective irrigations to alleviate moisture stress at critical stagesStress: Rainfed stress block

Table.4. Growth and yield parameters in low and high stomatal number genotypes under two moisture regimes.

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age, its proximity to the sink and its vantage position to intercept the considerable proportion of solar radiation. The total leaf surface contributes nearly 60 percent of the photosynthates to the ear head. The grain yield was also correlated to the leaf area per shoot at the time of anthesis. Stem and sheath also photosynthesise and contribute nearly 30 percent towards the grain yield. The participation of photosynthates from the ear head towards grain yield is 8.5 per cent. The photosynthetic rate and its translocation find a positive correlation to the major veins of the leaves (Natarajaratnam, 1984).

The differences in stomatal number per plant were also highly significant but the differences were more because of differences in leaf area. However, based on leaf area, stomatal number per plant, total biomass and harvest index, it was possible to identify genotypes which differed only in total stomatal number per plant, but having high drymatter and high harvest index. Genotypes TNAU 1005, CO 8, CO 7, Karipoottai and IE 349 had a low leaf area, low stomatal number per plant with drymatter production and productivity equivalent to that of the high leaf area types TNAU 946, TNAU 995, TNAU 1003, TNAU 1018 and CO 10.This is due to high CER in these genotypes which could be mainly due to high mesophyll conductances. Genotypes with high mesophyll conductances, but having low stomatal frequencies will still have higher CER with low transpiration rate. Such genotypes will have a low transpiration co-efficient and high water use efficiency and would be more productive under stress conditions.

ConclusionThe production potential of any genotype depends

on the total biomass produced and its partitioning to the reproductive organs. A high total biomass production is therefore the most important prerequisite for higher productivity. Under field conditions total biomass is dependent on the crop growth rate and this in turn is dependent predominantly on functional area of the photosynthetic apparatus and the carbon exchange rate. The CER is influenced by the stomatal conductances. However, the total number of stomata per plant is more important than stomatal frequency. A higher stomatal number per plant would also increase the CER and hence the total biomass but would also increase the total transpirational water loss concurrently. For crops grown under dryland conditions, genotypes with low canopy transpiration rates are desirable. This is possible by identifying genotypes with low plant conductances but not by sacrificing the ability to produce higher dry matter. The transpiration quotient in such genotypes will be low and hence, the water use efficiency would be high. In this experiment also, a positive significant relationship between the total biological yield and the grain yield was recorded. Further, in this set of 70 genotypes, there was a relationship between leaf area during dough stage (85 DAS) and biological yield at harvest. So, leaf area as an important component of total biomass production is proved. Mutual shading and low leaf area index below the critical level normally reduce the yield. Actually, the flag leaf contributes13.5 per cent to grain yield. The high efficiency of the flag leaf is partly due to is younger

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References1. Amonymous, 1986. Annual Report of the All India Millet Improvement Project, Fingeermillet, ICAR.2. Bierhuzien, J.F.1976.Irrigation and water use efficiency. In: Water and plant life, Eds.O.L.Lange, L.Kappen and

E.D.Schulze. Springer, Berline pp.421-431.3. Blum, A. and C.Y.Sullivan.1986. Comparative drought resistance of land races of sorghum and millet from dry

and humid regions. Annals of Botany, 57:835-846.4. Gurumurthy, B.R.1982.Desirable plant characteristics in relation to productivity in fingermillet (Eleusine coracana

Gaertn): A physiological analysis.M.Sc. (Agri.) dissertation.Univ. of Agri.Sci., Bangalore.5. Jones, H.G. 1977. Transpiration in barely leaves with differing stomatal frequencies. J.of Expt. Bot., 28: 162-

1686. Levitt, J.1980. Water, radiation, salt and other stress. In: Responses of plants to environment stress, Vol.II.Academic

Press, Newyork.7. Malathi, C., K.S. Arun, T.G.Prasad and M.UdayaKumar.1986. Genotypic differences in water use efficiency amongst

soybean genotypes. Indian J. Plant Physiol., 14.8. Natarajaratnam, N. 1984. Physiological basis of productivity in cumbu and ragi. In: Proceedings of state level

Training Programme on Ragi production held at Tamil Nadu Agricultural University, Coimbatore from 25-28th July, 1984.

9. Passioura, J.B.1981. Water collection by roots. In: The physiology and biochemistry of drought resistance in plants. Eds.L.Paleg and D.Aspinall. Academic Press, Sydney.pp 39-53.

10. Perumal, K.R.1982. Genotypic variation in photosynthetic efficiency and translocation and its relation to leaf character, growth and productivity in fingermillet (Eleusine coracana Gaertn). Ph.D. thesis.

11. Sashidhar,V.R., T.G.Prasad, A. Seetharam, M. UdayaKumar and K.S. Krishna Sastry.1984. The balance between leaf area and photosynthetic activity in determining productivity of foxtailmillet (Setaria italica) under rainfed conditions. Experimental Agriculture (Great Britain) 21: 241-247.

12. Sastry, K.S.K., M.Udaya Kumar and H.R.Viswanath.1982, Desirable plant characteristics in genotype of fingermillet (Eleusine coracana Gaertn) for rainfed conditions.Proc. Indian Nat, Sci.Acad. 48: 264-270.

13. Seetharam, A.1989.Genetic Resources of smallmillets in India. In: Smallmillets in Global Agriculture.Eds. A.Seetharam, K.W.Riley and G.Harinarayana. Oxford and IBH publishing Co.Put. New Delhi.pp. 45-58.

14. UdayaKumar, M., V.K.Sashidhar and T.G.Prasad. 1989. Physiological Approaches for Improving Productivity of Fingermillet under Rainfed Conditions. Smallmillets in Global Agriculture. Eds. A.Seetharam, K.W.Riley and G.Harinarayana. Oxford and IBH publishing Co. Put. New Delhi.pp.179-208.

15. Visvanatha, H.R.1977.Evalution of fingermillet (Eleusine coracana Gaertn) genotypes for relative drought tolerance based on physiological parameters and field performance. M.Sc. (Agri.) thesis submitted to Univ. of Agri.Sci., Bangalore, India.

16. Yoshida, S. and S.Hasegawa. 1982. The rice root systems: Its development and function. In: Drought resistance in crops with emphasis on rice. International Rice Research Institute, Manila, Philippines.pp.97-114.

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Community Resource Management: Much Needed Strategy in Tank Irrigation

System in IndiaM. Jegadeesan and K. Fujita

21

IntroductionTank irrigation is passing through defining

moment in India today. Tank irrigation contributes significantly to agricultural production in India in general and particularly in Andhra Pradesh, Tamil Nadu and Karnataka. Tank irrigation system is one of a vast network of thousands of water bodies that constituted a distinctive landscape which was medieval in origin but still was the basis of livelihood in the dry southern plains (Mosse, 2003). Tank is a small reservoir constructed across the slope of the valley to catch and store water during rainy season. Water is controlled by sluices attached to the tank bank and it is delivered to paddy field by distributing channels. Tank is considered as a common property resource. The National Sample Survey Organization defines common property resources as the resources that are accessible to and collectively owned, managed by identifiable community and on which no individual has exclusive property rights (NSSO, 1999). The role of tank is not only providing irrigation water but

also it provide biomass, fuel wood, fodder for livestock and other forms of economic livelihood sustenance of villagers (Chopra and Dasgupta, 2008). Tank irrigation get special significance as it provides livelihood support to large number of marginal, small farmers and landless agricultural labours (Palanisami, 2000). This system then once well maintained by villagers, slowly disintegrated over the period of time due to various reasons like changes in land holding pattern, development of large scale irrigation project and ground water development and change in preference of livelihood strategies among villagers and so on (Sakthivadivel et al, 2004).

However, based on the presupposition that local population has a greater interest in the sustainable use of resources than does the state or distant corporate manager; that local communities are more cognizant of the intricacies of local socio-ecological process and practices and they are more able to effectively manage those resources through local or traditional forms of access (Brosius, Tsing and Zerner, 1998; Li

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2002). In recognition of this fact, government and Non Governmental Organizations (NGO) put their effort to motivate farmers to rebuild the institution which was destabilized. Even then things would not happen in the way one would have expected. In this connection, the main focus of this paper is to i) compare effectiveness of traditional irrigational institution with government sponsored and NGOs sponsored one. ii) Analyze its functioning style and its efficiency of these institutions at tank system level. iii) Find out possible reason for disintegrating.

MethodologyThe study has been conducted in three tank

villages in Madurai district of Tamil Nadu, India. These study villages has been selected purposefully as they represent different kind of irrigation institution. Considering availability of water is the main motivational factor to organize farmers themselves, care must be taken to identify study villages, which are receiving more or less same amount of rainfall. From the vicinity area, totally three villages were selected, tank village 1 represent traditional institution, tank village 2 represent institution promoted by government, and tank village 3, represent the institution promoted by NGO.

The data has been collected through pre-tested, semi-structured interview schedule paying personal visit to the villages. Simple random sampling was employed to identify sample respondents (farmers). The data

were collected through personal interview; focus group interaction and discussing with opinion leaders. The study has been conducted during the year 2007.

General Characteristic of The Study Villages

The table 1 presented general characteristics of the selected study villages. The study villages Kadaneri, Kovalapuram and Menachipuram are located in Peraiyur taluk of Madurai districts. All the selected villages almost depend on agriculture and allied activities for their livelihood. The fate of agriculture is determined or influenced through rain fed tank irrigation system in the villages. The major crops cultivated are paddy, cotton and pulses. Mostly single season crop and rarely, farmers are going for second crop. In the last 10 years there was no intervention on these tanks to improve its performance. As a result, employment generated through tank irrigated agriculture is in terminal decline. In recognition of this, the government of Tamil Nadu, brought this villages under the National Rural Employment Guarantee Scheme (NREGS) to provide supplementary non-farm employment to assist them (BDO, 2007). Out of three tanks, two tanks are managed by Public Works Department, and one is coming under Panchayat Union management regime.

Characteristics Tank village 1 Tank Village 2 Tank village 3

Total population 2234 520 440

Command area (Ha) 41.60 62.26 7.94

Management authority Public Works Dept. Public Works Dept. Panchayat Union

Type of Institution Traditional Govt. sponsored NGO Sponsored

Basin Location Vaipar Vaipar Vaipar

Tank capacity (mcft) 14.0 17.66 9.20

Source of water supply Rain fed Rain fed Rain fed

No. of sluices 1 2 1

No. of supply channels 2 2 2

Extent of encroachment (Ha) 0.21 Not available Not available

No. of wells in command area 12 18 1

No. of castes in village 9 5 2

Total No. of households 387 133 110Farming households 214 67 53Landless Agricultural labors 148 43 42Non farming households 25 23 15

Major cropping pattern Paddy, pulses Paddy, cotton, pulses Paddy

Tank intervention in last 10 years No No Yes. By NGO (2006)

Tank performance (farmerÊs perception) Moderate Poor Moderate

Source: Water resource atlas of Madurai district, and Field survey in 2007

Table 1: General characteristics of study tank villages

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Tank Water InstitutionsThe villagers generally have traditional, informal

association other than village panchayat. These associations have a leader who is respected by villagers, some of them by virtue of their age and service rendered in the past and social status, wield considerable influence in village.

Traditional Irrigation InstitutionTraditional irrigation institution may be referred

to the evolution of principles for collective action of users, for broad spectrum of social responsibilities such as system maintenance, water sharing and conflict resolution (Coward, 1980; Vaidyanathan, 1985 and Janakarajan, 1993). Even today villagers have traditional institution in many villages to manage the tanks effectively as common property resources. Traditional system of water distribution was based on their beliefs, customs and the concept of equality. The water allocation ensured smooth sharing to all its members without any default. The performance of these tank irrigation systems depends on collective decision they made and keep. These institutions characterized by socio-cultural and contextual arrangement in order to provide services to village community. These institutions have rules and regulation in the form of ethics and norms as it is resultant of complex pattern of behavior of large no of people over protracted period of time (Basu, 2000).

Government Sponsored InstitutionsEffective functioning of tank system is simply based

on how its different components like physical, technical and institutional parameters are managed. In the earlier days, villagers considered tank as system. Over the period of time, when government took over these structures, it is failed to considered as system, consequently it is said to be managed by five different departments and acting as separate entity in different directions. After some period, government concentrates only on physical improvements of the tanks. But still they did not yield fruitful result as there are no institutional structures to maintenance. Thus institutional problems crop up and it was hasten

by changing social structures, land holding pattern and demographic� population pressure on the lands. After the 1980s when international donor agencies funded for tank modernization, they asked to form water user association at tank level. As a result, the government has shown interest to form institution at tank level as it was stipulated by donor agencies.

NGO Sponsored InstitutionMany NGOs in India are working with rural

people in tank command area, promoting participatory management. They follow different methods to organize farmers and develop institution in the community level in order to provide collective action to tank system management. They employed locally known persons as negotiator to inspire people to participate in the institutions.

Field ObservationsThe research demonstrates some specific

observation about the difference in strategy, notion, structure and functioning style among all three institutions in the study villages. Overall aim of all the stakeholders involved in this campaign was creating successful local, independent and self-organizing institution at community or village level. But notably, these groups varied tremendously in their values, attitudes and beliefs towards the cooperation and the best means to achieve their desired ends. All initiatives look for the active participation of rural people in working out a better livelihood access for themselves. New policies and schemes have been set in the place both by the government and NGOs to facilitate this process of involvement.

Table 2 shows the nature and way of existence of institution in the villages. Institutional arrangement of management of tank resources is carefully constructed and designed to serve specific purpose are at the cross roads now. In all three types of institutions, irrespective of its functioning style, its efficiency and activeness are dramatically low. The most important ingredient for the

Criteria Traditional Govt. Sponsored NGOs sponsoredResponsibility of organizing villagers Villagers themselves Govt. official in charge of village Facilitator appointed by NGOSelection of leaders Villagers By election By group opinion & rotationalFunctioning style Informal Formal Semi formal Financial support Collective contribution Villagers & Govt. Villager, NGO and Govt.Work execution Regular Demand based RegularActiveness Relatively Active Inactive Relatively Active

Table 2: Functioning structure of tank institutions

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institutional building is a sense of belonging, mutual trust and empathic cooperation. But unfortunately these ingredients are missing or not given due importance to create it.

Trust building, sense of belonging and social affiliation towards institutions will come when the villagers perceived that their participation yield good livelihood base for them. Looking at closer view of these institutions, it is important to distinguish between different kind of faith or involvement that people pay within their socio-economic and -cultural context such as bonding, bridging and linking with these institutions.

Generally bonding relationship is viewed as strong or thick, while bridging relation is weak or thin (Narayanan, 1999; Onyx and Bullen, 2000; Putnam, 2001; Woolcock, 2001). Thus, bonding relationship is existed in traditional institution, which refers that villagers have close relationship with this institution. These people tend to make close relationship as they have similar interest and common affiliation. Ann Dale and Jennie Sparkes (2007) argued that adhesiveness within this network is a sense of deep trust held among members, which is often highly relational, personalized and thus, has potential for conflict when their trust and commonalities break down. Once, the tank irrigation system has been considered as a sole livelihood provider. Almost entire village population depends on it. During the 1980-81, population depended on agriculture in the study villages was 92 percent. But in 2007, it is 67 percent. (Block statistics, 2007). Over the period of time, due to changes in government policy and education opens various avenues for villagers. This is aggravated still by frequently failed rainfall. Match box, fire work and cotton industries are coming to exist in nearby towns and they opened opportunity especially for youngsters. They also offered relatively high salary than agriculture. Slowly, youngsters move out from the village to search better opportunity. Consequently, farmers faced with labour shortage as they could not able to attract labourers through competitive wages. Most farmers leased out their land or left fallow. They are also looking for non-agricultural employment in the vicinity of the villages and meantime they receive remittance from their son or daughters who are moved out from villages. The government also announced programs like Sampoorna Grama Rozgar Yojana (SGRY), National Rural Employment Guaranty Scheme (NREGS), Swarna Jayanthi Grama Swarozgar Yojana (SGSY) and Ananithu Grama Anna Marumalarchi Thittam

(AGAMT). Basic objectives of all these programs are to give supplementary wage employment to rural labourers. Moreover, upper caste farmers who are enjoyed control over lower caste people, lost their control due to changes in social structure and land holding pattern. Hence, once reason for coming united, common goal is broken, the traditional institutionÊs disintegration gets started. As our research shows, the role of peopleÊs participation in institution is much diminished now but not entirely forgotten.

In the case of Government sponsored institution, the cohesive force could be termed as „Bridging‰. This relationship characterized by more impersonal and villagers participation is merely perfunctory not intuitive. It is often viewed as weak and opportunistic tie that facilitate access to resources. „Bridging‰ occurs when someone from the government try to connect with local people through some agenda (Granovetter, 1973). Here, the trust among members are often thin and tend broke when the bridger from the government side left the village or once his agenda or program completes. This type of institutions tends to provide comprehensive solutions that have tried to exorcize the factors which hinder the progress and simply do not work as expected. It is often conceived as designed to provide comic relief but not constant relief. This system failed to understand the fact that villagers are divided into many groups, based on their caste, income status and land holding etc. To connect or bring them into one group as tank command areas farmers, connecting thread is diluted by communal force and widespread social disparity. Government sponsored institution is not concentrated on this aspect. They try to identify all the farmers as tank farmers. They have time limit to implement program and within these time limit, they could not able or not interested to address this problem.

Regarding NGOs sponsored institutions, the core principle employed is „Linking‰. They try to mobilize the farmers themselves and made link with government agencies and other financial institutions. The prime objective of this „Linking‰ is to get accustomed to use government program for the benefit of common. It is also considered as opportunistic ties and viewed as the capacity provider for institution to lever resources, ideas and information from the formal institution (Woolcock, 2001). NGOs showed interest to operate in village only when favorable condition exist or assure to provide. When they find difficulty to operate, they withdraw from these villages and automatically from institution building

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process. In our experience, in the study village, from 1992-2002, the NGO called ASSEFA (Association of Sarva Seva Farm) came to create sound institutional and regulatory framework as well as enabling environment for peopleÊs participation by providing loans. But after the initial involvement they exhibit, they failed to imbibe a sense of self-help and a sense of sustainable progress. In the long run, villagers attained the mindset that „they will do‰ mentality. Once conducive environment disappearing, the NGO also slowly came out from the village. There is an argument that NGOs looking for conducive climate to operate on in order to impress their funding agencies. It is easy for the NGOs to operate in new villages rather than operate one village for longer time. After ASSEFA withdraw, another NGO called DHAN foundation came to operate in this village. Considering that relatively small village with single community, the basic platform to launch its program was already initiated by earlier one. This NGO also did its level best to organize the farmers to form tank institution called „Vayalagam‰. They showed substantial and positive improvement in tank performance surpassing initial hurdles. Even then priority between farmers and NGO is differing. This system also will not yield good result if they fail to understand in changes happened in the external environment. Bolding (1994) argued that any external involvement, no matter how well intentioned, can be perceived as meddling and even be feared. Hence, what they need to do is not bringing expert from outside, but an awakening of the expertise within the villagers.

Functioning Style of InstitutionsTraditional irrigational institution is functioning

as a two tier system. In the top level, there will be commanding position called „Nattamai‰ (informal village leader) usually occupied by upper caste people. In the lower level, there will be an executing position as irrigation worker called „Neerkatti‰ (water manager) „Neerpachi‰ (water distributor) and „Thotti‰ (field assistant) are employed. These all post usually hired from scheduled caste household on rotation basis. In government sponsored institution, they will organize

water user association with membership of all the ayacut (tank command) farmers. They are expected to elect three positions like president, secretary and treasurer. Based on the number of villages included in association, they will select members also. Apart from this elected body, this system also employs irrigation workers from scheduled caste households. In case of NGO sponsored institution, the NGO appoint one person as negotiator to motivate farmer to join in irrigational institution. The member farmers elect or select their president, secretary and treasurer. The NGO provide accountant staff to help the farmer to maintain their accounts.

Role ExecutionTraditional tank water institution is existing here

from the time immemorial. Then, these institutions have complete control over the common resources. The way they approach to the problems are perhaps most incisive and provide constructive contribution to its better performance. Rules and roles that operate, maintain and manage these systems are strongly shaped by caste hierarchy. These institutions took the responsibility of supply channel maintenance, de-silting tank bed (farmers are allowed to remove top fertile layer of silt for their manure need), strengthening of tank bund, maintaining of tank physical structure (sluice and surplus weir), water distribution, resolving dispute and conflict resolution. However, the present situation is that most of the functions are not executed as external environment explicitly changed. Farmers are not allowed to take silt from the tank as social forestry program implemented by the government. Due to this misplaced priority, regular de-siltation did by farmers are stopped. As a result, every year about 2 percent of tank capacity is lost due to silt accumulation. Supply channels and catchment area are also encroached and but these institution have no power to deal with them. Thus, at present in majority of the tank water institution have only limited responsibility that too not regularly (Janakarajan, 1993 and Palanisami, 2006).

Roles assumed Traditional Govt. Sponsored NGO Sponsored

Supply channel cleaning Occasionally Occasionally Yes

De-silting tank bed No No No

Strengthening tank bund No Yes No

Sluice and weir maintenance Yes Occasionally Yes

Outlet channel maintenance Yes No Yes

Water distribution Yes No No

Conflict resolution Yes No No

Table 3: Role execution of Institutions

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Table 2 delineated that the gap between perceived roles and performed roles is large and illuminating. In government sponsored institution, water user association was active only during tank rehabilitation program implemented in 1996-1998. After completion of this European Economic Community assisted program, officials responsible for water users association, failed to maintain its tempo of their members (Palanisami et al, 2007). Farmers also complained that they spent much money on tank structures. The main problem is that its catchment and supply channel has been encroached upon, and nothing has been done about it. Farmers are also opined that they are motivated to participate in ongoing process but hardly vested with any power. These kinds of participation are often criticized as tokenist, giving participant with no power (Smith, 1998). It is assumed that people provided with option of passive participation. Certainly, farmers who are expected to participate in institutional building should provide with power to make decision and their priority and choices of investment. If it is not ensured, it is mere sophistry to say that it is participation and institutional success. Pearce and Stiefel (1980) concluded that the promotion of participatory institutional building may be regarded as no more than rhetoric unless communities have some degree of power over the services. Smith (1998) also argued that passive participation in the name of consultation is the weakest form of participation in decision making, is often said to be a mean of indoctrinating the public in the values and priorities of the planner to ensure that they obtain public endorsement of their decision, rather than understanding of local needs and priorities.

As we discussed earlier, due to the government policy transfer of land holding is happened from upper caste to lower caste people. It is not simply considered as land transfer but also power transfer. Power sharing is not viewed in right way by upper caste people. They physically accept but are mentally and emotionally much reluctant and not ready to accept that lower caste farmers empowered through land. Upper caster people also leased or sold their lands to landless labourers and lower caste farmers. Villagers those who entirely depend on mercy or goodwill of large or upper caste farmers to get employment, became self-employed. In the mean time, the entry of more and more caste based political party into the village system damaged the village cohesiveness and consequently wipes off cooperative attitude within and between farmers and villages. This could be a possible reason for dismantling traditional

institutions. Disintegration of joint family, promotion of education, development of cottage industry are hastened the process. As Agarwal (2001) rightly put if farmers have earning activities that are not reliant on common resources, their incentives to the collective management will be reduced. The degree of dependency on small scale irrigation will depend both on farmerÊs capacity to exploit it and on what alternative livelihood options are available to them. Our observation confirmed that farmers are slowly losing their ability to exploit potential benefit from tank irrigation system because of their weak institutional power. When compare to Government sponsored institution, traditional and NGO sponsored institution showed incremental increase in the delivery system. In these two organizations farmers strives continuously to subjugate impossibility and then try to succeed.

Role Execution of Irrigation Functionaries

An institution, irrespective of its nature or governance, is assisted by a group of irrigation workers called „Neerkatties‰ (water man) who are generally hired from scheduled caste house hold in rotation in the tank village. If a particular tank village does not have that particular schedule caste community, they employed „Neerkatties‰ from nearby villages. The discussion about „Neerkattis‰ becomes important, considering the service they render to tank institution. They are the specialist in water management, having rules to allocate water in the time of scarcity, on the basis of detailed knowledge of the needs of individual wetland fields, thus mitigating usual tension between head and tail-enders (Mosse, 2006) The „Neerkatties‰ are omnipresent who are work almost all the tank villages making their livelihood based on their services like sluice operation, irrigation to the field, protecting tank resources and so on. In the mean time, like any other institution, tank as an institution, has also changed a lot and profiles of these functionaries also changed. In many cases, our field experience showed that, such changes have played havoc with their lives, but still many are thriving by adopting themselves to the changes (Vasimalai, 2003). Among the study villages, two villages have „Neerkatti‰ community and one village did not have „Neerkatti‰ community. By custom, the „Neerkatties‰ are expected to execute some responsibilities (Table 3). It is clear from the table 3 that mere existence of „Neerkatti‰ family in the village is no guaranty for execution of expected work. During our interview with „Neerkatties‰ in the

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village, they accepted that they are not doing jobs what their father or grandfather as a „Neerkatti‰ did. They spelled out some the reasons for their hesitance.

Dependency: In the past 10 years, because of the uncertainty and insufficient rainfall tank not received water enough to cater farmers need. Studies showed that only 2 years in the last 10 year tank received water its full capacity. As a result, most of the farmers ended with crop failure or left fallow. One „Neerkatti‰ needs to work for at least 30 acres of farmersÊ field as water man to get justifiable income. When this falls down, he encountered with insufficient income and struggle to maintain family. Thus, he preferred to go out for other agricultural or non-agricultural jobs.

Payment: Usually after the crop harvest, the „Neerkatties‰ are entitled to have 12 kg of grain per acre. This type of payment is applicable only during normal tank season. When tank fails or partially performed they are not sure about their payment. Again some farmers, even if they are reaped good harvest are reluctant to come forward to pay their due to „Neerkatties‰. This type of problems cropped up day by day. They have often involved in quarrel with „Neerkatties‰ about their work execution. These all dissipate the custom of payment to „Neerkatti‰. Hence, they are reluctant to perform their duties as they perceived. Another reason would be as we discussed earlier that disintegration of caste based hierarchy and dismantling of institution. The majority of them were not able to produce enough income through agriculture and start doing or searching on wide array of off-farm activities to supplement the income gap. When they opted out non-agricultural opportunities, they could not fully concentrate on „Neerkatti‰ work as they did earlier.

ConclusionThe thinking of community was of lowest level

of aggregation at which people organize for common efforts; i.e. a small, homogenous, harmonious and territorially bound unit (Kumar, 2005). Many researches showed that the rural or traditional communities are in harmony with local customs and demonstrate long established patterns of sustainable and equitable resource use (Li, 1996). Traditional or institutional approach to common property received wide spread acceptance and resulted successful for quite a long period. It is proved that community can own, manage, sustain and enhance resources such as tank irrigation system (Berkes, 1989 and Ostrom, 1990). But present situation, tank irrigation system as an institution fail to deliver what it is capable of. Reasons are multifold and deep rooted as we discussed.

The main flaw in todayÊs approach to tank institution is its fragmented approach and the need is holistic approach. Tank irrigation system is involved physical structures, technical aspects and institutional factors. All the attempts made so far to modernize or rehabilitate the tank system fully concentrates only on physical improvements. That too was not as good as farmers expected. The institutional aspects completely ignored until international donor agencies is asked to do so. Even then reports showed that government spent 71 percent of money in physical improvement and 27 percent spent towards administrative purpose. Meager 2 percent was spent on institutional aspects and after maintenance (ADB, 2006). Importantly, the institutional factors and physical factors do not act in isolation; they are so complex and often interact with each other. Hence, it is recommended that due importance will be given to address institutional aspects. About 10 percent of the cost could be spent towards institutional and system maintenance.

Assumed Roles Traditional Govt. Sponsored NGO Sponsored

Mobilize village farmer Yes No Yes

Watch and ward of tank asset No No No

Water management Yes No No

Farm management No No No

Arranging religious ceremony Yes Yes Yes

Sluice operation Yes No Yes

Moderator of dispute between farmers Yes No Yes

Common fund collector Yes No Yes

Announcer Yes Yes Yes

Directing Neerpatchi and Thotti No No No

Table 4: Role execution of Neerkatti

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The farmers asserted that government induced participation is often purely exploitative. They administer some temporary palliatives to address much deep rooted problems. As a result things would not happen in the way one would have expected. The minor irrigation system is to be treated as one integral holistic unit comprising catchment, water spread, tank structures and tank command. As experience showed that most of the encroachment occurred in catchment and supply channel which is fall in some other village panchayat. So the institution could not exhibit its power on this chronic problem. These institutions are provided with power to evict encroachment and safeguard its resources. In over view, true attempt could be made for revival of traditional irrigation institution with its original vibrant. The policy should underpinned by principles of sustainability and equity. Women are widely encouraged to participate in the institution. Like in the Pudhucherry, women and men from every agricultural household could become member in the institution. It is undeniably true that if we reestablish relationship between farmers and tank

institution and reinvent its role as independent arbiter through radically different and inspiring, innovative approach will strengthen the hopes of farmer who still evidently banking on the tank irrigation as their savior. A sustainable tank irrigated agriculture with all its uncertainties and complexities cannot be envisaged without all the actors being involved with real enthusiasm in all aspects of planning, execution and management process.

AcknowledgementWe would like to express our sincere thanks to our

interviewees for their cooperation and also we sincerely thank JSPS, Japan and the Suntory Foundation for their financial assistance.

M.Jegadeesan is JSPS Post-Doctoral Fellow, Center for Southeast Asian Studies, Kyoto University, Japan.

K. Fujita is Professor, Center for Southeast Asian Studies, Kyoto University, Japan

References • Agarwal, A. (1999) Community in conservation: tracing the outlines of an enchanting concept, in R.Jeffery and

N.Sundar,eds A New moral economy for IndiaÊs forests? Discourse of community and participation, Sage Pulication, New Delhi.

• Ann Dale and Jennie Sparkes. (2008) Protecting ecosystems: network structure and social capital mobilization, Community Development Journal, Vol. 43, pp 143-156, April 2008

• Asian Development Bank. (2006) The rehabilitation and management of tanks in India: A study of selected states.• Basu, K. (2000) Prelude to political economy: A study of the social and political foundations of economics, OUP,

Oxford.• BDO. (2007) Block development office, policy note.• Berkes, F. (1989) Common Property Resources: Ecology and community based sustainable development, Belhaven

press, London.• Block statistics. (2007) Block statistical office, Govt. of Tamil Nadu.• Bolding, A. (1994) We thought we knew it all, Zinwesi News letter, University of Zimbabwe and Wageningen

Agricultural University, Mutare, (3).• Brosius, J. P.;Tsing, A. L. and Zerner, C. (1998) Representing communities: histories and politics of community

based natural resource management, Society and Natural Resources, 11 (2), 157-168.• Chopra, K and P. Dasgupta, (2008) Nature of household dependence on common pool resources: An Empirical

study, Economic and Political Weekly, Feb 23, pp 58-66.• Coward Jr, E Walter (1980) Irrigation development: institutional and organizational issues in Coward Jr E Walter

(ed), Irrigation and Agricultural Development in Asia: Perspectives from social sciences, Cornell University press, London.

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• Granovetter, M. (1973) The strength of weak ties, The American Journal of Sociology, 78 (6), 1360-1380.• Janakarajan, S. (1993) In search of Tanks: some hidden facts, Economic and Political Weekly, June 26, pp A53-

A60.• Kumar, C.(2005) Revisiting community in community based natural resource management, Community Development

Journal, Vol. 40 No 3, July 2005 pp 275-285.• Li, T.M. (1996) Images of community: Discourse and strategy in property relations, Development and Change, 27

(3), 501-528.• Li, T.M. (2002) Engaging simplification: Community base natural resource management, market processes and state

agendas in upland Southeast Asia, World Development,30 (2), 265-283.• Mosse, David. (2003) The rule of water: Statecraft, ecology and collective action in South India, Oxford university

press, Delhi.• Mosse,David. (2006) Collective action, common property and social capital in South India: An Anthropological

commentary, Economic Development and Cultural Change, Vol. 54, Issue 3, pp 695-724, April.• Narayanan, D. (1999) Bonds and Bridges: social capital and poverty, World Bank, Washington, DC.• NSSO. (1999) Common property resources in India, NSSO 54th round survey (Jan 98- June 98), Govt. of India.• Onyx, J. and Bullen, P. (2000) Measuring social capital in five communities, The Journal of Applied Behavioral

Science, 36 (1), 23-42.• Ostrom, E.(1990) Governing the commons: The evolution of institutions for collective action, Cambridge university

press, Cambridge, UK.• Palanisami, K. (2000) Tank irrigation: Revival for prosperity, Asian Publication Services, New Delhi.• Palanisami, K. (2006) Sustainable management of tank irrigation system in India, Journal of Developments in

Sustainable Agriculture, 1:34-40.• Palanisami, K.; M. Jegadeesan; K. Fujita and Y. Kono (2008) Impacts of tank modernization programs in Tamil

Nadu state, India. Working paper series, CSEAS, Kyoto University• Pearse, A. and Stiefel, M. (1980) Enquiry into participation. A Research approach (eds). United Nations Research

Institute for Social Development, Geneva.• Putnam, R. (2001) Social capita measurement and consequences, ISUMA, 2 (1), 41-52.• Sakthivadivel, R.; P. Gomathinayagam and Tushaar Shah (2004) Rejuvenating irrigation tanks through local institutions,

Economic and Political Weekly, July 31, pp 3521-3526.• Smith, B.C. (1998) Participation without power: subterfuge or development, Community Development Journal, Vol.

33 No. 3, July pp. 197-204.• Vaidyanathan, A. (1985) Water control Institution and agriculture: A comparative perspective, Indian Economic

Review, Vol. XX. No 1.• Vasimalai, M. P. (2003) Neerkatties: The Rural water manager (eds. by Seenivasan. R), DHAN Foundation, Madurai,

India.• Woolcock, M. (2001) The place of social capital in understanding social and economic outcomes, ISUMA, 2 (1),

11-17.

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Rethinking The Strategic Approach including Adaptation

of Rainwater Harvesting for Landscape Irrigation and Agricultural Use-A Review

S. K. Samanta & D. B. Saha

22

IntroductionRainwater is valued for its purity and it is free

after all. Despite having bestowed with the plenty of rainfall, India is under pressure in water sector in some states due to fast growing population, industries, agriculture etc as well as the potential changes in climatic condition. One way of reducing demand-supply gap is to use suitable rainwater harvesting technique. Since, irrigation consumes over 80% of the available water and conventional irrigation of all rain fed lands is not feasible, there is a tremendous scope for improving the productivity through rain water harvesting. It provides a water source where no source of water exists or ground water is unacceptable or unavailable. The state of the art technology may be utilized in various sectors namely domestic water supply, industry, mining, agriculture, landscape irrigation, livestock and business to augment freshwater through the techniques of water conservation, water quality improvement, and reuse for augmentation of fresh water.

India is characterized by wide variations of physiographic, climatic, soil, environmental and socio-economic conditions. Therefore, water harvesting techniques are highly location specific. In the sector of landscape irrigation and agricultural use, rainwater may be harvested for irrigation of arable land through following techniques, i.e.

(1) Rainwater Harvesting from Rooftop Catchments,

(2) Rainwater Harvesting in situ,

(3) Runoff Collection from Paved and Unpaved Roads,

(4) Runoff Collection using Surface and Underground Structures,

(5) Raised Planting Beds,

(6) Small-Scale Clay Pot and Porous Capsule Irrigation,

(7) Automatic Surge Flow and Gravitational Tank Irrigation.

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Desert adapted plants are to be grown in cultivable high land due to its low irrigation water-use. Depending on the local agro-climatic condition, evapotranspiration, nature of soil, soil moisture, etc, the cash crops like maize, wheat/buckwheat, barley, ginger, millet, mustard, sorghum, groundnut, arecanut, vegetables, fruit trees, pastures are given the preference to be grown considering the inter-crop concept with high plant density. The distribution infrastructure, centralized treatment facility etc. are excluded in this system. Rainwater harvesting can reduce the volume of storm water and ultimately lessen the impact of erosion. Sometimes, community participation is needed to get sustainable, good quality water. The volume of rainwater captured from a large catchment surface of a building should be cost-effective for several uses, such as landscape irrigation, toilet flushing etc. A pilot project may be undertaken to evaluate the feasibility of suitable rainwater harvesting technique in an area.

Rainfall DistributionIn India, on an average, about 30% area of the

country receives less than 750 mm rainfall, 42% receives between 750 and 1250 mm and 20% experiences rainfall between 1250 and 2000 mm. Temporally, the total rainfall occurs in less than 150 hours and half of it descends in not more than 20 to 30 hours of heavy spells. Hence, runoff is a prominent feature of the hydrologic cycle.

Basic Components of Rainwater Harvesting System

In the history of irrigation in South India, natural and manmade tanks which helped store and conserve the rain runoff played a prominent role. At the end of the First Five Year Plan, Andhra Pradesh had 58,527 tanks with an irrigated area of over 26 lakh acres. The water overflowing from the tank heads was collected in the lower ends so that no wastage of water took place. The process augmented groundwater reservoir. In the decades following the 1950s, tank irrigation system suffered a steady decline due to unavoidable reasons.

In general, rainwater harvesting is the combined process of the capture, diversion, and storage of rainwater for a number of different purposes including landscape irrigation. It may be as simple as channeling rain runoff in un-guttered roof to a planted landscape in a residential or small-scale scheme. The water can be stored down slope in bermed landscape holding area for

direct use of lawn grass or plants to prevent erosion on sloped surfaces.

The basic components regardless of the complexity of the system are :

Catchment surface: the collection surface from which rainwater runs off.

The roof of a building or house is the first choice for catchment. For additional capacity, an open-sided rain barn or pole barn may be built. Water quality from different roof catchments is the function of the type of roof material, climatic conditions etc. A commonly used roofing material such as corrugated galvanized metallic sheet is suitable for rainwater harvesting. Clay and concrete tiles are both porous, but it still serves as a good roofing material for rainwater harvesting for irrigation. Roofing with wood shingle, composite shingle, tar, and gravel materials are rare, and the water harvested is usually suitable only for irrigation due to leaching of toxins.

Gutters and downspouts: channel water from the roof to the tank.

Gutters are fitted to capture rainwater running off the eaves of a building. The most common materials for gutters and downspouts are half-round PVC, seamless aluminum and galvanized steel. Other necessary components are the drop outlet, 45-degree elbows etc. Sometimes, controlling factors for spillage or overrunning of gutters including rain fall intensity, an inadequate number of downspouts, excessively long roof distances from ridge to eave, steep roof slopes, and inadequate gutter maintenance should be taken into consideration. The strategies may be suitably applied to minimize possible overrunning to improve catchment efficiency etc. Gutters should be installed with the slope towards the downspout.

Leaf Screens, First-flush Diverters, and Roof Washers

These are the components which remove debris, birdÊs dropping, dust etc from the captured rainwater before it gets accumulated in the storage tank. Mesh screens are used to remove debris both before and after the storage tank without clogging irrigation emitters. It is to find out the suitable method that works better. Leaf screens must be regularly cleaned to be effective. The first-flush diverter routes the first flow of rainwater from the catchment surface away from the storage tank. The

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flushed water can be routed to a planted area at ease for landscape irrigation. The simplest first-flush diverter is a PVC standpipe. Roof washers must be cleaned. Without proper maintenance, it becomes clogged and restricts the flow of rainwater.

One or More Storage Tanks, Also Called Cisterns

The storage tank or cistern is the most expensive component of the rainwater harvesting system. The size of storage tank is dictated by several variables like the precipitation, the demand, the projected length of dry spells without rain, the catchment surface area, aesthetics, personal preference, and overall budget. Tanks are located as close as possible to supply and demand points to reduce the distance to that water is conveyed. To evade the utility of the pump, tanks should be placed as high as practicable. Of course, the tank inlet must be lower than the lowest downspout from the catchment area. Tanks should be placed on a stable, level pad. Otherwise, a concrete pad may be constructed. The runoff from other parts of the property or from the tank overflow will not undermine the pad. The pad or bed should be checked after intense rainfall events. PVC tanks are cost effective and commonly used for storage uses. Concrete tanks can be constructed above ground or below ground. A type of concrete tank is constructed of stacked rings with sealant around the joints. Ferrocement is a low-cost steel and mortar composite material. Ferrocement structures have commonly been used for water storage due to low cost and availability of materials. One of the simplest and practical choices for urban dwellers is 50 - 75 gallon drum to be used as a rain barrel for landscape irrigation.

Delivery System: Gravity-fed Harvested rainwater may be delivered to

landscape through PVC pipes under gravity as it is most cost effective.

Hydrometeorological StudiesThese are undertaken to decipher the rainfall,

rainy days intensity, evaporation, availability of surplus water, evapotranspiration losses etc which are helpful in designing the storage capacity. In semi arid regions of India, evaporation losses are significant after the month of January. As an example, Chennai City receives annual rainfall ranging from 1100 to 1200 mm. As per statistics, a house (223 sq. m.) may get about 700 litres of water a day from that amount of rainfall.

Crop Water RequirementsThe water consumed by a crop is described

interchangeably by the terms like crop water use, consumptive use and evapo-transpiration (ET) etc. Different crops have different water-use requirements under the same weather condition. Water requirement depends mainly on the nature, stage of growth of the crop and the environmental conditions. The consumptive use of the crop at different growth stages is computed by the water-balance methodology (wherein inflow and outflow of the water is calculated through suitable measurements) using the crop-coefficients appropriate to the specific crop along with the reference evapo-transpiration. Crops transpire water at the maximum rate when soil water is at field capacity. Usually, the transpiration rate does not decrease significantly until the soil moisture falls below 50% of field capacity. Crop coefficient is dynamic in nature and varies according to crop characteristics (crop height, crop roughness), dates of (trans) planting, stage of growth, soil cover and climatic conditions. Computer model CROPWAT (FAO Manual, Irrigation and Drainage Paper- 24 on Crop Water Requirements) may be used to calculate the crop ET and irrigation requirements of different crops from crop coefficients data generated at local research institutes. The cash crops like maize, wheat/buckwheat, barley, ginger, arecanut, soybean, millet, mustard, sorghum, groundnut, vegetables and fruit trees are generally preferred.

The irrigation schedule is to supply the right quantity of water at right time through an appropriate application method to satisfy the crop water requirements. It serves applying water at a reasonable cost along with the fulfillment of the objectives of high yield of good quality, attaining high water use efficiency without causing any damage to soil productivity. In case of limited amount of water, the aim is to maximize production per unit of water by rationalizing its distribution over the available land and also applying it at more sensitive stages of crop growth.

Water Balance and System SizingThe basic rule for sizing any rainwater harvesting

system is that the volume of water that can be captured and stored (the supply) must equal or exceed the volume of water used (the demand). If rainwater is to be used only for irrigation, a rough estimate of demand, supply, and storage capacity may be sufficient. To ensure a year-round water supply, the catchment area and storage capacity must be sized to meet water demand through

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the longest expected interval without rain. Many urban dwellers capture rainwater for irrigation of vegetables and horticulture gardens. For its superior nature, rainwater promotes healthy plant growth. Historical evapo-transpiration data may be used to project potential water demands for crop.

The following principles are generally followed for water-wise landscaping practice.

(a) Plan and design for water conservation.

(b) Create practical turf areas.

(c) Group plants of similar water needs together.

(d) Use soil amendments like compost to allow the soil to retain more water.

(e) Use mulches, especially in high and moderate watering zones, to lessen soil evaporation.

(f) Irrigate efficiently by applying the right amount of water at the right time.

(g) Maintain the landscape appropriately by fertilizing, mowing, and pruning.

The basic monthly water balance calculation is

Water available = Initial volume in storage + Water captured � Water used

Sizing of the storage tank is calculated from the following equation,

Rooftop Rainwater Harvesting = Catchment Area x Average Annual Rainfall x Runoff Co-efficient

Considering rainfall data, climate data, soil data, cropping pattern in the area, irrigation water-use is calculated with the help of Computer model CROPWAT.

Gray Water, The Appalling Result of Urbanization

In the larger metropolitan cities like Delhi, Mumbai, Chennai, Kolkata etc., there is tremendous

waste of water, in our anxiety to promote particularly urban sanitation. The bulk of the purified and filtered water contributed by surface and ground water is being used for flushing toilets. A few treatment plants of limited capacity are stated to be functioning but the gray water in the tune of 1,000 mld (million litres a day) produced as in the fate of a city like Bangalore may be utilized in landscape irrigation other than releasing to storm drainage channels, ultimately to pollute rivers downstream without any restriction. The slums are sprouting and occupying the only available low lying area which is best suited for channeling the polluted water discharged from the multistoried luxurious modern complexes in the name of so called urban sanitation. Rainwater harvesting may be encouraged in large commercial and industrial buildings augmenting fresh water coupled with condensate from air conditioning systems. An advantage of capturing condensate is that its production is more during the hot and humid month of the year, when landscape irrigation is badly needed.

ConclusionFree and non-committed rainfall can be harvested

at homes, schools, parks, parking lots, apartment complexes, commercial facilities, residential complexes and cultivable high land devoid of any water source. Many methods are available to harvest rain water for landscape and agricultural uses. Some of them are inexpensive and easy to construct. Storing water in a barrel for later use or constructing small berms and drainages to direct water to a row of trees may be achieved with some attention and initiatives. All is needed to get started with some precipitation and desired plants that require irrigation. Even the simplest methods provide benefits. The community achieves long-term benefits which reduce groundwater use and promote soil conservation. On the other hand, gray water discharged from the small huts/multistoried modern complexes may also be economically used in landscape irrigation. Capturing condensate in large commercial and industrial buildings for landscape irrigation has also to be considered.

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ReferencesFinal Report of the Workshop on Alternative Technologies for Freshwater Augmentation in the Caribbean (Barbados,

24-27 October 1995), OAS/UNEP.Guide on Artificial Recharge to Ground Water, Central Ground Water Board, Ministry of Water Resources, New

Delhi, May, 2000 Gelt, Joe, Home Use of Graywater, Rainwater Conserves Water·and May Save Money, http://ag.arizona.edu/

AZWATER/arroyo/071rain.htmlRajput, Diksha, Conserving the Heritage of Water Harvesting, PIB, Govt. of India, http://pib.nic.in/feature/feyr2000/

fmay2000/f250520001.htmlRadhakrishna, B.P., Water Supply and Sanitation in the Indian Context, Jour.Geol.Soc.India, Vol.71, May2008Sharma, Bharat R., Sr. Researcher, Crop Water Requirements and Water Productivity: Concepts and Practices,

International Water Management Institute, Asia Regional Office, New Delhi, India Sharda,1 V.N., & Juyal2,G.P., Water Harvesting Techniques, Design of Small Dams and Hydraulic Complements,

1Director and 2Head (Div. of H&E), Central Soil & Water Conservation Research & Training Institute, Dehradun-248 195 (Uttaranchal), India.

