ISTITUTO AGRONOMICO

PER L'OLTREMARE

UNIVERSITÀ DEGLI STUDI DI FIRENZE

FIRST LEVEL MASTER DEGREE IN

IRRIGATION PROBLEMS

IN DEVELOPING COUNTRIES

THESIS ON

DESIGN OF DRIP IRRIGATION SYSTEM FOR PRODUCTION OF

COMMONLY GROWN VEGETABLE CROPS IN SEMI-ARID REGION OF

TIGRAY GEREB-BEATI DAM ETHIOPIA

Supervisor I Student Name

DR. AGR. IVAN SOLINAS ABEBATSEGAZA

A.A. 2012/2013

i

DEDICATION

I would like to dedicate my Thesis to My Beloved Parents

ii

ACKNOWLEDGEMENT

Many thanks to God for providing me with the opportunity to step in the excellent

World of science and giving me the strength and ability to complete this work.

It would not have been possible to complete this Thesis without the help and

support of the many kind people around me, to only some of whom it is possible to

give particular mention here.

Special thanks go to the IAO for offering me a scholarship to pursue the Masters,

and the entire IAO staff particularly, Dr. Giovanni Totino Director General, IAO;

Dr. Tiberio Chiari, Technical Director IAO and tutors; - Drs. Paolo Enrico Sertoli,

Andrea Merli, and Elisa Masi for having assisted and accompanied me throughout

the course duration.

I am particularly grateful to my supervisor, Dr. Solinas Ivan for the guidance you

gave me from start to the completion of the Thesis – I owe you a great deal

THANKS!

A lot of thanks go to Prof. Ing. Elena Bresci, the Masters Course Coordinator for

the good guidance you always us as students.

Finally, to all other people who, directly or indirectly, helped me during the study.

iii

APPROVAL

Dr. Agr. Ivan Solinas

Supervisor’s signature: ……………………......…………………..…….………….

Date: ………............................................................................................................

Student: Abeba Tsegazab

Student’s signature: ……………………………………………..…………..…...…

Date: …………………………………..…………………………………..…...….

iv

Table of Content pages

DEDICATION ..................................................................................................................... i

ACKNOWLEDGEMENT .................................................................................................. ii

APPROVAL .......................................................................................................................iii

LIST OF TABLES ............................................................................................................. vi

LIST OF FIGURES .......................................................................................................... vii

1. Introduction ..................................................................................................................... 1

1.2 .Problem Statement ......................................................................................................... 3

1.3 .Objective ........................................................................................................................ 4

A. General objective ............................................................................................................. 4

2. LITERATURE REVIEW .............................................................................................. 6

2.1 Water Requirement of Crop ............................................................................................ 8

2.2 .Irrigation Scheduling ..................................................................................................... 9

2.3 Irrigation Scheduling Under Drip irrigation ................................................................... 9

2.4: Advantages of a Drip Irrigation System ...................................................................... 11

2.5 . disadvantages of a Drip Irrigation System .................................................................. 11

2.6 Crop Production ............................................................................................................ 12

2.6.1 Tomato ...................................................................................................................... 13

2.6.1.Onion ......................................................................................................................... 15

3.1 Location and physiographic .......................................................................................... 20

3 .2 Methodology ................................................................................................................ 21

3.2. 1 Collection of agro-climatic data ................................................................................ 21

3.2.2 Geology and Soil ....................................................................................................... 21

3.2.3 Water source .............................................................................................................. 23

3.2.4. Climate ...................................................................................................................... 23

v

3.3. Determination of tomato, onion, pepper) grown crops water requirement .................. 24

3.3.1 The crop coefficient Kc ............................................................................................. 24

3.4. Design Software ........................................................................................................... 27

3.4.1. Choice of Plot ........................................................................................................... 29

4. Result and Discussion ................................................................................................... 31

4.1 Crop Water Requirements of Each Crop ...................................................................... 31

4.2 Cropping pattern ........................................................................................................... 34

4.3. Schemes supply ............................................................................................................ 35