The Texas Manual on Rainwater Harvesting, Texas Water Development Board in cooperation with Chris Brown Consulting, Jan Gerston Consulting, Stephen Colley/Architecture, Dr. Hari J. Krishna, P.E., Contract Manager, Third Edition, 2005 Austin, Texas

Waterfall, Patricia H., Extension Agent, Harvesting Rainwater for Landscape Use, University of Arizona Cooperative Extension, Low 4 Program, http://ag.arizona.edu/pubs/water/az1052/harvest.html

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Theme – 5Role of Research,

Extension and Education

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Participatory Irrigation Management – Need of an HourM. Shantha Sheela* and K.Palanisami**

23

IntroductionSince inception of community development

programme and also various agricultural development programmes from 1952 onwards, there has been an emphasis on transferring the technology to the farming community through the government agencies. But involvement of local people i.e is farmers, farmwomen, farm youth, local legitimizers and village -level peer groups was not much. That is why the tempo of agricultural and rural development could not catch up to the tune expected despite heavy resources and energy spent on achieving the objectives. The desire for the change did not come from within the heart of the rural people. They adopted the improved technology just because some amount o help/ subsidy/ credits/ inputs were supplied to them either on subsidized basis or free of cost. Further, the responsibility for mobilizing people at the gross-root level also rested with government machinery rather than the local people. Thus, the local people were not bound to fully implement the programmes and to see

that these programmes are sustained and they result into tangible gains. Now, it has been widely realized that organizations engaged in research and extension must have an effective feedback system from the users of the technology in order to make the research and extension system demand-driven and market-driven. Thus, the crucial factor in improving the feedback system is to organize farmers into functional groups. These groups are virtually acting as secondary disseminators of the improved water management technologies among the rest of the farmers. So the results are fruitful, only if the transfer of technology that involves farmers from assessing the project to implementation stage.

Irrigation sector will continue to play an important role in the socio-economic development of any country in 21st century. But at the same time it is observed that the profitability and productive capacity of the land is declining and other socio-economic problems of irrigation sector are emerging. This gives a signal that appropriate policies are necessary to maintain

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the profitability of irrigated agriculture in a sustainable manner in the new century. Among the states in India, Tamil Nadu is one of the water-starved states whose per capita availability is less than the national average. Tamil Nadu with seven per cent of the population and four per cent of land area has only about three per cent of CountryÊs water resources. Therefore, any improvement in on-farm water management will conserve water that can be used to expand more intensive agriculture that will increase farm income. The performance of monsoon rain will decide the water resources of Tamil Nadu. Among the area irrigated under different sources, significant reduction observed under tank irrigation over years. The share has declined from 28 to 24 per cent during this 20 year period. Introduction of proper water management strategies on the farm greatly enhance the percentage of land cultivation. Improving the on-farm water application efficiencies can increase the command area supported by a single tank. In the case of well irrigation, the major issue is the over-exploitation of the aquifers. Number of wells in the state has increased from 60,000 in 1960Ês to 1.8 million in 1990Ês and about 1.4 million wells are energized. The average area irrigated per well has declined from 1.5 ha from 1960Ês to 0.6 ha in 1960Ês. The cost of well investment has also increased from Rs. 30,000 to Rs. 1.5 lakh during the above period. The average failure rate of tube-well is about 67 per cent. The externalities to the small and marginal farmers are so high that the well abandonment is also increasing over years. Improved water management strategies in this area not only save the losses occurring due to surface irrigation, it also reduce the over exploitation of wells and borewells. Among the districts Coimbatore district the water scarcity is high and the area irrigated by wells, canals and tank was 134223 ha (72.32 %), 48675 ha (26.23 %) and 2696 ha (1.45 %) respectively. Eventhough, there are three sources of irrigation which are not able to meet the irrigation demand of farmers in Coimbatore district. Water Technology centre at TNAU involves few technology transfer projects. All these projects it involves people from the identification of the location, technology suited to the crop and field to field trails. ThatÊs why the transferred technology is viable and sustainable.

Objectives(a) FarmersÊ discussion and Participatory Irrigation Management (PIM)

(b) Water and soil resources

(c) Implementation of improved irrigation practices

(d) Impact of the improved irrigation practices

(e) Facilitate the transfer of technology by conducting field day

Methodology

Selection of Study AreaAgragarasamakulam village in Coimbatore

district of Tamil Nadu State was selected for the present study. Achieving this task was found to be easier in this district in the early stage of the study itself, because of their familiarity with Tamil Nadu Agricultural University and the farmers progressiveness towards the use of new concepts and methods in farming.

Selection of RespondentsThe introductory meeting of the project

„Implementation of System Improvement and Water Management Strategies in Agragarasamakulam Tank in Coimbatore District‰ was conducted at Agragarasamakulam village. All farmers in the villages were invited with the help of village panchayat presidents to attend the meeting. The interested farmers were attended the meeting. Discussion with scientists and farmers were arranged.

After that, the senior research fellows who are involved in the project visited the farmersÊ field and conducted a preference survey to identify which type of irrigation technology they prefer to adopt in their field. Based on water availability, crops grown and present water management practices, the fields were selected. Those farmers who were accepted to give their co-operation for making demonstration plots in their farm and to take care of the demonstration plots were selected.

The selected farmers were taken to TNAU- WTC- irrigation cafeteria to know about the various irrigation technologies demonstrated to different crops and also to farmers fields where these technologies were actually implemented by the farmers and finally nine farmers were selected.

Technology Farmers preferred Farmers selected

Drip irrigation 25 6

Drip fertigation 10 3

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Sl. Particulars Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec Total No. 1. Water 2601 1762 1951 1888 1625 1573 1300 1300 1888 2601 3147 3251 24892 currently available to the crop Effective rainfall 78 85 135 871 498 359 943 590 867 2352 2420 500 9698

2. Actual 2400 2400 2400 2400 2400 2400 1600 1600 1600 2880 2400 2400 26880 requirement of sugarcaneIrrigation requirement 2322 2315 2265 1529 1902 2041 657 1010 733 528 -20 1900 17182

Excess / deficit 279 -553 -314 359 -277 -468 643 290 1155 2073 3167 1351 7705

3. Irrigation 1600 1600 1600 1600 1600 1600 1120 1120 1120 1760 1600 1600 17920 requirement if drip is used to sugarcaneExcess / deficit 1079 247 486 1159 523 332 1123 770 1635 3193 3967 2151 16670

Table 2. Present status of water use and water budgeting to sugarcane for 4 acres (m3)

S.No. Area Crop Total water Rainfall Actual req. Total water availability (ha) available / (m3 / year) of the crop (m3) / year year (m3)

Excess months Deficit months

1 1.6 Sugarcane 21388 12426 26880 9 3

2 3.2 Sugarcane 44640 24852 53440 9 3

3 2.0 Sugarcane 43466 15532 34320 10 2

4 4.0 Coconut 29478 31065 28800 12 0

5 1.6 Sugarcane 30672 12426 26880 11 1

6 2.3 Sugarcane 22355 17940 38577 5 7

7 1.6 Sugarcane 24892 12426 26880 8 4

8 8.0 Coconut 35916 62130 57600 8 4

9 5.0 Mulbery 22210 34320 57360 9 3

Table 1. Water resources of selected farmers

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Identification of Irrigation Management Strategies Based on Farmers Need

To identify the cost effective irrigation method the details of crop and interest of farmers were collected and field visits were made. Most of the farmers prefer drip and drip fertigation systems. Drip system is economical, if the design provides optimum size of main, sub-main and laterals. Discharge and spacing is important to give the required quantum of water and wetted area for the crop. Besides proper design, economical layout is important in deciding the cost of the systems for annual and close spaced crops such as banana, turmeric, curry leaf and vegetables etc., since the cost of laterals and emitters decide the cost of the system. So it is important to reduce the length of laterals and number of drippers required per unit area by properly adjusting the crop geometry, without sacrificing the population of the crop. Based on the crop spacing the layout such as single line drip, alternate row (in line) drip and paired row drip is decided. Fertigation is advantageous along with drip irrigation to save fertilizer and labour and also yield and quality improvement. Venturi assembly is used for fertigation in the drip system.

Water and Soil ResourcesSoil and water samples from the selected farmersÊ

fields were collected and analysed for their nutritional status and quality.

The selected farmers were supplied with a Tamil Nadu Agricultural University - Soil Health card for maintaining and updating their soil health status periodically.

In this village the farmers are using only the ground water for cultivation of the crops. The existing crops are irrigated with well water with a depth of more than 100 feet in open wells and 650 - 750 feet in bore wells in all farms. The crops are under irrigated because

of the poor rainfall and deficit water supply. Water budgeting was worked out for the selected farmers and alternative strategies were suggested for successful farming with the available water.

The working out of water budgeting is given in Table 2. as an example for one farmer. Similarly the water resources of the selected farmers were worked out and presented in Table 1.

Impact of the improved irrigation practices

Drip Irrigation in SugarcaneThe farmer was happy and equated the water

requirement of 1.25 acre of sugarcane in surface irrigation to three acre under drip irrigation. The results of the study indicated about 40 % water saving with 25 % increase in production. A comparison of the drip irrigation with surface irrigation in sugarcane is presented in Table 3.

Drip Fertigation in BananaThe farm has water saving of 40 % in drip

irrigation. Since the water is delivered exactly at the root zone of the crop there is no possibility of weeds grown in other areas which considerably reduces the labour on weed management. The fertilizers are also mixed with water and readily available to the crop and also matching the requirement of the crop. The farmer was happy with a yield of 28.75 t ha-1 as against 20 t ha-1 through conventional irrigation practices, which is 44 % higher yield. Now the farmer is convinced and wanted to lay drip irrigation system to vegetable crops also. The benefits realized because of the irrigation system are presented in Table 4.

1. Annualised drip system cost (Rs ha-1) - 10,000

2. Cost of cultivation (Rs ha-1) 60,250 54,125

Total 60,250 64,125

3. Gross income (Rs ha-1) 1,02,500 1,33,250

4. Profit (Rs ha-1) 42,250 69,125

5. Benefit Cost ratio 1.70 2.46

6. Water used (mm) 1900 1140

7. Water saving (mm) - 760 (40 %)

8. Yield (t ha-1) 117 147

9. Water use efficiency (kg ha-1mm-1) 61 128

Table 3. Comparison of drip with surface irrigation in sugarcane

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Drip Irrigation in MulberryMr. Uthayakumar a farmer with a well water of

high EC, Ca, Mg and Na salts and not amenable for surface irrigation because of the fear that it will pollute the entire soil column approached for improved water management strategies in mulberry. Drip irrigation in mulberry was suggested to the farmer. The farmer is now happy with a strong feed back that he reduced the water application to 1/10th of the water he applied earlier by surface irrigation. The other interesting features were control of weeds, restricted fertilizer application zone, alleviation of micro nutrient deficiency and improvement in the quality of the leaf. A comparison of the drip irrigation with the surface irrigation is given in Table 5.

Drip Irrigation for CoconutThe farmer expressed the water saving of 52

% i.e., 96 liters of water is applied daily through four drippers of 8 LPH for three hours than 200 liters tree-1 day-1 in the conventional surface irrigation. The yield of nuts were around 80 tree-1 year-1. Now he is expanding the drip system for the entire 8 acre of coconut. The comparison is given in Table 6.

The selected beneficiaries had an overall impact of water saving and increased yield obtained as a result of improved method of irrigation. The water saving could be attributed because of no water loss in the field and conveyance. The farmers had a very positive ranking that the scientists are with them for any technical know how for their implementation and maintenance which

created a lot of confidence. It is expected that other farmers within the village as well as in the neighboring villages will be able to adopt these technologies on their own investment.

tems Surface irrigation Drip fertigation

1. Annualised drip system cost (Rs ha-1) - 10,000

2. Cost of cultivation (Rs ha-1) 53,080 52,230

Total 53,080 62,230

3. Gross income (Rs ha-1) 1,40,000 1,75,000

4. Profit (Rs ha-1) 86,920 1,12,770

5. Benefit Cost ratio 2.63 2.81

6. Water used (mm) 1900 1140

7. Water saving (mm) - 760 (40 %)

8. Yield (t ha-1) 20 28.75

9. Water use efficiency (kg ha-1mm-1) 10 25

10. Fertilizer use efficiency 14.82 21.92

Table 4. Comparison of drip fertigation with surface irrigation in banana

Items Surface irrigation Drip irrigation

1. Annualised drip system cost (Rs ha-1) - 10,000

2. Cost of cultivation (Rs ha-1) 49,325 45,075

Total 49,325 55,075

3. Gross income (Rs ha-1) 72,000 86,400

4. Profit (Rs ha-1) 22,675 26,325

5. Benefit Cost ratio 1.45 1.56

6. Water used (mm) 1800 1080

7. Water saving (mm) - 720 (40 %)

8. Leaf yield (t ha-1) 15 18.25

9. Water use efficiency (kg ha-1mm-1) 8.33 16.89

Table 5. Comparison of drip with surface irrigation in mulberry

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Table 7. Garret ranking in the over all impact, increased yield, water saving and perceptions on the implementation of improved irrigation practices.

Sl.No. Overall impact Garret Rank Increased Garret Rank score yield score

1 Increased water saving 100 1 Improved method of irrigation 99 1

2 Increased yield 88 2 Fertigation 77 2

3 Labour saving 66 3 Stress alleviation 55 3

4 Increased awareness 55 4 Weed control 44 4

5 Increased adoption 44 5 Easy operation 33 5

1 No water loss in the field 100 1 Scientific personnel at their reach 100 1

2 No conveyance loss 88 2 Technology in user friendly 77 2

3 Water applied in root zone 77 3 Problems alleviated with technical know how 66 3

4 Timely irrigation 66 4 Easy maintenance 55 4

5 No weeds 55 5 Suitable for high value crops 44 5

Items Surface irrigation Drip irrigation

1. Annualised drip system cost (Rs ha-1) - 2,900

2. Cost of cultivation (Rs ha-1) 7,520 6,270

Total 7,520 9,170

3. Gross income (Rs ha-1) 42,336 55,776

4. Profit (Rs ha-1) 34,816 46,606

5. Water used (lit tree-1) 200 75

6. Water saving (mm) - 125

7.Yield (Nuts ha-1) 10,080 13,440

Table 6. Comparison of drip with surface irrigation in coconut

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Field dayFinally field day was conducted to disseminate

the results of the demonstration. All the beneficiaries of the project expressed their happiness and the results achieved in their field. Those who attended the meeting are willing to implement the drip system, drip fertigation in their field of their own cost.

ConclusionAny research is fruitful if it is transferred effectively

to the needed people. For transferring the technology different extension strategies is needed. From this research still personal contact is the most effective tool in the Transfer of Technology. Combined with this the meetings, discussions, small tours, result demonstration and fieldday gave a great success in the transfer of micro- irrigation technologies in the Agragarasamakulam village.

ReferencePalanisami, K., Balasubramanian, R. and Mohamed Ali, A. (1997) Present status and future strategies of tank irrigation

in Tamil Nadu, Publication of Water Technology Centre, Tamil Nadu Agricultural University, Coimbatore.

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Augmentation of Ground Water Resources by Rain Water

Harvesting Case study from Chennai City, Tamil Nadu, IndiaD. Dhayamalar* & G.Y.Setty*

24

IntroductionChennai, erstwhile Madras, is the capital of

the state of Tamil Nadu and is one of the oldest of the presidential cities of India. Chennai Metropolitan city is located in the northeastern corner of Tamil Nadu and is bounded by Latitudes 13�02Ê30‰N and 13�14Ê00‰N and Longitudes 80�12Ê00‰E and 18�18Ê30‰E. The corporation of Madras, which was established in 1688, had a population of 40,000 and has steadily grown with high population density. Ground water utilisation in Chennai Metropolitan City has been increasing rapidly in the wake of increasing urbanisation/population density coupled with industrial development. This has resulted in greater demand far exceeding the available ground water resources. Statistical analysis reveals the entire city experiences a declining trend in water level in the post-monsoon period during 1994-2008, which implies manifold development of groundwater resources leading to a worsening groundwater scenario. Govt. of Tamil Nadu has made rooftop rainwater harvesting mandatory for all residential, private and government establishments

in the city by the end of 2004 for augmentation of ground water resources and to overcome the worsening groundwater scenario.

The present paper deals with a case study of artificial recharge structures constructed at CLRI, Chennai, and impact assessment after implementation of rainwater harvesting in the city area. Encouraging results, both in quality and quantity of ground water, have been observed after the implementation of rainwater harvesting. Occurrence of Fluoride in the range of 2.5�5.00 mg/l has been identified in ground water of semi-confined crystalline aquifers along the Tiruvanmiyur coast in Chennai city in 2001. Fluoride levels are being monitored regularly from surveillance observation wells at three monthsÊ interval. It is inferred that the Fluoride concentration in deeper aquifers of Tiruvanmiyur has come down to 0.99 mg/l as a result of rainwater harvesting.

Two percolation ponds, with combined storage capacity of 3850 Cu.m., were constructed in June 2002 under Central Sector Scheme by CGWB, in the premises

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of CLRI, Chennai City for artificially recharging the aquifer to augment ground water regime. The existing storm-water drains in the campus are modified to ensure that all the water available in the catchment is diverted into the percolation ponds. There is a sustainable rise in the water level in the order of 2-3 m during NE monsoon of 2002 after construction of percolation ponds.

Background Information Chennai city is located in the northeastern

corner of the state. It is bounded by the Bay of Bengal in the east, Tiruvallur District in the north and West and Kancheepuram District in the south. The district is bounded by Latitudes 13�02Ê30‰N and 13�14Ê00‰N and Longitudes 80�12Ê00‰E and 18�18Ê30‰E. The

geographical area of Chennai city is 162.29 sq. km while Chennai Metropolitan Area is 993.38 sq. km. The location map is shown in the Figure-1.

Marine transgression and regressions have resulted in the present day landforms. Sand bars are scattered along the course of the Adyar River and Cooum River drain the city. The river Cooum is highly polluted due to discharge of sewerage after the entry into the city, Buckingham canal is a manmade navigation canal, not in use for last four decades and presently act as sewerage carrier within the city. The Chennai city receives annual normal rainfall of 1445.8 mm of which 484.6 mm is received during SW monsoon, 856.3 mm during NE monsoon with the rest received during winter and summer.

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Projected Demand and Supply by Year 2011

The present water supply and the projected scenario by the year 2011 is presented in Tables1 & 2 respectively. The analysis of the water supply position gives the real magnitude of the problem even after all the possible measures taken by the government so far.

A perusal of the table-2 shows that the demand would be around 1283.2 MLD (@ 135 lpcd) & 1744 MLD (@ 200 lpcd), while the supply is expected to be around 1396.75 MLD, if full capacity of surface reservoirs and the groundwater supply projected were to be considered. However, the declining water level and erratic rainfall are making the projection unrealistic.

Details 1978 March 2007

Operational Area City 170 sq.km. City + Surrounding areas (175.18+7.88 sq.km.) Population 30 lakh About 53.75 lakh Water Produced (Normal Years) 240 mld 645 mld Area covered with piped supply 80% 99% Treatment capacity 182 mld 750 mld + (530 mld)* Length of water mains 1250 km. 2,887 km. No. of consumers 1,16,000 4,35,755 Distribution stations 3 Nos. 16 Nos.

Table -1 water supply – Chennai city

Sl. No. Parameter 2011 Situation

“135 lpcd “200 lpcd

A. DEMAND

1 Chennai City Population (MLD) 631.2 935.1 Industrial (MLD) 174.0 174.0 Total (MLD) 805.2 1109.1 2 Chennai Urban Agglomeration Population (MLD) 957.2 1418.0 Industrial (MLD) 326.0 326.0 Total (MLD) 1283.2 1744.0 B. SUPPLY

3 Existing Planned Sources (On full capacity MLD) (a) Surface Water (i) Poondi (77.20 MCM) (ii)Cholavaram (22.97 MCM) (iii)Red Hills (80.65 MCM) Total of (a) 254.5 (b) North Chennai Well Fields (MLD) (i) Minjur 27.3 (ii)Panjetty 31.8 (iii)Tamaraipakkam 36.4 (iv)Kannigaiper 13.6 (v) Poondi 27.3 (vi) Flood plains 13.6 Total of (b) 150.0

(c) South Chennai well Fields (MLD)

(i) Palavakkam 6.8

(ii)Porur well field 4.5

(iii)Belur near Kilpakkam 45.5

(iv)Palavakkam 4.5

Total of © 61.3

(d) Telugu Ganga Scheme

Total of a,b,c &d 1396.75

Actual anticipated Supply Position (MLD) 1024.31*

Table-2: Demand, Water supply & Deficit For Chennai City and Urban Agglomeration

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Actual anticipated Supply Position (MLD) 1024.31*

*The figure excludes a quantum of 372.38 MLD, which represents the evaporation, and transmission losses in respect of planned Telugu Ganga Water Supply to Tamil Nadu as indicated by the UNDP Studies in the existing reservoirs subject to good reservoir storage conditions.

Source: CGWB, 1993)

HydrogeologyChennai city is underlain by geological

formations ranging in age from Archaean to Recent. The geological formations can be grouped into three units viz., (1) Archaean Crystalline comprising Charnockites, gneisses and associated basic intrusives. (2) Consolidated Gondwana and Tertiary Sediments comprising sandstones, shales and clays and (3) Recent sediments consisting sand, silt, clay and their admixtures. Charnockites represent the major rock type and extend from Saidapet to Raja Annamalaipuram. The fractures are encountered down to a depth of 60 m at Saidapet and Adyar . Recent alluvium covers a major part of the city. The thickness of alluvium varies from 24 to 28 m. Ground water occurs in all geological formations in the city and is developed by means of dug wells, filter points, tube wells and bore wells. Hydrogeological details of different geological formation in Chennai Metropolitan area have been furnished in the Table-3.

Data Source, Material and MethodologyThe database for the analysis has been derived

from the periodic and routine monitoring of depth to water levels of observation wells being monitored by Central Ground Water Board, Chennai. The database and pre and post-monsoon water levels for the last 14 years have been considered for the study. The Statistical technique of Simple Linear Regression (SLR) was used for regression lines to determine the long-term trend of water table for the period of study.

Ground Water ScenarioMunicipal authorities are finding more and more

difficult to meet the water needs of this bourgeoning urban population. A classic example is the coastal city of Chennai (Madras), one of the four major metropolises of India and the capital of the state of Tamil Nadu. Inadequate supply of municipal water over the last two

decades has forced the populace to relentlessly tap groundwater for its needs. This over-exploitation has resulted in the sharp depletion of the groundwater table and to deterioration of its quality as well. Central Ground water board is monitoring the ground water regime since 1992 to study the long-term trends of ground water levels and its chemical quality.

Depth to Water LevelIn order to study the history of ground water

regime in Chennai City frequency distribution of wells showing different depth to water level ranges has been worked out for pre-monsoon (May) and Post monsoon periods have been furnished in the Table-4.

Long-Term Water Level TrendsThe water levels of 18 observation wells for

the period 1994 to 2008 have been analysed for the computation of the long-term trend. The hydrographs of observation wells indicate the trend of ground water levels before the year 2004 are declining in nature.

Pre-monsoon Water level Trend (May 1996-May 2007)

Declining water level trend, ranging from -0.0212 (Velachery) to �0.3464 m/year(Chetpet) has been recorded in 64 percent of the wells analysed and noticed in a major part of the city during the pre-monsoon period. Rising trend in water levels ranging from 0.0032 (Graems Road) to 0.1776 m/year (Villivakkam) was observed in 36 percent of the wells analysed. A map depicting pre-monsoon trend is shown in Figure-3.

Pre monsoon

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Table-4:Frequency distribution of wells - Depth to water level ranges Pre-monsoon (May) and Post monsoon (Jan)

Year and number of wells falling in the particular depth range

Depth 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 ranges (mbgl)

0-2 10 18 0 8 8 12 4 0 8 4 0 0 12 20

2 to 5 43 64 50 84 76 64 56 48 42 35 18 25 60 64

5 to 10 43 18 50 8 16 24 40 48 50 61 55 66 28 16

> 10 4 0 0 0 0 0 0 4 0 0 27 9 0 0

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

0-2 48 56 79 80 52 28 13 52 33 0 4 64 44 68

2 to 5 38 40 21 20 44 52 48 26 45 26 56 28 48 20

5 to 10 14 4 0 0 4 20 39 22 22 65 32 8 8 12

> 10 0 0 0 0 0 0 0 0 0 9 8 0 0 0

Geological Formation Occurrence of Ground Water Depth of wells Yield of wells (lps)

Crystalline Formations unconfined condition to Semi-confined 1 � 3 Gondwana formations unconfined 20 - 60 1 � 3 Tertiary Sediments unconfined 2 � 3 Recent sediments Unconfined, Semi confined and confined conditions 10 - 30 5 � 100(m3/d)

Table 3: Hydrogeological details of different geological formation In Chennai Metropolitan area.

*Distribution in Percentage

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Post-monsoon Water Level Trend (Jan 1997-Jan 2008)

The post-monsoon water level trend map reveals a declining trend in water levels ranging from 0.0166 (Tondiarpet) to 0.3804m/year (Vepery). A negligible rising trend in water levels has been noticed at two isolated wells in Saidapet (0.0064m/year) and Graems Road (0.01m/year) respectively. A declining trend has been observed in a major part of the City. A map depicting the post-monsoon trend is shown in Figure-4.

Rainwater Harvesting in Chennai Metropolitan City

The ever-increasing population of Chennai, rapid urbanisation and accelerated ground water resource development without a systematic and scientific approach has resulted in the depletion of ground water levels creating a negative impact on the ground water resources. Hence, a scientific approach to develop, conserve and protect the resource is stressed upon to regulate the use of this precious natural resource. Rooftop rainwater harvesting in urban areas offers one of the methods/options for conserving the precious ground water supplementing the drinking water needs in particular.

Since May 2001, the government of Tamil Nadu has promoted awareness about RWH throughout the state by different means. In view of the deficit in Demand�Supply, the Tamil Nadu government enacted a law in October 2002, followed with an ordinance in June 2003, enforcing the compulsory implementation of RWH systems in all existing buildings in the entire state

of Tamil Nadu by October 11, 2003. Rooftop rainwater harvesting through existing and abandoned dug wells and bore wells has been implemented in the city in the premises of all residential, government and private establishments by 2003. Awareness programmes and regulatory options are conducted by State and Central agencies to check the large-scale unscientific extraction of ground water resources in the city.

Artificial Recharge Schemes Implemented by CGWB at CLRI, Adyar, Chennai

Two percolation ponds (Figure-5) with combined storage capacity of 3850 Cu. m were constructed in June 2002 under Central Sector Scheme by CGWB, in the premises of CLRI, Chennai City for artificially recharging the aquifer to augment ground water regime. Each pond has 3 percolation pits of 3.0 m. diameter and 3.0 m. depth, filled with pebbles for facilitating recharge the percolation ponds are provided with filtration units at the inlet points to ensure supply of silt-free water. The existing storm-water drains in the campus are modified to ensure that all the water available in the catchment is diverted into the percolation ponds. Total water harvested is 10612 Cu. M.

Impact of Rainwater harvesting on ground water regime.

Changes in Water Levels in Parts of Metropolitan City

Impact assessment of rainwater harvesting on the ground water regime has been carried out in Chennai metropolitan city. The study revealed that the water level, which ranged from 2.25 to 11.62 mbgl during May 1994, has risen to 1.5 to 7.5 mbgl during May 2007 (Table-5). The percentage of wells showing depth

Post Monsoon

Figure 5. Percolation pond at CLRI, Guindy after the Monsoon.

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to water level less than 5 mbgl is in increasing order after rainwater harvesting. The wells, which were dry during summer months (e.g. Aminjikarai, Velachery, Gandhi Nagar, Thiyagaraya Nagar and Besant Nagar) prior to the year 2004, are now recording rise in water levels. Vepery well has recorded a fall in water levels during the post-monsoon period, which may be due the impervious clay in the area.

It is clearly observed that the percentage of wells showing depth to water level of more than 5 mbgl was high between the years 2000 and 2005. It started slowly decreasing after the implementation of rainwater harvesting policy. The study points out that deficit rainfall occurred only during 2000 and 2003 during

the past decade. Despite normal/excess rain during the rest of the years, ground water depletion has taken place, which indicates the enormity of extraction. The trend scenario of ground water levels during pre- and post-implementation of rooftop rainwater harvesting policy has been illustrated by hydrographs at three important locations in the city (Figures: 6-8). The hydrographs indicate that the water levels are in an increasing trend after the implementation of the rooftop rainwater harvesting policy.

Impact of Artificial Recharge at CLRI, Guindy, Chennai

CGWG has constructed a purpose-built piezometer in the premises of Central Leather Research Institute, Guindy in 1999 under World Bank-assisted

Period Range of Water Year % of wells in the range of levels (mbgl) water levels

<5m >5m

Before Implementation of Rain Water harvesting 1.4 � 11.62 May 1994 Less High

After Implementation of Rain Water harvesting 0.33 � 6.9 May 2007 Increasing Decreasing after 2004 after 2004

Table 5: Changes in ground water levels after implementation of rainwater harvesting policy

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Hydrology Project. The hydrographs of the piezometer (Figures 9- & 10) show a appreciable rise in the water level in the order of 2-3 m after the construction of the percolation ponds.

Hydrographs of CLRI, Guindy

Thiruvanmiyur Coastal Aquifer in Chennai City

Changers in Quality of Ground WaterTwo types of aquifers exist in Thiruvanmiyur

coastal area: (a) Shallow Alluvial aquifer and (b) Deeper Crystalline aquifer. The thickness of the alluvium in the shallow aquifer ranges from 10 to 30 m. Productive aquifers occur as thin granular zones. Chemical quality of Ground water of Thiruvanmiyur aquifer is being monitored four times in a year. It has been observed that the Fluoride content in the ground water of deeper aquifer was 4-5 mg/l. The Fluoride concentration has been diluted from 5.00 to 0.99 mg/l as a result of implementation of rooftop rainwater harvesting in the area. The changes took place in the Fluoride concentration in ground water of deeper aquifers at a surveillance observation station has been presented

graphically in Figure�11. This is one of the methods for improving the quality of ground water.

Changes in Fluoride Concentration - Deeper aquifer � Well No: S03 - Thiruvanmiyur

ConclusionsThe impact assessment studies show that all the

wells have recorded rising trend in water level after the year 2004, thereby indicating the efficacy and efficiency of the rainwater harvesting policy. Optimum number of artificial recharge structures should be constructed in the catchment areas of existing reservoirs in the peri-urban areas of Chennai metropolis, so that the run off during the rainy season will be avoided and this can recharge the ground water system. Awareness of the public must be kindled and enhanced on use of recycled domestic water. Separate water supply can be made for the dual purposes of drinking water and others. Awareness campaign on rainwater harvesting through media should be continued regularly for the public to realise their social responsibility on water conservation. This will maintain the ground water scenario at a desirable and sustainable level.

AcknowledgementsThe authors are grateful to Sri B. M. Jha,

Chairman, CGWB, Faridabad and Dr. N. Varadaraj, Regional Director, CGWB, SECR, Chennai, for their constant encouragement and support in the completion of the paper and according permission to present it in the Symposium on „Water harvesting‰. The authors are also thankful to Sri E. Sampath Kumar Superintending Hydrogeologist, Shri B. Shyam Sundar, Scientist-D (HM) and Dr. S. Suresh, Scientist-D of CGWB, Chennai for their valuable suggestions.

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References1. Ground Water Exploration in Tamil Nadu and U.T of Pondicherry (as on 1996), CGWB, SECR, Chennai2. Chakkarapani.R, 1991;ground Water Resources and Development Potential of Chengai-MGR District, Unpublished

Report of CGWB3. Foster.S.S, Morris, B.L and Lawrence, A.R,1994.effects of Urbanisation on Ground Water Recharge, In:Wilkinson

W.B.(ed).Ground Water Problems in Urban Areas, Thomastelford, 43-634. Varadaraj, N.1993.Ground Water Resources and Development Prospects in Madras District, Tamil Nadu, Unpublished

Report on CGWB.5. N.Kittu, N.Varadaraj and R.Chakkarapani, impact of Urbanisation on ground water in the Madras coastal area,

tamil Nadu, India, Ground water in the urban environment:Selected City profiles, Chiton (ED).1999Balkema, Rotterdam, ISBN9054108371(39-50)

6. S.Suresh, Report on Urban Hydrogeology of Chennai City. Technical Report issued by Central Ground Water Board, South Eastern Coastal Region, Chennai, 49 p , 2004 (Unpublished)

7. S.Suresh, Report on Hydrodynamics of Coastal Aquifers in southern part of Chennai Metropoliton Area, Tamil Nadu.Technical Report issued by Central Ground Water Board, South Eastern Coastal Region, Chennai, 63 p, 2008 (Unpublished).

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129

Plan for Augmentation of Ground Water Resources in

Critical Cumbum Block, Theni District, Tamil Nadu

A.Ravi* & GY Setty*

25

IntroductionCumbum block falling in Theni District is divided

into 4 Panchayats and 8 villages. The location map is shown in Figure-1. The block is falling East flowing in Vaigai river basin of Tamlinadu. Suruliar and Vairavanar are the important minor basins. The Vairavanar river flows in northeasterly direction until it joins the Suruliar river. Suruliar originates in high wavy mountains or popularly known as Megamalai ranges at an altitude of 1000 to 1200 m a msl.

The rainfall station located at Uthamapalayam, the taluk headquarters of Cumbum block recorded the normal annual rainfall of 773.89 mm (Period 1901 - 1992). The block enjoys a tropical climate. Cumbum block forms part of the upland plateau region of Tamil Nadu with many hill ranges. The prominent geomorphic units identified in the block through interpretation of Satellite imagery are 1) Ridges, 2) Valley fill 3) Shallow

Pediments, 4) Deep Pediments and 5) Floodplains. The soils of Cumbum block can be broadly classified into 5 major soils types viz., Red Soil, Black Soil, Brown soil, Alluvial and Colluvial Soil and Forest Soil.

130

Ground Water Scenario

HydrogeologyThe block is underlain by both porous and fissured

formations. The important aquifer systems in the block are constituted by i) unconsolidated formations and ii)

weathered fissured and fractured crystalline rocks. The thickness porous formations ranging from 5 to 20 m. Gneisses, Charnockites, granites and other associated rocks, represent the hard consolidated crystalline rocks. Ground water occurs under phreatic conditions in the weathered mantle and under semi-confined conditions in the fractured zones. The shallow aquifers in the major part of the block occur within the depth of 10 m while

in the northern part of Cumbum block, they are around 25 m. The yield of large diameter wells in the block, tapping the weathered mantle of crystalline rocks ranges from 50 to 300 lpm and are able to sustain pumping for 2 to 4 hours per day. The specific capacity in the fissured formation ranges from 118 to 201.72 lpm/m/

dd. The yield of bore wells of 50 to 100 m deep ranged from 1.00 to 5.00 Lps and it is 1.89 to 18.97 lps for the boreholes of 200 m deep. The depth to water level in the block varied between 5.26 to 20.36 m bgl during pre-monsoon 4.12 to 18.42 m bgl during post monsoon (Figure-2).

The salient features of the ground water resources computations as on 31st March 200 4are furnished the Table 1.

The estimation of groundwater resources for the block has shown that the block is falling under critical category. Dug wells and bore wells are the most common ground water abstraction structures used for irrigation in the block.

Table 1. Computation of Ground Water Resources of Cumbum Block, Tamil Nadu ( 2004)

( As per GEC 1997 Methodology)(in ha.m)

Sl.No. Block Net Irrigation Existing Allocation Existing Balance Sstage Category Ground on Gross for Ground Ground of (As in Water Draft ground Domestic Water Water Ground Jan Availability water and Draft Available water 2004) draft for Industrial for Development Domestic Requirement Future & Industrial for next Development Water 25 Years Supply

1 Cumbum 5262.80 4772.34 181.57 189.13 4953.91 301.33 94% Critical

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Groundwater Management Strategy

Groundwater developmentIn view of high level of ground water development

of the block and the quality problems due to geogenic and anthropogenic factors, it is necessary to exercise caution while planning further development of available ground water resources in the block. The development

of ground water for irrigation in the block is mainly through dug wells tapping the weathered residuum. The yields of dug wells are improved at favorable locations by construction of extension bores, which are 40 to 100m. deep. In recent years, a large number of bore wells have also been drilled by farmers for irrigation purposes. The map showing the development prospects for the block is shown in the Figure - 3

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Plan for Conservation and Augmentation of Ground Water Resources

About 35 percent of the total geographical area of Cumbum block is covered by hills and forests. Another 3 percent of the area has been put to non-agricultural uses. Hence, about 62 per cent of the total geographical area is available for planning of development of ground water resources in the block.

The level of ground water development, balance irrigation potential to be harnessed and behavior of ground water levels are the principal factors to be considered while planning for future development of ground water resources. The present level of ground water development in Cumbum block (2004) is about 94 percent, which is likely to go up by 3 percent in the next 5 years. The balance irrigation potential to be harnessed has been computed as 301.33 ha. Trend analysis of long-term water level data indicates a falling

trend in the major part of the block. Two hydrographs are given in Figure 5 & 6.

As the level of ground water development in the block is comparatively high,existing ground water development has to be carried out judiciously. With this in view, construction of artificial recharge structures at suitable locations has been recommended in the block. Conjunctive use of surface and ground water can also be considered in the command areas of major tanks and surface water bodies after detailed study.

Flood plains buried pediments and valley fills are the most favourable locales for augment of ground water. Fractures and lineaments hold prospects may also be used for artificial recharge in deeper aquifers. The bazada zones along the fringes of hills are also promising zones. Shallow pediments possess thin soil cover and the ground water potential is limited to the weathered and fractured zones. The number and type of artificial recharge structures recommended for the over

133

exploited, Cumbum block is shown in Table -2 . Some of the suitable sites for artificial recharge are demarcated in the drainage of Cumbum block in the Figure-4. On going „Artificial Recharge through irrigation dug wells‰ scheme has to be implemented to the maximum extend and the impact assessment will reveal the gaps to be attented. The further Artificial Recharge structers may be considered as envisaged.

AcknowledgementsThe authors are grateful to Sri B.M.Jha,

Area Suitable for GW development 401.1 Sq.km Harnessable surface water 35.40 MCM Committed supply Nil Existing Tanks Nil Possible percolation pond 27 numbers @ 1 in 15 sq. km with a capacity of 0.1 MCM Possible Check Dam 80 numbers @ 1 in 5 sq. km with a capacity of 0.01 MCM Unit cost of a P.P 20 lakhs Unit cost of a C.D 2 lakhs Total cost of P.P 27*20 = 540 lakhs Total cost of C.D 80*2 = 160 lakhs

Chairman, CGWB, Faridabad and Sri N.Varadaraj, Regional Director, CGWB, SECR, Chennai for constant encouragement and support in completion of the paper and permitting to present/publish in the seminar. The authors are also thankful to Sri E.Sampathkumar Superintending Hydrogeologist and Dr.S.Suresh Scientist-D of CGWB, Chennai for their valuable suggestions and also to Dr.S.K.Jain Scientist D and TS to the Member (SAM), CGWB, Faridabad for his kind co-operation in getting approval from the competent authority

References1. District Ground water Brochure, Cumbam block. Tamil Nadu, CGWB, SECR. Chennai April 2008.2. Ground Water Exploration in Tamil Nadu and U.T of Pondicherry (as on 1996), CGWB, SECR, Chennai.3. Ground Water Resources and Development Potential of Theni District, Unpublished Report of CGWB.

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Table 2.

134

Development of Natural springs for Sustainable Drinking Water Supply in Himalayan Region of

IndiaS. S. Rawat1, H. C. Sharma2, B. R. Nikam1, S. K. Mishra1, U. C. Chaube1 M. K. Jain1

26

IntroductionSurface water, flowing in the form of rivers, and

subsurface water, occurring in the form of springs, is two main sources of water supply in Himalayan region. In the high altitude areas, the river flow in deep valley at the toe of slopes rarely serve any purpose as far as domestic water supply and irrigation are concerned. Thus, in Himalayan region of India natural springs are the available major source of water. About 90 per cent of the rural population of this region depends on natural springs for their water demands. ThatÊs why the villages in hills are clustered around the springs. There is hardly any settlement where there is no spring. It has been estimated that only less than 15 per cent of the rainwater is able to percolate down through deforested slopes to recharge the catchment area of springs. The remaining flows down as runoff and cause floods in plains. In most of the springs in Himalayan area the spring flow has decreased by 50 per cent within last 30 years and the piped drinking water in hilly areas is failing due to drying-

up of springs and has adversely affected the water supply in the irrigation channels. Bahuguna (1990) and Chopra (1997) expressed that under these circumstances people will move wherever water moves. Studies (Valdiya and Bartarya, 1989 and 1991 ) indicates that deforestation, grazing and trampling by livestock, erosion of top fertile soil, forest fires and developmental activities (e.g. road cutting, mining, building construction etc.) are the causes of the spring flow reduction. Almost, negligible numbers of springs are being monitored presently for their flow and other hydrological parameters and there is no systematic study of the spring flow for developing these springs as dependable and sustainable sources of water for rural population in remote Himalayan region.

Keeping the above in view, the present study was conducted to understand the year wise hydrological trend of two natural springs in the mid Himalayans region of Uttarakhand and to suggest a strategy for the development of theses spring to maintain the regular supply of drinking water in this region.

135

Study AreaThe study was conducted at Hill Campus of

G. B. Pant University of Agriculture and Technology, Ranichauri located at latitude of 300 15Ê N, longitude of 780 2Ê E and an altitude of 2000 m above mean sea level, in Tehri Garwhal district of Uttarakhand state of India. This area falls under the middle Himalayas and sometimes called the outer or lesser Himalayas and area is strongly undulating and hilly. Mean annual rainfall is about 1176 mm and ranges between 4 mm (November) and 246 mm (August). The catchment of Hill Campus spring having dense forest mainly oak (Quercus leucotricophora), deodar (Cedrus deodara), burans (Rhododendron arborium), morpankhi (Thuja orientalius), etc. While maximum part of Fakua spring catchment is covered by shrubs like wild rose (Rosa burunii), kirmora (Barbaris asiatica) and rest part by some trees of Chirpine (Pinus ronburghii), surai etc.

In this study four years (2002 to 2005) daily rainfall and spring discharge data were collected from the observatory of Hill Campus, Ranichauri of G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand and analyzed.

Methodology

Estimation of Discharge VariabilityThe variability of monthly average discharge of

these springs was calculated as:

Where,

Qmax

= maximum monthly spring discharge (lpm),

Qmin

= minimum monthly spring discharge (lpm), and

Qave

= average monthly spring discharge (lpm).

Determination of Depletion TimeThe analysis of recession curve defines the regime

of flow of a spring. The recession curve characterizes the storage depletion or a base flow from an aquifer during the period of zero or negligible precipitation (Karanjac and Altug, 1980). The physical process of release of

water from groundwater storage is a phenomenon which can be described by an exponential law which is same as that used for baseflow (Chow, 1964 and Singh, 1989). One of the convenient ways to express the exponential law is:

Q(t+Δt) = Q(t) exp (-Δt/t0) ⁄(2)

where Q(t) = spring flow at time t during recession, Δt is the time increment and t

0 = a parameter of the

spring and is designated as depletion time and has dimension of time.

According to Eq.2, the variation of logarithm of spring flow with time is linear. The reciprocal of the product of negative of the slope of the straight line (log

10Q vs t) and 2.3, is designated as the depletion

time in time unit. A small depletion time indicates a small recharge area or high permeability and low porosity aquifer or there is a substantial groundwater abstraction or a combination of all or some of these factors (steep slope). Whereas a high depletion time indicates a large dynamic storage or slow drainage or groundwater replenishment (flat slope). Depletion time is a characteristic parameter for a groundwater flow domain. It represents recession characteristic and depends on geology and geomorphology of a basin. It can be treated as a model parameter for mathematical models for spring flow. Any change in the slope of the line is indicative of interference in the groundwater system. A progressive flattening of the slope indicates replenishment of the aquifer in the dry season and steepening of the slope indicates groundwater abstraction from the aquifer and reduction in natural recharge. Dynamic groundwater reserve in the spring flow domain at any time t during recession that maintains spring flow is Q(t). t

0 .

Computation of Minimum Required Storage

The computation of minimum storage required to fulfill the variable demands of the user have been done by doing simple arithmetic calculations for hill Campus spring only. Assuming that the storage reservoir is full at the beginning of the dry periods (when inflow rate is less than the demand rate), the maximum amount of water drawn from storage is the cumulative difference between the supply and demand volumes from the beginning of the dry season.

136

Results and Discussion

Spring discharge variationMonthly variation in Hill Campus and Fakua

spring discharge from year 2002 to year 2005 has been calculated by Equation 1. The minimum and maximum values of variability of daily spring discharge for Hill Campus spring were found to be 0 percent ( January ) and 139 percent ( September ) in 2002; 2.42 percent (february) and 86.98 percent (august) in 2003; 2.47 percent (february) and 115.61 percent (august) in 2004 and 9.09 (june) and 165.12 (july) in 2005. For Fakua spring 0 per cent (June) and 201.79 percent (september) in 2002; 8.93 percent (May) and 175 percent (July) in 2003. 12.73 percent (April) and 278.57 percent (July) in 2004; 23.81 percent (June) and 252.89 percent (February) in 2005.

From above it is clear that the Fakua Springflow is more variable in comparison to Hill Campus spring. Average monthly variation in the flow of Hill Campus spring varied from 9% to 70% and for Fakua it varied from 21% to 167%.These springs can be put in the category of variable discharge springs.

Depletion TimeThe depletion time were estimated for different

years for Hill Campus and Fakua springs.

Hill Campus spring The depletion time value was found to be 58 days

in the year 2002; 86 days in the year 2003; 89 days in year 2004 and 59 days in the year 2005.The average value of depletion time was found to be 73 days. Spring flow curves for the year wise determination of depletion time for Hill Campus are shown in Fig 1. Any change in the slope of depletion line is indicative of interference in the ground water system. Fig 1 shows that the depletion line for the year 2003 was more flatter than for the year 2002, even the catchment received good rainfall(1255 mm) in the year 2002 in compare to the rainfall of year 2003 (1173 mm). As per the information provided by Forest Department of Uttarakhand, more than 65 per cent of forest area of Hill campus spring catchment was affected by severe forest fire during the year 2002 and damaging most of the vegetation. Since vegetation plays a big role in recharging the catchment of spring. Therefore, maximum part of rainfall was contributed as surface runoff and depletion line is steeper in the year 2002 in compare to 2003, even catchment received

high rainfall. For year 2004, depletion line was slightly flatter than the line of previous year even annual rainfall was almost similar i.e. 1173.8 mm and 1174.9 mm. From the rainfall data of Ranichauri, it is clear that the distribution of rainfall in the year 2004 is more uniform than the rainfall of the year 2003. It indicates that the Hill campus spring was also recharged in dry season and depletion line become slightly flatter than the previous year. The depletion line of year 2005 become steeper than the year 2004 even the catchment received high rainfall (1386 mm) in year 2005. Since more than 70 percent rainfall in year 2005 occurred in only three monsoonal month of the year and rest period is dried. Therefore, spring was recharged only a small part of the year and depletion line becomes steeper.

Fakua SpringThe depletion time value was found to be 30

days in the year 2002; 31 days in the year 2003; 20 days in the year 2004 and 15 days in the year 2005. The average value of depletion time was found to be 24 days. Spring flow curves for year wise determination of depletion time for Fakua spring are shown in Fig 2. Years 2002 and 2003 were having similar rainfall pattern but during the year 2002 the vegetation was damaged due to forest fire. Therefore, the depletion line for the year 2003 is flatter than the year 2002. For the year 2004 the depletion line was relatively steeper than the depletion line for the year 2003. In dry period of year 2003, Fakua catchment received 332 mm rainfall in comparison to 121 mm of the year 2004. In this way Fakua catchment was recharged in dry period also. Fakua soils have low values of clay and moisture content. The catchment area is covered with shrubs and Pine trees. All these factors reduce the water holding capacity of Fakua catchment. Therefore, most of the rainfall goes as runoff instead of recharging the aquifer. It makes the depletion line for the year 2005 steeper than for the year 2004, even though Fakua catchment received good rainfall (1386 mm) in year 2005.

From Depletion time and spring flow variation, it is clear that Hill Campus spring is more stable and reliable source of water than the Fakua spring even both spring situated in same meteorological region. Both springs have a low value of t

0 which shows that these

springs are emerging from high permeability and low porosity aquifer. According to Karanjac and Altug (1980) these springs can be put in the category of 2nd group of opening i.e., flow is primarily in large fractures.

137

Planning for Sustained DevelopmentThe Hill Campus spring is located in the locality

of university people so, it will be very useful to estimate the adequate capacity of storage tank for this spring which will match the water demand of the livelihood people. Keeping it in view, the flow volume of Hill Campus spring and water demand of Hill Campus Ranichauri in each month was estimated. From month of feburary to the month of july the excess of demand over the inflow and thus this excess demand of water from time to time has to met by storage. The maximum value of cumulative excess volume represents the minimum storage, necessary to fulfill the demand. The water demand for different month was estimated on the basis of daily requirement of drinking water per capita, which would vary with time due to climatic variation in different months of the year. The storage requirement in the present case has been estimated to be 544.73 m3. Accordingly the storage tank of the same capacity will be desirable so that it may get filled as per the demand. The storage tank will start refilling again in the august and will complete fill in the mid of October. From the month of October to January the availability of the water will be more than the demand i. e. the surplus water which can be utilize for irrigation and other purpose. Sometime it is not feasible to construct a large capacity cement concrete tank in hilly areas. In that situation the only solution of the problem may be the increase of the depletion time to make these springs as sustainable source of water by interlinking the natural resources viz, water-land-vegetation in the springÊs recharge area.

Land-vegetation combination may be taken care by phase wise implementing various developmental plans requiring either afforestation or replacement of undesired vegetation. The examination of slope of the plot of spring flow and estimation of dynamic reserve time to time or year-wise will be good monitoring tool to review the result of the developmental programme regularly. The estimated recharge and discharge from spring should not fall beyond some pre-determined threshold values due to development of any combination of natural resources. Determination of the threshold values will be a management decision requiring information about

supply and demand of these resources for a healthy and viable growth.

A successful social forestry programme may lead to increase in recharge allowing the planner to go in for little more urbanization and quarrying elsewhere in the recharge area affecting spring flow in a negligible way. The idea of complementary forestry could take shape for action in this approach of natural resources development.

Conclusion

Spring water, prime natural resources in mountainous region is fastly detoriating due to its improper utilization, assessment and management. The protection and proper management of this natural resource is essential to maintain its quality and quantity especially for the period when its availability is less. However, there is no appropriate inventory of the springs in the country. Further spring flow time series have not been systematically recorded and recharge area of these springs are not demarcated. These difficulties to study/monitor the spring flow based on hydrological principles focused herein should be urgently addressed. The study of two springs located in the hill campus of G.B.Pant University of Agriculture and Technology at Ranichauri in Tehri Garhwal district of Uttarakhand using a simple, convenient, and implementable methodology based on hydrologic principles, not only demonstrates efficacy of the methodology, but essentially focuses the need to use the methodology to interlink the development of main natural resources of a hilly area compatible and supplemental amongst one another instead of development of each of the natural resources at isolation at cross purposes. The methodology besides other merits discussed above, will check the soil erosion and will contribute immensely in decreasing sedimentation in our costly reservoirs in the plains, thereby increasing their lifespan.

Acknowledgement The authors wish to thanks Dr. A. K. Bhar,

former Scientist „F‰, National Institute of Hydrology, Roorkee for their support and encouragement during the course of this study.

138

ReferencesBahuguna, S., 1990. „Himalayan Tragedy‰, 1st ed., Chapter 48 of Himalaya: environment, resources and development,

ed. by Sah et al., Shree Almora Book Depot, Almora,.Chopra, R., 1997. „Mitti aur pani mein sona hai‰, Nayan Singh Rawat memorial lecture, U.P. Academy of

Administration, Nainital, pp. 18.Chow, V.T., 1964. Chapter 14-8 on „Run-off in Handbook of Applied Hydrology‰, McGraw Hill, Newyork.Karanjac, J. and A. Altug., 1980. „ Karastic spring recession hydrograph and temperature analysis : Oymapinar dam

project, Turkey‰, Journal of Hydrology, 45 : 203-217.Singh,V.P., 1989.Chapter 9 on „Baseflow Recession in Hydrologic Systems-watershed Modeling‰, Vol.II, Prentice

Hall, New JersyValdiya, K.S. and Bartarya, S.K., 1989. „Diminishing discharges of mountain springs in a part of Kumaun Himalaya‰.

Current Science, 58(8): 417-426.Valdiya, K.S. and Bartarya, S.K., 1991. ‰Hydrological studies of springs in the catchment of Gaula river, Kumaun

lesser Himalaya‰, J. of Resource and Development, 11(3): 239-248.

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139

Validation of Length of Growing Period Developed

Through Models for Minimising the Climatic Risk under Dryland

S. Anitta Fanish., V. Geethalakshmi and K. Ponnuswamy

27

IntroductionIndia with advancement in science and technology

is in a position to launch an Ever Green Revolution (EGR) that can help to increase the yield and income per unit of land and rainfall. Dryland farming has a distinct place in Indian agriculture occupying about 68 per cent of cultivable area and it contributes 44 per cent to the total national food basket. In Indian agriculture, extending further additional areas under irrigation becomes limited because of obvious reasons and hence the existing drylands would persist as drylands forever. In Tamil Nadu, 54 per cent of total cultivable area (4 m ha) is critically under drylands. Considering the future food demand, research and development activities for dry land must be given top most priority.

In tropical regions, for drylands, there is no limitation for solar radiation during most part of the year, but precipitation fall short of potential evapotranspiration and thus crop production becomes a risky enterprise.

Time of sowing is the most important factor, so as to tap higher input efficiency from all the resource applied so as to minimize cost of production without sacrificing the productivity anticipated. Time of

sowing is a dependable variable especially for dryland on independent variables viz., rainfall and potential evapotranspiration and this is scientifically called as Length of Growing Period (LGP). Identification of suitable growing period is very much important to choose a suitable crop, its variety, management technology and this LGP forms as a decision tool for farmers living in fragile environment viz., dryland.

Among many annual crops, sorghum was cultivated under dryland situation because of their adaptability and capacity to withstand intraseasonal agricultural drought. In India, sorghum crop occupies 12.23 million ha with an annual production of 8.36 million tonnes. In Tamil Nadu, sorghum crop is cultivated in 0.58 million ha with an annual production of 0.71 million tonnes. Since the possibility of increasing land area under individual crop is quite limited with the shrinking resources over years, intensive research on timely sowing and suitable cropping system must be evaluated for sustainable production from drylands.

Pre-monsoon sowing (10-15 days earlier to monsoon onset through first rain) becomes an alternate technology to sustain the crop production in dryland

140

condition, since the sown seeds utilize the first monsoon rain for establishment.

Many scientific models are available to identify LGP and précised time of sowing, but these were not evaluated fully for the benefit of dryland agriculture. Considering this, a study was attempted to compute the Length of Growing Period (LGP) by three models and to evaluate the potential rainfed cropping system under computed LGP.

MATERIALS AND METHODSField experiment was conducted at farmerÊs

field at Chinnamathapalayam, which is 15 km from Tamil Nadu Agricultural University, Coimbatore during the year 2003-2004. The weather data on maximum temperature, minimum temperature, mean bright sunshine hours that prevailed during the cropping period were collected from agromet observatory of Department of Agricultural Meteorology, Tamil Nadu Agricultural University, Coimbatore. Daily rainfall data were collected from the rain gauge that is installed in the farmerÊs holding. The soil in the study area was sandy loam with a pH of 7.2 and EC of 0.19 d s m-1. The soil was low in available nitrogen (158 kg ha-1), medium in available phosphorus (14.2 kg ha-1) and high in available potassium (390 kg ha-1).

In the present investigation, LGP for study village was fixed through three methods viz., weekly moisture availability index (Sarker and Biswas, 1988), Weekly R/PE ratio (Jeevananda Reddy, 1983) and weekly moisture availability period more than 50 per cent PET based on FAO model (Higgins and Kassam, 1981). Weekly rainfall and weekly potential evapotranspiration were used as inputs for these models. For computing mean weekly rainfall of Coimbatore, daily rainfall data for forty years from 1961� 2000 were collected from Department of Agricultural Meteorology, Tamil Nadu Agricultural University, Coimbatore. Daily rainfall data were aggregated to weekly rainfall data as per 52 meteorological standard weeks. From the forty years weekly rainfall, mean weekly rainfall data were computed. Weekly Potential Evapo-

Transpiration (PET) was computed as per Penman (1948) method by multiplying open pan evaporation data with pan coefficient value.

According to Sarker and Biswas model if the ratio between the weekly precipitation (dependable) and weekly PET is > 0.3 that particular week was suitable for growing crops. Dependable rainfall varied from place to place. In a particular place, if the annual rainfall is <400 mm, 30 per cent of dependable precipitation is to be considered. If the annual rainfall is >400 mm, 50 per cent dependable rainfall is to be taken for computing MAI. Dependable rainfall was computed through initial probability method. As the mean annual rainfall of the study location is > 400 mm, 50 per cent dependable rainfall was taken to compute the MAI.

50 % Weekly Dependable rainfall

MAI = ····················-

Weekly PET

In Jeevananda Reddy method, a mathematical tool called moving average was used. Rainfall / Potential Evapotranspiration (R/PE) ratio was computed for each week and fourteen week moving average of R/PE was also calculated. According to FAO model the period in which the rainfall exceeds 0.5 PET, is considered as starting of length of growing period. This model also takes into account of the stored moisture in soil after the termination of rainfall. As per this model, growing period starts when precipitation exceeds 0.5 PET and ends with the utilization of assumed quantum of stored soil moisture after precipitation falls below 0.5 PET.

Based on these three models, sowing dates and pre-monsoon sowing dates were identified and the results are presented in Table 1. Mid day of the first week / starting week of LGP as per the model results was taken as normal date of sowing and 10 days prior to the normal dates of sowing were fixed as pre-monsoon sowing dates. The experiment was laid in Complete Randomized Block Design (CRBD) and the treatments were replicated thrice with gross plot size of 24.3 m2 and the net plot size was 15.08 m2.

Model Length of No. of Sowing Date

growing week Pre monsoon sowing Normal sowing period

Sarker and Biswas 36th - 49th MSW 14 27.08.03 (35th MSW) 06.09.03 (36th MSW) Jeevananda Reedy 37th- 50th MSW 14 03.09.03 (36th MSW) 13.09.03 (37th MSW)FAO 38th � 51st MSW 14 10.09.03 (37th MSW) 20.09.03 (38th MSW)

Table 1. Computed sowing dates as per model output

141

MSW (Meteorological Standard Week)The treatments followed in the experiment were

as follows:

Factor 1 : Dates of sowing

M1 : 10 days prior to Sarker and Biswas model

(27.08.2003) LGP

M2 : 10 days prior to Jeevananda Reddy model

(03.09.2003) LGP

M3 : 10 days prior to FAO model (10.09.2003) LGP

M4 : Starting week of LGP from Sarker and Biswas

model (06.09.2003)

M5 : Starting week of LGP from Jeevananda Reddy

model (13.09.2003)

M6 : Starting week of LGP from FAO model

(20.09.2003)

Factor 2 : Crops

S1 : Sole Sorghum

S2 : Sorghum + green gram at 2:1 ratio (additive series)

RESULTS AND DISCUSSION

Fixing Length of Growing Period for sowing

Length of Growing Period (LGP) is a part of a year in which the soil moisture is adequate for crop evapotranspiration either fully or atleast at threshold level. The importance of length of growing period is witnessed particularly in dryland agriculture. The results from three models are presented in Table 2 to 4.According to Sarker and Biswas model, continuous period in which the MAI of >0.33 was observed from 36th to 49th MSW (14 weeks). From 36th MSW, MAI values gradually increased, reached its peak during 45th MSW (2.75) and got declined. Based on this model, the safe length of growing period was 14 weeks starting from 36th MSW and got terminated by 49th MSW. Eventhough risk factor was introduced under Sarker and Biswas (1988) weekly moisture availability index model, this model assumes that if 33 per cent of the PET is met by rainfall, the crop will escape from moisture stress. Moreover, this method does not give any information regarding the wet and dry spells that may occur within the crop growing period. These few lacunae were taken care of by weekly R / PE ratio method suggested by (1983).

According to Jeevananda Reddy model, the growing period (G) starts when the 14 weeks R/PE moving average value is > 0.75 and at the same time, the value of the simple R/PE must be > 0.5. In the present analysis, though, the moving average values of R/PE crossed 0.75 at 36th MSW, the simple R/PE value was equal to 0.5 only during 37th MSW and hence the available effective rainy period (G period) of 14 weeks started only from 37th MSW and ended with 50th MSW (September 10 � 16 to December 3 � 9). It indicated that Coimbatore had a potential crop growing period of 14 weeks (91 days) under dryland. Within the growing period, wet spell occurred from 42nd � 45th MSW (October 15 � 21 to November 5 � 11) as simple R/PE ratio was > 1.5 and no dry spell could be observed within the growing period. In the present investigation, it is noted that as per Jeevananda Reddy model output the wet spell occurred in the same MSW (42nd to 45th MSW) in reality. However, this model failed to predict the wet spell week of 41st MSW which occurred in reality during the course of investigation.

Length of growing period computed through FAO model indicated that the growing period fell between 38th MSW (September 17 � 23) and 51st MSW (December 17-23) including the utilization of stored soil moisture (14 weeks). The computed growing period started from the 38th MSW (Rainfall > 0.5PET) and ended with 50th MSW (Rainfall< 0.5 PET). This period was added to the stored soil moisture and that came to 51st MSW.

Influence of sowing dates and cropping system on yield of sorghum

The data on mean grain yield of sorghum are presented in Table 5. Time of sowing and cropping systems evaluated significantly influenced the grain yield of sorghum. The results revealed that pre-monsoon sowing treatments (M

1 M

2 and M

3) recorded higher yield than the

normal sowings (M4 M

5 and M

6). Pre-monsoon sowing

treatments of Sarker and Biswas (1988), Jeevananda Reddy Model (1983) and FAO model (1981) produced 12.7, 51.8 and 24.3 per cent increase in grain yield over their normal sown crops.

Under pre-monsoon sowing treatments, among the three models tried, Jeevananda Reddy model (M

2)

produced significantly higher sorghum grain yield of 2764 kg ha-1 followed by M

1 (Sarker and Biswas model)

and M3. Between the two cropping systems evaluated,

S1 (Sole cropping) registered significantly higher grain

yield of 2178 kg ha-1. Sorghum when sown with inter

142

crop, green gram (S2) recorded only 1788 kg ha-1. The

per cent increase of sorghum yield in S1 over S

2 was

22 per cent. The straw yield was altered significantly by different times of sowing.

Among the different sowing dates M2 registered

higher straw yield of 6578 kg ha-1 followed by M

1 sowing.

Lowest straw yield was recorded in M6 sowing. The straw

yield increase in M2 over M

6 was 26 per cent. Cropping

systems had a significant influence on the straw yield of sorghum. Sole sorghum recorded significantly higher straw yield (6016 kg ha-1) over S

2 treatment (intercropped

with green gram).

Different times of sowing had a significant influence on harvest index of sorghum crop. M

2 sown

crop registered significantly higher harvest index and it was at par with M

1 sown crop and superior to other four

sowing treatments. Non significant difference between S

1 and S

2 cropping systems was noticed.

Dates of sowing Vs cropping system

The interaction was significant between sowing dates and cropping system in respect of sorghum (Table 5a). The results indicated that sole sorghum or sorghum with intercrop had given higher grain yield when the seeds were sown under M

2 date of sowing. This might

be due to the favourable environment in to M2 date of

sowing for better establishment, crop growth and finally on grain yield.

ConclusionBased on the study, it is concluded that pre-

monsoon sowing of sorghum during 36th MSW (based on Jeevananda Reddy model) with green gram as an intercrop is ideal for maximum productivity. This technology would be more economical under the risky dryland environment of the study village Chinnamathapalayam at Coimbatore district.

Table 2. Weekly dependable rainfall, mean weekly PET and MAI for Coimbatore (Sarker and Biswas, 1988)

Standard Dependable Mean MAI Standard Dependable Mean MAI week rainfall (mm) weekly week rainfall (mm) weekly at 50% PET at 50 % PET probability (mm) probability (mm)

1 0.0 23.4 0.00 27 5.5 29.6 0.19 2 0.0 22.7 0.00 28 6.2 26.6 0.23 3 0.0 24.3 0.00 29 3.0 25.6 0.12 4 0.0 26.7 0.00 30 3.8 25.3 0.15 5 0.0 28.7 0.00 31 3.5 26.5 0.13 6 0.0 29.6 0.00 32 3.4 25.0 0.14 7 0.0 29.8 0.00 33 4.7 28.3 0.17 8 0.0 33.0 0.00 34 8.2 28.0 0.29 9 0.0 34.1 0.00 35 8.7 30.0 0.29 10 0.0 33.8 0.00 36 10.3 28.2 0.37 11 0.0 34.5 0.00 37 13.7 25.9 0.53 12 0.0 34.9 0.00 38 25.5 26.7 0.96 13 0.0 36.0 0.00 39 28.0 26.6 1.05 14 1.0 35.8 0.03 40 39.4 25.6 1.54 15 0.5 35.2 0.01 41 46.2 26.3 1.76 16 8.0 36.6 0.22 42 58.3 26.3 2.22 17 3.0 35.7 0.08 43 60.1 22.2 2.71 18 11.4 34.3 0.33 44 51.6 20.9 2.47 19 7.6 34.0 0.22 45 53.3 19.4 2.75 20 11.4 33.7 0.34 46 26.5 24.3 1.09 21 3.3 34.4 0.10 47 31.0 24.0 1.29 22 3.5 29.6 0.12 48 15.2 22.5 0.68 23 2.4 27.9 0.09 49 15.3 19.8 0.77 24 4.1 25.9 0.16 50 5.0 21.6 0.23 25 2.0 28.2 0.07 51 4.3 21.9 0.20 26 4.6 27.6 0.17 52 0.0 22.0 0.00

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Table 3. Weekly simple R/PE ratio and 14 weeks R/PE moving average forCoimbatore (Jeevananda Reddy Model, 1983)

MSW Mean Mean Simple R/PE 14 MSW Mean Mean Simple R/PE 14 weekly weekly R/PE weeks weekly weekly R/PE weeks rainfall PET ratio moving rainfall PET ratio moving (mm) (mm) average (mm) (mm) average

1 3.7 23.4 0.16 0.366 27 13.7 29.6 0.46 0.347

2 1.3 22.7 0.06 0.283 28 14.0 26.6 0.53 0.342

3 3.4 24.3 0.14 0.235 29 8.0 25.6 0.31 0.350

4 0.1 26.7 0.00 0.187 30 13.6 25.3 0.54 0.378

5 0.5 28.7 0.02 0.128 31 6.4 26.5 0.24 0.416

6 1.0 29.6 0.03 0.103 32 7.9 25.0 0.32 0.458

7 2.7 29.8 0.09 0.096 33 9.7 28.3 0.34 0.505

8 3.7 33.0 0.11 0.116 34 9.5 28.0 0.34 0.567

9 2.5 34.1 0.07 0.138 35 7.2 30.0 0.24 0.661

10 7.2 33.8 0.21 0.163 36 6.1 28.2 0.22 0.772

11 2.9 34.5 0.08 0.198 37 13.8 25.9 0.53 0.888

12 1.5 34.9 0.04 0.230 38 19.2 26.7 0.72 0.990

13 2.8 36.0 0.08 0.255 39 23.8 26.6 0.90 1.055

14 6.5 35.8 0.18 0.270 40 26.1 25.6 1.02 1.090

15 9.8 35.2 0.28 0.281 41 31.6 26.3 1.20 1.128

16 17.7 36.6 0.48 0.288 42 40.1 26.3 1.52 1.174

17 11.7 35.7 0.33 0.297 43 43.5 22.2 1.96 1.177

18 18.5 34.3 0.54 0.319 44 41.6 20.9 1.99 1.149

19 15.9 34.0 0.47 0.347 45 39.5 19.4 2.04 1.108

20 16.0 33.7 0.47 0.373 46 33.4 24.3 1.38 1.047

21 11.9 34.4 0.35 0.386 47 26.8 24.0 1.12 0.975

22 7.8 29.6 0.26 0.389 48 11.8 22.5 0.52 0.882

23 6.6 27.9 0.24 0.388 49 22.2 19.8 1.12 0.759

24 6.5 25.9 0.25 0.377 50 13.9 21.6 0.64 0.620

25 8.4 28.2 0.30 0.365 51 4.0 21.9 0.18 0.480

26 12.0 27.6 0.44 0.356 52 6.2 22.0 0.28 0.374

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Table 4. Average weekly rainfall and Weekly Moisture Availability Period for Coimbatore (FAO Model, 1981)

MSW Mean 100 % 50 % MSW Mean 100 % 50 % Weekly PET PET Weekly PET PET rainfall (mm) (mm) rainfall (mm) (mm) (mm) (mm)

1 3.7 23.4 11.7 27 13.7 29.6 14.8 2 1.3 22.7 11.4 28 14.0 26.6 13.3 3 3.4 24.3 12.2 29 8.0 25.6 12.8 4 0.1 26.7 13.4 30 13.6 25.3 12.7 5 0.5 28.7 14.4 31 6.4 26.5 13.3 6 1.0 29.6 14.8 32 7.9 25.0 12.5 7 2.7 29.8 14.9 33 9.7 28.3 14.2 8 3.7 33.0 16.5 34 9.5 28.0 14.0 9 2.5 34.1 17.1 35 7.2 30.0 15.0 10 7.2 33.8 16.9 36 6.1 28.2 14.1 11 2.9 34.5 17.3 37 13.8 25.9 13.0 12 1.5 34.9 17.5 38 19.2 26.7 13.4 13 2.8 36.0 18.0 39 23.8 26.6 13.3 14 6.5 35.8 17.9 40 26.1 25.6 12.8 15 9.8 35.2 17.6 41 31.6 26.3 13.2 16 17.7 36.6 18.3 42 40.1 26.3 13.2 17 11.7 35.7 17.9 43 43.5 22.2 11.1 18 18.5 34.3 17.2 44 41.6 20.9 10.5 19 15.9 34.0 17.0 45 39.5 19.4 9.7 20 16.0 33.7 16.9 46 33.4 24.3 12.2 21 11.9 34.4 17.2 47 26.8 24.0 12.0 22 7.8 29.6 14.8 48 11.8 22.5 11.3 23 6.6 27.9 14.0 49 22.2 19.8 9.9 24 6.5 25.9 13.0 50 13.9 21.6 10.8 25 8.4 28.2 14.1 51 4.0 21.9 11.0 26 12.0 27.6 13.8 52 6.2 22.0 11.0

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Table 5. Effect of times of sowing and cropping systems on grain yield,straw yield and harvest index of sorghum

Treatments Grain Yield Straw yield Harvest Index (kg ha-1) (kg ha-1)

Sowing DatesM

1 2637 6278 29.35

M2 2730 6578 29.67

M3 1630 5478 24.32

M4 2300 5618 27.86

M5 1331 5183 20.52

M6 1233 4840 20.28

SEd 65.72 110.41 0.71

CD(P=0.05) 135.31 228.56 1.48 Cropping systemsS

1 2177 6016 26.57

S2 1788 5751 25.68

SEd 52.41 78.95 0.42

CD (P=0.05) 108.80 183.45 0.87

Interaction

M X S

SEd 92.95 154.58 1.00

CD (P=0.05) 192.77 NS NS

NS � Not Significant

Table 5a. Interaction effect of times of sowing and cropping systems on grain yield of sorghum

S S1 S

2 Mean

M M

1 3033 2240 2637

M2 3026 2502 2764

M3 1862 1398 1630

M4 2691 1910 2300

M5 1534 1128 1331

M6 1438 1028 1233

Mean 2178 1788 SEd CD M 65.73 136.31 S 52.41 108.8 M x S 92.95 192.77

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Identification of Promising Rice Hybrids for Aerobic Condition Based on Physiological Traits

K. Amudha, K. Thiyagarajan

28

IntroductionFood security in Asia depends on irrigated rice

ecosystem, which contributes about 75 per cent of the global rice production . However, the water use efficiency of rice is low and hence requires large amount of water. Savings in irrigation water and increase in water productivity is possible if rice is grown under aerobic conditions like an irrigated upland crop. For rice to succeed as an aerobic crop, it should tolerate intermittent water deficits and high soil impedance created due to aerobic conditions (Lafitte and Bennett 2002). Therefore, any breeding programme towards the development of rice genotypes for aerobic environment must emphasize on the physiological and root traits associated with the water uptake, maintenance of plant water status and plant growth under water stress. Hybrid rice with its vigorous and more active root system tolerates moderate stresses caused due to limited irrigation water and therefore can be exploited under aerobic conditions .So far, there

has been no major efforts on this front. Keeping this in view, the present investigation was carried out to identify suitable rice hybrids for aerobic condition based on characters associated with water stress tolerance.

Materials and MethodsAn experiment was carried out with thirty

rice hybrids under aerobic condition Tamil Nadu Agricultural University, Coimbatore during Rabi, 2005. The experimental material comprising of thirty rice hybrids were obtained by crossing six drought tolerant CGMS lines with five male parents (testers) in Line x Tester design. Well-preserved seeds from the thirty cross combinations were sown in raised nursery beds. Twenty-five days old seedlings were transplanted in the main field in a randomized block design (RBD) replicated twice adopting a spacing of 20 cm between rows and 10 cm between plants. Single seedling was transplanted per hill in single row of two-metre length (20 plants per row) in each replication. The transplanted crop

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was maintained under flooded condition (2-3 cm water layer) for 15 days to ease the establishment of the crop. Thereafter, aerobic condition was imposed by irrigating the crop up to field capacity after it has reached a certain lower threshold (e.g., half way between field capacity and wilting point) as suggested by Bouman (2001). A total of 12 irrigations were given during the crop growth period. Every day soil samples were drawn and the soil moisture content was estimated using gravimetric method. Data were recorded in ten plants per replication. Physiological traits were recorded at flowering stage and plants were uprooted at maturity and root traits were recorded. For recording physiological traits like relative water content (Weatherly 1950), membrane integrity (per cent leakage) (Deshmukh et. al. 1991) and catalase activity (Deshmukh et. al. 1991) standard procedures were followed. Transpiration rate and stomatal conductance were measured in the fully expanded flag leaf using Steady State Porometer PMR 5. For recording leaf rolling, the leaf was cut near the base without ligules at the noon time (2-3 pm) and the time taken for the cut leaf to roll was noted with the help of stopwatch and expressed in seconds (Misra et. al. 2004).

Results and DiscussionThe mean for various traits studied are given

in (Table 1). Under aerobic condition, early maturing hybrids are desirable as they are more efficient in partitioning carbohydrate to the panicle and producing more yields per day (Lafitte and Bennett 2002). Russo (2004) also found that early maturing cultivars were more adapted to aerobic conditions than late maturing ones and suggested earliness as a suitable criterion for selection of improved varieties. In the present study, five hybrids viz., IR 68885A / CT-6510-24-1-2, IR 68885A / IR 73718-3-1-3-3, IR 68887A / PSBRC 80, IR 68887A / PSBRC 82 and IR 70369A / IR 73718-3-1-3-3 exhibited early flowering and were found suitable for aerobic conditions.

Maintenance of higher plant water status under drought plays a central role in stabilizing the various plant processes and yield (Kumar and Kajur 2003). Relative water content is one of the important measures which gives an idea of plant water status and therefore used as a most meaningful index for identifying genotypes with dehydration tolerance. In the present investigation, water stress significantly lowered the relative water content in the hybrids at flowering stage. However, the reduction was low in four hybrids namely IR 67684A /

CT-6510-24-1-2, IR 70372A / IR 73718-3-1-3-3, IR 68281A / IR 73718-3-1-3-3, and IR 70372A / PSBRC 80 indicating their tolerance to water stress. Tyagi et al. (1999) also observed higher relative water content in drought tolerant genotypes under water stress compared to susceptible genotypes.

With reference to catalase (an active oxygen species (AOS) scavenging enzyme under water stress) sixteen hybrids were identified to be superior. Higher catalase activity in these genotypes are suggestive of increase in the activity of free radical scavenging system leading to lower lipid peroxidation and maintenance of membrane structure contributing to drought tolerance (Chandrashekara Reddy et al. 1998).

Maintenance of membrane integrity and function under water stress was used as a measure of drought tolerance by Deshmukh et. al.( 1991). A total of twelve hybrids exhibiting significant mean values for catalase activity showed lesser percentage of leakage and were found to possess higher membrane integrity. Among them, the hybrid IR 68885A / IR 73718-3-1-3-3 exhibited highest membrane integrity and were found to be highly suited for aerobic conditions. On the other hand, the hybrid IR 67684A / IR 73718-3-1-3-3 showed minimum membrane integrity under water stress. Lower membrane integrity or higher injury reflects the extent of lipid peroxidation which in turn is a consequence of higher oxidative stress due to water deficit (Leibler et al. 1986).

The leaves of rice plant roll readily under water deficit and it has been used as an indicator of plant water status under stress (Courtois 2000). Ten hybrids involving aerobic rice cultures CT-6510-24-1-2 and PSBRC 80 as one of the parents exhibited small degree of leaf rolling under aerobic conditions. Fukai and Cooper (1990) reported that the cultivars with small degree of leaf rolling maintain high leaf water potential under stress. Therefore, these hybrids with minimum leaf rolling can be well exploited for the maintenance of high leaf water potential under water deficit conditions.

Low rate of transpiration and reduced stomatal conductance are considered advantageous under drought as they are associated with conservation of leaf moisture and maintenance of higher leaf water potential under water stress (Selvi et al. 2001). In the present study, six hybrids viz., IR 67684A / CT-6510-24-1-2, IR 67684A / IR 73005-23-1-3-3, IR 68885A / IR 73718-3-1-3-3, IR 68887A / PSBRC 80, IR 68887A /

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IR 73718-3-1-3-3 and IR 70369A / IR 73005-23-1-3-3 exhibited low transpiration rate and reduced stomatal conductance. Jalaluddin and Prize (1994) observed low stomatal conductance due to drought and suggested it as a result of partial closure of stomata and / or osmotic adjustment.

Deep rooting has been emphasized as an important adaptation to stress in rice (Nguyen et al. 1997). Among the thirty hybrids, twelve hybrids had significant mean values for root length under aerobic conditions. Among them, the best five hybrids were IR 70372A / IR 73718-3-1-3-3, IR 67684A / CT-6510-24-1-2, IR 68885A / IR 73718-3-1-3-3, IR 68887A / PSBRC 82, and IR 70369A / IR 73718-3-1-3-3. In aerobic systems, generally deep roots are required to penetrate through hard pan and fully explore the soil profile for effective absorption of water at deeper layers (Lafitte and Bennett 2002). With respect to root dry weight, eleven hybrids exhibited significantly higher mean values. Among them, the best five hybrids were IR 70369A / IR 73718-3-1-3-3, IR 70372A / PSBRC 80, IR 70369A / CT-6510-24-1-2, IR 68887A / IR 73005-23-1-3-3 and IR 70372A / IR 73718-3-1-3-3.

Sorte et al. (1992) reported that generally drought tolerant cultivar partitions its dry weight more in root for extracting more water from soil and had higher root dry weight under water stress than susceptible one.

Grain yield, an economic output of the plant was found to be significantly higher in nine hybrids under aerobic conditions. The hybrid IR 67684A / CT-6510-24-1-2 out yielded the other hybrid combinations by recording 19.78 g/plant, followed by the hybrids IR 70372A / IR 73718-3-1-3-3, IR 68885A / IR 73718-3-1-3-3, IR 70369A / IR 73718-3-1-3-3 and IR 70372A / PSBRC 80.

In the present study none of the hybrids showed desirable performance for all the traits studied. However, five hybrids viz., IR 68885A / IR 73718-3-1-3-3, IR 67684A / CT-6510-24-1- 2, IR 70369A / IR 73718-3-1-3-3, IR 70372A / PSBRC 80 and IR 70372A / IR 73718-3-1-3-3 recorded desirable mean values for maximum number of characters and exhibited better adaptability to aerobic conditions. The hybrid rice seed production techniques of these hybrids have to be standardised for commercial exploitation .

149

References

• Bouman, B.A.M. (2001). Water efficient management strategies in rice production. Int. Rice Res. Notes., 26(2): 17-22.

•� Chandrashekara Reddy, P., S.N. Vajranabhaian and M. Udayakumar. (1998). Lipid peroxidation as a mechanism of stress tolerance in upland rice (Oryza sativa L.). Calli. Indian. J. Plant Physiol., 3(1): 68-70.

• Courtois, B., G. McLaren, P.K. Sinha, E. Prasad, R. Yadav and L. Shen. (2000). Mapping QTLs associated with drought avoidance in upland rice. Mol. Breed., 6: 55-66.

•� Deshmukh, P.S., R.F. Sairam and D.S. Shukla. (1991). Measurement of ion leakage as a screening technique for drought resistance in wheat genotypes. Indian J. Plant Physiol., 34: 89-91.

• Jalaluddin, M.D. and M.Price. (1994). Photosynthesis and stomatal conductance in rice as affected by drought stress. Int. Rice Res. Notes, 19: 52-53.

�• Kumar, R. and R. Kajur. (2003). Role of secondary traits in improving the drought tolerance during flowering stage in rice. Indian J. Plant Physiol., 8: 236-240.

•� Lafitte, H.R. and J. Bennett. (2002). Requirements for aerobic rice : physiological and molecular considerations. In: Water Wise Rice Production. Proceedings of the International Workshop on Water-wise Rice Production, 8-11 April (Eds. Bouman, B.A.M., H. Hengsdijk, B. Hardy, P.S. Bindraban, J.P. Twong and J.K. Ladha), IRRI, Los Banos, Philippines, pp.259-271.

•� Leibler, D.C., K.P.S. Kling and D.J. Reed. (1986). Antioxidant protection of phospholipid bilayers by tocopherol. Control of tocopherol status and lipid peroxidation by ascorbic acid and glutathione. J. Biol. Chem., 261: 12114-12119.

•� Misra, B., C.H.M. Vijayakumar and S.R. Voleti. (2004). Breeding for aerobic rice adapted to non-flooded irrigated conditions. In: Proc. Workshop on Resilient Crops for Water Limited Environments. Cuernavata, Mexico, pp.175-178.

• Nguyen, H.T., R.C. Babu and A. Blum.(1997). Breeding for drought resistance in rice: physiological and molecular considerations. Crop Sci., 37: 1426-1434.

•� Russo, S. (2004). Preliminary studies on rice varieties adaptability to aerobic irrigation, Cahiers options. Mediterraneinnes. 15: 35-39.

•� Selvi, B., P. Rangasamy and N. Nadarajan. (2001). Combining ability analysis for physiological traits in rice. Oryza, 38(1&2): 13-16.

•� Sorte, N.V., R.D. Deotale, M.N. Patankar, A.H. Narkhede, V.J. Golliwar and B.D. Katole. (1992). Root and shoot physiology as influenced by short term water stress in upland paddy. J. Soils and Crops, 2(1): 86-91.

•� Tyagi, A., N. Kumar and S. Sairam.(1999). Efficacy of RWC, membrane stability, osmotic potential, endogenous ABA and root biomass as indices for selection against water stress in rice. Indian J. Plant Physiol., 4: 302-306.

• Weatherly, P.E. (1950). Studies in the water relations of the cotton plant. I. The field measurement of water deficits in leaves. New Phytol., 49: 81-97.

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Aerobic Rice - A New Tool for Water Scarcity Management

M. Govindaraj1, K. Ashokkumar2 and P. Anbu2

29

Introduction Rice deserves a special status among cereals as

worldÊs most important wetland crop. Rice grain provides 35-80 per cent of total calorie uptake to more than 2.7 billion people in the world (Gorantla et al., 2005). Globally, about 79 million ha of irrigated lowlands provide 75 per cent of the total rice production. It is estimated that irrigated lowland rice receives some 34-43 per cent of the total worldÊs irrigation water, or 24-30 per cent of the total worldÊs freshwater withdrawals. Rice consumes more than 50 per cent of the water used for irrigation in Asia (Barker et al., 1999). Rice is mostly grown under submerged soil conditions and requires much more water compared with other crops. The declining availability and increasing costs of water threaten the traditional way of growing rice under irrigated conditions. Moreover, the lack of rainfall is a major production constraint in rainfed areas where many poor farmers live. Efficiency in the use of water is critical to help reduce poverty and safeguard food security in water-scarce areas in Asia.

Rice is grown in widely under rainfed conditions in Asia; about 45 per cent of the total rice area is estimated to have no irrigation input. In rice ecosystems, the rainfed lowland ecosystem occupies a larger area than the upland and flood-prone ecosystems. The increase in yield in the rainfed rice ecosystem has been much less than in the irrigated rice for the last 30 years. In Tamil Nadu from 1.4 million ha, 3.2 million tonnes rice was produced with the productivity of 2308kg ha-1. In India during 2007-2008, 93 million tonnes of rice was produced from an area of 43 million ha, with the productivity of 2051kg ha-1 (Economic survey 2007-08). It is estimated that demand for rice in 2010 will be 100 million tonnes and in 2025, it will be 140 million tonnes (Singh, 2004).

The looming global water crisis threatens the sustainability of irrigated rice, which is the AsiaÊs biggest water user. Aerobic rice is a new concept of growing rice in non-puddled and non flooded aerobic soil. Water requirements can be lowered by reducing water losses due to seepage, percolation, and evaporation.

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Promising technologies include saturated soil culture and intermittent irrigation during the growing period. However, these technologies still use prolonged periods of flooding, so, water losses remain high. A fundamentally different approach is to grow rice like an upland crop, such as wheat, on non-flooded aerobic soils, thereby eliminating continuous seepage and percolation and greatly reducing evaporation. Traditional upland rice has been bred for the unfavourable uplands to give a stable, though low, yield with minimal external inputs. Growing high-yielding lowland rice under aerobic conditions has shown great potential to save water but it has severe yield penalty. Hence, a new type of rice is needed to achieve high yields under high-input aerobic conditions.

Why Aerobic Rice?The reason for going to aerobic rice stands valid

because,

In wetland preparation a soaked and saturated soil is essentially required. The water requirement for this in wetland is about 434mm where as it is only 2mm in dry or upland conditions.

Field submergence after crop establishment is a must in wetland, which consumes on an average 1325mm of water where as in aerobic or upland condition it is only 830mm.

Nearly 1325mm water was lost by seepage, percolation and evaporation in wetland, whereas itÊs nearly half the quantity in aerobic situation.

In total 1000-2000mm of water is required in lowland as against only 375-500mm of water in aerobic condition.

Rice EcosystemsRice is produced in a wide range of locations and

under a variety of climatic conditions. Rice production is classified into four ecosystems based on water supply during cultivation (Khush, 1997) they are, Irrigated rice, Rainfed lowland rice, Upland rice and Flood-prone rice. Water consumption for per kg of rice ranges from 1000 � 5000 litters depending on rice ecosystem, soil conditions and crop management, which is about two to three times more than is needed to produce other cereals such as wheat or maize (Cantrell and Hettel, 2005).

There is a growing scarcity of water worldwide, which has already started to influence conventional irrigated rice production (Bouman et al., 2005). By

2025, a Âphysical water scarcityÊ is projected for more than 2 million ha of irrigated dry-season rice and 13 million ha of irrigated wet-season rice in Asia, and an Âeconomic water scarcityÊ is expected to hamper most of AsiaÊs 22 million ha of irrigated dry-season rice (Bouman et al., 2005). Obviously, the most important irrigated rice ecosystem for human beings is being increasingly threatened by water scarcity (Fig.1).

The increasing water scarcity for agriculture, and competition for water from non-agricultural sectors, point to an urgent need to improve crop water productivity to ensure adequate food for future generations with the same or less water than is presently available to agriculture. Two types of water-saving systems may be used to replace the traditional irrigated rice production schemes that are now under threat (Cantrell and Hettel, 2005), Alternate wetting and drying and Aerobic rice. In the later system, rice is sown directly into dry soil, like wheat or maize, and irrigation is applied to keep the soil sufficiently moist for good plant growth, but the soil is never saturated. Aerobic rice systems can reduce water requirements for rice production by over 44 per cent relative to conventionally transplanted systems, by reducing percolation, seepage, and evaporation losses, while maintaining yield at an acceptable level (Bouman et al., 2005).

Physiological features

Root developmentA month after transplanting in flooded condition,

about 75 per cent of the rice roots growing in saturated soil are concentrated in upper 6cm of soil. As it remains nearer to the surface of soil, it obtains oxygen only from the irrigated water. Such truncated root systems can access nutrients from only a limited volume of soil, having to rely mostly on nutrients provided through fertilizers. Conversely; when rice is grown with intermittent flooding, roots extend downward 30-50cm and can access nutrients from deeper layer of soil.

Aerenchyma FormationWhen rice plants are grown under continuously

flooded conditions, much of the root cortex disintegrates to for aerenchyma (air pockets). This process occur both in varieties bred for irrigated cultivation and upland cultivation. However, neither irrigated nor upland varieties form aerenchyma when they are grown in well drained soil. The difference between these two

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categories of rice is that the former are able to create a larger and more regular aerenchyma that enable roots to continue functioning and to survive longer in flooded soil. Formation of aerenchyma appears to the sub optimizing rather than an ideal adaptation to hypoxic conditions.

Prolonged Root ActivitiesBy the time of flowering when grain production

begins, about 75 per cent of roots of rice plants that are growing in continuously saturated soil are degenerated, whereas there is little or no degeneration of roots in well drained condition.

Then Why Flooded Conditions?Because rice can survive inundation and favour

effective weed control when it is grown in stagnating water, if water resources are plenty. Rice grows well in aerobic condition. Further aerobic conditions promote a developed root system there by saving water, efficient use of land, labour and capital and higher uptake of nutrients.

Rice as a Focus of Water-Saving Initiatives

Among the agricultural crop rice is the major user of available fresh water in Asia. It is one of the major crops in India, and in some areas it is grown subsequently with wheat. The usual way of growing rice is by transplanting in flooded and puddled soil. Rice is grown with standing water throughout the growing season. This practice of growing rice needs a relatively large amount of water compared with other cereals. However, most of the supplied water in the field evaporates in the atmosphere or drains deep down and across the soil layer. With the looming problem of water scarcity, International Rice Research Institute (IRRI) rice scientists and hydrologists, and partners from the national agricultural research and extension systems, have begun conducting research activities with farmers to control this problem. One of the potential water-saving technologies being studied is the aerobic rice system. The Irrigated Rice Research Consortium and the Challenge Program on Water and Food are two programs that support the ongoing research activities on aerobic rice in India through the Water Technology Centre (WTC) of the Indian Agricultural Research Institute (IARI).

Aerobic rice requires almost half the water needed to grow conventional varieties. As against 5,000 litres of water required to produce one kg of conventional rice,

the aerobic rice requires between 2,000-2,500 litres, adding the crop could also be grown in low rainfall areas. As part of a participatory plant breeding exercise along with farmers, many crop research institutes such as University of Agricultural Science (UAS) Bangalore, currently, is undertaking trials of different varieties of aerobic rice at different locations across the country (Bangalore, Chhattisgarh, Cuttack, Faizabad, Coimbatore and Hazaribagh).

Lowland rice is traditionally grown in bunded fields (paddies) that are continuously flooded from crop establishment to close to harvest. It is estimated that irrigated lowland rice receives some 34-43 per cent of the total worldÊs irrigation water, or 24-30 per cent of the total worldÊs freshwater withdrawals. The yield is about 55 quintals per hectares, on par with the traditional varieties, but saves labour costs as this variety does not need transplanting like conventional variety and could be sown directly, UAS has developed different types of aerobic rice, which taste like the conventional types. They are also looking at developing aromatic rice on these lines, and the aerobic rice does not require pesticides. A collaborative project on new water-saving rice technologies, specifically aerobic rice, is being developed for Bangladesh, India, Nepal, and Pakistan. In South Asia, it has been estimated that, by 2012, 12 million hectares of irrigated rice may suffer from severe water shortage, seriously affecting the regionÊs food security and social stability. With increasing water scarcity, the sustainability, food production, and ecosystem services of rice fields are threatened. Therefore, there is need to develop a cultivars which is suitable for aerobic ecosystem, that can help farmers during the water scarcity situations.

Research on Aerobic RiceRice scientists have been urged to take up

research of aerobic rice, while going in for a reduction in the area under the crop by 10 - 15 per cent due to widespread water-stressed situation. Research on aerobic rice assumes significance since; it does not require standing water and has greater water use efficiency. Large declines are expected in India, too, in the coming years, but this should be considered an opportunity for furthering the Indian rice varieties on the export front.

The major yield reduction would appear to be due to incomplete grain filling and high florets sterility. However, good performing rice may be among earlier maturing cultivars. The varied cultivar responses to

153

stresses from non flooded conditions show, a potential for genetic improvement. Aerobic rice production may be adapted to non traditional rice areas where soil flooding is problematic or water cost prohibitive. The advantages of dry rice methods are: i) reducing water consumption; ii) economizing the costs of machinery usage; iii) reducing the constraints at planting time; iv) improving the rice stand establishment (Russo, 1994).

Many countries are involved in the development of aerobic rice such as China, Philippines, Brazil and India. However, Special aerobic rice cultivars, called Han Dao, have been developed by the China Agricultural University (CAU), Beijing. In Philippines, participatory testing of aerobic rice by farmers is being done in the provinces of Tarlac, Nueva Ecija, Bulacan, and Bohol. The earlier studies show that yield of rice up to 6.4 tonnes per hectare. Farmers in India are also trying out aerobic rice in their fields, and they have identified well-performing varieties. Water savings were also achieved at 30-40 per cent for production levels of 4 tons per hectare. Varieties are being tested in Lao PeopleÊs Democratic Republic, while activities in northeast Thailand are set to evaluate genotypes and start on-farm tests to overcome problems of labour shortage and weeds.

Special FeaturesUnlike the conventional varieties that have

shorter roots, the long roots of aerobic rice, almost thrice the length of conventional types at about 30cm, help better absorption of water, nutrients and facilitate better air circulation. As a result, the process of methanogenesis (emission of methane through decomposition of organic compounds) is prevented. This is because of soil bacteria decompose organic matter under aerobic conditions. Normally, methane is produced during flooded rice cultivation by the anaerobic (without oxygen) decomposition of organic matter in the soil. It is estimated that paddy cultivation accounts for 20-25 per cent of the methane gases emitted in the atmosphere. Developed over a period of six years using the hybridisation process, the aerobic rice is a result of cross-breeding of local variety and IR64 procured from IRRI, Philippines. The advantages of aerobic rice are: i) reducing water consumption; ii) economizing the costs of machinery usage; iii) reducing the constraints at planting time; iv) improving the rice stand establishment (Russo, 1994).

Aerobic PracticesDry sowing of rice with minimum land

preparation i.e., in non-puddled and non-flooded soil.Efficient seed coating technology either with suitable phosphobacterium or rhizobial culture.Square sowing with wider spacing to avoid root competitions for crop growth.Maintenance of moist soil but aerated soil during vegetative growth period.Efficient weed management either by use of herbicides or by the use of frequent hand weeding especially in the early stage of crop.Allowing a thin film of water (1-2cm) to be maintained after panicle initiation.

Hence, large savings in water used for rice production are possible in tropical Asia through a use of aerobic production systems. Optimization of aerobic systems will likely require the development of new cultivar type combing moderate drought tolerant, high rates of tillering, high harvest index and lodging resistant. Some cultivars of this type have already been developed in china and now underway by the asian upland rice breeding programme in IRRI as well as in India and its expected that new generation of improved cultivars for aerobic systems will be available for tropical Asian rice producer in the near future years.

ConclusionThe days are gone when rice grown in unflooded

soils was considered a low productivity, poor quality, high risk, low technology crop. Matching grain quality with shifting consumer preferences had a great impact on profitability of aerobic rice, making it more competitive. Inserted into novel cropping systems, either in rotation with soybeans or a tool for pasture renewal, aerobic rice can contribute to environmental sustainability. The production of rice in aerobic systems also allows national demand to be met without the large investments in infrastructure and associated heavy use of fresh water for irrigated lowland rice. Use of dedicated aerobic screening facilities for screening in the wet-season as a routine part of the plant breeding program would enhance the identification of drought resistance in advanced lines that may be eventually released as new cultivars. Further research will be needed to identify particular traits that are associated with aerobic responsive traits in different aerobic conditions. Similarly the importance of aerobic responsive traits, relative to other putative traits for aerobic ecosystem, needs to be tested in various lowland environments; particularly rice growing countries such as China, India and Thailand.

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References Barker, R., D. Dawe, T.P. Tuong, S.I. Bhuiyan and L.C. Guerra. 1999. The outlook of water resources in the year

2020 : Challenges for research on water management in rice production. In : Assessment and Orientation towards the 21st century. Proceedings of 19th session of the International Rice Commission, Cario, Egypt. 7-9 September, 1998. pp. 96-109. FAO, Rome (Italy).

Bouman, B.A.M., Peng, S., Castañeda, A.R., Visperas, R.M., 2005. Yield and water use of tropical aerobic rice systems. Agric. Water Manag. 74:87-105.

Cantrell, R.P., Hettel, G.P., 2005. Research strategy for rice in the 21st century. In:Toriyama, K., Heong, K.L., Hardy, B. (Eds.), Rice is life: Scientific perspectives for the 21st century. Proceedings of the World Rice Research Conference held in Tokyo and Tsukuba, Japan, 4-7 November 2004. Los Baños (Philippines): International Rice Research Institute, and Tsukuba (Japan): Japan International Research Center for Agricultural Sciences. CD-ROM, pp. 26-37.

Economic survey 2007-08. (Government of India). pp. 156-168.Gorantla, M., P.R. Babu, V.B. Reddy Lachagiri, E. Alex Feltus, Andrew H. Paterson and Arjula Reddy. 2005. Functional

genomics of drought stress responses in rice: transcript mapping of annotated unigenes of an indica rice (Oryza sativa L. ev. Naginazz). Current Sci. 89(39): 496-514.

Khush, G.A., 1997. Origin, dispersal, cultivation and variation of rice. Plant Molecular Biology 35:25-34.Salvatore Russo.1994. Preliminary studies on rice varieties adaptability to aerobic irrigation. Cahiers Options

Méditerranéennes, vol. 15,p: 36-39.Singh, A. K. 2004. Enhancing water use efficiency in rice. In: International Symposium on Rice: From green Revolution

to Gene Revolution. Extended summaries, Vol. I. pp. 13. October 4-6. DRR, Rajendranagar, Hyderabad, India.

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Standardization of Fertigation for Cucumber under Polyhouse

using Soilless MediaS. Janapriya1, Dr. D.Palanisamy2 and Dr. M. V. Rangaswamy3

30

IntroductionFertigation is a new concept recently practiced

in several parts of the world in horticultural crops. Inorganic fertilizers were probably the first chemicals to be injected into the trickle irrigation system. It was reported that 40% saving in fertilizer use could obtained by drip fertigation with substantial increase in yield (Magar, 1988). Fertigation improves nutrient use efficiency besides water and fertilizer use efficiency, it is one of the most effective and convenient method of supplying nutrients and water according to the specific requirements of the crop to maintain optimum soil fertility and better quality produce.

Materials and MethodsThe experiment was conducted in TNAU,

Coimbatore, to study the effect of growing media and fertigation under polyhouse as a package in cucumber variety Greenlong with a spacing of 60 ´ 30 cm. The experiment was laid out in a factorial randomized block design. There were nine different media levels and

two fertigation levels thus there were 18 treatment combination replicated twice (Fig 1). The treatment details are given below:

Treatment Growing media (v/v)

T1 Peat: sand (5:1)

T2 Peat: vermicompost: sand (2.5:2.5:1)

T3 Vermiculite: sand (5:1)

T4 Vermiculite:Vermicompost: sand (2.5:2.5:1)

T5 Coir pith: sand (5:1)

T6 Coir pith: vermicompost: sand (2.5:2.5:1)

T7 Sawdust: sand (5:1)

T8 Sawdust: vermicompost: sand (2.5:2.5:1)

T9 Soil + FYM

F1 100% of recommended dose of N, P and K

F2 80% of recommended dose of N, P and K

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Fertigation through fertigation tank Urea and muriate of potash were dissolved in water in the ratio of 1:5 and the solution was diluted in fertigation tank and it was allowed for fertigation

Fertilizer SchedulingDuring vegetative stage the fertilizer was applied

at weekly intervals. During flowering the fertilizer was applied at three days intervals and during fruiting stage it was applied again at weekly intervals. The fertilizer schedule adopted is given in Table 1.

Basal application = 10 %

The quantity of fertilizer applied during the various stage is given in Table 2

Recommended fertilizer level is 150:75:100 kg/ha

Urea - 73.23 g/plant

Super phosphate - 105.46 g/plant

MoP - 37.57 g/plant

Results and discussion

Plant HeightThe data on plant height (cm) in the polyhouse

and open field recorded at 15,30,45,60,75 and 90 DAS (Days after sowing) are presented in the Fig.2 and 3.In both greenhouse and open field conditions, T2F1 recorded higher plant height compared to other treatments. This might be due to high organic matter, macro and micronutrients that might have contributed to better growth. Fertigation of greenhouse tomatoes with nitrogen fertilizers and potassium fertilizers especially K2SO4 produced excellent results in improvement of plant quantitative characters (Sharma et al., 1994).

Fruit YieldThe data on fruit yield per plant and yield per

hectare was the highest in T2F1 (2.05 kg and 113.89 t/ha), followed by T4F1 (1.96 kg and 108.89 t/ha) and the lowest yield was recorded in T9F2 (0.58 kg and 32.32 t/ha) respectively under polyhouse condition (Fig 3). The result revealed that the polyhouse condition had higher plant growth Getting higher yield of cucumber in off-season fetches the farmer a remunerative price. All the plants under open field condition under different treatments was infected disease buying reduce fruit quality and average weight of the fruit. Plant growth

is enhanced only when the supply of assimilates is greater than the requirement of respiration. Good yield increase not only depends on the media but also on the nutrient content. In case of different fertilizer dose on fruit growth, application of 100% fertigation resulted in higher yields than 80% fertigation. This is particularly true where a small volume of growing medium is used per plant, resulting in marked fluctuations in nutrient levels, Combined application of N, P and K produced the highest fruit yield per plant and fruit yield per hectare (Sharma, 1995).

Fig. 1. A view of experimental layout under the polyhouse and open field.

Stage N % P2O5 % K2O % Frequency of fertigation

Vegetative (1-30 days after sowing) 30 30 30 Once in a week Flowering (30-45 days after sowing) 50 50 40 Once in three days Fruiting (30-90 days after sowing) 10 10 20 Once in a week

Table 1. The fertilizer schedule adopted at different growth stages

Table 2. Details of fertilizer applied during different growth stages

Stage Urea (g/plant) Super phosphate (g/plant) MoP (g/plant)

Vegetative (1-30 days after sowing) 21.97 31.64 11.27Flowering (30-45 days after sowing) 36.615 52.73 15.03Fruiting (30-90 days after sowing) 7.323 10.55 7.51

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Water Utilized by The PlantThe effect of differential amount of fertilizer

added through drip irrigation system showed significant improvement on irrigation water use efficiency and fertilizer use efficiency. The total water utilized for polyhouse and open field are given in Tables 4.23 and 4.24. The total water utilized for tomato crop was lesser in polyhouse in all the treatments during the crop duration (93.75mm) compared to that of control plot (230.07 mm). The control plot received more quantity of water for the first crop and less water received. The reason for less quantity of water utilized may be due to less evaporation losses and more crop foliage.

Water Use EfficiencyIt has been observed from the Fig. 4, that the

highest water use efficiency (1215 kg/ha.mm) was obtained in T2F1 and the lowest was obtained in T9F2 (344 kg/ha.mm) under polyhouse. The open field recorded a high water use efficiency of 418 kg/ha.mm in T2F1 and the least value (87 kg/ha.mm) was obtained in T9F2.

Fertilizer Use EfficiencyThe influences of irrigation and fertilizer levels

on N fertilizer use efficiency are furnished in Fig. 5. Increased fertilizer use efficiency with the decreased

level of fertilizer dose through drip was observed. The highest N fertilizer use efficiency of 880 kg/ ha.kg of N was recorded in T2F2 at 80 % of fertigation followed by T4F2 (838 kg /ha.kg of N) and the least efficiency was noted in T9F1 (222 kg/ ha. kg of N) under polyhouse condition. In open field, the highest was N fertilizer use efficiency of 773 kg/ ha.kg of N was recorded in T2F2 at 80 % of fertigation and the least efficiency was noted in T9F1 (148 kg/ ha.kg of N).The influences of irrigation and fertilizer levels on K fertilizer use efficiency are furnished in Fig5. The highest K fertilizer use efficiency of 1319 kg/ ha kg of K was recorded in T2F2 at 80 % of fertigation and the least efficiency (333 kg /ha.kg of K) was noted in T9F2 in polyhouse condition. In open field the highest K fertilizer use efficiency of 1160 kg/ ha.kg of K was recorded in T2F2 at 80% of fertigation and the least efficiency (222 kg /ha. kg of K) was noted in T9F1.The nutrient use efficiency was more under polyhouse, which might be due to more development of more root length, that inturn might have increased the availability of nutrients to the plants. It was reported that 40% saving in fertilizer use could obtained by drip fertigation with substantial increase in yield (Magar, 1988).Fertigation improves nutrient use efficiency besides water use efficiency (Cook and Sanders, 1991).

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Economics of Cucumber Cultivation Under Polyhouse

The highest cost benefit ratio (3.43) recorded in T2F1, and the lowest cost benefit ratio (1.56) was recorded in T3F2 under polyhouse. In open field condition the highest cost benefit ratio (2.36) was recorded in T2F1 and the lowest (0.80) was recorded T3F2.

The results have indicated that the polyhouse cultivation of cucumber using soilless media has most

benefit than open field condition, in terms of yield, quality, water use efficiency, fertilizer use efficiency and benefit cost ratio. The supreme performance of cultivation of cucumber under polyhouse in soilless media can be attributed to the prevalence of optimum microclimatic conditions created by the protected structure as well as the ideal growing medium. ence, it is concluded that growing cucumber under naturally ventilated polyhouse in a growing medium consisting of peat: vermicompost: sand (T2F1) can be highly profitable.

ReferencesCook, V.P., and Sanders,D.C. 1991. Nitrogen application frequency for drip �irrigated tomatoes. Hort.Sci., 26:

250-252.Magar,S.S. 1988. Progress and prospective of drip irrigation in Maharashtra state. A joint argesco report submitted to M.P.K.V., Rahuri, Maharashtra.Sharma , K.C., Singh, A.K. and Sharma, S.K. 1994. Studies on nitrogen requirement and pre- requirement of tomato

hybrids. Acta Hort., 366: 133-137.Savvas,D., 2002. General introduction .In: Savvas, D., Passam,H.C. (Eds.), Hydroponic Production of Vegetables

and Ornamentals. Embryo Publications. Athens, Greece, pp.15-23.Sharma, S.K. 1995. Response of nitrogen and phosphorous on plant growth and fruit yield in hybrid sweet pepper

cultivar Pusa Deepti. Veg.Sci., 22(1): 19-21.

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A Review of the Water Harvesting Programmesin

Dryland WatershedsB. Maheshwara Babu, D. C. Sahoo, J. K. Neelakanth and Prasad S. Kulkanri

31

IntroductionThe vital role of water in the socio-economic

success or failure of human communities in arid and semi-arid is becoming very clear. In such areas, annual rainfalls are low and precipitation usually falls in few showers. In many rainfall events, most of the water is „lost‰ by runoff. In other words, out of the limited rainfall that precipitates in such areas, only a fraction infiltrates into the soil and may be stored for future use by the natural vegetation. This amount is usually far less than the requirements of commercial crops for full seasonal growth. Therefore, extensive agricultural crop production in these regions has been mostly achieved through supplemental irrigation. However, age-old practices as well as new advances in science and technology have made it possible to grow agricultural crops in such areas without constructing extensive irrigation networks. The key to this achievement is to „harvest‰ rainwater where it falls and use it efficiently for growing trees, grasslands and suitable crops.

One application of supplemental irrigation during the growing season could be life saving for rainfed crops in dry arid lands. Moreover, the extended water availability during the dry season widens the farmersÊ choices among different cropping patterns and farming systems that can be used. Therefore, water harvesting can be considered as a key water resources management tool in any agro biodiversity conservation scheme in dry areas. To feed the growing population in the dry areas of the world, more irrigation is needed but the quantity of irrigation water is extremely limited.

Promotion of Water Harvesting Programmes on Watershed Basis

The Watershed approach has conventionally aimed at treating degraded lands with the help of low cost and locally accessed technologies such as in-situ soil and moisture conservation measures, afforestation etc. and through a participatory approach that seeks to secure close involvement of the user-communities.

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The broad objective was the promotion of the overall economic development and improvement of the socio-economic conditions of the resource poor sections of people inhabiting the programme areas. Many projects designed within this approach were, at different points of time, taken up by the Government of India. The Drought Prone Areas Programme (DPAP) and the Desert Development Programme (DDP) were brought into the watershed mode in 1987. The Integrated Wasteland Development Programme (IWDP) launched in 1989 under the aegis of the National Wasteland Development Board also aimed at the development of wastelands on watershed basis.

All these three programmes were brought under the Guidelines for Watershed Development with effect from 1.4.1995. Other major programmes now being implemented through this approach are the National Watershed Development Project in Rainfed Areas (NWDPRA) and the Watershed Development in Shifting Cultivation Areas (WDSCA) of the Ministry of Agriculture (MoA).

The focus of these programmes has, with the advent of the Department of Land Resources (DoLR), Ministry of Rural Development, GoI shifted to the enhancement of the viability and quality of rural livelihood support systems. While the programmes of DoLR are designed to address areas characterized by a relatively difficult terrain and preponderance of community resources, those of Ministry of Agriculture are expected to aim at increasing production and enhancing productivity in cultivated areas largely privately owned.

While the focus of these programmes may have differed, the common theme that underpinned their structure has been the basic objective of land and water resource management for sustainable development of natural resources and community empowerment. The Watershed Development Projects under DPAP/DDP will be taken up in the Blocks notified under respective Programmes. Such Projects, under IWDP will generally be implemented in the Blocks other than those notified under DPAP/DDP as well as the Blocks having similar projects under International Cooperation Schemes such as Sustainability of Livelihood/Watershed Development projects funded by international donor agencies.

The watershed approach is a project based, ridge to valley approach for in situ soil and water conservation, afforestration etc. Unit of development will be a watershed area of about 500 ha each in watershed development

projects. However, the actual area of a project may vary keeping in view the geographical location, the size of village etc. The thematic maps generated from satellite data for different themes such as land use/land cover, hydro geo -morphology, soils etc. may be used for selection of a watershed area. The project will primarily aim at treatment of non-forest wastelands and identified drought prone and desert areas. However, if any watershed area consists of some forestlands, it should also be treated simultaneously under the project.

The objectives of Watershed Development Projects will be

Developing wastelands/degraded lands, drought-prone and desert areas on watershed basis, keeping in view the capability of land, site-conditions and local needs. Promoting the overall economic development and improving the socio-economic condition of the resource poor and disadvantaged sections inhabiting the programme areas. Mitigating the adverse effects of extreme climatic conditions such as drought and desertification on crops, human and livestock population for their overall improvement. Restoring ecological balance by harnessing, conserving and developing natural resources i.e. land, water, vegetative cover.

These programmes will be implemented, mainly, through the Zilla Parishads (ZPs)/District Rural Development Agencies (DRDA). However, wherever it is expedient in the interest of Watershed Development Programmes, the projects can be implemented through any Department of the State Government or autonomous agencies of Central Government or State Governments. The items, inter alia that can be included in the Watershed Development Plan are:

Land Development including in-situ soil and moisture conservation measures like contour and graded bunds fortified by plantation, bench terracing in hilly terrain, nursery raising for fodder, timber, fuel wood, horticulture & Non Timber Forest Product Species.

A forestation including block plantations, agro- forestry and horticultural development. Shelterbelt plantations, sand dune stabilization, etc.

Drainage line treatment with a combination of vegetative and engineering structures.

Development of small water harvesting structures such as low-cost farm ponds, nalla bunds, check-dams and percolation tanks & ground water recharge measures.

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Renovation and augmentation of water resources, desiltation of tanks for drinking water/irrigation.

Pasture development either by itself or in conjunction with plantations.

Repair, restoration and up-gradation of existing common properly assets and structures in the watershed to obtain optimum & sustained benefits from previous public investments.

Crop demonstrations for popularizing new crops/ varieties or innovative management practices

Promotion and propagation of non-conventional energy saving devices and energy conservation measures.

District Rural Development Agency (DRDA)

The District Rural Development Agency (DRDA) has traditionally been the principal organ at the District level to oversee the implementation of different anti-poverty programmes. Since its inception, the administrative costs of the DRDAs were met by way of setting apart a share of the allocations for each programme.

However, of late, the number of the programmes had increased and while some of the programmes provided for administrative costs of the DRDAs, others did not. There was no uniformity among the different programmes with reference to administrative costs. Keeping in view the need for an effective agency at the district level to coordinate the anti-poverty effort, a new Centrally Sponsored Scheme for strengthening the DRDAs has been introduced with effect from 1st April, 1999. Accordingly, the administrative costs are met by providing a separate budget provisions. This scheme which is funded on a 75:25 basis between Centre and States, aims at strengthening and professionalsing the DRDAs.

The role of the DRDA is in terms of planning for effective implementation of anti-poverty programmes; coordinating with other agencies-Governmental, non-Governmental, technical and financial for successful programme implementation; enabling the community and the rural poor to participate in the decision making process, overseeing the implementation to ensure adherence to guidelines, quality, equity and efficiency; reporting to the prescribed authorities on the implementation; and promoting transparency in decision making and implementation.Each DRDA will have the watershed wings:

Watershed WingA Watershed Wing responsible in the DRDA

in all such districts where IWDP / DPAP /DDP is in operation. This wing is consisting of a Project Officer, assisted by a small complement of staff. This staff would be independent of the programme support in the form of PIAs or Watershed committees.

Drought Prone Areas ProgrammeThe basic objective of the programme is to

minimize the adverse effects of drought on production of crops and livestock and productivity of land, water and human resources ultimately leading to drought proofing of the affected areas. The programme also aims to promote overall economic development and improving the socio-economic conditions of the resource poor and disadvantaged sections inhabiting the programme areas.

Upto 1994-95, DPAP was in operation in 627 blocks of 96 districts in 13 States. From 1995-96 total blocks covered under DPAP became 947. These 947 blocks were in 164 districts in 13 States. Subsequently, with the re-organization of States, Districts and Blocks, the programme is now covered in 972 blocks of 183 districts in 16 States. These States are Andhra Pradesh, Bihar, Chattisgarh, Gujarat, Himachal Pradesh, Jammu & Kashmir, Jharkhand, Karnataka, Madhya Pradesh, Maharashtra, Orissa, Rajasthan, Tamil Nadu, Uttar Pradesh, Uttaranchal and West Bengal (Table 1). The identified dry sub humid area under the programme is about 7.46 lakh sq. km (74.6 m ha).

The prevailing cost for a prescribed watershed project of 500 ha is Rs. 30.00 lakh i.e. Rs. 6,000 per ha Central and State Government in the ratio of 75: 25 share the cost. 80% (85% under Hariyali) of the cost is devoted towards watershed development activities and rest 20% (15% under Hariyali) for community organization, training and administrative jobs. The central share is released in 7 installments (5 insts. under Hariyali). The project is to be completed over a period of five years.

Since the adoption of watershed approach in the year 1995-96 till 2005-2006, 24363 projects have been sanctioned to treat 121.82 lakh ha of drought prone area. The project period of 6089 projects sanctioned from 1995-96 to 1998-99 has however been over; of these 4325 projects are deemed complete and funding stopped to 1764 projects. Among 18274 projects

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sanctioned from 1999-2000 to 2005-06, 1392 projects are deemed complete and 16882 projects are ongoing as on 31.3.2006. Thus, a total of 5717 projects are deemed complete, funding has been stopped to 1764 projects and 16882 projects are ongoing.

The Union Government sanction block wise new projects every year to programme districts taking in to consideration primarily the DPAP coverage, performance of the on-going projects, capacity to absorb new projects and annual budget outlay etc. During the year 2005-06, 3000 new watershed projects have been sanctioned under DPAP to treat an area of 15 lakh ha at a total cost of Rs. 900 crore over a period of five years.

The estimated area treated under DPAP from inception till 31.3.1995 - 57.14 lakh ha under watershed approach:

Desert Development Programme (DDP)The basic object of the programme is to minimise

the adverse effect of drought and control desertification through rejuvenation of natural resource base of the identified desert areas. The programme strives to achieve ecological balance in the long run. The programme also aims at promoting overall economic development and improving the socio-economic conditions of the

resource poor and disadvantaged sections inhabiting the programme areas.

From 1995-96 total blocks covered under DDP became 227 in 40 districts of 7 States. Subsequently, with the re-organization of Districts and Blocks, the programme is now covered in 235 blocks of 40 districts in 7 States of Andhra Pradesh, Gujarat, Haryana, Jammu & Kashmir Karnataka and Rajasthan. The corresponding physical area under the programme is about 4.57 lakh sq. km (Table 2).

Since the adoption of watershed approach in the year 1995-96 till 2005-2006, 13476 projects have been sanctioned to treat 67.38 lakh ha of arid area. The project period of 2194 projects sanctioned from 1995-96 to 1998-99 has however been over; of these 1894 projects are deemed complete and funding stopped to 300 projects. Among 11282 projects sanctioned from 1999-2000 to 2005-06, 689 projects are deemed complete and 10593 projects are ongoing as on

31.3.2006. Thus, a total of 2583 projects are deemed complete, funding stopped to 300 projects and 10593 projects are ongoing.

The Union Government sanctions new projects every year taking in to consideration primarily the DDP coverage in the States, performance of the on-going projects, capacity to absorb new projects and annual budget outlay etc. During the year 2005-06, 2000 new watershed projects have been sanctioned under DDP to

Sl.No. Name of the State No. of Districts No. of Blocks Area in Sq. Kms.

1. Andhra Pradesh 11 94 99218

2. Bihar 6 30 9533

3. Chattisgarh 8 29 21801

4. Gujarat 14 67 43938

5. Haryana - - -

6. Himachal Pradesh 3 10 3319

7. Jammu & Kashmir 2 22 14705

8. Jharkhand 14 100 34843

9. Karnataka 15 81 84332

10. Madhya Pradesh 23 105 89101

11. Maharashtra 25 149 194473

12. Orissa 8 47 26178

13. Rajasthan 11 32 31969

14. Tamil Nadu 17 80 29416

15. Uttar Pradesh 15 60 35698

16. Uttaranchal 7 30 15796

17. West Bengal 4 36 11594

Total 183 972 745914

(Source: www.rural.nic.in/drda.htm)

Table 1. States, districts and blocks covered under drought prone areas programme (DPAP)

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treat an area of 10 lakh ha at a total cost of Rs. 600 crore over a period of five years.

The area treated under DDP so far from inception till 31.3.1995 - 5.15 lakh ha. From 1.4.1995 till 2005-06 is 35.31 lakh ha.

Watershed Programmes in Tamilnadu by Tamil Nadu Watershed Development AgencyDistribution of Government Wasteland to Landless Agricultural Labourer Families

The Government has announced this massive scheme during 2006-07and is being implemented till date. After the land identified by the Revenue Department, wherever the land development is required it is undertaken by Agricultural Engineering Department. Out of 41,506 acre requiring land development, so far 39,673 acre have been developed. For irrigation and ground water recharge, the farm ponds are created of the size of 15 X 3X 1.5 cu,m, or 15X6X1.5 cu,m, at the rate of Rs.2,750/-, Rs.4,650/- per pond respectively. In total, 10,470 farm ponds have been completed by dovetailing various departmentsÊ ongoing programmes (www.tn.gov.in/policynotes).

Restructured National Watershed Development Project for Rainfed Areas (NWDPRA)

Under Restructured NWDPRA for XI Five Year Plan period (2007-2012), it is proposed to take up 500 watersheds in 22 districts, where the area has less than 30% assured means of irrigation in arable lands and having slopes less than 8%. The pattern of assistance is in the ratio of 90:10 for the Centre and State respectively.

The minimum area for a watershed is 500 Ha.

Objectives� Conservation, development and sustainable management of natural resources including their use.

� Enhancement of Agricultural productivity and production in a sustainable manner.

� Restoration of ecological balance in the degraded and fragile rain fed eco-systems by greening these areas through appropriate mix of trees and shrubs.

� Reduction in regional disparity between irrigated and rainfed areas.

� Creation of sustained employment opportunities for the rural community including the landless.

During the X Five Year Plan project, the scheme was implemented in Tamil Nadu with community approach in 755 watersheds in 155 blocks in 23 districts. During the XI Five Year Plan project, the scheme will be implemented in 22 districts excluding Coimbatore district which has been saturated and as there is no new watershed available for treatment. The scheme is implemented under the Chairmanship of the Collectors through District Watershed Development Agency at District level and through Watershed committees/Associations at Village level.

Watershed Development Fund assisted by NABARD

Watershed Development Fund in Tamil Nadu has been created to treat 100 watershed projects at a cost of Rs. 60 Crores with the assistance of National Bank for Agriculture and Rural Development (NABARD). The scheme has been in operation since 2004-05 and the duration of the scheme is six years.

Sl.No. Name of the State No. of Districts No. of Blocks Area in Sq. Kms.

1. Andhra Pradesh 1 16 19136

2. Gujarat 6 52 55424

3. Haryana 7 44 20542

4. Himachal Pradesh 2 3 35107

5. Jammu & Kashmir 2 12 96701

6. Karnataka 6 22 32295

7. Rajasthan 16 85 198744

Total 40 234 457949

(Source: www.rural.nic.in/drda.htm)

Table 2. States, districts and blocks covered under desert development programme (DDP)

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Objective of The Scheme1. To spread the message of participatory Watershed Development.

2. Involvement of Government, NGOs/Voluntary organization in implementation.

3. Constitution of Watershed Association & watershed committee to develop the watershed based on the local needs.

Total Period - 6 YearsAt present the programme is being implemented

in the following 20 Districts in the State. Cuddalore, Dharmapuri, Dindigul, Kancheepuram, Karur, Krishnagiri, Madurai, Namakkal, Perambalur, Pudukottai, Ramnad, Sivaganga, Theni, Thoothukudi, Tirunelveli, Tiruvallur, Tiruvannamalai, Vellore, Villupuram, Virudhunagar. Apart form the regular watersheds that are being approved by the State Steering Committee there are 5 PPID projects (Pilot Project for Integrated Development of Backward Blocks) in 5 Districts namely Ramnad, Dindigul, Thoothukudi, Trichy and Nagapattinam which is being completely funded by NABARD.

National Agricultural Development Programme -Rashtriya Krishi Vikas Yojana

The National Agricultural Development Programme has been launched to achieve 4% annual growth rate in agricultural sector. The objective of the scheme is to more participation of farmers in agriculture, reducing yield gap in key crops through focused interventions, maximize returns to the farmers and bringing quantifiable changes in the production and productivity of agriculture and allied sectors. The pattern of funding is 100% grant by the Government of India. Under the programme Agriculture, Animal Husbandry, Milk Production, Fisheries Development and Irrigation Development schemes are being implemented. During 2007-08, nine districts namely Coimbatore, Dharmapuri, Dindigul, Krishnagiri, Namakkal, Perambalur, Ramanathapuram, Salem and Villupuram have been identified as focused districts. The Tamil Nadu Watershed Development Agency is the Nodal Agency for the scheme being implemented by the departments of Agriculture, Horticulture, Agriculture Engineering, Public Works Department, Fisheries, Animal Husbandry, Dairy Development, Pubic Works Department, Tamil Nadu

Veterinary and Animal Sciences University and Tamil Nadu Agricultural University.

As a part of National Agricultural Development Programme

Drought Prone Areas ProgrammeThis programme has been in implementation in

parts of Tamil Nadu from 1972-73. Presently 80 notified blocks of 17 districts viz., Coimbatore, Dharmapuri, Dindigul, Karur, Krishnagiri, Namakkal, Perambalur, Pudukkottai, Ramanathapuram, Salem, Sivagangai, Tiruvannamalai, Thoothukudi, Tiruchirappalli, Tirunelveli, Vellore and Virudhunagar have been identified by the Government of India as drought prone areas and efforts are on to mitigate the adverse effects of drought conditions. A watershed project covers an area of 500 ha. The unit cost per hectare is Rs.6000/-. The Government of India and State Government share the expenditure for a watershed project in the ratio of 75:25. The duration of the project is five years.

Over the years, the objectives of the programme and the mode of implementation have undergone modifications from infrastructure creation and employment generation to rainwater harvesting and overall economic development through water-based activities. On the operational side, implementation has shifted from line departments to Village Panchayats wherein the user groups have identified the works and execute the works through Village Panchayats. Watershed approach with peoplesÊ participation is given importance to tackle the problems of desertification.

The works being taken up under this Drought Prone Areas Programme are of a special nature and involve a variety of activities such as:-

Plantation Activities: Horticulture Plantation, Fodder Development, Crop Demonstration, Community Nursery, Homestead Garden, Agro Forestry and Social Forestry.

Land Development: Land Leveling, Summer Ploughing, Vegetative Bunding, Contour Bunding, Stone Bunding, Retaining Wall, Continuous trenching and Silt Application.

Water Resources Development: Formation of Supply Channel and desilting, Check Dams, Cattle Pond, Farm Pond, Percolation Pond,Formation of Oorani, Desilting of Tanks, and Development of Drinking Water Resources.

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Integrated Waste Land Development Programme

Integrated Wasteland Development Programme aims at tackling the non-forest wasteland in non-DPAP blocks. The basic theme of the programme is to harvest the rainwater and to bring the degraded lands into productive use. At present, this programme is being implemented in 99 blocks of 24 districts viz., Coimbatore, Cuddalore, Dharmapuri, Dindigul, Erode, Kancheepuram, Karur, Krishnagiri, Madurai, Namakkal, Perambalur, Pudukkottai, Ramanathapuram, Salem, Sivagangai, Theni, Thoothukudi, Tiruchirappalli, Tirunelveli, Tiruvallur, Tiruvannamalai, Vellore, Villupuram and Virudhunagar. This programme has been under implementation since 1993-94. From 1st April 1995, the programme has also been brought under the purview of the Common Guidelines like Drought Prone Areas Programme. The unit cost per hectare is Rs.6000/-.The works taken up under this Integrated Waste Land Development Programme are of a special nature and involve a variety of activities such as:

Plantation Activities: Agro Forestry, Horticulture Plantation, Fodder Development, Crop Demonstration, Community Nursery, Social Forestry and Homestead Garden.

Land Development: Land Leveling, Contour Bunding, Silt Application, Stone Bunding, Retaining Wall, Summer Ploughing, Vegetative Bunding and Continuous trenching.

Water Resources Development: Cattle Pond, Farm Pond, Formation of Oorani, Desilting of Tanks, Formation of Supply Channel and Desilting, Check Dams, Percolation Pond and Development of Drinking Water Resources in the State. The total expenditure incurred under these projects stood at Rs.14,446.24 lakhs (89%). The total area that has been treated under these projects up to the end of February 2008 was 2,31,227 ha and the remaining 2,26,369 ha is under treatment.

ConclusionNumber of water harvesting measures/

structures are implemented on watershed basis through the different schemes sponsored by different government agencies to boost the water resources in dryland areas their by promoting overall economic development and improving the socio-economic conditions of the resource poor farmers in the areas.

Referenceswww.tn.gov.in/policynotes/pdf/agriculture/watershed_development.pdfwww.rural.nic.in/drda.htm

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Impact of Rainwater Harvesting On Water Budgeting and

Irrigation Potential at Orchard and Eastern Farm in Tnau

CampusM. Manikandan1 and Dr. M. V. Ranghaswami2

32

IntroductionWater is a natureÊs gift that is available through

rain, snowmelt and as groundwater. The quantity and quality of water available for human use is linked to the ecosystem, sustainable management of natural resources and giving priority of water uses between different sectors. Factors like deforestation, disruption of hydrological cycle, surface runoff, over extraction of groundwater, pollution of water sources, silting of lakes and tanks etc., contribute mainly to the scarcity of water. India is a monsoonic country. Rainfall is highly undependable and highly variable. Though our country is blessed with abundant land and water resources, acute water shortages are not uncommon due to failure in monsoons. Usually there is a surplus of water during the period of monsoon and deficit during the rest of the year. Thus, the need for the harvest of surplus water is evident.

Excessive deforestation has resulted in poor receipt of rainfall and unscrupulous pumping of groundwater has caused drastic depletion in underground aquifer reserves. Extensive urbanization

and industrialization have also contributed to increasing demand for non-agricultural usage of water. Agriculture has always remained a gamble with monsoon and the situation is further assuming precarious levels due to non-adherence of implementing water-harvesting strategies. Rainwater harvesting methods formerly developed for mere existence are now a days receiving recent renewed attention because they can contribute to increased water supplies for agriculture and domestic uses.

Irrigation in TNAU campus is mainly dependent on groundwater and rainfall. As it is feared that over exploitation of groundwater is being done, a water budgeting study is necessary to know the present situation of the study area. Indiscriminate use of groundwater may lead to serious situations and may cause excessive drawdown or mining of aquifers. When progress magnifies and adds new problems, efforts are put forth to solve these problems. This is especially true in respect of groundwater, where in studies have been undertaken in various parts of the world to know as to how much water is available and how much economically the same can be utilized. The present study aims to evaluate the water balance (water availability and usage)

167

and to assess the rainwater harvesting potential and the impact of rainwater harvesting on water budgeting and Irrigation requirements.

Materials and Methods

Location of Tnau CampusThe TNAU campus is located at latitude of 110

N and longitude of 770 E with an elevation of 426.72 m above mean sea level. It is situated 3 km away from Coimbatore city in the west direction. Coimbatore has a subtropical, semi-arid climate with hot summer. The mean annual rainfall is 696.21 mm distributed in 50 rainy days. The important soil series in the campus are Peelamedu, Palathurai and Periyanaickenpalayam series. The texture of the soil is found to be clay, clay loam and loam. Orchard and Eastern farm consists of clay soil.

Area of TNAU Campus The campus has an area of 323.88 ha used for

agricultural and non-agricultural purposes. The area of 174.61 ha under agricultural use is divided into seven zones such as Paddy Breeding Station, Wetland, Orchard, Eastern farm, Cotton Breeding Station, Millet Breeding Station and Botanical garden and 13 ha under non-agricultural areas that are used for office\departments, residential areas and hostels. For study purpose Orchard and Eastern Farm were taken and water budgeting was done for each zone. The cropping programme (2000-2001) for Orchard and Eastern Farm was obtained from respective farm manager and is given in Table 2.1. The

crops are cultivated in three seasons viz. I season (June-September), II season (October-January) and III Season (Feb-May).

Water Supply for Orchard and Eastern Farm

The rainfall is considered as the only source of water supply for water budgeting. Effective rainfall is used to calculate the total water supply. The volume of rainwater collected from agricultural area was found by multiplying the cultivable area by the effective rainfall.

Rainfall Data Weekly rainfall data was obtained from the

meteorological station of the university. Rainfall for standard week was worked out by weekly rainfall data for the recent 25 years (1978-2002). During I, II and III season total number of rainy days are 9, 20 and 21 respectively.

Effective RainfallEffective rainfall means useful or utilizable

rainfall. Not all the rainfall is effective and a part of it may be lost by surface runoff and deep percolation or evaporation. Effective rainfall can be determined by the evapotranspiration and precipitation ratio method given by USDA SCS (Dastane, 1977). The relationship between average weekly effective rainfall and mean weekly rainfall is shown for different values of average weekly crop evapotranspiration, which is given in Table 2.2. Using Thornthwaite formula, the weekly potential evapotranspiration (PET) was calculated. Then consumptive use (ET crop) was calculated by multiplying

Sl. No. Station Area (ha)

Total (ha) Cultiable Area I Season II Season III Season

1 Orchard

Banana 4.66 4.66 4.66

Vegetables 6.44 6.44 6.44

Coconut 2.03 2.03 2.03

Fruit Trees 6.04 6.04 6.04

Total (ha) 20.85 19.17 19.17 19.17 19.17

2 Eastern Farm

Oil Seeds 4.42 4.76 0

Maize 1.02 0.91 0

Vegetables 1.69 1.06 0.77

Millets, Cotton, Mulbery 10.39 17.91 7.72

Sugarcane, Coconut 2.83 2.83 2.83

Trees 6.66 6.66 6.66

Fodder, Pulses 5.86 6.22 3.79

Total (ha) 46.29 42.6 32.87 40.35 21.77

Table 2.1 Cropping Programme of TNAU Campus (2000-2001)

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PET by the average crop coefficient (Kc) of different crops. The standard weekly rainfall collected from meteorology department of TNAU was used to estimate the weekly effective rainfall using Table 2.2.

Utilization of GroundwaterThe present utilization of groundwater was

observed. Out of 51 wells in the campus, 38 wells are functioning including one open well in Wetland, 30 bore wells in agricultural areas and 7 bore wells in non agricultural area. Details regarding number of bore and open wells present in each area including its HP, depth (m) and pumping head (m) were collected and is given in Table 2.3. Based on the information obtained, total discharge of the pump and total water pumped from each area for each season were calculated. The discharge of the pump was calculated by using the following formula.

Q = 75 HP/ W H

Where, Q = Discharge lit per sec, HP = Horse power, W = Unit weight of water, H = Total pumping head (m), = Overall efficiency of the pump (0.6 assumed). The seasonal discharge was calculated considering pumping hours/day and number of pumping days. Number of pumping days per season was obtained by deducting the number of rainy days in a season from total number of days in a season. For five days of pumping per week and 17 weeks for I and III seasons and 18 weeks for II season were assumed.

Water Demand for Orchard and Eastern Farm

To workout the weekly irrigation water requirement of each agricultural crop, effective rainfall and crop evapotranspiration are the major parameters required. Irrigation water requirement (mm) was calculated by deducting the weekly effective rainfall from weekly

evapotranspiration of crop for each crop. Weekly total water demand for each crop (ha cm) is got by multiplying the water requirement (mm) for each crop by cropping area (ha).

Crop Evapotranspiration (ETC)The water requirement of each crop is calculated

to meet the crop evapotranspiration rate. There exists a close relationship between the rate of consumptive use by crops and the rate of evaporation (EP) from properly located pan evaporation meter. The equations given below are used to find out the crop evapotranspiration (Doorenbos et al, 1977)

Reference Evapotranspiration ETO = KP . EP

Where EP = Pan evaporation, KP = Pan coefficient

Crop Evapotranspiration ETc = KC . ETO

Where KC=Crop coefficient

Weekly pan evaporation was collected from the meteorological department of TNAU campus. Reference evapotranspiration (ETO) was worked out by multiplying the pan evaporation (EP) by pan coefficient (KP), which is taken as 0.85. The crop evapotranspiration (ETC) was calculated by multiplying reference evapotranspiration (ETO) by crop coefficient (KC). The different crop coefficient values are given in the Table 2.4.

Water Budgeting StudiesTo prepare the water budget of Orchard and

Eastern Farm of TNAU campus, the weekly demands and supplies are worked out. Water demand for Orchard and Eastern Farm involve irrigation requirement of

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Table 2.4. Crop Coefficient (KC) of different crops (Michael, 1999, Allen G.Richard et al,, Doorenbos et al, 1977).

S. No. Crops Kc S.No Crops Kc

1 Maize 0.86 8 Coconut 0.90

2 Sugarcane 0.90 9 Fruit Trees 0.52

3 Millets 0.70 10 Oil Seeds 0.63

4 Banana 0.98 11 Cotton 0.70

5 Fodder 0.75 12 Mulberry 0.85

6 Pulses 0.75 13 Trees 0.60

7 Vegetables 0.50

169

Roof Top Rain Water Harvesting and its Potential in

TNAU CampusM. Manikandan1 and Dr. M. V. Ranghaswami2

33

IntroductionLife on earth cannot be sustained without water,

whether of human beings, animals flora or fauna. Water is a natureÊs gift that is available through rain, snowmelt and as groundwater. The quantity and quality of water available for human use is linked to the ecosystem, sustainable management of natural resources and giving priority of water uses between different sectors. Factors like deforestation, disruption of hydrological cycle, surface runoff, over extraction of groundwater, pollution of water sources, silting of lakes and tanks etc., contribute mainly to the scarcity of water. Demand for fresh water is constantly increasing with the rapid increase in population and the development of industry and agriculture in the country.

Excessive deforestation has resulted in poor receipt of rainfall and unscrupulous pumping of groundwater has caused drastic depletion in underground aquifer reserves. Extensive urbanization and industrialization have also contributed to increasing demand for non-

agricultural usage of water. Agriculture has always remained a gamble with monsoon and the situation is further assuming precarious levels due to non-adherence of implementing water-harvesting strategies.

In semi-arid and arid region the surface water and ground water are scarce. Therefore, attempts are made in these regions to collect and preserve rainwater to the maximum possible extent. The concept of water harvesting is very much the need of the hour in order to narrow down the supply-demand gaps of water. The central idea behind any water harvesting strategy should be such that the excess water available during rainy period should be collected and stored for a compensate usage during non-rainy periods. That is the supply-demand gap during non-rainy season can be brought down by supplemental usage of harvested water.

Rainwater harvesting can be done both on a large scale such as watershed planning as well as on a smaller scale like roof top water harvesting from individual houses. While the large scale water harvesting helps

170

damming of water to sustain agriculture, roof top water harvesting helps to meet the local needs of community. It is often observed that rainwater draining down from rooftop surface is simply disposed off, through sewage network or stream network wastefully. This often leads to poor ground water recharge due to runoff(Myers, L. E. 1975). Rooftop surfaces offer greater scope for domestic storage of relatively pure water and in addition augmentation of groundwater tables in-situ. Urban

areas where a lot of housing colonies and commercial complexes are coming up, rainwater harvesting from roof top is the only feasible solution to develop water resources in order to meet the local needs of water with self sustainability(Fink, D.H., Ehrler W.L. 1978).

As it is feared that over exploitation of groundwater is being done, a water budgeting study is necessary to know the present situation of the study area. Indiscriminate use of groundwater may lead to serious situations and may cause excessive drawdowns or mining of aquifers. When progress magnifies and adds new problems, efforts are put forth to solve these problems. This is especially true in respect of groundwater, where in studies have been undertaken in various parts of the world to know as to how much water is available and how much economically the same can be utilized. With the above background the following objectives are undertaken. The present study aims to assess the rainwater harvesting potential through water budgeting (water availability and usage) method.

Materials and Methods

Area of TNAU CampusThe campus has an area of 323.88 ha used for

agricultural and non-agricultural purposes. The area of 174.61 ha under agricultural use is divided into seven zones such as Paddy Breeding Station, Wetland, Orchard, Eastern farm, Cotton Breeding Station, Millet Breeding Station and Botanical garden and 13 ha under non-agricultural areas that are used for office\departments, residential areas and hostels. The remaining area covers roads, playground, parking places and fallow lands etc for which water budgeting was not estimated.

Non Agricultural AreasWater budgeting study was conducted to know

rainwater harvesting potential for Office / Departments buildings and Residential areas in TNAU campus. The data regarding roof area, lawn area, number of persons working, number of labs in departments were collected under these groups and given in Table 2.1.

Office/ Departmental AreasThis includes various buildings like RI building,

Ramasamy Sivam building, Ramasamy Sivam PG block, Golden Jubilee building, Freeman building, Library, AEC & RI, Horticultural College and Basic Science building which have various departments and laboratories.

Residential AreasIt includes various quarters meant for teaching,

non-teaching staff, married scholars, south house and north house used for VIPs.

Water Supply for Office/Departmental and Residential Areas

Weekly rainfall data and evaporation was obtained from the meteorological station of the university. Rainfall for standard week was worked out by weekly rainfall data for the recent 25 years (1978-2002). During I, II and III season total number of rainy days are 9, 20 and 21 respectively. Effective rainfall can be determined by the evapotranspiration and precipitation ratio method given by USDA SCS (Dastane, 1977). At present for office/departments and residential areas water is supplied by groundwater pumping and municipal (Siruvani) water supply through estate office. The volume of rainwater that can be collected from the rooftops can be calculated by the following formula

Vr = Dr × A × C

Where,

Vr = Rainwater harvested from roof per week, lit

Dr = Depth of rainfall received during the standard week, mm

Sl. No. Areas Roof Area Lawn Area No of No of Labs (m2) (m2) Persons

1. Office/Departments 52442.75 30529 2207 87 2. Residential Areas 34695 1078 1258 -

Table 2.1. Abstract of Non Agricultural Areas

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A = Area of the roof surface, m2

C = Runoff coefficient.

The runoff coefficient ranges from 0.7 to 0.9 as given below for different roof surfaces. For example 0.7-Concrete, 0.75-Tiled, 0.8-Asbestos and 0.9-GI Sheet. However in this study, most of roof surfaces are RCC roofs. So the value 0.7 was taken for C (Michael, 1999).

Water Demand for Office/ Departmental and Residential Areas

The water demand for each buildings (office/department buildings and residential areas) was assessed by assuming the appropriate quantity of water for laboratory/lavatory needs in each department/office and for drinking, cooking, bathing, washing and sanitary purposes in residential places. During the observations, the average number of persons working in each office, number of persons in each house was obtained. The weekly drinking water demand was estimated by multiplying the water requirement for drinking per person per week and the number of persons present in the building. Similarly weekly water requirements for cooking, bathing, washing, sanitary and for other demands were also obtained. The assumed value of per capita water demand is 135 lit/day for residential areas and for drinking 5 lit/day, toilet 10 lit/day, lab use 300 lit/day for office/ department buildings. Water requirement for lawn was computed by multiplying the lawn area by the ET crop. By adding all the different demands, the total water demand has been worked out for individual buildings.

Water Budgeting of Office/ Departmental and Residential Areas

To find the water budgeting of Office/ Departmental and Residential Areas, the weekly demands and supplies of water were obtained for office/departments buildings and residential areas. The various components of water demands are drinking, cooking, bathing, washing, sanitary purpose and lawn irrigation. The supply consists of the runoff collected from rooftop of individual buildings.

Surplus/Deficit WaterThe period of surplus or deficit of water can be

worked out for Office/ Departmental and Residential areas by comparing the total supply and the total demands

i.e. total water requirement for any week. Surplus water if any, can be effectively stored by rainwater harvesting which includes roof water harvesting and used during the period of deficit.

Rain Water Harvesting PotentialTo calculate the rainwater harvesting potential

of the TNAU campus, the rainwater harvestable from Office/ Departmental and Residential areas was estimated. The amount of water harvested has to be effectively stored in the rainwater harvesting structures (RWHS). The capacity of rainwater harvesting systems was calculated from surplus water.

Results and DiscussionPreparing the water budget is similar to operating

the bank account with debits and credits. Here the credit part involves the total amount of water applied out of storage by way of irrigation and net contribution of rainfall. The debit side involves expending water by ET from crop canopy, runoff and deep percolation losses, and soil moisture storage changes. This water balance is an integral part of water budgeting over a specified period of time, which may be over a week/month, season or a full year. Supply demand analysis is the essence of water budgeting.

The water budgeting study was conducted to know the rainwater harvesting potential and water demand Office/ Departmental and Residential areas in TNAU campus by considering rainfall as the only source of supply of water. Observations have been made to assess the present utilization of ground water. The results pertaining to the above are presented in this chapter.

Pumping Water Supply for Office/Departmental Areas and Residential Areas

There are 5 wells located in the office/departmental areas and residential areas in TNAU campus (Table 3.1). Each well supplies water to office/departmental areas and residential areas. Well Number WL K, 72 supply water to the residential areas situated in the southern side of the campus. Wells located in the south house and near examination hall supply water to the office/departments. Well located near professor quarterÊs supplies water to all the quarters in the northern side of the campus. Apart from this, corporation water (Siruvani Water) is also supplied for all the areas.

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Water Budgeting for Office/Departmental Areas and Residential Areas

Weekly rainwater supply (ha cm) was calculated by multiplying the roof area with weekly rainfall and runoff coefficient (which is taken as 0.7). The weekly water demand for drinking, toilet, laboratory, lawn was calculated for each zone. Finally surplus and deficit was calculated by detecting the water demand from rainwater supply.

Water Budgeting and Rainwater Harvesting Potential of Office/Department Buildings

Table 3.2. gives the details of water budgeting calculation for office/department buildings in TNAU campus. The total rainwater supply was calculated by multiplying the total roof area 52442.75 m2 by rainfall and runoff coefficient (0.70). The water requirement for lawn was computed by multiplying the area 30529 m2 by the ET crop (ETC) (KC =0.65) (Doorenbos,J. and W.C.Pruitt.1975).

The departmental areas have 87 laboratories for which water demand was calculated by multiplying the number of labs with the daily demand (300 lit/day). The water demand for human beings was worked out by multiplying the total number of persons (2207 Nos.) working in office with their daily demand of 5 lit/day/person for drinking and 10 lit/day/person for toilet. The total water demand (ha cm) was calculated by adding the water requirement for lawn areas, water requirement for laboratory and human beings.

From the Table 3.2. The total annual water requirement was found to be 306.16 ha cm, while we can harvest 255.58 ha cm of rainwater. Hence the annual deficit was estimated to be 50.58 ha cm of water.

Since rainwater harvesting can be implemented, the total volume of water that can be stored during rainy season was worked out to be 146.29 ha cm.

Fig 3.1 shows the water budgeting of office/departmental buildings. Form the Figure, it can be noted that the water demand curve showed a trend well above the water supply curve up to 37th week and then declined until 47th week and gradually raised towards the last. The potential period for rainwater harvesting was found to exist from 37th week to 47th week.

Water Budgeting and Rainwater Harvesting Potential of Residential Buildings

Table 3.3 presents the weekly water budgeting calculation of residential areas. Total rainwater supply (ha cm) was calculated by multiplying the total roof area 34695 m2 by depth of rainfall and runoff coefficient (0.70). The total water demand (ha cm) was calculated by adding water requirement for lawn areas and water demand for human beings. The water requirement for lawn was computed by multiplying the area 1078 m2 by the ET crop (ETC). The water demand for human beings was worked out by multiplying number of persons (1258 Nos.) working in office with daily demand.

From the Table 3.3. The total annual water requirement was found to be 623.56 ha cm, while 169.08 ha cm of rainwater can be harvested. The water harvesting potential was less than water demand. The annual water deficit was found to be 454.56 ha cm of water. From the above table it can be seen that there was no surplus water for the entire year.

Fig 3.2 shows the water budgeting of residential areas. Form the Figure, it can be noted that the water demand curve showed a trend well above the water supply curve up to 52 week.

S. No. Area Field No Depth HP Head Discharge Working I II III (m) (m) (l/hr) hr/day season season season (ha cm) (ha cm) (ha cm)

1. Residential Areas WL K 45.05 20 25 129600 21 2993.76 2857.68 3129.84

72 45.05 15 23 105652 21 2440.57 2329.63 2551.50

Prof.Quarters 30.03 7.5 22 55227 8 486.00 463.91 508.09

2. Office Areas South House 66.07 5 32 25313 12 334.13 318.94 349.31

Near exam hall 30.03 7.5 23 52826 8 464.87 443.74 486.00

Table 3.1. Well Details in office/departmental areas and residential areas

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Table 3.2.Water Budgeting of Office/Department Buildings

Std Rainfall Water Supply ET Water Demand

Week RF EF RTWH Supply E P ETO ET IR of Drinking Toilet Lab Total Deficit Surplus (mm) (mm) (lit) (ha cm) (mm) (mm) lawn Lawn (ha cm) (mm) 1 4.77 3.68 175033 1.75 26.60 22.61 14.70 336323 55175 110350 130500 6.32 -4.57 0.00 2 0.57 0.44 20925 0.21 27.30 23.21 15.08 447044 55175 110350 130500 7.43 -7.22 0.00 3 4.87 3.76 178777 1.79 29.40 24.99 16.24 381109 55175 110350 130500 6.77 -4.98 0.00 4 0.00 0.00 0 0.00 32.20 27.37 17.79 543126 55175 110350 130500 8.39 -8.39 0.00 5 0.00 0.00 0 0.00 35.70 30.35 19.72 602162 55175 110350 130500 8.98 -8.98 0.00 6 1.25 1.14 45887 0.46 32.90 27.97 18.18 520130 55175 110350 130500 8.16 -7.70 0.00 7 3.72 3.41 136561 1.37 37.80 32.13 20.88 533479 55175 110350 130500 8.30 -6.93 0.00 8 4.82 4.45 176942 1.77 33.60 28.56 18.56 430886 55175 110350 130500 7.27 -5.50 0.00 9 3.84 3.57 140966 1.41 39.90 33.92 22.04 564016 55175 110350 130500 8.60 -7.19 0.00 10 7.97 7.97 292578 2.93 42.00 35.70 23.21 465109 55175 110350 130500 7.61 -4.69 0.00 11 4.40 4.40 161524 1.62 42.70 36.30 23.59 585905 55175 110350 130500 8.82 -7.20 0.00 12 1.30 1.30 47723 0.48 47.60 40.46 26.30 763194 55175 110350 130500 10.59 -10.11 0.00 13 3.97 3.97 145738 1.46 47.60 40.46 26.30 681682 55175 110350 130500 9.78 -8.32 0.00 14 7.00 7.00 256969 2.57 43.40 36.89 23.98 518337 55175 110350 130500 8.14 -5.57 0.00 15 16.46 16.46 604245 6.04 44.80 38.08 24.75 253146 55175 110350 130500 5.49 0.00 0.55 16 14.31 14.31 525319 5.25 44.10 37.49 24.37 306977 55175 110350 130500 6.03 -0.78 0.00 17 10.99 10.99 403442 4.03 46.20 39.27 25.53 443754 55175 110350 130500 7.40 -3.36 0.00 18 19.19 19.19 704463 7.04 42.00 35.70 23.21 122574 55175 110350 130500 4.19 0.00 2.86 19 11.33 11.33 415923 4.16 40.60 34.51 22.43 338918 55175 110350 130500 6.35 -2.19 0.00 20 12.49 12.49 458507 4.59 53.20 45.22 29.39 516032 55175 110350 130500 8.12 -3.54 0.00 21 7.67 7.67 281565 2.82 47.60 40.46 26.30 568725 55175 110350 130500 8.65 -5.83 0.00 22 8.05 8.05 295515 2.96 44.10 37.49 24.37 498088 55175 110350 130500 7.94 -4.99 0.00 23 7.04 6.94 258438 2.58 49.00 41.65 27.07 614625 55175 110350 130500 9.11 -6.52 0.00 24 8.84 8.67 324516 3.25 49.00 41.65 27.07 561810 55175 110350 130500 8.58 -5.33 0.00 25 7.74 7.61 284135 2.84 48.30 41.06 26.69 582364 55175 110350 130500 8.78 -5.94 0.00 26 9.67 9.44 354985 3.55 49.00 41.65 27.07 538303 55175 110350 130500 8.34 -4.79 0.00

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27 8.66 7.48 317908 3.18 42.70 36.30 23.59 491876 55175 110350 130500 7.88 -4.70 0.00 28 16.35 13.82 600207 6.00 42.00 35.70 23.21 286515 55175 110350 130500 5.83 0.00 0.18 29 7.44 6.43 273122 2.73 46.90 39.87 25.91 594774 55175 110350 130500 8.91 -6.18 0.00 30 9.34 8.07 342871 3.43 39.90 33.92 22.04 426635 55175 110350 130500 7.23 -3.80 0.00 31 6.90 5.97 253298 2.53 48.30 41.06 26.69 632431 55175 110350 130500 9.28 -6.75 0.00 32 7.00 6.20 256969 2.57 40.60 34.51 22.43 495531 55175 110350 130500 7.92 -5.35 0.00 33 8.59 7.59 315338 3.15 39.90 33.92 22.04 441289 55175 110350 130500 7.37 -4.22 0.00 34 10.19 8.19 374074 3.74 44.10 37.49 24.37 493814 55175 110350 130500 7.90 -4.16 0.00 35 9.39 8.29 344706 3.45 35.70 30.35 19.72 349076 55175 110350 130500 6.45 -3.00 0.00 36 6.02 5.92 220994 2.21 39.20 33.32 21.66 480465 55175 110350 130500 7.76 -5.55 0.00 37 14.84 13.93 544775 5.45 37.10 31.54 20.50 200507 55175 110350 130500 4.97 0.00 0.48 38 20.16 18.35 740072 7.40 38.50 32.73 21.27 89183 55175 110350 130500 3.85 0.00 3.55 39 27.24 24.12 999978 10.00 40.60 34.51 22.43 -51548 55175 110350 130500 2.44 0.00 7.56 40 29.84 23.31 1095424 10.95 32.90 27.97 18.18 -156698 55175 110350 130500 1.39 0.00 9.56 41 34.44 26.46 1264290 12.64 30.10 25.59 16.63 -300092 55175 110350 130500 -0.04 0.00 12.68 42 37.06 28.19 1360470 13.60 25.90 22.02 14.31 -423750 55175 110350 130500 -1.28 0.00 14.88 43 45.73 33.32 1678745 16.79 24.50 20.83 13.54 -603978 55175 110350 130500 -3.08 0.00 19.87 44 50.18 35.56 1842104 18.42 21.70 18.45 11.99 -719591 55175 110350 130500 -4.24 0.00 22.66 45 54.68 33.57 2007299 20.07 19.60 16.66 10.83 -694260 55175 110350 130500 -3.98 0.00 24.06 46 40.06 27.00 1470600 14.71 21.70 18.45 11.99 -458263 55175 110350 130500 -1.62 0.00 16.33 47 28.86 21.34 1059448 10.59 18.20 15.47 10.06 -344505 55175 110350 130500 -0.48 0.00 11.08 48 10.27 7.70 377011 3.77 23.80 20.23 13.15 166368 55175 110350 130500 4.62 -0.85 0.00 49 7.86 5.81 288540 2.89 24.50 20.83 13.54 235875 55175 110350 130500 5.32 -2.43 0.00 50 12.59 9.14 462178 4.62 27.30 23.21 15.08 181441 55175 110350 130500 4.77 -0.15 0.00 51 3.08 2.21 113067 1.13 25.20 21.42 13.92 357586 55175 110350 130500 6.54 -5.41 0.00 52 7.18 5.29 263577 2.64 29.40 24.99 16.24 334399 55175 110350 130500 6.30 -3.67 0.00 Total Supply (ha cm) 255.58 Total Demand (ha cm) 306.16

Roof Area (m2) = 52442.75 Annual Deficit (ha cm) 50.58

Lawn Area (m2) = 30529 Annual Surplus (ha cm) -

No of Persons = 2207 Surplus which can be stored (ha cm) 146.29

No of Labs = 87

175

Table 3.3. Water Budgeting of Residential Areas

Std Rainfall Water Supply ET Water Demand (Lit)

Week RF EF RTWH Supply E P ETO ET IR of Total Reqt Total Deficit/Surplus (mm) (mm) (lit) (ha cm) (mm) (mm) lawn Lawn (ha cm) (mm) 1 4.77 3.68 115798 1.16 26.60 22.61 14.70 11876 1188810 12.01 -10.85 2 0.57 0.44 13843 0.14 27.30 23.21 15.08 15785 1188810 12.05 -11.91 3 4.87 3.76 118275 1.18 29.40 24.99 16.24 13457 1188810 12.02 -10.84 4 0.00 0.00 0 0.00 32.20 27.37 17.79 19178 1188810 12.08 -12.08 5 0.00 0.00 0 0.00 35.70 30.35 19.72 21263 1188810 12.10 -12.10 6 1.25 1.14 30358 0.30 32.90 27.97 18.18 18366 1188810 12.07 -11.77 7 3.72 3.41 90346 0.90 37.80 32.13 20.88 18838 1188810 12.08 -11.17 8 4.82 4.45 117061 1.17 33.60 28.56 18.56 15215 1188810 12.04 -10.87 9 3.84 3.57 93260 0.93 39.90 33.92 22.04 19916 1188810 12.09 -11.15 10 7.97 7.97 193563 1.94 42.00 35.70 23.21 16423 1188810 12.05 -10.12 11 4.40 4.40 106861 1.07 42.70 36.30 23.59 20689 1188810 12.09 -11.03 12 1.30 1.30 31572 0.32 47.60 40.46 26.30 26949 1188810 12.16 -11.84 13 3.97 3.97 96417 0.96 47.60 40.46 26.30 24071 1188810 12.13 -11.16 14 7.00 7.00 170006 1.70 43.40 36.89 23.98 18303 1188810 12.07 -10.37 15 16.46 16.46 399756 4.00 44.80 38.08 24.75 8939 1188810 11.98 -7.98 16 14.31 14.31 347540 3.48 44.10 37.49 24.37 10840 1188810 12.00 -8.52 17 10.99 10.99 266909 2.67 46.20 39.27 25.53 15669 1188810 12.04 -9.38 18 19.19 19.19 466058 4.66 42.00 35.70 23.21 4328 1188810 11.93 -7.27 19 11.33 11.33 275166 2.75 40.60 34.51 22.43 11967 1188810 12.01 -9.26 20 12.49 12.49 303338 3.03 53.20 45.22 29.39 18221 1188810 12.07 -9.04 21 7.67 7.67 186277 1.86 47.60 40.46 26.30 20082 1188810 12.09 -10.23 22 8.05 8.05 195506 1.96 44.10 37.49 24.37 17588 1188810 12.06 -10.11 23 7.04 6.94 170977 1.71 49.00 41.65 27.07 21703 1188810 12.11 -10.40 24 8.84 8.67 214693 2.15 49.00 41.65 27.07 19838 1188810 12.09 -9.94 25 7.74 7.61 187978 1.88 48.30 41.06 26.69 20564 1188810 12.09 -10.21

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26 9.67 9.44 234850 2.35 49.00 41.65 27.07 19008 1188810 12.08 -9.73 27 8.66 7.48 210321 2.10 42.70 36.30 23.59 17368 1188810 12.06 -9.96 28 16.35 13.82 397084 3.97 42.00 35.70 23.21 10117 1188810 11.99 -8.02 29 7.44 6.43 180692 1.81 46.90 39.87 25.91 21002 1188810 12.10 -10.29 30 9.34 8.07 226836 2.27 39.90 33.92 22.04 15065 1188810 12.04 -9.77 31 6.90 5.97 167577 1.68 48.30 41.06 26.69 22332 1188810 12.11 -10.44 32 7.00 6.20 170006 1.70 40.60 34.51 22.43 17498 1188810 12.06 -10.36 33 8.59 7.59 208621 2.09 39.90 33.92 22.04 15582 1188810 12.04 -9.96 34 10.19 8.19 247479 2.47 44.10 37.49 24.37 17437 1188810 12.06 -9.59 35 9.39 8.29 228050 2.28 35.70 30.35 19.72 12326 1188810 12.01 -9.73 36 6.02 5.92 146205 1.46 39.20 33.32 21.66 16966 1188810 12.06 -10.60 37 14.84 13.93 360412 3.60 37.10 31.54 20.50 7080 1188810 11.96 -8.35 38 20.16 18.35 489616 4.90 38.50 32.73 21.27 3149 1188810 11.92 -7.02 39 27.24 24.12 661564 6.62 40.60 34.51 22.43 -1820 1188810 11.87 -5.25 40 29.84 23.31 724709 7.25 32.90 27.97 18.18 -5533 1188810 11.83 -4.59 41 34.44 26.46 836427 8.36 30.10 25.59 16.63 -10596 1188810 11.78 -3.42 42 37.06 28.19 900058 9.00 25.90 22.02 14.31 -14963 1188810 11.74 -2.74 43 45.73 33.32 1110622 11.11 24.50 20.83 13.54 -21327 1188810 11.67 -0.57 44 50.18 35.56 1218697 12.19 21.70 18.45 11.99 -25409 1188810 11.63 0.55 45 54.68 33.57 1327986 13.28 19.60 16.66 10.83 -24515 1188810 11.64 1.64 46 40.06 27.00 972917 9.73 21.70 18.45 11.99 -16182 1188810 11.73 -2.00 47 28.86 21.34 700908 7.01 18.20 15.47 10.06 -12165 1188810 11.77 -4.76 48 10.27 7.70 249422 2.49 23.80 20.23 13.15 5875 1188810 11.95 -9.45 49 7.86 5.81 190892 1.91 24.50 20.83 13.54 8329 1188810 11.97 -10.06 50 12.59 9.14 305767 3.06 27.30 23.21 15.08 6407 1188810 11.95 -8.89 51 3.08 2.21 74802 0.75 25.20 21.42 13.92 12627 1188810 12.01 -11.27 52 7.18 5.29 174377 1.74 29.40 24.99 16.24 11808 1188810 12.01 -10.26 Total Supply (ha cm) 169.08 Total Demand (ha cm) 623.56

Roof Area (m2) = 34695 Annual Deficit (ha cm) 454.47

Lawn Area (m2) = 1078 Annual Surplus (ha cm) -

No of Persons = 1258 Surplus which can be stored (ha cm) -

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Table 3.4 gives the details of seasonal water demand and rainwater harvesting potential in office/department buildings and residential areas. From the table, it was found the seasonal water demand was more than seasonal rainwater supply in the first and third season whereas in second season the demand was very less compared to rainwater supply in office/departmental areas. In residential areas all the three seasons water demand was more than the rain water supply (Fig 3.3.). The annual water demand was more than the annual water supply

ConclusionWater budgeting study for office/departmental

areas and residential areas was conducted to know the water harvesting potential. The water demand in each zones for meeting the various needs were calculated. The rainwater harvesting potential was got by multiplying the roof area by rainfall and runoff coefficient. By subtracting water demand from the rainwater harvesting potential, water surplus or deficit was found out. The surplus water during rainy season, which is estimated in water budgeting works, can be effectively stored in the RWHS.

Table 3.4. Seasonal RWHP and water demand

Sl.No Zones Season RWHP Demand Status (ha cm) (ha cm)

1 Office/Departmental Areas I Season 68.06 122.60

II Season 136.57 52.13

III Season 50.94 131.43

Total 255.58 306.16 Deficit

2 Residential Areas I Season 45.03 204.65

II Season 90.36 213.94

III Season 33.70 204.96

Total 169.08 623.56 Deficit

The water stored in RWHS can be used to irrigate lawn area and recharging the groundwater.

The water harvesting potential in non-agricultural areas which includes office/department and residential areas were estimated to be 255.58 and 169.08 ha cm respectively. However, the water demand in these areas were found to be 306.16 and 623.56 ha cm respectively in order to meet the supplemental irrigation for lawns, the domestic needs in residential areas and laboratory needs in the departments. The water demand in all these areas is more than rainwater supply. Hence, these areas are described as water deficit areas. The additional water needs to overcome these deficit has to be managed by external water supply and groundwater pumping. Temporary Surplus water from office/departmental areas which can be stored in rainwater harvesting structure during rainy season was estimated as 146.29 ha cm. The calculated quantity of water stored in RWHS can be used to irrigate lawn area and recharging the groundwater during next season. This study was an attempt to look into the potential of rainwater harvesting in TNAU campus and see how far it can be a solace to the over exploitation of ground water.

References1. Allen G.Richard,Luis S.Pereira,. Crop Evapotranspitration (guidelines for computing crop water requirements), FAO

Irrigation and Drainage Paper-56. pp: 109-114 Dastane.N.G. 1977. Effective rainfall in irrigated agriculture. FAO Irrigation and Drainage Paper-25. pp.16-18.

2. Doorenbos,J. and W.C.Pruitt.1975.Guidelines for predicting crop water requirements. Irrigation and Drainage paper- 24, FAO, Rome.

3. Fink, D.H., Ehrler W.L. 1978. Salvaging wasted waters for desert household gardening. Hydrology and water resources in Arizon and Southwest.

4. Micheal. A.M. 1999.Irrigation Theory and Practice. 5. Myers, L. E. 1975. Recent advances in water harvesting. Journal of Soil and Water Conservation. 5, pp. 95-97.

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179

Traditional Water Harvesting Systems in India

Neelakanth J.K.1, B. Maheswara Babu1, D. C. Sahoo1 and Tamilmani D2.

34

TankasTankas (small tank) are underground tanks,

found traditionally in most Bikaner houses. They are built in the main house or in the courtyard. They were circular holes made in the ground, lined with fine polished lime, in which raiwater was collected. Tankas were often beautifully decorated with tiles, which helped to keep the water cool. The water was used only for drinking. If in any year there was less than normal rainfall and the tankas did not get filled, water from nearby wells and tanks would be obtained to fill the household tankas. In this way, the people of Bikaner were able to meet their water requirements. The tanka system is also to be found in the pilgrim town of Dwarka where it has been in existence for centuries. It continues to be used in residential areas, temples, dharamshalas and hotels.

KhadinA khadin, also called a dhora, is an ingenious

construction designed to harvest surface runoff water for agriculture. Its main feature is a very long (100-300 m) earthen embankment built across the lower hill slopes lying below gravelly uplands. Sluices and spillways allow excess water to drain off. The khadin system is based on the principle of harvesting rainwater on farmland and subsequent use of this water-saturated land for crop production.

First designed by the Paliwal Brahmins of Jaisalmer, western Rajasthan in the 15th century, this system has great similarity with the irrigation methods of the people of Ur (present Iraq) around 4500 BC and later of the Nabateans in the Middle East. A similar system is

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also reported to have been practised 4,000 years ago in the Negev desert, and in southwestern Colorado 500 years ago.

Vav / Vavdi / Baoli / BavadiTraditional stepwells are called vav or vavadi in

Gujarat, or baolis or bavadis in Rajasthan and northern India. Built by the nobility usually for strategic and/or philanthropical reasons, they were secular structures from which everyone could draw water. Most of them are defunct today. The construction of stepwells date from four periods: Pre-Solanki period (8th to 11th century CE); Solanki period (11th to 12th century CE); Vaghela period (mid-13th to end-14th century CE); and the Sultanate period (mid-13th to end-15th century CE). Sculptures and inscriptions in stepwells demonstrate their importance to the traditional social and cultural lives of people.

Stepwell locations often suggested the way in which they would be used. When a stepwell was located within or at the edge of a village, it was mainly used for utilitarian purposes and as a cool place for social gatherings. When stepwells were located outside the village, on trade routes, they were often frequented as resting places. Many important stepwells are located on the major military and trade routes from Patan in the north to the sea coast of Saurashtra. When stepwells were used exclusively for irrigation, a sluice was constructed at the rim to receive the lifted water and lead it to a trough or pond, from where it ran through a drainage system and was channelled into the fields. A major reason for the breakdown of this traditional system is the pressure of centralization and agricultural intensification.

Ahar Pynes This traditional floodwater harvesting system is

indigenous to south Bihar. In south Bihar, the terrain has a marked slope · 1 m per km · from south to north. The soil here is sandy and does not retain water. Groundwater levels are low. Rivers in this region swell only during the monsoon, but the water is swiftly carried away or percolates down into the sand. All these factors make floodwater harvesting the best option here, to which this system is admirably suited.

An ahar is a catchment basin embanked on three sides, the ÂfourthÊ side being the natural gradient of the land itself. Ahar beds were also used to grow a rabi (winter) crop after draining out the excess water that remained after kharif (summer) cultivation.

Pynes are articifial channels constructed to utilise river water in agricultural fields. Starting out from the river, pynes meander through fields to end up in an ahar. Most pynes flow within 10 km of a river and their length is not more than 20 km.

The ahar-pyne system received a death-blow under the nineteenth-century British colonial regime. The post-independent state was hardly better. In 1949, a Flood Advisory Committee investigating continuous floods in BiharÊs Gaya district came to the conclusion that „the fundamental reason for recurrence of floods was the destruction of the old irrigational system in the district.

Paar systemPaar is a common water harvesting practice in

the western Rajasthan region. It is a common place where the rainwater flows from the agar (catchment) and in the process percolates into the sandy soil. In order to access the rajani pani (percolated water) kuis or beris are dug in the agor (storage area). Kuis or beris are normally 5 metres (m) to 12 m deep. The structure was constructed through traditional masonary technology. Normally six to ten of them are constructed in a paar. However depending on the size of the paar the numbers of kuis or beris are decided. Bhatti mentions that there are paars in Jaisalmer district where there are more than 20 kuis are in operation. This is the most predominant form of rainwater harvesting in the region. Rainwater harvested through PAAR technique is known as Patali paani.

Talab / BandhisTalabs are reservoirs. They may be natural,

such as the ponds (pokhariyan) at Tikamgarh in the Bundelkhand region. They can be human-made, such the lakes in Udaipur. A reservoir area of less than five bighas is called a talai; a medium sized lake is called a bandhi or talab; bigger lakes are called sagar or samand. The pokhariyan serve irrigation and drinking purposes. When the water in these reserviors dries up just a few days after the monsoon, the pond beds are cultivated with rice.

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Saza KuvaAn open well with multiple owners (saza =

partner), saza kuva is the most important source of irrigation in the Aravalli hills in Mewar, eastern Rajasthan. The soil dug out to make the well pit is used to construct a huge circular foundation or an elevated platform sloping away from the well. The first is built to accomodate the rehat, a traditional water lifting device; the sloping platform is for the chada, in which buffaloes are used to lift water. Saza kuva construction is generally taken up by a group of farmers with adjacent landholdings; a harva, a man with special skills in groundwater detection, helps fix the site.

JohadJohads are small earthen check dams that

capture and conserve rainwater, improving percolation and groundwater recharge. Starting 1984, the last sixteen years have seen the revival of some 3000 johads spread across more than 650 villages in Alwar district, Rajasthan. This has resulted in a general rise of the groundwater level by almost 6 metres and a 33 percent increase in the forest cover in the area. Five rivers that used to go dry immediately following the monsoon have now become perennial, such as the River Arvari, has come alive.

PatBhitada village , Jhabua district of Madhya

pradesh developed the unique pat system. This system was devised according to the peculiarities of the terrain to divert water from swift-flowing hill streams into irrigation channels called pats.

The diversion bunds across the stream are made by piling up stones and then lining them with teak leaves and mud to make them leak proof. The pat channel has to negotiate small nullahs that join the stream off and on and also sheer cliffs before reaching the fields. These sections invariably get washed away during the monsoons. Stone aqueducts have to be built to span the intervening nullahs.

The villagers irrigate their fields by turns. The channel requires constant maintenance and it is the duty of the family irrigating the fields on a particular day to take care of the pat on that particular day. It takes about two weeks to get the pat flowing and the winter crop is sown in early November.

Rapat: A rapat is a percolation tank, with a bund to impound rainwater flowing through a watershed and a waste weir to dispose of the surplus flow. If the height of the structure is small, the bund may be built of masonry, otherwise earth is used. Rajasthan rapats, being small, are all masonry structures. Rapats and percolation tanks do not directly irrigate land, but recharges well within a distance of 3-5 km downstream. Silting is a serious problem with small rapats and the estimated life of a rapat varies from 5 to 20 years.

FIG: SAZA KUVA

FIG : JOHAD

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Naada / BandhaNaada / bandha are found in the Mewar region

of the Thar desert. It is a stone check dam, constructed across a stream or gully, to capture monsoon runoff on a stretch of land. Submerged in water, the land becomes fertile as silt deposits on it and the soil retains substantial amounts of water.

Chandela TankThese tanks were constructed by stopping the

flow of water in rivulets flowing between hills by erecting massive earthen embankments, having width of 60m or more. These hills with long stretches of quartz reefs running underneath them, acted as natural ground water barrier helping to trap water between the ridges. The earthen embankments were supported on both sides with walls of coarse stones, forming a series of stone steps. These tanks are made up of lime and mortar and this is the reason why these tanks survived even after thousand years but the only problem, which these tanks are facing, is siltation of tank beds. Chandela tanks usually had a convex curvature somewhere in the middle of the embankment; many older and smaller tanks were

constructed near the human settlement or near the slopes of a cluster of hills. These tanks served to satisfy the drinking water needs of villagers and cattle.

Kunds / KundisA kund or kundi looks like an upturned cup

nestling in a saucer. These structures harvest rainwater for drinking, and dot the sandier tracts of the Thar Desert in western Rajasthan and some areas in Gujarat. Essentially a circular underground well, kunds have a saucer-shaped catchment area that gently slopes towards the centre where the well is situated. A wire mesh across water-inlets prevents debris from falling into the well-pit. The sides of the well-pit are covered with (disinfectant) lime and ash. Most pits have a dome-shaped cover, or at least a lid, to protect the water. If need be, water can be drawn out with a bucket. The depth and diameter of kunds depend on their use (drinking, or domestic water requirements). They can be owned by only those with money to invest and land to construct it. Thus for the poor, large public kunds have to be built.

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Kuis / BerisFound in western Rajasthan, these are 10-12 m

deep pits dug near tanks to collect the seepage. Kuis can also be used to harvest rainwater in areas with meager rainfall. The mouth of the pit is usually made very narrow. This prevents the collected water from evaporating. The pit gets wider as it burrows under the ground, so that water can seep in into a large surface area. The openings of these entirely kuchcha (earthen) structures are generally covered with planks of wood, or put under lock and key. The water is used sparingly, as a last resource in crisis Magga Ram Suthar, of village Pithla in Jaisalmer district in Rajasthan, is an engineer skilled in making kuis/beris.

Baoris/BersBaoris or bers are community wells, found in

Rajasthan, that are used mainly for drinking. Most of them are very old and were built by banjaras (mobile trading communities) for their drinking water needs. They can hold water for a long time because of almost negligible water evaporation.

JhalarasJhalaras were human-made tanks, found in

Rajasthan and Gujarat, essentially meant for community use and for religious rites. Often rectangular in design, jhalaras have steps on three or four sides. Jhalars are ground water bodies which are built to ensure easy & regular supply of water to the surrounding areas. The jhalars are rectangular in shape with steps on three or even on all the four sides of the tank the steps are built on a series of levels .The jhalaras collect subterranean seepage of a talab or a lake located upstream . The water from these jhalaras was not used for drinking but for only community bathing and religious rites. Jhodhpur city has eight jhalaras two of which are inside the town & six are found outside the city .The oldest jhalara is the mahamandir jhalara which dates back to 1660 AD.

NadisNadis are village ponds, found near Jodhpur

in Rajasthan. They are used for storing water from an adjoining natural catchment during the rainy season. The site was selected by the villagers based on an available natural catchments and its water yield potential. Water availability from nadi would range from two months to a year after the rains. They are dune areas range from 1.5

to 4.0 meters and those in sandy plains varied from 3 to 12 meters. The location of the nadi had a strong bearing on its storage capacity due to the related catchment and runoff characteristics.

TankasTankas (small tank) are underground tanks, found

traditionally in most Bikaner houses. They are built in the main house or in the courtyard. They were circular holes made in the ground, lined with fine polished lime, in which rainwater was collected. Tankas were often beautifully decorated with tiles, which helped to keep the water cool. The water was used only for drinking. If in any year there was less than normal rainfall and the tankas did not get filled, water from nearby wells and tanks would be obtained to fill the household tankas. In this way, the people of Bikaner were able to meet their water requirements. The tanka system is also to be found in the pilgrim town of Dwarka where it has been in existence for centuries. It continues to be used in residential areas, temples, dharamshalas and hotels.

CheruvuCheruvu are found in Chitoor and Cuddapah

districts in Andhra Pradesh. They are reservoirs to store runoff. Cheruvu embankments are fitted with thoomu (sluices), alugu or marva or kalju (flood weir) and kalava (canal).

BhandarasThese are check dams or diversion weirs built

across rivers. A traditional system found in Maharashtra, their presence raises the water level of the rivers so that it begins to flow into channels. They are also used to impound water and form a large reservoir. Where a bandhara was built across a small stream, the water supply would usually last for a few months after the rains. They are built either by villagers or by private persons who received rent-free land in return for their public act Most Bandharas are defunct today.

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KereTanks, called kere in Kannada, were the

predominant traditional method of irrigation in the Central Karnataka Plateau, and were fed either by channels branching off from anicuts (check dams) built across streams, or by streams in valleys. The outflow of one tank supplied the next all the way down the course of the stream; the tanks were built in a series, usually situated a few kilometers apart. This ensured a) no wastage through overflow, and b) the seepage of a tank higher up in the series would be collected in the next lower one.

The Ramtek model has been named after water harvesting structures in the town of Ramtek, Maharashtra. A scientific analysis revealed an intricate network of groundwater and surface waterbodies, intrinsically connected through surface and underground canals. A fully evolved system, this model harvested runoff through tanks, supported by high yielding wells and structures like baories, kundis, and waterholes. This system, intelligently designed to utlise every raindrop falling in the watershed area is disintegrating due to neglect and ignorance. Constructed and maintained mostly by malguzars (landowners), these tanks form a chain, extending from the foothills to the plains, conserving about 60-70 per cent of the total runoff. Once tanks located in the upper reaches close to the hills were filled to capacity, the water flowed down to fill successive tanks, generally through

interconnecting channels. This sequential arrangement generally ended in a small waterhole to store whatever water remained unstored. The presence of the Ramtek ridge in the middle, having a steep slope on both sides, results in quick runoffs and little percolation. This might have led the residents of the southern plains of the Ramtek hills to construct different types of water conservation structures where they could trap the maximum.

ZaboThe zabo (the word means Âimpounding run-offÊ)

system is practiced in Nagaland in north-eastern India. Also known as the ruza system, it combines water conservation with forestry, agriculture and animal care.

Villages such as Kikruma, where zabos are found even today, are located on a high ridge. Though drinking water is a major problem, the area receives high rainfall. The rain falls on a patch of protected forest on the hilltop; as the water runs off along the slope, it passes through various terraces. The water is collected in pond-like structures in the middle terraces; below are cattle yards, and towards the foot of the hill are paddy fields, where the run-off ultimately meanders into.

Eri

Approximately one-third of the irrigated area of Tamil Nadu is watered by eris (tanks). Eris have played several important roles in maintaining ecological harmony as flood-control systems, preventing soil erosion and wastage of runoff during periods of heavy rainfall, and recharging the groundwater in the surrounding areas. The presence of eris provided an appropriate micro-climate for the local areas. Without eris, paddy cultivation would have been impossible. Till the British arrived, local communities maintained eris. Historical data from Chengalpattu district, for instance, indicates that in the 18th century about 4-5 per cent of the gross produce of each village was allocated to maintain eris and other irrigation structures. Assignments of revenue-

185

free lands, called manyams, were made to support village functionaries who undertook to maintain and manage eris. These allocations ensured eri upkeep through regular desilting and maintenance of sluices, inlets and irrigation channels.

The early British rule saw disastrous experiments with the land tenure system in quest for larger land revenues. The enormous expropriation of village resources by the state led to the disintegration of the traditional society, its economy and polity. Allocations for maintenance of eris could no longer be supported by the village communities, and these extraordinary water harvesting systems began to decline.

VirdasVirdas are shallow wells dug in low depressions

called jheels (tanks). They are found all over the Banni grasslands, a part of the Great Rann of Kutch in Gujarat. They are systems built by the nomadic Maldharis, who used to roam these grasslands. Now settled, they persist in using virdas. These structures harvest rainwater. The topography of the area is undulating, with depressions on the ground. By studying the flow of water during the monsoon, the Maldharis identify these depressions and make their virdas there. Essentially, the structures use a technology that helps the Maldharis separate potable freshwater from unpotable salt water. After rainwater infiltrates the soil, it gets stored at a level above the salty groundwater because of the difference in their density. A structure is built to reach down (about 1 m) to this upper layer of accumulated rainwater. Between these two layers of sweet and saline water, there exists a zone of brackish water. As freshwater is removed, the brackish water moves upwards, and accumulates towards the bottom of the virda.

Katas / Mundas / BandhasThe katas, mundas and bandhas were the

main irrigation sources in the ancient tribal kingdom of the Gonds (now in Orissa and Madhya Pradesh). Most of these katas were built by the village headmen known as gountias, who in turn, received the land from the Gond kings. Land here is classified into four groups on the basis of its topography: aat, (highland); mal (sloped land); berna (medium land); and bahal (low land). This classification helps to select A kata is constructed north to south, or east to west, of a village. A strong earthen embankment, curved at either end, is built across a drainage line to hold up an irregularly-shaped sheet of water. The undulations of the country usually determine its shape as that of a long isosceles triangle, of which the dam forms the base. It commands a valley, the bottom of which is the bahal land and the sides are the mal terrace. As a rule, there is a cut high up on the slope near one end of the embankment from where water is led either by a small channel or tal, or from field to field along terraces, going lower down to the fields. In years of normal rainfall, irrigation was not needed because of moisture from percolation and, in that case, the surplus flow was passed into a nullah. In years of scanty rainfall, the centre of the tank was sometimes cut so that the lowest land could be irrigated.714 BC, this technology had spread to Egypt, Persia (now Iran) and India. The initial cost of digging a surangam (Rs 100-150 per 0.72 m dug) is the only expenditure needed, as it hardly requires any maintenance. Traditionally, a surangam was excavated at a very slow pace and was completed over generations. Today, engineers such as Kunnikannan Nair are faster and keep the tradition alive.

ConclusionTraditional water harvesting systems in India

followed by our forefathers was Scientific and technically feasible and used for drinking, irrigation, culture and temples so that the holy water worshipped as „Gaga‰ as still now in Gangetic plains of Northern parts of India. A material, used for construction of traditional water harvesting systems was lime mortar, stones and other indigenous materials and technology applied was also indigenous. Traditional water harvesting systems was the importance in basic several needs as of the essential commodities such as Irrigations, Drinking purposes, worshiping of Gods etc

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References1. http.//www.cse.rainwaterharvesting.com/crisis2. http.//www.cse.rainwaterharvesting.com/conflicts3. http.//www.cse.rainwaterharvesting.com/solutions4. 1.http.//www.cse.rainwaterharvesting.com/people/policy5. 1.http.//www.cse.rainwaterharvesting.com/urban

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Effect of Fertigation on Biochemical, Yield and

Economics of Paprika (Capsicum annuum var.longum)

T. Prabhu, G. Balakrishnamoorthi and S. Santhana Bosu

35

IntroductionPaprika is the Hungarian word for plants in

the genus Capsicum, belongs to family solanaceae has its origin from Western Hemisphere of the world. International spice traders use the term paprika for non pungent, red capsicum powder. The word paprika derived from the Greek or Latin „Peperi-piper‰ meaning pepper. Capsicum in a fresh state is very rich in vitamin C (ascorbic acid), as was shown by Szent Gyorgyi, the Hungarian scientist, who was awarded the Noble prize in 1937 for isolating Vitamin C from paprika fruits (Anu and Peter, 2000). Paprika is the ground product from the mild or sweet varieties of capsicum, where as red chilli peppers are blends of different varieties of more pungent pepper. Though the fertigation techniques were standardized for major vegetable crops during the last two decades, no report of research work is available on fertigation of paprika as pure crop under open condition and as inter crop under thirty years old coconut tree shade. Therefore keeping this in view the immediate need for standardization of fertigation techniques, trials were taken up under open and coconut shade conditions with the following objectives: To optimize the fertilizer

requirement through fertigation and to study the effect of fertigation on biochemical, yield and economic of paprika.

Materials and MethodsThe present investigation on „Standardization

of fertigation techniques in paprika under open and coconut shade conditions‰ was carried out at the University Orchard and Coconut Farm, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore during the period from 2004 to 2006. The experiment was laid out in FRBD design with 11 treatments replicated thrice. A plot size of 7 x 4.5 m was followed for each treatment. The two separate field experiments were conducted under open and coconut shade conditions.

Treatment details

T1 - Drip fertigation with water soluble fertilizer at

120 % RDF

T2 - Drip fertigation with water soluble fertilizer at

100 % RDF

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T3 - Drip fertigation with water soluble fertilizer at

80 % RDF

T4 - Drip fertigation with water soluble fertilizer at

60 % RDF

T5 - Drip fertigation with water soluble fertilizer at

120 % RDF + micronutrients as foliar spray

T6 - Drip fertigation with water soluble fertilizer at

100 % RDF + micronutrients as foliar spray

T7 - Drip fertigation with water soluble fertilizer at

80 % RDF + micronutrients as foliar spray

T8 - Drip fertigation with water soluble fertilizer at

60 % RDF + micronutrients as foliar spray

T9 - *Drip fertigation with normal fertilizer (N, K) at

100% RDF

T10

- Drip irrigation plus soil application of normal fertilizer at 100% RDF

T11

- Recommended normal fertilizer applied to soil with furrow irrigation

* Ortho phosphoric acid was given for P nutrition source in T

9

Results and Discussion

Iaa OxidaseThe data on IAA oxidase activity are presented

in Table 1.

The treatment T11

(NPK applied to soil with furrow irrigation) registered the highest activity of 21.06 and 20.08 mg g-1hr-1 at harvesting stage during season I and II respectively. Considering the treatments and stage of growth, the treatment showed T

11 (NPK applied to

soil with furrow irrigation) registered highest activity of 19.69 and 18.79 mg g-1 hr-1 under open condition at harvesting stage during season I and II respectively. Indole Acetic Acid (IAA), a primer bioregulator regulates the apical dominance and initiation of vegetative and flower buds. The aminoacid tryptophan and zinc levels in the leaves influence the IAA. Fertigation treatment of 100 per cent water soluble fertilizer plus micronutrients showed its profound effect on suppressing the oxidation of auxin as observed in the present study. It was also revealed that high yielding plants have favourable auxin balance through IAA oxidative degradation. In plants with lesser levels of available nutrients, IAA synthesis would have been insufficient for suppressing IAA oxidative metabolism (Janwal et al., 1996).

Nitrate Reductase ActivityThe nitrate reductase activity, showed an

increasing trend during growth period and the data (Table 2) recorded at vegetative, flowering and harvesting stages revealed significant differences than control. Open condition (7.17 and 7.38 mg NO

2 g-1 h-1) showed higher

nitrate reductase activity at harvesting stage during seasons I and II respectively. Among the fertigation treatments, 100 per cent water soluble fertilizer plus micronutrients (T

6) showed the highest (8.62 and 8.91

mg NO2

g-1 h-1) nitrate activity during seasons I and season II respectively. Considering the treatments and stage of growth, the treatment effects showed that T

6

(100 per cent water soluble fertilizer with micronutrients) under open condition performed the best with 8.71 and 8.92 mg NO

2/g/h at harvesting stage during seasons

I and II respectively. Nitrate Reductase activity occurs in cytoplasm and catalyses the conversion of nitrate to ammonia in a two-step manner viz., nitrate to nitrite and then to ammonia, involving enzyme and further utilization of nitrogen for metabolism and physiology of plants. The nitrate redutase activity as a control point in nitrogen metabolism has been considered due to its importance in yielding ability. In the present investigation application of 100 per cent water soluble fertilizer plus micronutrients has improved the enzyme activity at all stages of crop growth under open. The nitrate reductase would have favourably influenced the protein synthesis leading to improved productivity. Similar trend of results have been documented by Sachdev et al. (1987). Utilization of N depends upon this enzyme and high activity was related to yield and protein content of many crops (Mishra et al., 1980).

Yield per hectareThe effect of fertigation on yield per hectare of

paprika under open and coconut shade condition are presented in the Table 3 and Fig. 1. Application of 100 per cent water soluble fertilizer in combination with micronutrients (T

6) recorded the highest yield per hectare

of 16.77 and 17.44 t ha-1 at harvesting stage during summer and kharif season respectively. The lowest yield per hectare was registered in the treatment applied with recommended NPK applied to soil with furrow irrigation (T

11) with values of 10.89 and 11.64 t ha-1 during summer

and kharif season respectively at harvesting stage. Drip fertigation with 100 per cent water soluble fertilizer plus micronutrients had produced higher fruit yield in both the seasons which might be due to application of optimum

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level of fertigation which could increase the drymatter at harvest, ultimately contributing to the higher number of fruits per plant and single fruit weight. Another possible reason was the timely availability of nutrients during

the flowering which favourably increases the number of flowers per plant. Felipe and Casanova (2000) in tomato and Walid et al. (1999) in bell pepper also noted the similar response for fertigation in the crops indicated

References1. Anu, A. and K.V. Peter. 2000. The chemistry of paprika. Capsicum and Egg Plant Newsl., 19: 19-22.2. Felipe, E.F. and O.E. Casanova. 2000. Nitrogen, phosphorus and potassium fertilization in tomato (Lycopersicon

esculentum Mill.) in the alluvial bank soils of the Guarico river. Revista Unillez de Ciencia y Technologia, 17: 21-44.

3. Janwal, R.S., Parveen Kumar and Jagmohan Kumar. 1996. Correlation and path coefficient studies in cabbage (Brassica oleracea var. Capitata L.). South Ind. Hort., 44: 19-22.

4. Mishra, S.P., S.K. Sinha and N.G.P. Rao. 1980. Genetic analysis of nitrate reductase in relation to yield in heterosis sorghum. Z. Pflanzenzenbta, 85: 16-18.

5. Sachdev, P., D.L. Debe and D.K. Rastogi. 1987. Effect of varying levels of zinc and molybdenum on plant constituents and enzyme activity at different growth stages of wheat. J. Nuclear Agric. and Bio., 16(4): 187-196.

6. Syherri, C.L.M., C. Pinzino and Izzo. 1993. Chemical changes and superoxide production in thylakoid membrane under water stress. Physiol. Plant., 87: 211-216.

7. Walid, Q., M.J. Mohammad, Husam Najim and R. Qubursi. 1999. Response of bell pepper grown inside plastic houses to nitrogen fertigation. Commn. Soil Sci. and Plant Anal., 30(17/18): 2499-2509.

���

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Table 1. Effect of fertigation on IAA oxidase activity (μg g-1 h-1) at different growth stages in paprikaunder open and coconut shade conditions

IAA oxidase activity (mg g-1 h-1)

Treat- Season I Season II

ments

Vegetative Flowering Harvesting Vegetative Flowering Harvesting Stage Stage Stage Stage Stage Stage Open Shade Mean Open Shade Mean Open Shade Mean Open Shade Mean Open Shade Mean Open Shade Mean T

1 14.58 10.79 12.68 17.58 13.79 15.69 20.78 18.21 19.50 13.77 10.37 12.07 16.75 12.79 14.77 19.25 16.79 18.02

T2

15.03 11.23 13.13 17.80 14.30 16.05 21.00 18.49 19.75 14.17 10.45 12.31 16.72 13.21 14.96 19.77 17.12 18.44

T3

15.32 11.45 13.39 18.16 14.56 16.36 21.21 18.75 19.98 14.32 10.66 12.49 17.26 13.46 15.36 20.31 17.48 18.90

T4 15.75 11.78 13.76 18.48 14.75 16.61 21.44 18.94 20.19 14.63 10.89 12.76 18.38 13.76 16.07 20.62 17.75 19.18

T5 13.12 10.17 11.65 16.37 12.98 14.68 19.46 17.16 18.31 12.13 9.22 10.67 15.43 12.12 13.78 18.16 16.21 17.19

T6 13.50 10.10 11.80 16.80 12.59 14.69 19.92 16.65 18.29 12.43 9.01 10.72 15.25 12.02 13.64 18.17 16.09 17.13

T7 13.86 10.39 12.12 17.04 13.22 15.13 20.14 17.45 18.80 12.76 9.42 11.09 16.03 12.32 14.18 19.13 16.32 17.73

T8 14.21 10.55 12.38 17.27 13.45 15.36 20.46 17.79 19.12 13.17 9.70 11.44 16.24 12.45 14.35 19.38 16.61 18.00

T9 16.33 12.19 14.26 18.80 15.18 16.99 21.79 19.25 20.52 15.15 11.12 13.13 17.69 14.17 15.93 20.69 18.32 19.51

T10

16.64 12.43 14.54 19.13 15.46 17.30 22.14 19.45 20.80 15.43 11.39 13.41 18.12 14.45 16.29 21.13 18.45 19.79

T11

16.87 12.79 14.83 19.55 15.89 17.72 22.43 19.69 21.06 15.77 11.69 13.73 18.49 14.69 16.59 21.37 18.79 20.08

Mean 15.02 11.26 13.14 17.91 14.20 13.14 20.98 18.39 19.69 13.98 10.36 19.68 16.94 13.22 15.08 19.84 17.27 18.55

C T C × T C T C × T C T C × T C T C × T C T C × T C T C × T

SEd 0.0171 0.0400 0.0566 0.0167 0.0391 0.0553 0.0124 0.0292 0.0413 0.0165 0.0386 0.0547 0.0166 0.0389 0.0550 0.0127 0.0297 0.0421

CD 0.05) 0.0344 0.0807 0.1142 0.0337 0.0790 0.1117 0.0251 0.0589 0.0833 0.0333 0.0780 0.1103 0.0335 0.0785 0.1110 0.0256 0.0600 0.0849

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Table 2. Effect of fertigation on nitrate reductase activity (NO2 g-1 h-1) at different growth stages in

paprika under open and coconut shade conditions

Nitrate reductase activity (NO2 g-1 h-1)

Treat- Season I Season II

ments

Vegetative Flowering Harvesting Vegetative Flowering Harvesting Stage Stage Stage Stage Stage Stage Open Shade Mean Open Shade Mean Open Shade Mean Open Shade Mean Open Shade Mean Open Shade Mean T

1 6.15 6.13 6.14 9.39 9.37 9.38 8.19 8.13 8.16 6.69 6.65 6.67 9.56 9.51 9.53 8.28 8.21 8.25

T2

6.21 6.18 6.20 9.47 9.42 9.45 8.25 8.17 8.21 6.76 6.71 6.73 9.61 9.59 9.60 8.37 8.26 8.32

T3

5.67 5.61 5.64 8.78 8.69 8.73 7.34 7.28 7.31 6.21 6.19 6.20 8.92 8.90 8.91 7.52 7.49 7.50

T4 4.82 4.79 4.81 8.12 8.09 8.11 6.28 6.21 6.25 5.73 5.68 5.71 8.37 8.34 8.36 6.76 6.71 6.73

T5 6.18 6.16 6.17 9.43 9.40 9.42 8.23 8.15 8.19 6.74 6.69 6.71 9.58 9.56 9.57 8.34 8.24 8.29

T6 6.87 6.73 6.80 9.89 9.81 9.85 8.71 8.53 8.62 6.95 6.89 6.92 9.97 9.92 9.95 8.92 8.89 8.91

T7 5.89 5.81 5.85 9.01 8.98 9.00 7.83 7.79 7.81 6.54 6.51 6.53 9.21 9.19 9.20 7.98 7.96 7.97

T8 5.21 5.13 5.17 8.43 8.39 8.41 6.72 6.69 6.70 5.97 5.93 5.95 8.67 8.62 8.64 7.16 7.14 7.15

T9 4.37 4.30 4.34 7.76 7.68 7.72 5.97 5.92 5.95 5.29 5.18 5.24 8.02 7.92 7.97 6.12 6.10 6.11

T10

3.97 3.89 3.93 7.47 7.41 7.44 5.75 5.69 5.72 4.92 4.87 4.90 7.89 7.81 7.85 5.92 5.89 5.91

T11

3.75 3.69 3.72 7.24 7.19 7.22 5.59 5.49 5.54 4.63 4.51 4.57 7.38 7.27 7.33 5.78 5.76 5.77

Mean 5.37 5.31 5.34 8.64 8.58 8.61 7.17 7.10 7.13 6.04 5.98 6.01 8.83 8.78 8.81 7.38 7.33 7.35

C T C × T C T C × T C T C × T C T C × T C T C × T C T C × T

SEd 0.0078 0.0182 0.0258 0.0069 0.0163 0.0230 0.0084 0.0198 0.0280 0.0061 0.0144 0.0203 0.0066 0.0154 0.0218 0.0083 0.0195 0.0276

CD (0.05) 0.0157 0.0368 0.0520 0.0140 0.0328 0.0464 0.0170 0.0400 0.0565 0.0124 0.0290 0.0410 0.0133 0.0311 0.0440 0.0168 0.0393 0.0556

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Table 3. Effect of fertigation on yield per hectare (t/ha) in paprika under open and coconut shade conditions

Yield per hectare (t/ha)

Treatments Season I Season II

Open Shade Mean Open Shade Mean

T1 17.56 10.11 13.84 19.96 10.62 15.29

T2 20.12 11.65 15.89 21.08 11.91 16.50

T3 16.84 9.14 12.99 18.64 9.35 13.40

T4 15.86 8.92 12.39 17.55 8.98 13.27

T5 18.96 10.75 14.86 20.34 11.05 15.69

T6 21.54 12.00 16.77 22.31 12.58 17.44

T7 17.11 9.92 13.52 19.25 9.99 14.62

T8 16.15 9.00 12.58 18.11 9.10 13.61

T9 15.25 8.43 11.84 17.00 8.78 12.89

T10

15.00 8.28 11.64 16.58 8.68 12.63

T11

13.82 7.95 10.89 15.16 8.12 11.64

Mean 17.11 9.65 13.38 18.73 9.92 14.33

C T C x T C T C x T

SEd 0.0324 0.0760 0.1075 0.0371 0.0872 0.1233

CD (0.05) 0.0654 0.1535 0.2171 0.0750 0.1760 0.2490

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Water Harvesting for Agriculture in Drylands of India

Prasad S. Kulkarni, D. C. Sahoo.

36

IntroductionThe former President of India, Dr A. P. J. Abdul

Kalam has recently called for a second green revolution, while inaugurating the triennial conference on Global Forum on Agricultural Research at New Delhi. This is not the first time that somebody has spoken about this issue. By 2020, India has got to increase productivity above 340 million tonnes of food-grains in view of population growth, so Dr Kalam appealed agricultural scientists and technologists to work hard to double the productivity of available land in view of less area being available for cultivation, with limited water supply and diminishing number of available farmers. The drylands have to be targeted to increase productivity of food-grains through sustainable agriculture if India has to succeed in a second green revolution, without creating serious negative consequences to natural environment.

Dryland, the area receiving 375-1125 mm of rainfall (FAO,1993) covers about 41% of EarthÊs land surface and are inhabited by more than 2 billion people (about one third of world population). Four dryland subtypes are recognized viz dry subhumid, semiarid, arid, and hyper-arid; based on an increasing level of

aridity or moisture deficit (UNCCD,1999). Drylands are mainly characterized by scarcity of water which affects both natural and managed ecosystems. This constrains the production of crops, forage and other plants and has great impacts on livestock and humans. Vo¨ro¨smarty et al (2005) reported that, total renewable water supply from drylands is estimated to constitute only around 8% of the global renewable water supply (about 3.2 trillion cubic meters per year). Thus, almost one third of the people in the world depend on only 8% of the global renewable water resources, which makes per capita availability in drylands just 1,300 cubic meters per year which is already below the threshold of 2,000 cubic meters required for minimum human well-being and sustainable development. This is the main cause for the current socioeconomic condition of dryland people, about 90% of whom are in developing countries, lags significantly behind that of people in other areas.

If we focus on dryland agriculture ie rain-fed agriculture, that has a distinct place in Indian agriculture (occupying 67 per cent of the cultivated areas and contributing 44 per cent of the population) the resource poor infrastructure and low investment in technology

194

Figure 1. Drylands in India (CSE, 2007)

195

and inputs characterize it. Such dryland agriculture contributes about 45% of food grain production. An assessment on agriculture done by S M Jharwal, principal advisor to the government of India, shows that out of a net sown area of 141 million ha, 86 million ha is rainfed. State-wise assessment shows that 13 states account for about 92 per cent of the total rainfed area.

The main states are Maharashtra (14.49 million ha), Madhya Pradesh (9.31 million ha), Rajasthan (12.15 million ha), Karnataka (7.46 million ha), Uttar Pradesh (4.42 million ha), Andhra Pradesh (6.48 million ha), Gujarat (6.58 million ha) and West Bengal (2.54 million ha). Crop-wise analysis shows that major coarse cereals which are main source of food for IndiaÊs poor are grown in rainfed areas. For instance, 92 per cent, 94 per cent and 80 per cent of the total area under Jowar, Bajra, and Maize respectively is rainfed. Similarly, 86 per cent of the area under pulses is rainfed. Eighty three per cent groundnut and 99 per cent soybean are grown under rainfed conditions. About 73 per cent of area under cotton is rainfed. Though rainfed areas contribute in a major way to IndiaÊs agriculture, the difference between the output of rainfed and irrigated areas is remarkable (CSE, 2004). The production gap between irrigated agriculture and rain-fed agriculture is possible to reduce with the help of certain water harvesting and efficient water management techniques. Improvement of dry land farming is a key to the development of agriculture and removal of poverty in rain-fed areas. Also in order to increase production for feeding present as well as future population, emphasis must be placed on strengthening rain-fed farming through soil and water conservation, rain water as well as flood water harvesting, water management techniques and enhanced soil fertility.

Sivanappan (1997) reported from a study conducted in Punjab (India) that 54% of the catchment area can be irrigated once with 5 cm depth of water harvested. Further, it was observed that the average response of one such supplementary irrigation to maize and wheat at its most critical stage increased the grain yield by 0.4 t/ha in the case of maize and 0.77 t/ha in the case of wheat. This focuses on the importance of supplementary irrigation given to the crops at their critical growing stages.

In FAOÊs report on Water Harvesting (2001) some examples of successful water harvesting in India were discussed. Ranges of water harvesting techniques have been developed for both drinking water supply and

irrigation. Number of success stories of “greening of villages” has been developed in response to the severe droughts of the last three decades. In Rajasthan, Gujarat and Madhya Pradesh, communities that have undertaken water harvesting have a completely different livelihood situation compared to those without water harvesting. The projects have often been initiated by individual persons (especially famous are Anna Hazare and V Salunke) or by NGOÊs. A problem is that local institutions needed often are inconsistent with the predominant governmental structures and institutional set-up prevailing in the country.

Situation Analysis and Key Constraints

Why farmer’s yield in drylands (rainfed areas) is low?

Rainfall is highly erratic, and most rain falls as intensive, with very high rainfall intensity and extreme spatial and temporal rainfall variability. The result is a very high risk for annual droughts and intra-seasonal dry spells. Such short dry spells of water stress can have a serious effect on crop yields if occurring during water sensitive development stages like, e.g. during flowering. The annual (seasonal) variation of rainfall can typically range from a low of 1/3 of the long term average to a high of approximately double the average; meaning that a high rainfall year can have some 6 times higher rainfall than a dry year (Stewart, 1988). Statistically in a semi-arid region, severe crop reductions caused by a dry spell occurs 1-2 out of 5 years, and total crop failure caused by annual droughts once every 10 years. Thus the poor distribution of rainfall over time often constitutes a more common cause for crop failure than absolute water scarcity due to low cumulative annual rainfall.

Rainfall has an approximate range of 200 - 1000 mm from the dry semi-arid to the dry sub-humid zone. The length of growing period ranges from 75-120 days in the semi-arid zone, and 121 � 179 days in the dry sub-humid zone, which is determined by the relation between rainfall and the potential evapotranspiration (PET). PET varies between 1500 - 2300 mm per year. Rainfall in the drylands exceeds PET only during 2 - 4.5 months (Kanemasu et al., 1990). On an annual basis semi-arid areas are characterized by PET > annual rainfall (P) with the ration P/PET < 0.65 in the „wettest‰ dry sub-humid zone (UNESCO, 1977). Daily PET levels are high, ranging from 5 - 8 mm day-1 (FAO, 1986). This gives a cumulative PET for the growing season of

196

600 - 900 mm, which explains the limited water surplus recharging the aquifers and rivers.

Also the agro-hydrological challenge in drylands is not necessarily related to inadequate cumulative rainfall - at present basically only 1/8 - 1/3 of the rain is used in crop production on average. Instead the challenge is to manage the unreliable distribution of rainfall over time, and minimize non-productive water flow in the water balance. Research has shown often only a small fraction of rainwater reaches and remains in the root zone, long enough to be useful to the crops. It is estimated that in many farming systems, more than 70 percent of the direct rain falling on a crop-field is lost as nonproductive evaporation or flows into sinks before it is used by plants. It is only in extreme cases that only 4 -9 percent of rainwater is used for crop transpiration. Therefore, in rain-fed agriculture wastage of rainwater is a more common cause of low yields or complete crop failure than absolute shortage of cumulative seasonal rainfall.

High Yielding Hybrid Crop Varieties During recent years, the dryland regions of the

country have increasingly come under the hybrid crop varieties. While the crop yields from the hybrid varieties was surely high, the flip side of these varieties � these varieties are water guzzlers � was very conveniently ignored. For the sake of comparison, let us take the example of rice: The high-yielding varieties of rice normally require about 5000 litres of water under drylands to produce one kg of rice. Common sense tells us that the rice varieties cultivated in the dryland regions of the country should be those that require less amount of water. What is in reality happening is just the opposite. In the rainfed parts of Andhra Pradesh and Karnataka, hybrid rice varieties, which require roughly twice the quantity of irrigation water (than Punjab), are grown abundantly. Not only rice hybrids, all kind of hybrid varieties of sorghum, maize, cotton, bajra, and vegetables that require higher doses of water, are promoted in the dryland regions. (Kisan niti news website)

DroughtOccurrences and the effects of drought require

special attention in planning and management of natural and agricultural resources in dryland regions. A drought is a departure from the average or normal conditions in which shortage of water adversely impact ecosystem functioning and the resident populations of people. It is known that drought will likely occur in the future,

but it is not possible to reliably predict when they will occur, their severity, or how long they will last. Because of these uncertainties and the severity of the impacts, there are many considerations about drought that must be taken into account in harvesting and management of water resources in dry lands. Drought is generally characterized by shortages of water, food for people, and forage for livestock that can lead to unplanned and often unwise use of available agricultural and natural resources. Serious degradation of land and resources can result if contingency planning is not undertaken to meet these shortages.

Water ResourcesMuch of the water that is available to people living

in drylands regions is found in large rivers that originate in areas of higher elevation. These rivers include the Indus, the Ganga, Krishna etc. Groundwater resources can also be available to help support development. However, the relatively limited recharge of groundwater resources is dependent largely on the amount, intensity, and duration of the rainfall, and soil properties, the latter including infiltrations capacities and water-holding characteristics of the soil, which also influence the amount of surface runoff. Much of the rainfall is lost by evapotranspiration, and, as a result, groundwater is recharged only locally by seepage through the soil profile. Surface runoff events, soil moisture storage, and groundwater recharge in dryland regions are generally more variable and less reliable than in more humid regions. Groundwater is frequently used at rates that exceed recharge.

SolutionsWater Harvesting

Water Harvesting is the process of collecting, concentrating and improving the productive use of rainwater and reducing unproductive depletion. It is believed that water harvesting techniques originated in Iraq over 5000 years ago, where agriculture once started some 8000 BC. Water Harvesting involves collecting rainwater from a catchment area and channeling the runoff and using it to increase the water available in a relatively smaller growing area. In micro-catchment systems, water is collected from land adjacent to the growing area, while with macro-catchment systems large flows are diverted and used directly or stored for supplementary irrigation. The aim of water harvesting is to mitigate the effects of temporal shortages (but not insufficient cumulative amount) of rain, so-called dry spells; to cover both

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household needs (for drinking, cooking, sanitation, etc.) as well as for productive use (supplemental or protective irrigation, life saving irrigation etc.).

Water Collection Systems

Within field RWH refers to rain collected on the place it falls. Through various formations such as pits, the water will stagnate, infiltrate and thus made available to the plant root zone.

Flood or Gully WH involves the collecting of storm surface floods from gullies. The harvested surface water can be stored in a reservoir (for longer term storage) or be diverted directly to a field for direct infiltration by arresting the flow of water with the help of bunds, ditches and terraces (for shorter term storage).

Rill or Sheet flow WH is the collection of runoff of a gentler form than gully flooding. Here the slope does not exceed 1%, along a length shorter than 50-150 meters and that the surface runoff is mainly harvested in form of sheet and rill flow. Beyond 150 meters water will generally start to flow in minor gullies and eventually gullies.

Sub-surface or Ground WH is extraction of sub-surface water flow, from either soil water trapped in shallow sand layers or from the water table. Storing water under ground is attractive as it reduces evaporation losses and often contributes to high quality water thanks to filtration through especially sand. Sand dams and sub-surface dams, where water is trapped behind small dam-walls in sandy riverbeds, is a very efficient and cheap form of WH.

Roof-top WH involves collection of rainwater through a gutter or drain pipe from the roof. The system requires a tank to be built, which if correctly constructed can give water through piping straight into the house and thereby limit various forms of contamination. Roof-top Water Harvesting is primarily used for household use since the quantity obtained is seldom enough to cover agricultural needs greater than small-scale gardening. A combined area surface from several houses or school buildings, garage buildings, hospitals etc. can though produce considerable amounts of rainwater runoff, enough to be used for irrigation (Zhu and Li, 2000).

Runoff Enhancing MethodsThe methods include land alterations, soil

compaction, soil deflocculents and additives, spraying asphalt membranes, liners, cement lining, natural clay layers and pottery clay liners (burned) (Sivanappan,

1997). The percentage of runoff, combined with total rainfall and the aim of the water use will decide the size of the needed catchment area. In agriculture, the crop will be the water user, and normally the catchment requirement is described as the ratio of the runoff producing catchment to the cultivated area (C:CA ratio). A rule of thumb is a C: CA ratio of at least 3:1 (Anschutz et al., 1997). However, depending on the hydro-climate, runoff coefficients, and crop water requirements, catchment to cultivated area ratios will vary from 1:1 to 10:1. Depending on utilization, the runoff coefficient will vary greatly and the catchment area in relation to its intended use needs to be designed accordingly so as to correspond to the objective. The risk of contamination has to be observed depending on the intended use of the harvested water.

Storage

Whether for household or agriculture, water that is harvested for a longer time of duration, and tapped only when required, involves a storage component. Various forms that exist include:

Micro-dams, earth dams and farm ponds. Runoff water is stored in open structures, which can consist of small concrete dams, earth dams or simply ponds.

Sub-surface dams, sand dams. Water is stored under ground - in an artificially raised water table or local sub-surface reservoir (e.g. water stored in sand on top of a sealing layer of clay).

Tanks of various forms (plastic, cement, clay, soil etc.). These can be either under or above ground depending on space, technology, investment capacity and forms of extracting the water.

Storage Losses Seepage and evaporation losses are the main

forms of losses from storage reservoirs. Evaporation losses can be reduced through the minimization of open water surfaces and the covering of the surfaces. Sub-surface dams are one solution to prevent water surfaces to be fully exposed to atmospheric demands for water. Seepage losses can be considerable, especially in soils that are permeable. Prevention is done by reducing the wetted surface area, self sealing through siltation or applying various types of lining. Because of the high costs it is often cheaper to include the losses in the water needs calculations and construct storage capacities that include the losses as well (Critchley, 1991).

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Figure 2. Principle of water harvesting for plant production (FAO, 2001).

Figure 3. Classification of Water Harvesting Systems on criteria of source of water and duration of storage (Fox, 2001).

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Choice of Water Harvesting Technology

The choice of WH technique depends on biophysical fit, socio-economic environment and capacity to maintain the system. All systems require various degrees of maintenance, mostly of erosive damage caused by rainfall and runoff. Also the time the structures lay idle through the dry seasons can give rise to needs of maintenance. This must be included in the operation procedures of the technique. The choice of technique will also be affected by the type of crop production (Table 3).

The factors determining which system to use depend on several factors:

Potential source of water: WH is particularly suited for semi-arid regions ie regions with 300-700 mm average annual rainfall (Anschutz et al., 1997) but is also used in more arid regions such as some parts of Rajasthan. In more arid regions the implementation costs are higher due to the need of larger catchment structures.

Storage capacity (in time): In agriculture if the purpose is supplemental irrigation, then irrigation requirements and scheduling need to be assessed in relation to (i) the depth of water required, (ii) most likely timing of yield affecting crop water stress (iii) the possible depth of water that can be harvested

Purpose of use: single or multi purpose use (i.e. a combination of objectives such as irrigation, household water, livestock etc.)

Volume of water required: It can be obtained by analyzing rainfall data to assess probabilities of dry spell or stress occurrence and the actual requirements of water for the various intended uses (e.g. daily crop water requirements).

Investment capacity of the owner of the system (individual farmers, farmer groups, communities etc.).

Physical site conditions: Land availability including catchment availability and the runoff coefficient of the catchment surface are decisive factors in calculating runoff potentials. It is not recommended to conduct WH from slopes exceeding 5% due to uneven distribution of runoff, soil erosion and the high costs of the structures required.

The characteristics of the catchment area: It should preferably permit as much runoff as possible. The more compact (rocky), sealed and barren as possible, the better.

The application area: It is also important to realize that an investment in water harvesting may well result in a shift in crop production system. Therefore, in many cases the estimated costs and benefits from a

certain water harvesting system should be based on a different crop production system than the original system practiced prior to any WH introduction. For example, water harvesting structures with storage components are rarely seen as economically viable by farmers, if used only for staple food crops. Instead, the construction of, e.g., a farm pond, will most probably result in a shift in production system, toward high value crops such as tomatoes, garlic, onions, fruits, etc.

Small-Scale Irrigation SchemesLess complex, small-scale irrigation schemes run

either by individual farmers or by communities appear to be the most viable. This is especially the case when irrigation can be based on gravity. However, the initial investment cost is often too high for local communities to raise sufficient funds to build needed dams. One major problem, moreover, is that small-scale irrigation dams often fill rapidly with sediments. To avoid such problems it is important that soil and water conservation measures are in place in the dam watershed prior to its construction. Characteristics of successful small-scale irrigation projects found the following characteristics (Brown and Nooter, 1992):

The technology is simple and low cost.

The institutional arrangements are private or individual.

For rangeland and fodder For trees For crop- Planting pits - Contour bunds - Contour stone bunds- Contour bunds - Closed micro catchments - Earth bunds with stone spillways („Meskat‰)- Semi-circular bunds - Semi-circular bunds - Contour earth and/or vegetation bunds- Contour stone bunds - Infiltration pits - Living barriers - Planting pits (Zai) - Semi-circular bunds

Table 3. Runoff farming techniques for various production needs (Critchley, 1991)

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When institutional arrangements larger than individual ownership are needed, the most effective arrangements were found to be (in decreasing order of success): extended family groups, private voluntary groups, water users associations, and cooperatives.

Supporting infrastructure is important in order to have access to inputs and markets.

There is a high cash return to farmers at the time they need it.

The farmer is an active and committed participant in project design and implementation.

Irrigation PracticesThe general approach of flood irrigation often

leads to high losses of water to evaporation from the soil and water surface, leading to low productivity of water. Water productivity can be improved by introducing precision irrigation. This involves the application of the required quantity of water, when it is required and in the root zone where it is required. Technologies for achieving the necessary high levels of control are already available. The examples are micro-drip techniques for high frequency, low volume, partial-areas application of water and nutrients to crop fields. Precision irrigation overcomes the problems of unproductive depletion of water from the soil. By applying the water directly to the root zone, transpiration by plants is increased due to improved contact between water and roots while soil evaporation and deep percolation are reduced. This increases the productivity of water. Furthermore, improved control of the timing of application of water makes it easy to implement supplementary irrigation strategically to overcome seasonal dry spells. The number of supplemental or protective irrigations depends on the frequency and severity of dry spells as well as the amount of water available. The method of application of irrigation depends upon the landscape, the crop grown and investment capacity.

Incentives and Policies NeededSoil erosion, conservation of moisture and

soil nutrients are still problems in drylands of India, especially among small farmers. While the threat of land degradation is generally recognized, soil and water conservation is often denied the priority it deserves. The fact is that many rainfed farmers have to struggle for their daily subsistence. Few may have the resources, and state governments are providing incentives by way of subsidies covering as much as 30% of the cost of works.

The benefits of investment have been difficult to quantify in economic terms, though there are many direct and indirect benefits. Gestation periods are long, and returns to farmers are slow. Financing agencies are generally hesitant to support large-scale soil and water conservation works in developing countries. It is therefore necessary to have proper incentives at the farm level, and sound technical, institutional and legal frameworks are essential to achieve good land use. In addition, land users among the general public should be well informed of the need for means of improving soil productivity.

Social Constraints None of the development activities described

above could have been undertaken without the active support of the people in the area. There are non-government organizations or voluntary organizations in many places, and their services can be utilized profitably. The people should be educated through various means to understand the seriousness of the problems and the remedial measures. Pilot projects and demonstration plots can be introduced to illustrate the need for and advantages of these technologies for sustaining their livelihood. There are many constraints upon achieving these goals in the developing countries like India. These can be classified as sociocultural and economic constraints, and institutional cum political constraints. Sociocultural and economic constraints include the following (Sivanappan, 1997):

Caste, community

Religious institutions

Illiteracy

Poor economic status of the majority of the farmers

Farm size and fragmentation

Land ownership patterns and tenancy

The institutional cum political constraints are:

Policy instruments

Credit instruments (banks)

Marketing institutions (regulated market)

Research institutions

Appropriate technology for rainfed farming

Extension agencies for popularizing such technology

Role of NGOs and voluntary organizations

Policy and decision-making level (government/donor agencies)

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There may be numerous obstructions and constraints upon the dissemination and implementation of technologies and practices which have been proved successful. The factors promoting the spread of successful technology should be identified and acted upon for the future development of soil and moisture conservation and related activities.

SummaryThe drylands have to be targeted to increase

productivity of food-grains through sustainable agriculture if India has to succeed in a second green revolution. Sustainable agriculture will certainly play the major role in this revolution. But there are some constraints for lower yield from Indian drylands related to water. These are,

Rainfall is highly erratic. The result is a very high risk of annual droughts and intra-seasonal dry spells. Such short dry spells of water stress can have a serious effect on crop yields if occurring during water sensitive development stages.

Much of the rainfall is lost by evapotranspiration, so groundwater is recharged only locally by seepage through the soil profile. Surface runoff events, soil moisture storage, and groundwater recharge in dryland regions are generally more variable and less reliable. Groundwater is frequently used at rates that exceed recharge.

The high yielding hybrid crop varieties recommended in dryland region require high amount of water to achieve the expected yield. But due to rainfed agricultural practices being adopted frequent failure in rains causes frequent crop failures.

Drought, which is frequent in drylands is generally characterized by shortages of water, food for people, and

forage for livestock that can lead to unplanned and often unwise use of available agricultural and natural resources. Serious degradation of land and other resources is result of this.

Other than above, there are institutional, Socio- cultural and economic constraints which very well affect the water management practices in drylands.

The solutions for above problems can be as follows:

Various water harvesting practices listed above must be adopted in order to mitigate the effects of temporal shortages of rain, so-called dry spells; to cover both household needs (for drinking, cooking, sanitation, etc.) as well as for productive use (supplemental or protective irrigation).

Less complex, small-scale irrigation schemes run either by individual farmers or by communities need to be designed and constructed. These schemes should be linked to Precision Irrigation practices, instead of traditional flooding practices.

Soil and water conservation practices must be given sufficient importance in sustainable development of drylands in India. The non-government organizations or voluntary organizations of local people must come forward for dryland developments.

None of the development activities described above should undertake without the active support of the people in the area. The people should be educated through various means to understand the seriousness of the problems and the remedial measures. Pilot projects and demonstration plots can be introduced to illustrate the need for and advantages of these technologies for sustaining their livelihood.

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ReferencesAbdul Kalam, A.P.J., 2003,http://www.indianembassy.org/presidnt/jan25_03.html. Vo¨ro¨smarty, C.J., E.M. Douglas, P.A. Green, and C. Revenga, 2005. Geospatial indicators of emerging water

stress: An application to Africa. Ambio, 34, 230�236.Sivanappan R. K., 1995. Soil and water management in the dry lands of India. Land Use Policy, 12(2), 165-175Stewart, J.I., 1988. Response farming in rainfed agriculture. The Wharf Foundation Press, Davis, California, USA.

p 103.Unesco, 1977. World map of arid zones, Explanatory notes. MAB Technical notes No. 7, Unesco, Paris.Kanemasu E.T. Stewart, J.I., Van-Donk, S.J. and Virmani, S.M., 1990. Agroclimatic approaches for improving

agricultural productivity in semiarid tropics. Advances in soil science. Vol. 13. Dryland agriculture strategies for sustainability, pp 273 -309.

FAO, 1986. African agriculture: the next 25 years. FAO, Rome, Italy.Zhu, Q. and Li, Y., 2000. A breakthrough of the dry farming - rainwater harvesting irrigation project in the Gansu,

China. Paper presented at the Stockholm Water Symposium, 2000. SIWI, Stockholm.Anschütz, J., Kome, A., Nederlof, M., de Neef, R., van de Ven, T., 1997. Water harvesting and soil moisture retention.

Agrodok-series No. 13. Agromisa, Univ. of Wageningen. ISBN 90-72746-75-9. Fox, P., 2001. Supplemental irrigation and soil fertility management for yield gap reduction: On-farm experimentation

in semi-arid Burkina Faso. Licentiate in Philosophy Thesis 2001:5 in Natural Resources Management. Department of Systems Ecology, Stockholm University, Sweden.

Chritchley, W., and Siegert, K., 1991. Water Harvesting - A manual for the design and construction of water harvesting schemes for plant production. FAO, Rome, Italy. p 127.

http://www.fao.org, http://www.cseindia.org

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The Emerging Water Crisis in India and Possible Solutions to Address through Water

HarvestingD.C. Sahoo, Prasad S. Kulkanri, B.Maheshwara Babu and J.K.Neelakanth

37

Introduction“Water is life, Water is death”. Water is

one of the most precious elements of life on the planet. It is critical for satisfying the basic human needs, health, food production, energy and maintenance of regional and global ecosystems. Over 70% of the human body is made up of water. A human being may survive without food for several days but water deprivation can kill a person within a matter of hours. Life is, therefore, tied to water, as it is tied to air and food. And food is indeed tied to water. Water could well be the only natural resource to touch all aspects of human civilization.

“No single measure would do more to reduce disease and save lives in the developing world than bringing safe water and adequate sanitation” (Kofi Annan). Issues of food or health or sanitation, environment or cities or energy production, the 21st century has to deal with water quality and management. Yet, while water sustains life, it can also cause deaths if contaminated. Some of the deadliest

diseases, which kill millions around the world every year, are carried in unclean water. In fact, unsafe water and sanitation cause an estimated 80% of all diseases in the developing world, where as much as 90% of waste water is discharged without treatment. An estimated 50 to 100 lakhs people die every year-including one child every 15 second from diseases caused by poor water quality; 25,000 people are dying every day from malnutrition (Bajpai, 2005).

Global Water Crisis About 120 crores of people (20% of the global

population) spread across 40 countries do not have access to safe water; 240 crores of people lack adequate sanitation services (Ismail Serageldin, 1999). In the past 100 years, the world population was tripled but water use by humans has multiplied six fold. Women in Africa and Asia walk an average distance of 6 km a day to collect water. Fresh water, a key livelihood around the world, is under threat. The following statistics are indeed real, and startling.

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Nearly 450 million people in 29 countries currently face severe water shortages.

20 percent more water than is now available will be needed to feed the additional three billion people who will be alive by 2025 (Robert Svadlenka,2002).

As much as two-thirds of the world population could be water-stressed by 2025.

Aquifers, which supply one-third of the worldÊs population, are being pumped out faster than nature can replenish them.

Half the worldÊs rivers and lakes are seriously polluted.

Major rivers, such as the Yangtze, Ganges, and Colorado, do not flow to the sea for much of the year because of upstream withdrawals.

If the current inefficient and destructive practices of water utilization are allowed to continue in the face of growing population, global water resource limits will be reached in a few decades. The severity of this crisis has prompted the United Nations to conclude that water scarcity, not a lack of arable land, will be the chief constraint to increased food production in the next few decades. Thus, the threat to water resources stands as one of the major crises facing the planet, akin in urgency to climate change, rainforest destruction, and the depletion of the ozone layer. The water issue is indeed pervasive, tying together many other world problems, especially poverty, hunger, ecosystem destruction, desertification, climate change, and even world peace. A response that is commensurate with the immediacy and severity of the impending crisis is warranted from government and private institutions.

Looming Water Crisis in India Water has become the most commercial products

of the century. The stress on the multiple water resources is a result of a multitude of factors. On the one hand, the rapidly rising population and changing lifestyles have increased the need for fresh water. On the other hand, intense competitions among users in agriculture, industry and domestic sector is pushing the ground water table deeper. Water is the biggest crisis facing India in terms of spread and severity, affecting one in every three persons. Even in Chennai, Bangalore, Shimla and Delhi, water is being rationed and IndiaÊs food security is under threat. With the lives and livelihood of millions at risk, urban India is screaming for water.

To get bucket of drinking water is the daily struggle for most women in the country. The drought conditions have pushed villagers to move to cities in search of jobs, whereas women and girls have to trudge further. If opportunity costs were taken into account, it would be clear that in most rural areas, households are paying far more for water supply than the often-normal rates charged in urban areas. Also, if this cost of fetching water which is almost equivalent to 150 million women days each year, is covered into a loss for the national exchequer, it translates into a whopping 10 billion rupees per year. In India, there are many villages either with scarce water supply or without any source of water. In many rural areas, women still have to walk a distance of about 2.5 kms to reach the source of water. Women have to queue up in front of the public water taps, being at the lag end of the pipeline system, they get water only after the users ahead in the pipeline finish collecting water. Thus a rural womanÊs life is sheer drudgery.

Most women and girls in Rajasthan find themselves searching water for much of the year. They trudge bare foot in the hot sun for hours over wastelands, across thorny fields, or rough terrain in search of water, often life the colour of mud and brackish, but still welcome for the parched throats back home. On an average, a rural woman walks more than 14000 km a year just to fetch water. Their urban sisters are only slightly better off- they do not walk such distances, but stand in the long winding queues for hours on end to collect water from the roadside taps on the water lorries.

In brief:

Water source being open dug well, the quality of water is poor; dirty, saline and has turbidity.

Women have to make at least three trips at 5 am, 11 am and 5 pm and sometimes more.

Total distance traveled is 9-10 km, even higher

Total Time spent is 6-9 hours.

Total number of pots/buckets is about 3 pots, 30- 45 litres (one pot of 10-15 litres per trip)

Due to long distance, they have to take rest in the middle of the way. Dust storms aggravate their problem.

In Sriganganagar, the Indira Gandhi canal is the main source for drinking water. However, during the crisis period (either because of no water in the main canal/sub canal or due to the erratic power supply),

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women from poorhouse hold draw water from the village diggis, which is totally unfit for any kind of human activity. In Orissa drinking water is being privatized. The government first insists on the formation of water associations and conveniently pass the responsibilities on to these association. When this proves inefficient, water distribution rights are given away to private contractors. For example, the Orissa government initially stressed on the formation of Paani Panchayats (water associations). Later using police the government suppressed these panchayats justifying this by claiming that the villages were not being responsible enough. Titlagarh is the hottest town of India with no water, causing great misery to the women. In Titlagarh water problem is acute. People are buying water throughout the year for drinking and cooking purpose. In the month of May and June the rate of water increase three times, from Rs 2 per Dabba to Rs.8 per Dabba (container). This is the picture of urban areas, but in rural areas the problem is worse, where the tube wells all are becoming dry but people have no money to buy water.

In Uttranchal women are suffering a lot in every village where water problem is severe. Natural sources are drying up which adds the kilometers for women everyday to quench the thirst of their family as well as animals. Women collect the water required for cooking, cleaning, washing, bathing and drinking both for human beings and animals.The water problem in Chi tar and Gangoa is very severe, where men and women carry water on mules from 8-10 Km to the village. In Bundelkhand, women have no work but to collect drinking water on their heads from long distance. The grim situation of water may be best illustrated by one Bundelkhandi saying which roughly translated as „let the husband die but the earthen pot of water should not be broken‰. The scenario is worst in Patha in Chitrakut district where women have to travel a long distance to collect water for drinking.

Even in Delhi the water scenario is no better, being worst in Delhi slums. The water that comes from MCD pipe water has fixed time for water supply but it only comes for 1-2 hr in the evening (around 4.30 p.m.). At MCD pipe line people made bore and fetch water from it. The Water crisis is same in West Bengal. In all the districts, the water commons have ceased to exist, and have become open-access resources, with hardly anyone responsible to take care of the resources. Punjab; the name stands for abundance of water, but the present situation of water resources in the state is highly critical.

The ground water availability is drastically hampered. The village ponds are drying day by day. Women in the villages desperately need water. Near Talwandi Sabo, for some villages, the source for drinking water is about 8 km away. For Maharashtra, water is an abiding concern. In many villages women have to walk more than 3 kilometres everyday to fetch two huge vessels of water illegally from a government reservoir. They have to make at least three trips everyday. Images of women carrying the pots of water, walking miles and miles for one single pot are common in the state of Maharashtra. Women in Maharashtra have carried the water burden both as a result of scarcity and abundance. Women in Nandurbar district of North Maharashtra share their woes „forget about getting safe drinking water from wells, we spend most of our time locating streams and springs that quench our thrust‰. Many Women came as brides, their hair have gone dry, but the search for water has not ended.Karnataka is facing the worst kind of water crisis. In Bangalore, only 35% of the city gets water on daily basis, the rest on alternative days. In addition to the scarcity, erratic water supply is another problem. In Samadhanagar area, water generally comes in the morning at 11 A.M or in the middle of the night. Both these timings make it very difficult for women to collect water as they leave early in the morning to go to work. Social conflict and tension is high due to water crisis.

In brief, at an estimate about 150 Million-Woman Days and Rs 10 Billion are lost in fetching water (Radhakrishna, 2004).

Why the Crisis?Water covers 70% of the planet but more than

97.5% of the surface water is ocean which, obviously, is not usable in industry, agriculture or as drinking water. (Desalination is far too expensive to be for widespread adoption).The fresh water on which the world depends represents a mere 2.5% of available water. But then, three-quarters of this fresh water is trapped in the form of snow and ice. That is, all that is available for human use (and, of course, for animals as well) is 0.6% of the surface water (Rakesh Kumar et.al., 2005). Population growth, climate change, overuse/ misuse of water and pollution of available water are the principal causes of the crisis. Irrigation accounts for two-thirds of global use of fresh water. Farmers use water less efficiently and withdraw more water to compensate for water losses. In developing countries 60% is wasted or used inefficiently. Major sources of water pollution are human wastes,

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industrial wastes and chemicals and pesticides and fertilizers used for farming. We have been pumping groundwater faster than aquifers can recharge. Most of the water reservoirs are suffering reductions in storage capacity as a result of sedimentation caused by deforestation; on an average 1 % of the water storing capacity of the storage reservoirs is being lost annually (Gupta and Deshpande, 2004). Much of the municipal water supply is lost before it reaches consumers, leaking out of water mains, pipes or faucets or disappearing through illegal taps. In plain terms, as far as fresh water is concerned, the world has been living way beyond its means.

Of all the planetÊs renewable resources, fresh water may well be the most unforgiving; difficult to purify, expensive to transport and impossible to substitute.

Possible Ways to Address Water Crisis Restore the conventional methods of water

conservation like Baolis, Jhods, Ponds, Tankas.

Introduce rainwater harvesting.

Change the cropping pattern of agriculture. Instead of growing water intensive crop like paddy and sugarcane, introduce crops like millet, ragi, which consume less water.

In cities instead of Public Private Partnership (Privatisation of water) Public-Public partnership (Public and Government) is an alternative for water crisis.

Proper water conservation measures should be used. People should be made aware and trained on the techniques of water conservation.

Government schemes should be implemented properly.

Involve NGO in the management of rural water supply.

Women should be trained as water managers for the better domestic utilization.

Conservation- A Micro Approach to Water Harvesting

Water conservation is a loose and undefined concept which brings out the need for judicious use of water through engineering means to meet the human needs by modifying the space and time availability and

the quality of water. It brings out the need to store water, where such storage is necessary, due to a mismatch in timing between supply and demand and to the transportation of the water from the place of demand without unavoidable wastage.

Conservation, when applied to the solution of water crisis, it has two broad connotations viz.: Economical and optimal use including prevention of wastage/leakage, multiple use (reuse and recycling).In the hydrological sense, water conservation means improving the dependability of the water through augmenting additional resources, storage of rainwater in reservoirs, ponds, lakes, shallow and deep ground water or in the soil moistures. A present day definition may also include the conservation of water as defined above in both qualitative and quantitative assessment. As of now, the storage capacity created in the country is about 50% of the ultimate possibility.

Conservation through Optimal & Economical use of Water

Various crops need a certain quantum of water for maximum yields. It has been established that with a slightly less supply, the yields are not affected considerably. In fact, in scarcity conditions, there is a much better and optimal use of water.

Conservation through Multiple use - Reuse and Recycling

The third aspect of conservation would be to minimize the wastage and misuse of water if not prevent it altogether. This will again apply to all the uses of water. For example, it is estimated that in urban water supply almost 30 to 40% of the water is wasted through the distribution system. In almost all the major urban centres of the country there is already an acute problem of adequate water supply while the sources of augmentation are very few. It is, therefore, most significant to prevent such wastage. In industries also, there is a scope for economy in the use of water. For example, in India water used for production per ton of paper is 300 kiloliters while in USA it is only 20 kiloliters. It is estimated by the Bureau of Industrial Costs and Prices that 10 - 30 % saving is possible by recycling, modifications in processing, evaporation control etc.

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ReferencesB. P. Radhakrishna, Man-made drought and the looming water crisis, CURRENT SCIENCE, VOL. 87, NO.

1, 10 JULY 2004.Gupta, S. K. and Deshpande, R. D., Water for India 2050: First order assessment of available options. Current

Science., 2004, 86(9), 1216�1224.Ismail Serageldin, The World Water Gap - World’s Ability to Feed Itself Threatened by Water

Shortage , Press Release, March 20, 1999, World Commission on Water for the 21st Century. Lal, M., Climate change – Implications for India’s water resources. J. India Water Res. Soc., 2001, 21,

101�119.Nirupam Bajpai, Senior Development Adviser and Director, South Asian Programmes, Centre on Globalization and

Sustainable Development, Columbia University, New York.)Rakesh Kumar, R. D. Singh and K. D. Sharma.,Water resources of India, CURRENT SCIENCE, VOL. 89, NO.

5, 10 SEPTEMBER 2005.Robert Svadlenka. International Water management Institute, World water demand and supply, 1990 to

2025: Scenarios and Issues. Research Report 19, based on map prepared for „A Vision of Water for Food and Development‰2002.

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Rainfall Probability Analysis for Efficient Water Harvesting and

Crop Planning in NilgirisD.C. Sahoo

38

IntroductionThe scarcity of water is a well-known fact. In

spite of higher average annual rainfall in Nilgiris (1,210 mm) it does not have sufficient water at all times. Most of the rain falling on the surface tends to flow away rapidly, leaving very little for either for storage on surface or for the recharge of groundwater. As a result, most parts of time, the area experience lack of water even for agriculture as well as domestic uses. Surface water sources fail to meet the rising demands of water supply. This precarious situation needs to be rectified by construction of a series water harvesting structures. Hence, there is a need for proper design and construction of different water harvesting structures to ensure that rain falling over the region is stored as much as possible through water harvesting for direct use.

In Nilgiris commonly grown annual crops are Potato, Cabbage, Carrot, Beans, Peas, Radish, Cauliflower, Beetroot etc. The different crops are being raised under rainfed condition during first (May to August) and second (September to November) season depending

upon the availability of rainfall where as under irrigated condition in the third season (December to April). As the rainfall is unevenly distributed through out the year, analysis of rainfall and its distribution is very much important for crop planning and hydrological design of water harvesting structures used for storage of excess runoff and irrigation.

Weekly, monthly and seasonal rainfall data are very much useful for design of water harvesting structure as well as planning of agricultural operation. Probability and frequency analysis of rainfall data enables us to determine the expected rainfall at various percent chances. Rainfall at 80 per cent probability can be safely taken as assured rainfall while 50 per cent can be taken as maximum limit for taking any risks (Gupta et. al., 1975).

The knowledge of one day maximum rainfall is of great importance for hydrologic design of structure and planning of soil conservation measures for safe disposal of excess runoff. Probability analysis of one day maximum rainfall, weekly, monthly and seasonal rainfall

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has been attempted by many scientist at different places (Sharda and Bhushan,1985; Bhatt et.al.,1996; Mohanty et.al.,2001). Since the rainfall amount and its distribution are region specific, an attempt has been made in this paper for probability analysis of monthly, seasonal and annual total rainfall at different probability level, annual maximum daily rainfall at different return period and to develop depth-duration-frequency relationship.

Materials and MethodsNilgiris forms a part of the Nilgiris district of

Tamil Nadu which is located in the confluence of the Western and Eastern Ghats at a latitude of 11�11Ê N to 11�42ÊN and longitude of 76�14Ê E to 77�01ÊE. It is predominantly a hilly area with elevation ranging up to 2636m above MSL. The geographical area of the Nilgiris district is 2529 sq. kilometer. The area receives an annual rainfall of 1210 mm (average of 1960-2006) spread all over the three seasons of the year viz., May to August, September to November and December to April. This rainfall is mainly received through the South-West monsoon which spans from May to August and North- East Monsoon from September to November. In the remaining part of the year i.e. December to April, the rainfall is scanty and unevenly distributed.

Daily rainfall data of forty seven years (1960-2002) was collected from the meteorological observatory of CSWCRTI, Research center, Nilgiris and used for frequency analysis with the help of WeibullÊs formula as given by

P = m / (N+1).

Where

P = Probability of rainfall magnitude being equal to or exceeded to a given value.

m = Rank of the rainfall magnitude when arranged in descending order.

N = Number of years of records.

Rainfall at various probability levels was worked out for monthly, seasonal and annul time period. For the seasonal analysis the entire year is divided into three seasons based on the onset and end of the monsoons. The period that receives South-West monsoon is considered as first season (May to August), North-East monsoon (September to November) as second season and the remaining period (December to April) as third season.

For prediction of annual maximum daily rainfall for higher return period the extreme values type-I distribution function and Log-Pearson type III distribution function has been used.

The probability density function of extreme value type-I distribution (Chow et.el., 1988) is given as

y= � ln (ln 1/F(x)) ...(1)

Where

y = (x � u)/ a

u = x � 0.5772 a

a = Ö6 s/p

x and s are mean and standard deviation respectively.

F(x) is the probability of an event to be less than a given magnitude for a given return period and x is the variate of a random hydrologic series.

In Log-Pearson type III probability distribution function, the variates is first transformed into logarithmic form (base 10) and transferred data is then analysed (Subramanya, 1997).

The transferred logarithmic series z, for any recurrence interval T is given by

ZT=Z+ Kz Sz ...(2)

Where

Kz = a frequency factor which is a function of recurrence interval T

Sz = Standard deviation of the Z variate

Z = log x and x is the variate of a random hydrologic series.

A depth-duration-frequency relationship was developed for different durations and return periods. The duration was taken as all possible combination of 1 to 6 days of cumulative rainfall. Thus the annual maximum rainfall of 1 to 6 consecutive days in all combinations corresponding to different return periods were estimated.

Results and DiscussionThe expected occurrence of monthly, seasonal

and annual rainfall at different probability levels is given

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in table 1.The annual rainfall from 1960-2006 varies between a maximum of 1720 mm to a minimum of 835 mm. The average monthly rainfall of 215.4 mm was maximum in July. It is minimum (8.4 mm) in the month of February. At 80 per cent probability the monthly rainfall in the first season ranges between 65.2 and 112.7 mm. Similarly at 80 per cent level the rainfall in the second season ranges between 42.5 and 89.5 mm. In the third season the chance of occurrence of rainfall is very less at 80 per cent probability.

The expected rainfall at 80 per cent probability in the first, second and third season are 488.5, 289.0 and 82.3 mm respectively. At 90 per cent probability the rainfall in first, second and third season are 393.6, 245.1, 74.6 mm respectively. The rainfall at 80 per cent probability can be good enough in the first and second season to take any annual crop without facing water deficit where as in the third season it needs supplemental irrigation. Therefore the excess water can be harvested through suitable water harvesting structure during first and second season for the use in third season.

The main crops in the first and second seasons are potato, cabbage and radish with their water requirements in the first season are 290, 301 and 206 mm and in the second season 220, 277 and 166 mm respectively (Sikka et. el., 2001). So there is 90 per cent and 80 per cent success of getting the required amount of water without failure in the first and second season respectively.

The probable annual maximum daily rainfalls for the entire period of forty seven years were analyzed using WeibullÊs formula. The maximum one day rainfall expected to be equaled or exceeded to the given values at different return period is given in table 2. The maximum one day rainfall for 10, 20, 40 years return period were estimated as 145.5, 175.3 and 287.7mm. In the Nilgiris, the main crops are potato, cabbage and radish which are very much susceptible to water logging. To prevent from the crop damage, this can be used for designing the excess water disposal system. For the design of any soil conservation structure with respect to erosion control and/or water harvesting structure these extreme values at different return periods can also be used for any assumed expected life of the structure. For predicting annul maximum one day rainfall for higher return

period the extreme value type-I probability distribution function and Log Pearson type III probability distribution functions were used. These methods were used for lower return periods and compared with the WeibullÊs formula values. Chi-squire test showed lower discrepancy with type III function than the extreme value type-I function (table 2). The predicted values of one day maximum rainfall for higher return period was estimated using Log Pearson type III probability distribution function (table 3). The one day maximum rainfall for 50 and 100 years return period was found to be 237.5 and 294.4 mm, respectively.

The probable maximum rainfall for 1 to 6 consecutive days in all combination at different return period is presented in graphical form as depth-duration-frequency relationship (fig.1). The one day maximum rainfall for 5,10,20 years return period are 117.1,144.2 and 176.1 mm where as for two days maximum rainfall for the same return period were found to be 162.3,244.5 and 284.1 mm respectively. In Nilgiris, mostly farmers cultivate vegetable crops by converting the slope into bench terraces where there is chance of water logging/ stagnation in case of level and inward type terraces. The main crops are potato, cabbage and radish which are very much susceptible to water logging and needs to be prevented from the crop damage. Therefore, the estimated one day maximum rainfall for different return period can be used for designing the excess water disposal system. For the hydrologic design of any soil conservation structure and/or water harvesting structure, these extreme values at different return periods can be used for any assumed expected life of the structure.

ConclusionMonthly, Seasonal and annual rainfall at different

probability levels were estimated to ensure about the assured rainfall in different seasons for the crop growth. There is 90 per cent and 80 per cent success of getting the required amount of water without failure in the first and second season respectively for the commonly grown vegetable crops. Annual maximum one day rainfall for different return period were estimated from observed data and for higher return period using Log-Pearson type III probability distribution which were obtained as 237.5 and 294.4 mm for 50 and 100 years return period respectively.

211

ReferencesBhatt, V. K., Tiwari, A. K. and Sharma A.K. 1996. Probability models for prediction of annual maximum daily rainfall

of Datia. Indian J. of Soil Conservation, 24(1):25-27.Chow,V.T., Maidment, D.R. and Mays,L.W.1988.Applied Hydrology. Mc Graw Hill Book company.11,12:371-

415.Gupta, S. K., Ram Babu and Tejwani, K. G.1975. Weekly rainfall of India for planning cropping programme. Soil

Conservation Digest,3(1):31-39.Mohanty, S., Marathe, R. A. and Shayma Singh. 2001. Rainfall characteristics of Vidarbha region. Indian J. of Soil

Conservation,29(1):18-21.Sharda, V. N. and Bhusan,L.S. 1985. Probability analysis of annual maximum daily rainfall of Agra. Indian J. of Soil

Conservation,13(1):16-20.Sikka, A.K., Madhu, M. and Tripathi, K.P. 2001. Comparison of different methods of estimating evapotranspiration

in the Nilgiris, South India. Indian J. Soil Cons., 29(3): 213-219.Subramanya, K. (1997). Engineering hydrology. Tata McGraw-Hill Publishing company. pp 188-189.August 204.3 177.6 152.1 127.8 124.3 104.3 90.1 75.6 67.4

���

Fig.1. Depth-duration-Frequency Curve.

212

Period Probability (per cent)

10 20 30 40 50 60 70 80 90

January 27.8 18.2 9.7 7.1 3.2 0.97 0.00 0.00 0.00

February 31.7 17.8 5.6 2.1 1.7 0.00 0.00 0.00 0.00

March 61. 8 26.4 19.2 15.4 11.5 4.7 3.3 0.70 0.00

April 144.08 101. 2 74.52 62.1 55.1 48.4 44.4 26.8 15.4

May 216.5 198.1 125.4 118.7 110.60 98.5 84.7 65.2 44.3

June 232.0 203.8 178.6 170.4 144.3 124.3 98.7 64.4 54.3

July 310.1 291.7 254.3 241.8 196.7 156.5 134.3 112.7 86.8

August 204.3 177.6 152.1 127.8 124.3 104.3 90.1 75.6 67.4

September 278.7 211.6 173.2 144.8 127.6 114.6 112.3 76.6 62.1

October 270.6 242.0 196.8 176.5 150.4 135.3 117.8 89.5 72.1

November 236.8 194.3 144.5 105.6 86.4 83.5 76.1 42.5 24.8

December 125.1 95.6 68.4 55.8 40.8 19.3 14.5 6.5 3.2

Ist season 930.5 765.4 673.7 626.5 594.6 560.2 535.3 488.5 393.6

IInd season 615.8 544.8 506.2 465.4 436.5 379.7 357.5 289.2 245.1

IIIrd season 278.7 216.7 178.4 165.2 144.6 125.1 108.6 82.3 74.6

Annual 1590.8 1454.5 1340.4 1260.5 1179.4 1105.5 1038.2 989.1 957.4

Table 2. Expected one day maximum rainfall for lower return period

Return period (years) One day maximum rainfall (mm)

WeibullÊs formula Type-I p.d. function Log Pearson type III p.d. function

2 71.0 97.73 70.61

5 115.9 150.2 91.51

10 145.5 184.95 140.98

20 175.3 218.27 192.53

30 228.3 237.45 201.00

40 287.7 250.96 219.10

Table 3. Predicted one day maximum rainfall for higher return period

Return period (Years) One day maximum rainfall (mm)

50 237.5

60 247.8

70 260.5

80 274.3

90 282.1

100 294.4

Table 1. Expected rainfall (mm) at Nilgiris at different probability levels.

213

Time Series Modeling of Groundwater Level of Western Noyyal River Basin of Tamil

NaduS. S. Salunkhe; S. Santhana Bosu and C. Mayilswami

39

IntroductionIn India, development of irrigation through

exploitation of groundwater resources has significantly contributed in increasing the irrigated area for agricultural production. At present the groundwater in India contributes more than 58% for drinking water, 52% for agriculture production and 50% for urban and industrial sectors. As groundwater resources are more intensively used, one needs knowledge of the essential variables of groundwater system and of how they fluctuate over time. One of the most important hydrological variable is groundwater head, which is therefore monitored frequently at many locations.

Water managers are interested in spatial and temporal forecasting of the water table depth. The forecasts are either physical understanding of the process or on statistical analysis of the process popularly termed as the stochastic approach. Recently a combination of physical and stochastic approach is gaining more popularity in the field of hydrologic forecasting. One

dimensional models that describes the water table fluctuations include empirical models such as transfer � noise model which were used by Box and Jenkins (1970), Hipel and McLeod (1994), Knotters and Van Walsum (1997) and Van Geer and Zuur (1997). The data requirements for physical based models to simulate water table fluctuation are enormous and generally difficult or costly to satisfy in many cases. Therefore there is a need to devise time series model which is capable of representing the water table fluctuation with respect to time and space. Box and Jenkins (1970) have systematically discussed the time series models. A comprehensive discussion in the time series modeling of hydrological variable is presented by Salas et al. (1980). According to Yevjevich and Harmancioglu (1985) time series analysis is a major statistical technique used in the extraction of information on hydrologic and water resources random variables from the observed data. Forecasting from time series models are more accurate than costly, complex conceptual models (Hipel and McLeod, 1994).

214

The groundwater situation in Tamil Nadu is more precarious. The major sources of irrigation in the state are wells, canals and tanks. As per recent estimates, more than 60 percent of available groundwater resources are utilized, making it the major source for irrigation, domestic and drinking water supplies. In districts like Coimbatore and Salem the groundwater level has gone down to unimaginable depths. (Source: Central Groundwater Board, Chennai). This study was undertaken to develop a stochastic model of groundwater level of western part of Noyyal river basin in Tamil Nadu, India.

Materials and Methods

Study area DetailsThe Noyyal river basin of Tamil Nadu comprises

the entire drainage basin area of the Noyyal River (3510 km2) (Fig. 1) and a tributary of the Cauvery River. The Noyyal River basin located between North latitude 10056Ê and 11019Ê / East longitude 76041Ê and 77056Ê

and covered in the Survey of India topographic degree sheets 58A, 58B, 58E and 58F on scale 1:50000. The River Noyyal originates at the Vellingiri hills in Western Ghats and passes through Coimbatore, Erode and Karur districts in Tamil Nadu State and joins river Cauvery at Kodumudy. It has a length of about 140 km from west to east with an average width of 25 km.

Model DevelopmentMonthly data of groundwater table depths (below

ground level) for the 10 years, starting from 1995 to 2004 of 12 observation wells of western Noyyal river basin were collected from the Data Center, Public Works Department, Government of Tamil Nadu, Chennai. Monthly time series data of water table depth for ten years (1995-2004) was developed by monthly averaging the values of water table depths of 12 observation wells located in the study area and analyzed for their deterministic and stochastic components.

A decomposition model for the time series which divides a time series into four additive components is given as follows:

..(1)

A systematic identification and reduction of each component of Z

t of Equation (1) was accomplished from

the groundwater table data.

Testing of StationarityThe stationarity of developed monthly water

table depth series was tested by Augmented Dickey Fuller (ADF) test (Gujarati, 2003). To run the ADF test Excel Add-In software namely ADF (Annen, 2004) was used. If the series was found non stationary, it was transformed by first differencing (Chandrahas, 2003) and the differenced series was used for further analysis.

Yt = Z

t � Z

t-1 ...(2)

Determination of Trend ComponentThe trend component describes the long

smooth movement of the variable lasting over the span of observations, ignoring the short-term fluctuations. To check the presence of trend, the turning point test as suggested by Yevjevich (1972 a) was performed on Y

t series. The turning point test was used by several

authors for testing the presence of trend (Srikanthan et al., 1983; Jat et al., 2003; Kahya and Kalayc, 2004; Bhakar et al., 2006). Once it is established that the trend is present in the series, it was estimated by least square method (Yevjevich, 1972 a). Trend series (T

t)

was subtracted from differenced series (Yt) to obtain the

trend free water table depth series and used for further analysis.

Determination of Periodic ComponentThe periodic component concerns an oscillating

movement which is repetitive over a fixed interval of time (Kottegoda, 1980). The existence of periodic component could be identified by an autocorrelogram which is a plot of autocorrelation function of the trend free water table depth series (X

t) and time unit spacing

of the successive terms of the series. Computation and removal of periodic component was done by parametric approach as suggested by Yevjevich (1972 a). The estimated values of periodic mean (û

?) and periodic

standard deviation (ó?) of trend free water table depth

series (Xt) were obtained as follows:

...(3)

...(4)

In general, it is found that the first six harmonics of periodic parameters for a time series of any interval Δt ≤ 30 days are sufficient and should be tested for significance,

215

as several harmonics beyond the sixth harmonic add relatively small additional explanation of the variance of estimated value (Yevjevich, 1972 a). Hence Fourier coefficients were calculated for first six harmonics for the periodic series of mean (m

ô) and periodic series of

standard deviation (sô). Then the explained variance of

harmonics for periodic series of mean and standard deviation were obtained from their Fourier coefficients as suggested by Yevjevich (1972 a). Time series after removal of trend and periodic component (stochastic component) ε

1was expressed as:

...(5)

Since the series ε1 given by Equation (5) is only

approximately a standardized variable, its mean y� and standard deviation s

y were found out and standardized

stochastic component (St) was obtained by the

equation:

...(6)

Modeling of Stochastic ComponentThe stochastic component is constituted by

various random effects, which can not be estimated exactly and was modeled by autoregressive moving average (ARMA) family of models. ARMA models are linear stochastic models and are expressed as follows (Chatfield, 1984):

Autoregressive process of order p- AR (p) model

...(7)

Autoregressive Moving Average ARMA (p, q) model

...(8)

Anderson (1976) recommended that order of model should be tried for identification of an appropriate model. Mujumdar & Kumar (1990) suggested that AR parameters up to order 6 and MA parameters up to order 2 in general serve the purpose and hence in this study, the following models were tried: AR (1), AR (2), AR (3),

AR (4), AR (5), AR (6), ARMA (1,1), ARMA (2,1), ARMA (3,1), ARMA (1,2), ARMA (2,2). The best models was selected using the following five criteria a) adjusted sum of square b) residual variance c) log likelihood d) Akaike information criterion (AIC) and e) Schwartz Bayesian criterion (SBC) (Kumar et. al., 2006). The Statistical Package for Social Sciences (SPSS) was used to work out the values of above five criteria. The ARMA model which gave lowest value of adjusted sum of squares, residual variance, Akaike information criterion (AIC), Schwartz bayesian criterion (SBC) and highest value of log likelihood were initially selected.

The parameters u, α, β of ARMA (p,q) models were estimated using least square method and SPSS was used to work out the parameters of the different orders of ARMA models. The residual series (Rt) was obtained as the difference between observed and fitted values of stochastic component (St). Diagnostic checking of models concerns the verification for the adequacy of the fitted model. Test for the significance of residual mean (Mujumdar & Kumar, 1990) and Portmanteau test (Box & Jenkins, 1970) were used for this purpose. The coefficient of efficiency (C.E.) introduced by Nash & Sutcliffe (1970) was used to select the best fit model i.e. to asses the goodness of fit between models response to that of observed value.

...(9)

Results and Discussion

Testing of StationarityThe estimated value of ADF test statistics

(-3.1940) was found less than the test critical value (-3.4484) at 5% level. Hence water table depth series was found to be nonstationary and was transformed by first differencing as given by the Equation (2) and was used for further analysis.

Determination of Trend ComponentThe estimated value of test statistics obtained

from turning point test was found to be -2.63, which was not within the critical range of μ1.96 at 5 % level. Hence the trend was present in the series and it was estimated by using method of least squares by fitting a linear trend:

Y = -0.0012 X + 0.097 ...(10)

216

The obtained trend series (Tt) was separated

from original series and trend free series was used for further analysis.

Determination of Periodic ComponentIt was seen from the autocorrelogram of the

trend free water table depth series (Xt) that the peaks

and troughs were narrow and broad respectively (Fig. 2). It indicates the presence of hidden periodicity in the time series. For representing the periodic component, the number of significant harmonics was determined by using explained variance of harmonics. The percentage of explained variance by fifth harmonic of mean was found to be 0.08 % (Table 1). The first four harmonics explain 91.36 % of the variance. Hence only first four harmonics were considered as significant for the periodic series of mean. Similarly it was seen that first five harmonics were significant for periodic series of standard deviation. The estimated values of periodic mean (û

?)

and periodic standard deviation (ó?) of trend free water

table depth series (Xt), Time series after removal of trend

and periodic component and standardized stochastic component were obtained using Equations (3), (4), (5), and (6) respectively.

Modeling of Stochastic ComponentFor identification of an appropriate order of

model the values of adjusted sum of square, residual variance, log likelihood, Akaike information criterion (AIC), Schwartz Bayesian criterion (SBC) of tried models for stochastic component of water table depth series are presented in Table 2. The minimum value of adjusted sum of square, residual variance, AIC and SBC and maximum value of log likelihood were found to be 109.4340, 0.9457, 335.2568, 340.8151 and -165.6945 respectively and indicated by Â*Ê in the Table 2. On the basis of above five criteria AR (1), AR (2), ARMA (2,2) were initially selected for water table depth series.

Diagnostic checking of the initially selected models is presented in Table 3. It can be seen from the table that test statistics for both the tests were less than the critical value for all three selected models. Hence residual of all the three selected models passes both the tests indicating that selected models AR (1), AR (2) and ARMA (2,2) could be accepted for stochastic component of water table depth series.

Model StructureThe mathematical structure of additive model

combining both deterministic and stochastic components of water table depth series whose stochastic component was modeled by AR (1) model is represented as:

Z1 = T

1 + u

12 + σ

13 (St) + Zt � 1

Where,

Tt = � 0.0012 X + 0.097

St = � 0.0034 +0.2300 (S

t-1 + 0.0034) + R

t

In Equation (11) the term Zt-1

was added to the model to convert the differenced series (Y

t) to original

series (Zt), i.e. to undo the first deference which was

taken to convert original series (Zt) from non stationary

to stationary. Similarly model structure was developed for water table depth series whose stochastic component was modeled by AR (2) and ARMA (2,2) models. The regeneration of water table depth series for the period of 1995 to 2004 was done using developed models.

217

The values of coefficient of efficiency (C.E.) for selected models for water table depth series are presented in Table 4. It can be seen that coefficient of efficiency of all the three models was 0.9998. As AR (1) is most simple model, it was selected as the best fit model for the stochastic component of water table depth series and was finally selected.

Validation of The ModelValidation of model was tested by comparing

the historical and regenerated water table depth series for the period of 1995-2004 (Fig. 3.). A perusal of the figure indicates the closeness between the two series. It was seen from figure that historical and regenerated series were exactly coinciding with each other so that we cannot identify them separately. The closeness between historical and regenerated series was further confirmed from Table 5 as their mean and standard deviation were almost same. Similarly regenerated mean monthly water table depth series for the period of 1995 to 2004 was compared with historical series and presented in Fig. 4. It was seen from the figure that historical and regenerated mean monthly water table depth series were exactly coinciding with each other. The correlation coefficient

between the two series for ten year period (1995 to 2004) and for mean monthly series was found to be same as 0.99. The correlation coefficient was tested by t�test and was found to be highly significant at 1 % level of significance for both ten year and mean monthly water table depth series.

ConclusionsFinally it was concluded that AR (1) was found to

be the best fit model for stochastic component of water table depth series and was finally selected. The coefficient of efficiency of developed model was greater than 0.90, which indicates that it would give perfectly acceptable simulation. Validation of the model in the study showed that it is possible to obtain good predictions for ground water table depth using the developed model. The developed model for water table depth series could be used for further prediction of monthly water table depths. The study also shows that time series analysis and ARMA models are effective in predicting monthly ground water table depth. The time series modeling approach as presented in this study can provide scientists, engineers and water managers a comprehensive tool for carrying out systematic study of ground water fluctuations.

218

References

Anderson O D (1976). Time Series Analysis and Forecasting, the Box�Jenkins Approach. Butterworth and Co., London

Annen K (2004). Web: reg- Econometrics Add Ins. www.web.reg.deBhakar S R; Chhajed N; Bansal A K (2006). Stochastic modeling of evaporation at Udaipur. Proceedings of

40th ISAE Annual Convention and Symposium. Tamilnadu Agricultural University Coimbatore, SWC-HW, 109-152

Box G E P; Jenkins G M (1970). Time Series Analysis: Forecasting and Control. Holden � Day, San Francisco, Calif

Chandrahas (2003). Modeling and forecasting a univariate time series using Box- Jenkins methods. Forecasting Techniques in Agriculture. Summer School. Indian Agricultural Statistics Research Institute New Delhi, pp1-13

Chatfield C (1984). The Analysis of Time Series: An Introduction. Chapman and Hall Ltd., London Gujarati D N (2003). Basic Econometrics. McGraw � Hill, New YorkHipel K W; McLeod A I (1994). Time Series Modeling of Water Resources and Environmental Systems. Elsevier

Science, New YorkJat M L; Singh R; Bhakhar S R; Gupta A (2003). Stochastic modeling of water deficit under climatic condition

of Kota. Journal of Applied Hydrology, 16(2), 43-52Kahya E; Kalayc S (2004). Trend analysis of stream flow in Turkey. Journal of Hydrology, 289(1-4), 128-144Knotters M; van Walsum P E V (1997). Estimating fluctuating quantities from time series of water table depths

using models with a stochastic component. Journal of Hydrology, 197, 25-46Kottegoda N T (1980). Stochastic Water Resources Technology. Macmillan Press, LondonKumar S; Sondhi S K; Phogat V K (2006). Forecasting of water table behavior by using the regionalised time

series modeling in UBDC tract. Proceedings of 40th ISAE Annual Convention and Symposium. Tamilnadu Agricultural University Coimbatore, SWC-DG, 27-46.

Mujumdar P P; Kumar D N (1990). Stochastic models of stream flow: some case studies. Hydrological Sciences Journal, 35, 395-410.

Nash J E; Sutcliffe J V (1970). River flow forecasting through conceptual models, part- I- A discussion on principles. Journal of Hydrology, 10(3), 282-290. Salas S D; Delleur J W; Yevjevich V; Lane W L (1980). Applied Modeling of Hydrologic Time

Series. Water Resources Publication, Littleton, Colorado

Salunkhe S S (2006). Stochastic Modeling of Ground Water Status of Noyyal River Basin. M. Tech. Thesis, Tamil Nadu Agricultural University, Coimbatore, India.

Srikanthan R; McMahon T A; Irish J L (1983). Time series analysis of annual flows of Australian streams. Journal of Hydrology, 66, 213-226.

Van Geer F C; Zuur A F (1997). An extension of Box-Jenkins transfer/noise models for spatial interpolation of groundwater head series. Journal of Hydrology, 192, 65-80.

Yevjevich V (1972 a). Stochastic Processes in Hydrology. Water Resources Publications, Fort Collins, U.S.A

Yevjevich V (1972 b). Probability and Statistics in Hydrology. Water Resources Publications, Fort Collins, U.S.A

Yevjevich V; Harmancioglu N B (1985). Past and future of analysis of water resource time series. Water Resource Bulletin, 21(4), 625-633.

���

219

Notation

= Average observed water table depth.

= Autoregressive model parameter, k=1, 2, 3,⁄..pA

j and B

j = The Fourier coefficients

Dt = Dependent stochastic component

J = Harmonics number m = Number of significant harmonics m

x = Average monthly mean

m? = Monthly mean

N = Number of observations P = Order of autoregressive process Pt = Periodic component

q = Order of moving average process Q

c (t) = Predicted water table depth at time t

Qo (t) = Observed water table depth at time t

Rt = Independent stochastic component or Residual series

St = Stochastic component of the series

sx = Average monthly standard deviation

s? = Monthly standard deviation

T = Discrete values of time 1, 2, 3,⁄..n Tt = Trend component

u = ARMA Model constant. û? = Estimated values of periodic mean

Xt = Trend free series

Yt = First differenced series

Zt = Time series variable

Zt-1 = Value of time series Z

t at previous lag

βk

= Moving average model parameter, k=1, 2, 3,⁄..qσ?

= Estimated values of periodic standard deviation ? = 1, 2, 3,⁄⁄ù, with ù as n number of discrete values in yearFigure captions :Fig. 1. Noyyal river basin with stream linesFig. 2. Autocorrelogram of trend free water table depth series Fig. 3. Historical and regenerated monthly water table depth series Fig. 4. Historical and regenerated mean monthly water table depth series

220

Table 1. Explained variance of different harmonics of mean

Harmonic Explained Cumulative number Value of A Value of B (A2+B2)/2 variance of explained harmonic (%) variance (%)

1 -0.1913 0.2896 0.0602 59.1084 59.1084

2 -0.1644 0.0838 0.0170 16.7091 75.8175

3 -0.0931 0.1030 0.0096 9.4618 85.2793

4 -0.0364 0.1053 0.0062 6.0855 91.3649

5 0.0108 -0.0068 0.0001 0.0802 91.4450

6 -0.0276 0.0000 0.0004 0.3743 91.8193

Table 2. ARMA models for stochastic component of water table depth series

Order of Adjusted sum Residual Log Akaike Schwartz model of square variance likelihood information bayesian criterion criterion

AR (1) 112.7059 0.9629 -165.6284 335.2568* 340.8151*

AR (2) 112.6975 0.9711 -165.6945* 337.2689 345.6063

AR (3) 111.8190 0.9717 -165.1834 338.3668 349.4832

AR (4) 111.1679 0.9743 -164.8548 339.7095 353.6051

AR (5) 111.1579 0.9829 -164.8732 341.7464 358.4211

AR (6) 110.2456 0.9831 -164.4098 342.8197 362.2735

ARMA (1,1) 112.7029 0.9711 -165.6373 337.2746 345.6120

ARMA (2,1) 112.4971 0.9777 -165.5433 339.0866 350.2031

ARMA (3,1) 110.1054 0.9645 -164.2820 338.5641 352.4597

ARMA (1,2) 112.7634 0.9800 -165.6840 339.3680 350.4845

ARMA (2,2) 109.4340* 0.9457* -163.8905 337.7810 351.6766

* Indicates the selected modelTable 3. Diagnostic checking of ARMA models

Significance of residual mean Portmanteau test

Order of Test Critical Test Test Critical Test model statistics value result statistics value result

AR (1) 0.0127 1.9630 Pass 7.3157 42.5570 Pass

AR (2) 0.0134 1.9630 Pass 7.2858 41.3370 Pass

ARMA (2,2) -0.4480 1.9630 Pass 6.6135 38.8850 Pass

Table 4. Coefficient of efficiency of the selected models

Order of model Coefficient of efficiency (CE)

AR (1) 0.9998

AR (2) 0.9998

ARMA (2,2) 0.9998

Table 5. Statistical parameters of monthly water table depth series

Statistical parameters Historical series Regenerated series

Mean 16.9281 16.9098

Standard deviation 1.7733 1.7670

Variance 3.1446 3.1222

Skewness -0.0722 -0.0718

Kurtosis -0.3103 -0.2980

221

Geographical Information System for Evaluation of

Groundwater Potential Zones in Marudaiyar Basin of Tamilnadu

Senkuttuvan.P*. Sasikala.R** and S.Balaselvakumar***

40

IntroductionThe groundwater occurrence in any terrain

is largely controlled by prevalence of primary and secondary porosity and as such in conventional exploration methods delineation and mapping of different lithological, morphological units is difficult to its synoptic view. In addition to quantitative surface phenomenon like drainage network and geomorphology has a unique capsule of integrating the study. To understand the prevailing groundwater condition, nowadays satellite based remote sensing techniques are being regularly employed for the terrain resources mainly for delineating hydrogeomorphological units (Anonymous, 1979, 1988; Aravindan et.al., 1996; Baldev Sahai et al 1991; Jacob Novaine et al 1999; Obi Reddy et al 2000 and Krishnamoorthy, 1996). But only, very few studies have been attempted by integrating all the groundwater controlling parameters like geology, geomorphology, lineaments, quantitative morphometric characteristics, etc., especially using Geographical Information System

(GIS) as a tool. In the present study, GIS based model was developed, for delineating groundwater potential zones by integrating different thematic layers which have direct bearing on groundwater occurrence. The thematic layers were prepared from remote sensing data and from the data collected by conventional surveys. The GIS based groundwater potential zone model developed in the present study was built with the relevant logical conditions and reasoning and hence can be adopted elsewhere with suitable modifications.

Methodology

Study AreaMarudaiyar basin, the study area is located in

the central part of Tamil Nadu State concerning an area extent of 623 sq.km. It is geographically located between the latitudes 11�02Ç to 11�15Ç N and the longitudes 78�48Ç to 79�15Ç E. The area is composed of series of plains, valley bottoms, undulating uplands and broken chains of eastern - ghats viz., Pachamalai. The average

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height of Pachamalai hill is 100 meters. But few of its peak above 1020 meters from MSL. The elevation of the basin ranges from 250-400 meters. The Marudaiyar basin has its origin from the Pachamalai hills, and it flow in the southeastern direction, passing through the Perambalur, Kunnam, Ariyalur Udaiyarpalayam and Lalgudi taluks of Perambalur and Tiruchirappalli District before joining the Coleroon River. In the study area, the average annual rainfall ranges from 750mm to 1000mm. The area comes under the influence of both the southeast monsoon (June � September) and northeast monsoon (October - December) due to orographic effect. Most of the people in the study area are engaged in agricultural activities and the important crops cultivated in the area include paddy, sugarcane, cotton, groundnut, sorghum, pearl millet, finger miller, red gram and banana.

In order to demarcate the groundwater prospect zones of the Marudaiyar basin, different thematic maps at 1:50,000 scales were prepared from remotely sensed data and from conventional data. Thematic maps of geology, geomorphology and lineament were prepared using IRS ID LISS III data of 1:50, 000 scales. The satellite data was visually interpreted and after making through field check, the map was finalized. The maps of drainage density, lineament density and slope maps were prepared from 1: 50,000 scales topographic sheets of the Survey of India. The Arc Info /Arc View GIS software package was used for the creation of digital database, data integration and analysis. All thematic maps were digitized in continuous mode, in the vector format, and the digitized values were then edited. The different polygons in the thematic maps were labeled separately. Unique attributes were assigned for all the features of different thematic maps. The different polygons in thematic maps were categorized as follows i). Excellent, ii).Good, iii).Moderate and iv). Poor in terms of their importance with respect to groundwater occurrence. Then suitable weights were assigned to each

thematic feature after considering their characteristics. The criteria adopted to categorize different thematic layers are given in table 1. All the thematic layers have been integrated and analyzed using a model developed with logical conditions in the GIS. The methodology adopted in the present study is shown in the form of a flow chart (Fig. 1.).

FLOW CHART DEPICTING THE METHODOLOGY OF GROUNDWATER POTENTIAL ZONES

Result and Discussions

Geographical Information System (GIS)Geographic Information System (GIS) is a

computer based information system digitally used to represent and analyze the geographic features present on the EarthÊ surface and the events (non-spatial attributes linked to the geography under study) that taking place on it. The GIS has provided a new dimension of information processing-specially related to the processing of information of the Earth and its natural resources. It is a tool for storing, manipulating, retrieving and presenting both spatial and non-spatial data in a quick efficient and organizing way. Since most land information elements have a geographic implication, geographically referred data with GIS techniques come to the force in such an application. The term GIS refers to the locational attributes, which define the spatial

Theme Basis of Categorization

Lithology Rock type, weathering character, thickness of weathering, joints and fractures etc.Geomorphology Type, area extent, associated vegetationDrainage density Drainage density valueLineament density Lineament density valueResistively Massive and consolidated nature in relation to high resistively with respect to depths.

Table 1. Categorization Criteria of Thematic Layer

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positioning of the piece of information on the face of the earth. Preparation and maintained of data in the face of maps and referenced tabular files itself can be considered as a primitive form of GIS. However, with the advent of digital computers, with high data processing speed and the development of analytical tools there on to handle geographically referenced data with ease and flexibility, computer aided GIS has become a reality of late.

There are a number of positive developments in GIS technology that will help accelerate its use. The world over, the GIS applications are now commonplace in the utilities, land information and planning. GIS can be an effective tool in the design and monitoring of groundwater development and its uses. GIS has found a role in the analysis and management of all such areas where Âvariations in local and micro-elements influences the patternsÊ.There exists a potential in GIS applications to use remotely sensed data (images) to evaluate the potential of groundwater resources for agriculture and sustainable development. Recent researches have also proved that indigenous knowledge system and rapid and participatory rural / resources appraisal methods could be integrated with GIS.

Applications of GIS in Hydrological Studies

Groundwater resources are dynamic in nature as they grow with the expansion of irrigation activities, industrialization, urbanization etc. As it is the largest available source of fresh water laying beneath the ground it has become crucial not only for targeting of groundwater potential zones, but also monitoring and conserving these important resources. The role of GIS in hydrological applications such as groundwater resource assessment, planning, soil erosion and urban drainage system and the remote sensing data derivation has gained popularity in recent times with raster and vector in GIS environment (Burrough, 1989, Lyon 2003 and Brown 1995). Several researchers have utilized the GIS technology and the remote sensing derived data for water resource management, groundwater assessment and modeling.

Weights Assignment for Thematic Layers

After understanding their behavior with respect to groundwater control, the different classes were initially categorized. The feature-based categorizations of different thematic maps and the exact weight assigned to

each of the thematic features based on the relative merit and demerit with respect to groundwater occurrence is given in table 2. While considering the lithological variations, one need to understand the characteristics of rocks in terms of their compactness, weathering status, joints and fractures. In the study area, sedimentary rocks have been rated higher than the metamorphic rocks considering compactness characteristics. It can be noted that the different classes were given suitable weights according to their importance among other classes in the same thematic layer. The logical reasoning adopted for categorization and weight assignment for each of the thematic features are detailed below.

GeologyAmong the various rock types of the study area

(viz., alluvium, calcareous sandstone and limestone, shale, calcareous sandstone and clay, clay and sandy clay, peninsular gneiss) alluvium was assigned the maximum weightage (50) owing to their unconsolidated nature, high prosing and permeability (Table 2). The weightage values assigned for the other categories in a progressively decreasing order, which include calcareous sandstone and limestone (40), shale (35), calcareous sandstone and clay (30), clay and sandy clay (20) and peninsular gneiss (20). Thus the lowest weightage value was assigned for peninsular gneiss in view of their highly massive water and varies poor porosity and permeability.

GeomorphologyAmong the various landforms of the study

area alluvial plains were assigned the maximum value (70) in view of the fact that this landform is essentially composed of alluvial materials, which are unconsolidated and highly porous, and permeable (Table 2). Moreover as this landform is very close to the rivers, these alluvial plains gets recharged guide often and hence naturally this landform possess excellent groundwater. The valley fills, which are the unconsolidated materials of varying sizes, confined to the valleys are also rich in groundwater, as this landform possess favorable constituent in consolidated materials, which facilitates instant infiltration of groundwater making them on of the groundwater rich landform hence it was assigned a weightage of 65. Progressively lower weightage were assigned to landforms such as pediplain over sedimentary rocks (50), Pediplain over gneisses (35), Pediment (20), gullied land (20) badland topography and denudation hill (10).

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Parameters Weightage Class Rank

Geology

Alluvium 50 Excellent 1

Calcareous sandstone and lime stone 40 Excellent 1

Shale 35 Good 2

Calcareous sandstone and clay 30 Good 2

Clay and sandy clay 20 Moderate 3

Peninsular gneiss 20 Moderate 3

Geomorphology

Alluvial plain 70 Excellent 1

Valley fills 65 Excellent 1

Pediplain over sedimentary 50 Good 2

Pediplain over gneisses 35 Good 2

Pediment 20 Moderate 3

Gullied land 20 Moderate 3

Badland topography 10 Poor 4

Denudational hills 10 Poor 4

Drainage density (in km/ sq.km)

<1 50 Excellent 1

1-2 40 Good 2

2-3 30 Moderate 3

3-4 20 Moderate 3

>4 10 Poor 4

Lineament density (in km/ sq.km)

>3 40 Excellent 1

2-3 30 Good 2

1-2 20 Moderate 3

<1 10 Poor 4

Slope (in À)

<1 50 Excellent 1

1-2 40 Excellent 1

2-5 30 Good 2

5-10 20 Moderate 3

>10 10 Poor 4

Table 2. Rank and Weightage Assigned for Various Thematic Layers with Respect to Groundwater Prospects

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Drainage DensityHigh drainage density reflects the higher surface

runoff and low infiltration of surface water with the ground. On the other hand low drainage density reflects poor surface runoff and high infiltration of surface water into the ground or subsurface flow. This fact was considered in assigning the weightage for the various drainage density classes of the study area. Drainage density class of less than 1km per sq.km was assigned the maximum weightage value (50); progressively lower weightage were assigned to the drainage density classes of 1-2 km/sq.km; 2-3 km/sq.km; 3-4 km/sq.km and >4 km/sq.km(Table 2).

Lineament DensityThe lineaments especially those representing

geologically weak zones especially fractures, joints, faults, sheer zones are good rechargeable zones. If the density of the lineaments is more than, the possibility for higher recharge is more and this character was considered to assign weightage for different lineament density zones of the study area. Areas with highest lineament density (>3 km/sq.km) was assigned the maximum weightage (40) and progressively lower weightage were assigned for the lineament density classes of 2-3 km/sq.km; 1-2 km/sq.km and the least weightage was assigned to the lineament density class of < km/sq.km (Table 2).

SlopeIn areas with higher slopes, the water, which

flows on the surface rapidly, drains off, greatly reducing the chances of water infiltrating into the ground. On the other hand in flat areas /plains, water which flows on the surface with lower velocities and hence the possibility of water infiltrating into the ground is more and hence it is grunt natural to expect plain areas with higher groundwater potential than areas with higher degrees

of slopes. This fact was considered while assigning the weightage for the various slope classes. Thus areas with slopes less than 1À were assigned higher weightage (50) and progressively lower weightage was assigned to the slope classes of 1À-2À, 2À-5À, 5À-10À and >10À (Table 2).

Integration of Thematic LayersTo demarcate different groundwater potential

zones, all the thematic layers were integrated with one another according to their importance with respect to groundwater prospects through GIS union concept. The sequences adopted in the present exercise are as follows: i) geology, ii) geomorphology, iii) drainage density, iv) lineament density and v) slope. In the present study, the delineation of groundwater potential zones was made by grouping the polygons of the integrated layers, into different potential zones, such as excellent, good, moderate and poor (Fig. 2). Instead of just dividing the maximum and minimum values into different categories, which has limited logical reasoning, a model has been developed using relevant logical conditions through Geographical Information System. The table 3 gives the integrated groundwater categories after adding the weightage in different thematic layers derived for demarcation of the groundwater prospecting areas.

Categories Weightage values

Excellent 240 � 180

Good 180 � 120

Moderate 120 � 60

Poor Less than 60

After adding all the polygon the maximum weightage is 240, the polygon were divided with an interval of 60 as weightage difference and accordingly excellent prospect was delineated by grouping the polygon which have weightage from 240 to 180, good (180 to 120), moderate (120 to 60) and poor prospective zone as polygons which are having the weightage factors less than 60 (table 3). By utilizing the above-discussed model a map showing different groundwater potential zones of the study area was prepared (Fig. 2).

ConclusionIn order to understand the groundwater potential

in the study area, thematic layers of parameters which affect the groundwater potential in an area such as

Table 3. Groundwater Categories after Integration

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lithology, slope, geomorphology, lineament density and drainage density were integrated and analyzed using Arc GIS software. For each of the above parameters suitable weightage values were assigned based on their ability to store water. As a as lithology is concerned alluvium was assigned the maximum weightage value followed by limestone, shale, calcareous sandstone and clay, clay and sandy clay, and gneisses in the decreasing order. Areas with less than 1� slope were assigned higher weightage and progressively lower weightages were assigned to the slope classes of 1À-2À, 2À-5À, 5À-10À and >10À. Among the various landforms of the study area maximum weightage value was assigned for alluvial plains, followed by valley fills, pediplain over sedimentary rocks, pediplain over gneisses, pediment, gullied land, badland topography and denudation hill in the decreasing order. As for as lineament density parameter is concerned, maximum weightage value was assigned to areas with highest lineament density (>3 km/sq.km). Progressively lower weightage values were assigned for the lineament density

classes of 2-3 km/sq.km; 1-2 km/sq.km. Among the various drainage density classes, higher weightage value was assigned to areas with low drainage density and vice-versa. After assigning weightage values for various classes of each of these parameters, these thematic layers were integrated and the resultant map was re-classed showing zones of excellent, good, moderate and poor groundwater potentials. The analysis thus carried out has revealed that the area extents of zones with excellent, good, moderate and poor groundwater potentials are 152 sq.km, 432 sq.km, 28 sq.km and 13 sq.km respectively. In general it is found that in the study area, areas with excellent and good groundwater potentials are spread over most part of the study area, occupying 24.32 per cent and 69.12 per cent of the study area respectively. On the other hand, zones of moderate and poor groundwater potentials occupy just about 4.48per cent and 2.08 per cent of the study area respectively and these categories are mostly confined to the western part of the study area.

ReferencesAnbalagan, S. and Archana M. Nair, (2004): „Geographic Information System and Groundwater Quality Mapping in

Panvel Basin, Maharashtra, India‰, Environmental Geology, Vol. 45, pp. 753-761.Erhan Sener, Aysen Davraz and Mehmet Ozcelik., (2004): „ An Integration of GIS and Remote sensing in Groundwater

Investigations: A Case Stduy in Burdur, Turkey‰, Hydrogeology Journal, Vol. 12, No.6, pp. 714-722.Hong-IL Ahn and Hyo-Taek Chon (1999): „Assessment of Groundwater Contamination using Geographic Information

Systems‰, Environmental Geochemistry and Health, Vol. 21, pp. 273-289Karanth, K. R., (1987): „Groundwater Assessment, Development and Management‰, Tata McGraw- Hill Publishing

Company Limited, New Delhi, p.720.Kumar, Ashok, L. B. Prasad, B. B. Prasad and Nisha Mendiratta (2000): „GIS and GWW is tool for creating groundwater

information system (GWIS)- A case study Upper Barkar Basin‰, Bihar. www.gisdevelopment.netLin Zhen and Routray Jayant, K., (2002): „Groundwater Resource Use Practices and Implications for Sustainable

Agricultural Development in the North China Plain: A Case Study in Ningjin Country of Shandong Province, PR China‰, Water Resources Development, Vol. 18, No. 4, pp.581-593

Murthy, K.S.R., (2000): „Groundwater Potential in a Semi-arid Region of Andhra Pradesh: A Geographical Information System Approach‰, International Journal of Remote Sensing, Vol. 21 No. 9, 1867-1884.

Radu Constantin Gogu et. al, (2001): „GIS-based Hydro-geological Databases and Groundwater Modeling‰, Hydrogeology Journal, Vol. 9, pp. 555-569.

Satti, R. Sudheer and Jennifer M. Jacobs (2004): „A GIS based Model to Estimate the Regionally Distributed Drought Water Demand‰, Agricultural Water Management, Vol. 66, pp. 1-13 (www.elsevier.com/locate/agwat)

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Engineering of Photorespiration Mechanism in Crop Plants for Higher Productivity in Drought

Prone AreasK. Silvas Jebakumar Prince, P .Kanagaraj, K.S. Vijay and J. Annie Sheeba

41

IntroductionTerrestrial plants are classified into three major

photosynthetic types, namely, C3, C4 and Crassulacean acidmetabolism (CAM) plants, according to the mechanism of their photosynthetic carbon assimilation. About 90% of terrestrial plant species, which include major crops such as rice (Oryza sativa), wheat (Triticum aestivum), soybean (Glycine max), and potato (Solanum tuberosum), are classified as C3 plants, and they assimilate CO2 directly through the C3 photosynthetic pathway, also called the Calvin cycle or the photosynthetic carbon reduction (PCR) cycle. C4 and CAM plants possess a unique photosynthetic pathway, in addition to the C3 pathway, which allows them to adapt to specific environments. While C3 plants grow well in temperate climates, CAM plants such as stonecrops and cactus adapt to extreme arid conditions, but their photosynthetic capacity is very low. By contrast, C4 plants such as maize (Zea mays) and sugarcane (Saccharum officinarum) adapt to high light, arid and warm environments and achieve

higher photosynthetic capacity and higher water- and nitrogen-use efficiencies compared with C3 plants. Both C4 and CAM plants evolved from ancestral C3 species in response to changes in environmental conditions that caused a decrease in CO2 availability. C4 plants evolved in response to the low atmospheric CO2 concentrations, while the CAM plants evolved either in response to the selection of increased water-use efficiency or for increased carbon gain (Ehleringer and Monson, 1993).

In leaves of C3 plants, all of the photosynthetic reactions from the capture of solar light energy to assimilation of carbon into carbohydrates (triosephosphates) proceed in the chloroplasts of the mesophyll cells. The primary CO2 fixation step in the C3 pathway is catalysed by ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco). However, Rubisco also reacts with O2 at its catalytic site (oxygenase reaction), leading to photorespiration. Photorespiration plays a role in protecting photosynthesis from photoinhibition (Osmond and Grace,1995), but it wastes fixed carbon

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as released CO2 and decreases the efficiency of photosynthetic CO2 assimilation in C3 plants (Leegood et al., 1995). Under current atmospheric conditions (0.036% CO2, 21% O2), up to 50% of the fixed carbon is lost by photorespiration. C4 plants have evolved the C4 photosynthetic pathway, a mechanism to concentrate CO2 at the site of the reaction of Rubisco, and thereby overcame photorespiration.

CO2 concentrating mechanisms This CO2-concentrating mechanism, together

with modification of leaf anatomy, enabled C4 plants to achieve high photosynthetic efficiency. Leaves of C4 plants have two types of photosynthetic cells, the mesophyll and bundle sheath cells that contain chloroplasts of different functions. While all the photosynthetic enzymes are confined in the mesophyll cells in C3 plants, they are localized in the mesophyll and/or bundle sheath cells in C4 plants. The enzymes involved in the C3 pathway are located in the chloroplasts of the bundle sheath cells while those involved in the C4 pathway in the mesophyll and/or bundle sheath cells. The C4 pathway consists of three key steps: (i) The initial fixation of CO2 in the cytosol of the mesophyll cells by phosphoenolpyruvate carboxylase (PEPC) to form a C4 acid, oxaloacetate (OAA), (ii) Decarboxylation of a C4 acid in the bundle sheath cells to release CO2, and (iii) Regeneration of the primary CO2 acceptor phosphoenolpyruvate (PEP). As a whole, one molecule of CO2 is pumped up from the cytosol of the mesophyll cells into the vicinity of Rubisco in the chloroplast of the bundle sheath cells, consuming two molecules of ATP. The decarboxylation reaction is catalysed by one or more of the three enzymes, namely, NADP-malic enzyme (NADP-ME), NAD-malic enzyme (NAD-ME), and phosphoenolpyruvate carboxykinase (PEP-CK), and C4 plants are classified into three subtypes depending on these major decarboxylation enzyme. The C4 acid exported from the mesophyll to bundle sheathcells are also different. Before being exported, OAA is reduced to malate by NADP-malate dehydrogenase (NADP-MDH) or transaminated to aspartate by aspartate aminotransferase (AspAT) in the NADP-ME type and the NAD-ME and PEP-CK types, respectively. Regeneration of PEP is catalysed by pyruvate, orthophosphate dikinase (PPDK) located in the mesophyll cell chloroplasts in all subtypes, although PEP-CK in the bundle sheath cell cytosol also participates in this process in the PEP-CK type. Maize and sugarcane use NADP-ME for the decarboxylation and these are classified as the NADP-ME type.

Transfer of C4 traits to C3 PlantsSince the discovery of the C4 pathway, it has

been postulated that the transfer of C4 traits to C3 plants should improve the photosynthetic performance of C3 plants. Initially, conventional hybridization between C3 and C4 plants was carried out. This approach was available only in several plant genera and most C3-C4 hybrids were infertile (Brown and Bouton, 1993). Another approach that has been adopted in the last ten years involves the use of recombinant DNA technology. With this technology, understanding of the evolution of C4 photosynthetic genes has been expanded and it is now possible to express C4 enzymes at high levels and in desired locations in the leaves of C3 plants. The evolution of C4 genes together with techniques with which to overproduce C4 enzymes in the leaves of C3 plants is a successful path towards photorespiration engineering. The regulation and physiological impacts of overproduced C4 enzymes in transgenic rice plants are also presented. The physiological impacts of the overproduction in potato, tobacco (Nicotiana tabacum) and Arabidopsis thaliana as well as rice have been reviewed, Ha˚usler et al., 2002.

Factors affecting the expression levels of C4 transgenes

The expression of transgenes is hampered by many mechanisms including the positional effects (Gelvin, 1998), silencing (Gallie, 1998; Chandler and Vaucheret, 2001) and rearrangement (Hiei et al., 1994) of transgenes. During overproducing C4 enzymes studies, it was found that the rearrangement occurs frequently during the gene transfer mediated by Agrobacterium tumefaciens. A significant fraction of transgenic rice plants introduced with the intact maize C4-specific gene showed activities of C4 enzymes comparable to or even lower that that of non-transformants (Ku et al., 1999; Fukayama et al., 2001). DNA gel-blot analysis of these low-expressing lines showed that transgenes in all lines tested sustained partial deletion and/or chimeric linking (Fukayama et al., 2001). Such rearrangement is not peculiar to long transgenes with complex exon-intron structures, and it did occur in five out of nine transgenic rice plants introduced with a cDNA construct of 4.4 kb. It is possible that cis-acting elements and/or the transit sequence are selectively deleted from an introduced gene, altering the level and/or location of a C4 enzyme in transgenic C3 plants. The overproduction of C4 enzymes in C3 plants can be achieved by introducing appropriate

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gene constructs. It is also necessary to screen a number of transgenic plants to obtain a desired expression level of a C4 enzyme and to confirm the enzyme location in the leaves of C3 plants.

Applications of overproduction of C4 enzymes

A major objective of overproduction of C4 enzymes in C3 plants is to improve the photosynthetic performance. Ha˚usler et al.,2002 reported none of the positive effects on photosynthesis have been observed in transgenic C3 plants overproducing a single C4 enzyme. Transgenic C3 plants overproducing multiple enzymes are being produced and analysed in successful manner. Although the introduction of the ÂC4-likeÊ pathway into the mesophyll cells of C3 plants is one strategy being adopted (Mann,1999; Surridge, 2002), whether or not this pathway can operate with desirable effects on C3 photosynthesis is a matter of controversy (Edwards, 1999; Leegood, 2002;Ha˚usler et al. 2002). Considering the C4 pathway operating in a single cell found in some aquatic organisms (Leegood, 2002), it might be possible that the C4-like pathway could support C3 photosynthesis under some stress conditions such as drought, in which the CO2 availability is limited. Apart from photosynthesis, overproduction of a single C4 enzyme seems to have some positive effects on physiology of C3 plants. It has been reported that overproduction of the chloroplastic, but not cytosolic, PPDK increased the number of seeds per seed capsule and the weight of each seed capsule in transgenic tobacco (Sheriff et al., 1998), and that overproduction of the maize C4-specificc PEPC improved resistance to aluminium with root elongation in transgenic rice (Miyao et al., 2001). It is of prime importance to elucidate mechanisms for these effects and to confirm whether or not similar phenomena can be generally observed in different plant species. Taking account of a variety of housekeeping functions of the C3-specific enzymes, it is not unlikely that overproduction of C4 enzymes could improve various features of C3 plants.

FUTURE PERSPECTIVESThere has been considerable progress in recent

years in the molecular engineering of C4 photosynthesis. The technology to express the C4 enzymes at high levels and in the desired locations in the leaves of C3 species

is becoming well established, and it is now possible to produce transgenic C3 plants that express at least a set of key enzymes of the C4 pathway. Thus, we have just reached the starting point in introducing the basic biochemical elements of the C4 pathway into C3 plants. Apart from the goal of installation of a complete C4 pathway into C3 plants, some transgenic C3 plants that overproduce a single C4 enzyme show alterations in carbon metabolism. These plants are also proving to be useful tools in probing the „housekeeping‰ function(s) of the C4-like enzymes in C3 plants and the evolution of the C4 photosynthetic genes. Experiments with transgenic plants have reinforced the fact that the C4 mechanism is a finely tuned metabolic „machine‰ where both a high degree of precision in gene expression and structural morphology work together to concentrate CO2 efficiently at the site of Rubisco.Work with transgenic C4 Flaveria and also transgenic C3 plants shows that relatively small changes in leaf biochemistry, induced by transgene action, can have major deleterious effects on photosynthetic competence. First, we should deliver the degree of precision required to coexpress the necessary genes at the correct levels and ratios in the correct compartments. For the primary enzymes of the C4 pathway these preliminary results are promising but correct posttranslational regulation of the introduced, heterologous enzymes, fine-tuning of the levels of ancillary enzymes (such as CA, adenylate kinase, and pyrophosphatase) and metabolite transporters must also be addressed. We should create an efficient CO2 concentrating mechanism in a plant lacking Kranz leaf anatomy, a morphological feature independently arrived at several times through the convergent evolution of C4 plants. In connection with the key issue, there are good examples of higher plant CO2 concentrating mechanisms without Kranzanatomy, namely, the submersed aquatic macrophytes (SAMs) such as Hydrilla verticillata, in which an intracellular C4-like pathway is induced in response to a decline of ambient CO2 concentration. Studies on the mechanisms of induction of a C4-like pathway in SAM plants may help us to understand how to introduce an effective C4-like mechanism to MCs of C3 plants. However, the performance of an artificially introduced C4 pathway in C3 crops can only be obtained by the generation and comprehensive analysis of transgenic crop plants currently being produced.

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Water Efficient Rice Cultivation Strategy

C.Sudhalakshmi, V.Velu and T.M. Thiyagarajan

42

IntroductionIrrigated agriculture consumes more than two

thirds of the available water. Rice is a profligate user of water. More than 5 tonnes of water is needed to grow one kilogram of rice. Water use efficiency of rice is only 3.7 kg/ha/mm (Subbian et al., 2000) which is the lowest compared to any other cereal crop. Opportunities for the development of new water resources are dwindling. If food security must be maintained, ways of increasing the productivity of water must be explored. Rice is not naturally an aquatic plant (Paurd et al., 1989), which deserves the fact that limited irrigation may suffice attaining enhanced yields and outruns the age-old notion, more the water, higher the crop yields which strongly persists with a majority of cultivators. Hence the present investigation was framed to bring out the possibility of water saving rice cultivation by System of Rice Intensification method which encompasses modified planting, irrigation, weeding and nutrient management strategies.

Materials and MethodsField experiments were designed in the wetlands

of Tamil Nadu Agricultural University (110 N 770 E) during the wet season (September 2001 � January 2002) with rice hybrid CORH2 (125 days duration) and during the dry season (February - June 2002) with rice hybrid ADTRH1 (115 days duration). The soil of the experimental site was clay loam in texture with pH of 8.3, electrical conductivity was 0.54 dSm-1, organic carbon content was 8.2 g kg-1, available N (KMnO4 � N) was 232 kg ha-1 at the start of the wet season and 190 kg ha-1 at the start of the dry season, Olsen � P was 32 kg ha-1 and available K (NH4 O Ac � K ) was 740 kg ha-1.

The treatments included two methods under each of the four factors studied viz., planting, irrigation, weeding and nutrition.

P1: Transplanting 24 days old conventional nursery seedlings at 20 x 20 cm spacing.

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P2: Transplanting 10 � 12 days old dapog nursery seedlings at 20 x 20 cm spacing during wet season and direct seeding during dry season.

I1: Irrigating the field to 5 cm one day after the disappearance of ponded water

I2: Irrigating the field to 2 cm after the development of hairline cracks.

W1: Manual hand weeding twice as per the farmersÊ practice (weeds removed)

W2: Weeding by conoweeder at 10 days interval upto maximum vegetative period (weeds buried)

N1: Recommended level of N, P, K and Zn without the addition of green manures

N2: Recommended level of N, P, K and Zn with the addition of green manures @ 6.25 t ha-1.

The experiment was laid out in strip plot design with the treatments replicated four times. Water management was effected using parshall flume placed in the field. Rainwater during the experimental period was also monitored. Grain yields (14 % moisture) were based on 13.5 and 13.0 m2 of each plot in the wet and dry seasons respectively. Gross size of the plots in both the seasons was 26.4 m2. Plant samples were collected as suggested by Thiyagarajan et al., 1995 and the crop data were analysed using GENSTAT (Payne et al., 2002).

Results and DiscussionIt can be inferred from the table that water saving

irrigation, though has resulted in reduced grain yields during wet season, it did not show statistical significance with that of yield recorded under conventional irrigation (Table 1). Ramamoorthy et al. (1993) reported that intermittent application of irrigation water 1 to 5 days after the disappearance of standing water saved 25 to 50 % irrigation water compared to continuous submerged conditions. Purushothaman and Jeyaraman (1992) observed that partial submergence of rice fields at critical stages of growth gave similar yields as continuous

submergence. But during dry season, conventional irrigation has registered a significantly higher grain yield (6492 kg ha-1) as against 6171 kg ha-1 observed under limited irrigation (Table 2).

In the wet season, grain yield under limited irrigation was similar to that recorded under conventional irrigation which implies that there is immense scope for water saving rice culture in wet season. However the rate of uptake of nutrients was less under modified irrigation which depicts the occurrence of internal water stress due to reduced water potential. The productivity of major nutrients was also lower under limited irrigation during both the seasons which would have attributed for this decline in yield. During dry season, limited irrigation was continued upto maturity as compared to flowering in the wet season. The extended period of limited irrigation reduced yields in the dry season.

During crop growth, the total rainfall was 3560 m3ha-1 in the wet season and only 560 m3ha-1 in the dry season. The total number of irrigations and frequency of irrigation were higher in the dry season. Water productivity (grain yield per unit of total water used, i.e. irrigation and rainfall) was higher under limited irrigation during both the seasons irrespective of the methods of planting. Also water productivity was higher during dry season compared to wet season (Table 3). The water productivity levels realized with limited irrigation are in the range typical for Philippines, i.e., 0.3 � 1.1 kg m-3 (Bouman and Toung, 2000).

ConclusionFrom the results obtained from the present study

it is quite evident that limited irrigation can suit only during wet season without drastic reduction in yield. Limited irrigation does not suit dry season due to reduced internal water potential. However the duration of the limited irrigation is an important factor in maintaining yield levels currently realized with flood irrigation. Limited irrigation thus has immense scope during wet season but during dry season, the duration of limited irrigation must be considered to sustain rice productivity.

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Table 1. Grain yield of rice hybrid CORH 2 in wet season (2001 - 02)

P1 P2 Mean Mean

W1 N1 6151 6199 6841 6268 6365 6076

N2 6000 6195 5893 5059 5787

W2 N1 6008 6908 6838 6707 6615 6737

N2 6343 6349 7612 7126 6858

Mean 6269 6543 6407

Mean I1 = 6461 I2 = 6352 N1= 6490 N2 = 6322

Table 2. Grain yield of rice hybrid ADTRH 1 in dry season (2001 - 02)

P1 P2 Mean Mean

W1 N1 6009 5694 6682 6366 6187 6226

N2 6261 5809 6600 6391 6265

W2 N1 6240 6014 6890 6400 6386 6436

N2 6311 6080 6941 6612 6486

Mean 6052 6610 6311

Mean I1 = 6492 I2 = 6171 N1= 6287 N2 = 6376

Table 3. Water productivity of irrigation regimes in SRI

Particulars Wet season Dry season

I1 I2 I1 I2

Number of irrigations 15 10 23 17

Amount of irrigation water supplied (m3 ha-1) 12600 5952 15020 7316

Rainfall in growing season (m3 ha-1) 3560 3560 560 560

Total supply (m3 ha-1) 16025 9512 15580 7876

Yield (kg ha-1) 6461 6352 6492 6171

Water productivity (kg m-3) 0.400 0.673 0.419 0.795

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ReferencesBouman, B.A.M. and Toung, T.P. 2000. Field water management to save water and increase its productivity in

irrigated lowland rice. Agricultural Water Management. 1615 : 1- 20.Paurd, M., Couchat, P and Laseve, G. 1989. Etude des mecnisms d adaptation du riz aux contraintes du milieu I :

Modification de lÊ anaomic cellulaire. LÊ Agronomic Tropicale. 44: 156-173.Payne, R., Murray, D., Harding, S., Baird, D., Sontar, D. and Lane, P. 2002. Genstat for window TM (6th edition).

Introduction VSN International.Purushothaman, S. and Jeyaraman, S. 1992. Influence of weed control methods under different irrigation regimes

on total water requirement and water use efficiency in transplanted rice. Madras Agric. J., 79 : 641 � 644.Ramamoorhty, K., Selvaraj, K.V. and Chinnaswami, K.N. 1993. Varietal response of rice (Oryza sativa) to different

irrigation regimes. Indian J. Agron., 38 : 468 � 469.Subbian, P., Annadurai, K. and Palaniappan, S.P. 2000. In : Agriculture: facts and figures. Kalyani Publishers,

Ludhiana.Thiyagarajan, T.M., Sivasamy, R. and Budhar, M.N. 1995. Procedure for collecting plant samples at different growth

stages of transplanted rice crop. In: Nitrogen management studies in irrigated rice. Proceedings of the SARP applications workshops held at the International Rice Research Institute, Los Banos, Philippines.

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234

A Study on Adoption Behaviour of Dry Land Farmers

K. Thangaraja*, C. Karthikeyan** J.Venkatapirabu**& M.Asokhan**

43

IntroductionDry land agriculture in India is always a

challenge, since crop production in dry land depends on monsoon showers. Dry land area receives less than 750 mm rainfall. Out of the net sown area of 136.18 m ha, the dry land accounts for 93.13 m ha (68.4%) and contribute 55 million tonnes of food production. This dryland agriculture from 93m ha supports 40 per cent of human population, 60 per cent of cattle heads and contributes 44 per cent to total food production in India (Kannaiyan et al; 2001). Area under rainfed crops included sorghum to a tune of 93.8 per cent and maize 77.4 per cent. About 42 per cent of total food grain production of the country is received from dry farming regions. Almost the entire quantity of coarse grains, 90 per cent of sorghum is produced in dry farming regions. So, for meeting the targeted food grain production of 240 million tonnes in the beginning of 21st century, production from dry lands has to be increased from 60 million tonnes to about 144 million tones by 2000 AD (Veerabadran et al., 2000).

In Tamil Nadu, area under dry farming constitutes 52 per cent of the total cultivable area contributing to 40 per cent of total food production. The productivity of crops grown in dryland is not only low but also remains stagnant over years. Tamil Nadu has a total geographical area of 13 m ha, of which 7 m ha is cultivable area. From the total cultivable area, around 3.1m ha are occupied by dry land crops. Most of the areas in Tamil Nadu come under semi arid tropical climate except the hilly regions and East coast. Out of 5.50 m ha of net sown area, nearly 3.20 m ha are rain fed (Kannaiyan et al., 2001).

Majority of the dry land farmers are small farmers with scarce resources. The poor resource base allows only low input subsistence farming with low and unstable crop yield. ThereÊs a strong need to channelise the efforts to increase the crop yield in dry land. Increased population and less per capita availability of land created an immediate necessity to increase productivity and bridge the gap between the potential yield and actual yield. Thus, there is a need to identify the socio-economic characteristics of the farmers which may influence the

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rate of adoption of dryland technologies leading to increased yield and to tap the untapped land, labour and available technical resources. Hence a study was taken up to assess the extent of adoption of selected dry land crops in Reddiarchataram block of Dindigul district.

METHODOLOGYThe study was taken up in Dindigul district of

Tamil Nadu. Reddiarchatram block was purposively selected for the study, since their main occupation of most of the people was agriculture, which depended on poor and erratic rainfall, majority of the farmers in the sampled block had been practicing dry farming. The sample size was 90 farmers consisting 45 maize growers and 45 sorghum growers. The selection of 30 farmers was done at random in each village. Thus, 10 farmers were selected from each of the nine villages covering three revenue villages using simple random sampling technique. The data were collected with well-structured and pre-tested interview schedule. Percentage analysis was used for data analysis.

Findings and DiscussionPractice wise Extent of adoption of the dry

land technologies in maize and sorghum The extent of adoption of the selected 12 recommended practices in maize and sorghum crops by the dry land farmers was studied in terms of full adoption, partial adoption and non-adoption and the results are presented in table.

Summer PloughingIt is seen from the table that, more than three-

fourth (82.22%) of the maize growers had full adoption (3-4 ploughing) of summer ploughing practice while 17.78 per cent had partial adoption. Similarly, a majority (66.67%) of the sorghum growers had adopted summer ploughing fully (i.e. 2-3 times). The rest of 22.22 per cent of the sorghum growers had partial adoption of summer ploughing. Summer ploughing is important for eradication of weeds and conserving the soil moisture in dry land area.

Recommended Variety / HybridCent percent of the maize growers have not

adopted the recommended variety / hybrid in maize crops. But they adopted ÂIcelÊ hybrid and kargil variety. Like wise cent percent of the sorghum growers had full adoption of recommended sorghum variety namely ÂK3Ê and ÂK4Ê.

Seed RateMore than three-fourth (88.89%) of the maize

growers had full adoption of recommended quantity of seed rate (7 kg/ac). While about 11.11 per cent of the farmers had partial adoption. Like wise 17.78 per cent of the sorghum growers had full adoption of recommended quantity of seed rate (5 kg/ac), the rest more than three-fourth (82.22%) of the sorghum growers had partial adoption, this might be due to the reason that the germination is low in dry land area. so, they had used higher seed rate.

Seed Treatment Very few maize growers (8.89%) had full

adoption of bio-fertilizers in general i.e., Azospirillum / Phosphobacteria 4 pockets /ac in their field and 11.11 per cent of the farmers had partial adoption and remaining 80.00 per cent of the farmers did not adopt the biofertilizers. More than one-tenth (11.11%)of the sorghum growers had full adoption of bio-fertilizers, Azospirillum 4 pockets/ac in their field and 4.44 per cent of the farmers had partial adoption. The rest 84.44 per cent of the sorghum growers did not adopt the bio-fertilizers. The reason might be that the non-availability of bio-fertilizers and lack of knowledge about the use of bio-fertilizers.

SpacingAbout 40.00 per cent of the maize growers

adopted the recommended spacing (45 x 20 cm) and 60.00 per cent of them had partial adoption. Similarly cent per cent of the sorghum growers had partial adopt. This might be due to their lack of knowledge about the spacing to be adopted for dry land crops (maize and sorghum).

Manures More than one-fourth (31.11%) of the maize

growers had full adoption about the application of 5.0t FYM/ac during the last ploughing, while majority (68%) of the farmers had partial adoption. Likewise majority (80%) of the sorghum growers had partial adoption followed by one-fifth (20%) of them did not adoption. Normally organic matter application was done to improve soil fertility. Wherever it was available they might have applied, while few had not applied the recommended level depending on its availability.

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FertilizersMore than one-tenth (11.11%) of the maize

growers had full adoption of application of (90 kg urea + 70 kg DAP + 45 kg potash per acre) fertilizer and majority (88.89%) of the farmers had shown partial adoption. Similarly majority (64.44%) of the sorghum growers had partial adoption of application of (16: 8: 0 NPK kg/ac) fertilizers followed by 35.56 per cent of the farmers expressed non-adoption. The farmers might not have the knowledge about the benefit of split application of fertilizers coupled with lack of money for investment and this may be the reason for such results.

MicronutrientLess than one-tenth (8.89%) of the maize growers

had revealed full adoption of micronutrients. A few of them 6.67% adopted Znso4 10 kg/ac partially followed by majority (84.44%) of them did not adopt. Similarly, few (4.44%) of the sorghum growers had full adoption of micronutrients (Znso4 10kg/ac) followed by less than one-tenth (8.89%) of farmers had partial adoption. The rest (86.67%) of the farmers did not adopt. This is due to the lack of knowledge and awareness about the advantages of micronutrient application to the crops.

Weedicide ApplicationAbout one-tenth (8.89%) of the maize growers

had partially adopted post emergence herbicides i.e., 15 DAS (Atrazine 500 g/ac) followed by majority (91.11%) of the farmers did not adopt. Like wise cent percent of the sorghum growers did not adopt any weedicide application. The reason for non-adoption of majority of the farmers was due to the high cost of herbicide and lack of knowledge on herbicide usage.

Major Pest ManagementMore than one-tenth (11.11%) of the maize

growers had partial adoption of pest management i.e., stem borer, cob borer controlled by application of pesticides (Endosulfan 500 ml/ac or Quinolphos 25 EC 500 ml/ac) followed by majority (88.89%) of farmers did not adopt any pest management practices. Similarly cent percent of the sorghum growers did not adopt any pest management practices. The reason was maize and sorghum crops are more resistant to pest attack in dry land area.

Major Disease ManagementVery few (6.67%) maize growers had partial

adoption of disease management i.e., leaf spot, powdery mildew controlled by application of Metalaxyl 72 wp @ 500 g/ac or Mangozeb 500 g/ac 30 DAS. While about a majority (93.33%) of the farmers did not adopt the practice. Similarly cent percent of the sorghum growers did not adopt any disease management practice in dry land area. This might be due to less pest and disease incidence in the crop.

Stage of HarvestMajority (62.22%) of the maize growers had

harvested the crop in the right time after the maturity, which had reflected in full adoption followed by 37.78 per cent of farmers had revealed partial adoption. Likewise 71.11 per cent of the sorghum growers had full adoption of the practice. The rest of 28.89 per cent of the farmers had partial adoption of the practice. The reason for this was due to the demand of labour and high cost of labour during harvesting of maize and sorghum (January �February).

ConclusionThis study clearly shows the practice wise

adoption of dry land technologies by farmers. Accordingly full adoption was found against summer ploughing, recommended variety in sorghum, usage of seed rate in maize, timely harvesting followed by partial adoption was found against the usage of seed rate in sorghum, adoption of spacing and application of manures and fertilizers in maize and sorghum crops. Similarly non-adoption was found against recommended variety/hybrid in maize, seed treatment with biofertilizers, application of micronutrients and weedicide, major pest and disease management. It was observed that the dry land farmers due to inadequate investment could not get timely inputs like seeds and fertilizers and other agricultural inputs. Lack of farm power and lack of contact with agricultural officers, would have been the possible reasons for low level of adoption of dry land technologies. It is suggested to provide timely inputs at subsidized rate by government societies and agriculture depots. Village level extension officers should take efforts to conduct meetings and demonstrations for out reach of technologies. Field visit may be organized to further promote the adoption of dry land technologies among the farming community in dry land areas.

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ReferencesKannaiyan, S., T.M. Thiyagarajan, M. Subramanian, T.N. Balasubramanian and

R.Selvaraj. 2001. Dryland green revolution in Tamil Nadu : The Perspectives, Tamil Nadu Agricultural University Press, Coimbatore.

Veerabadran, V., B. Gururajan and B.J. Pandian. 2000. Dry farming and its importance in Indian Agriculture, Dry farming, Agriculture College and Research Institute, Madurai.

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Table. Distribution of farmers according to technology- wise extent of adoption

Sl. No. Technologies Extent of adoption

Maize (n=45) Sorghum (n=45)

Full Partial Non Full Partial Non adoption adoption adoption adoption adoption adoption

No. % No. % No. % No. % No. % No. %

1. Summer ploughing 37 82.22 8 17.78 - - 30 66.67 10 22.22 - -

2. Recommended variety / hybrid - - - - 45 100.00 45 100.00 - - - -

3. Seed rate 40 88.89 5 11.11 - - 8 17.78 37 82.22 - -

4. Seed treatment *Bio-fertilizers 4 8.89 5 11.11 36 80.00 5 11.11 2 4.44 38 84.44 *Fungicide

5. Spacing 18 40.00 27 60.00 - - - - 45 100.00 - -

6. Manures 14 31.11 31 68.89 - - - - 36 80.00 9 20.00

7. Fertilizer 5 11.11 40 88.89 - - - - 29 64.44 16 35.56

8. Micronutrient 4 8.89 3 6.67 38 84.44 2 4.44 4 8.89 39 86.67

9. Weedicide application - - 4 8.89 41 91.11 - - - - 45 100.00

10. Major pest management - - 5 11.11 40 88.89 - - - - 45 100.00

11. Major disease management - - 3 6.67 42 93.33 - - - - 45 100.00

12. Stage of harvest 28 62.22 17 37.78 - - 32 71.11 13 28.89 - -

238

Effect of Crop Geometry Cropping System in Bhendi

Under Drip FertigationG.Vijayakumar1, D.Palanisamy2, M.V. Ranghaswami3 and D. Tamilmani2

44

IntroductionIndiaÊs crop production suffers mainly from the

availability of water. Thus, water is the most limiting factor in the Indian agricultural scenario. Due to water scarcity, the available water resources should be very effectively utilized through water saving irrigation technologies such as drip and sprinkler irrigation. Now a day, the irrigation technology is growing day by day; among the irrigation methods, drip irrigation may be more desirable over sprinkler and surface irrigation methods, as it minimizes losses due to runoff, deep percolation and possible soil water evaporation. Also, fertigation offers the best solution for intensive and economical crop production where both water and fertilizers are delivered to crop through drip system.

Materials

Field locationField studies were conducted at Thondamuthur

in Coimbatore district, Tamil Nadu during the year 2004. The field is located at 110 N latitude, 770 E longitude with an altitude of 256 m above MSL. In the

experimental field soil having sandy loam soil in texture with 7.66 pH and 1.13 dSm-1 of electrical conductivity. Also, the available N, P and K of the experiment field is 84.07, 74.21 and 261.3 kg/ha respectively.

Methods

Experimental detailsAccording to Jadhav et al., (2002) the irrigation

of experimental field were scheduled as given below,

WR = Water requirement of crop in lit/day

Epan = Pan evaporation in mm,

Kp = Pan factor, Kc = Crop factor,

Wp = Wetted percentage (0.4, adopted from FAO paper, 1980, Vol.36) and

A = Crop area in Sq.mt. (0.3 x 0.3 m).

Hence, the time scheduling of drip irrigation operation in minutes for different cropping stages of bhendi was determined and given in Table. 1.

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Design and TreatmentsThe experimental plot was laid out in a

randomized block design with four treatments and seven replication for the study.

T1 � Nitrogen at 100 % of recommended level,

T2 � Nitrogen at 80 % of recommended level,

T3 � Nitrogen at 60 % of recommended level,

T4 � Nitrogen at 100 % of recommended level by manual feeding.

Experiment LayoutFrom the water source, the water was pumped

through 15 HP motor and conveyed to the field with 50 mm diameter PVC main pipe line. From the main line, 40 mm diameter sub main PVC pipes were taken off. Then, the 16mm LLDPE lateral pipes were taken on both the sides to irrigate the fields from sub main pipe line; finally the water is distributed to crops with an 8 lph on line emitters.

Fertilizer Application The recommended fertilizer level of bhendi crop

is 40:50:30 kg/ha N, P and K respectively. The entire phosphorus and one fifth of nitrogen and potash were applied as basal. The balance nitrogen and potassium were applied in nine equal splits at 10, 20, 30, 40, 50, 60, 70, 80 and 90 days after sowing (DAS) through ventury fitted in the main pipe line.

EvaluationThe effect of plant height, number of leaves per

plant, weed properties, depth of root formation and yield components was evaluated under different fertilizer recommendation levels of bhendi crop.

Fertilizer Use EfficiencyFertilizer use efficiency was calculated by using

the following formula and expressed in per cent.

Fertilizer Use Efficiency (%) = Yield (kg/ha)/ Fertilizer Utilized (kg/ha)

Moisture distribution pattern in drip irrigation

Wetting front advance and depth of wetting in drip systems were recorded for different times of emissions, before and after irrigation to fix the optimum and economical emitter spacing. The soil moisture contour maps were plotted using the computer software package ÂsurferÊ of windows version.

EconomicsGross and net income per ha and benefit- cost

ratios were worked out based on the cost of cultivation, cost of input and sale of produce.

Results

Soil moisture distribution patternMoisture contents were observed in drip irrigated

experimental plot at surface, 15, 30 and 45 cm depth at a distance of 15 and 45 cm from emitter on both sides. Observed moisture content from emitter point, the moisture content was gradually decreased while the distance from the emitter increased. The moisture content on surface is lower compared at 15 cm and 30 cm depths, because of pores space of the sandy loam soil and gravitational force of the water. It shows that the moisture available was evenly distributed before irrigation and it was then gradually increased with increase in depth. Near the surface, the soil moisture was minimum (12.1 to 12.9 per cent). The soil moisture obtained before irrigation up to 45 cm depth was 12.1 to 15.1 per cent. The contour maps are shown in Figures 2 and 3.

Fig. 1. Experimental layout of four rows planting.

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Effect of nitrogen levels on growth parameters

Shoot length The height of bhendi crop 15 days after sowing

(DAS), the maximum plant height of 34.6 cm was recorded under drip irrigation at 80 per cent nitrogen fertilizer recommended level (T2). The plant heights of 32.8, 31.6 and 29.8 cm were recorded in T1, T3 and T4 respectively. The CD and SEd values were found to be 1.99 and 0.911 respectively. The T1, T3 and T4 are on par each other. By increasing nitrogen levels, the plant height was increased during the cropping season. Drip irrigation at 80 per cent nitrogen fertilizer recommended level (T2) produced taller plants of 36.82 cm at 15 DAS. The taller plants of 74.68, 116.28, 151.28, 187.28 and 221.34 cm in T2 were recorded 30, 45, 60, 75 and 90 DAS.

Number of leaves per plantThe number of leaves per plant was recorded

at 15 days interval after sowing to study the aspect of influence of nitrogen levels. Nitrogen at 80 per cent of recommended level (T2) registered significantly more number of leaves of 5.4. Nitrogen at 100 per cent of recommended level (T1) average number of leaves were 4.6 closely followed by 4.4 in nitrogen at 60 per cent of recommended level (T3), where as the number of leaves in control plot (T4) was 4.7. The results of analysis of

variance showed that among the treatments treatment (T2) was found to be significant at 5 per cent level of significance. The CD and SEd values were found to be 1.50 and 0.69 respectively at 90 DAS. The T1, T3 are on par each other and T4 were found to be poorest performing treatment.

Root GrowthNitrogen levels greatly influenced the root depth

formation during the cropping season. The depth was greater in drip irrigation at 80 per cent nitrogen recommended level (T2) of 28.6 cm at harvest stage. The root depths of 26.4, 25.4 and 22.5 cm were recorded in T1, T3 and T4 respectively. The diameter of the root spread was was highest of (52.9) cm under drip irrigation at 100 per cent nitrogen fertilizer recommended level (T1), whereas the root diameter of 51.1, 50.5, and 50.3 cm were measured in T2, T3 and T4 respectively.

The analysis of data observed that among the treatments tried, treatment (T2) was found to be significant in number of roots per plant at 5 per cent level of significance at harvest.

The CD and SEd values were found to be 4.64 and 2.13 respectively. The T1, T2 are on par each other. The T4 was poorest performing treatment. The root diameter and tap root length were found to be significant in T1 at 5 per cent level of significant. The CD and SEd values were 0.39 and 0.85 respectively.

Influences of nitrogen levels on yieldNitrogen at 80 per cent recommended level (T2)

gave the highest yield of 10,676.01 and 9931.707 kg/ha by the treatment T1 followed by the treatment T4 with the yield of 9874.07 kg/ha, where as the lowest yield was recorded in the treatment in nitrogen at 60 per cent recommended level (T3) of 9499.97 kg/ha.

The analysis of data revealed that among the treatments tried, treatment (T2) was found to be significant at 5 per cent level of significance. The plant height and number of leaves were high in T2 resulted in higher yield, due to more number of inter nodes and more number of flowering.

Fertilizer use efficiencyThe highest fertilizer use efficiency of 95.32

per cent was found out in drip irrigation with nitrogen at 80 per cent of recommended level (T2) due to high yield of bhendi with effective fertilizer utilized as

241

compared to other treatments, where as in 60 per cent of recommended level (T3) the efficiency was worked out as 91.34 per cent. The fertilizer use efficiency of 82.76 per cent and 82.28 per cent were recorded in T1 and T4 treatments respectively.

A relatively high yield of 10676.01 kg/ha was recorded in T2 at 80 per cent effective nitrogen recommended level as compared to the yield of 9874.07 kg/ha in T4. The CD and SEd values were found to be 5.18 and 3.54 respectively.

Cost EconomicsThe life of the drip material was taken as 6

years, interest at 8 per cent of fixed cost, the repair and maintenance cost at 2 per cent of fixed cost were taken in to consideration to work out the cost economics. The fixed cost of the installation of drip irrigation was Rs. 43,143 per ha for the first three treatments and control treatment, the fixed cost of installation for drip irrigation was Rs. 75,000 per ha due to closer lateral spacing. The gross income per ha were obtained from treatment T1, T2, T3 and T4 were Rs. 49,658, 53,380, 47,499 and 47,370 respectively.

The treatment T2 registered the highest gross income of Rs.53, 380 per ha because of high yield due to effective and optimal nitrogen uptake. The benefit-cost ratio was also higher (2.01) in this treatment (T2) compared to all other treatments (Table 2). In control plot (T4) the benefit-cost ratio was low of 1.41 than fertigated treatments.

ConclusionsThe suitable drip system was designed, based

on the observations recorded on the physio-chemical properties of soil and water of the experimental plot. From the study, it could be concluded that for bhendi crop,

To reduce the initial investment cost of drip system, the laterals may be laid at 240 cm spacing and recommended to adopt 4 rows of planting at a plant spacing of 30X30 cm. By adopting this new technique it is possible to reduce the system cost by 17.4 per cent.

Drip irrigation with nitrogen at 80 per cent of recommended level (T2) was found to be effective in producing highest fertilizer use efficiency and maximum return.

ReferencesHegin, J. and A. Lowengart (1995). Fertigation for minimizing environment pollution by fertilizers. Fort. Research

Kluwer Academic Publishers 1995/1996. 43: 5-7.Jadhav, A.S. patil, M.T and P.V.Patil (2002). Protected cultivation, Hi-tech floriculture and vegetable project, college

of agriculture, Pune. Pp 71-72.Kaul, R.K (1979). Hydraulic of moisture front advance in drip irrigation, Ph.D thesis submitted to IARI, New Delhi,

India.Klepper, B (1991). Crop root system response to irrigation. Irrigation Science, 12: 105-106.Selvaraj, P.K. 1997 Optimization of irrigation scheduling and nitrogen fertigation for maximizing the water use efficiency

of turmeric in drip irrigation PhD Thesis submitted to Tamil Nadu Agricultural University, Coimbatore.

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Table. 1 Time schedule of drip irrigation operation under cropping stages.

Sl. Water Water released per Time of No. Stage of crop growth requirement emitter (lpd) operation (lit/crop) (8 Plants) (min) 1 Emergency to early growth 0.5 4 30 2 Initial period to growth 0.75 6 45 3 Major crop growth period 1.25 10 75 4 Flowering stage 2 16 120 5 Harvesting stage 1.5 12 90

Table. 2 Cost economics of drip irrigation system for bhendi in 1 ha

Sl. No. Description Treatments

T1 T2 T3 T4

1. Fixed cost (Rs). 43,143 43,143 43,143 75,000 Life (year) 6 6 6 6 Depreciation (Rs) 7190 7190 7190 12,500 Interest @ 8 % (Rs) 3,451 3,451 3,451 6,000 Repair and Maintenance (Rs) 862 862 862 1,500 2. Total cost, (Rs). 11,503 11,503 11,503 20,000 3. Cost of cultivation, (Rs/ha) 15,000 15,000 15,000 15,000 4. Seasonal total cost, (Rs). 26,503 26,503 26,503 35,000 5. Yield produce (t/ha) 9.9317 10.676 9.4999 9.874 6. Selling price (Rs/t) 5,000 5,000 5,000 5,000 7 Income from produce, (Rs). 49,658 53,380 47,499 49,370 8. Net seasonal income (Rs) 23,155 26,877 20,996 14,370 Benefit - Cost ratio 1.87 2.01 1.79 1.41