4.3 Network of the design ................................................................................................... 39

4.5 System in operation ...................................................................................................... 40

4.2 Characteristics of system components .......................................................................... 42

6. Conclusion and recommendation ................................................................................ 43

5. Reference ....................................................................................................................... 45

Appendix ............................................................................................................................ 48

vi

LIST OF TABLES Table 1: soil mapping unit ................................................................................................. 22

Table 2: Tomato Growth Stages and Crop Coefficient Kc ................................................ 24

Table 3: onion Growth Stages and Crop Coefficient Kc ................................................... 25

Table 4 : Potato Growth Stages and Crop Coefficient Kc ................................................. 25

Table 5: Climate data ......................................................................................................... 26

Table 6: monthly Rainfall .................................................................................................. 26

Table 7: Felid measurements ............................................................................................. 30

Table 8: Tomato crop water requirement ........................................................................... 31

Table 9: Potato crop water requirements ........................................................................... 32

Table 10: crop water requirements of onion ..................................................................... 33

Table 11: scheme supply .................................................................................................... 35

Table 12: system components ............................................................................................ 42

vii

LIST OF FIGURES Figure 1: location of Gereb Beati ....................................................................................... 20

Figure 2: Vegetation period of Gereb beati ....................................................................... 23

Figure 3 :plot division ........................................................................................................ 30

Figure 4:area cropping pattern ........................................................................................... 34

Figure 5 :drip line for potato .............................................................................................. 36

Figure 6: checking drip ...................................................................................................... 36

Figure 7: pressure compensating ....................................................................................... 37

Figure 8 :onion drip line .................................................................................................... 38

Figure 9: Tomato ............................................................................................................... 39

Figure 10: Network of the design ...................................................................................... 39

Figure 11: system watering of field one ............................................................................ 40

Figure 12 : system watering of field two ........................................................................... 40

Figure 13: system watering of field 3 part lot 1 ................................................................. 40

Figure 14: system watering of field 3 part lot .................................................................... 41

viii

ABBREVIATIONS

Asl above sea level

BoAN Bureau of agriculture and natural resources

BoANR Bureau of Agriculture and Natural Resource

COSAERT Commission for Sustainable Agriculture and Environmental

Rehabilitation in Tigray

DA’s Development Agent

ERHA the Ethiopian Rainwater Harvesting Association

FAO Food and Agricultural Organization

IWMI International water management institute

MoAR Ministry of Agriculture and Rural Development

MOWR Ministry of Water Resource

REST Relief Society of Tigray

RIS Relative irrigation supply

RWS Relative water supply

SARET sustainable agriculture and environmental rehabilitation Tigray

UNDP United Nation Development Program

WDC Water delivery capacity

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Abstract

This research was conducted with the aim of designing a drip irrigation system for

production of commonly grown vegetable crops in the semi-arid area of Gereb-

Beati, Tigray region, Ethiopia. These crops include maize, tomato and onion. Crop

water requirement and irrigation scheduling for each of the crops was determined

by using 30-year climatic data in CROPWAT. In this study, various software like

Google earth, CLIMWAT 2.0, SPAW, the CROPWAT, Ve.pro.LG.s, and

EPANET 2.0 were used to evaluate field and coordinates, get climatic data,

determine soil characteristics, the crop water requirements, determine efficiency of

the irrigation system are used respectively in the selected agricultural district.

Cropping pattern of the vegetable crops is 44% tomato, 33% onion and 23% potato

coverage. Having identified and ranked the drip lines available with the software

Ve.Pro.LG, the drip line best drip line from select 11 drip lines is stream line

,having uniformity of 93.6 ,spacing 0.4 inlet pressure 8 and discharge of 2.04 l/h m

and irrigation intensity of 4.1mm/h.

1

1. Introduction

Globally rainfed agriculture is practiced in almost all hydro climatic zones, it is

practiced on 83 percent of cultivated land, and supplies more than 60 percent of

the world's food. In water-scarce tropical regions such as the Sahelian countries,

rainfed agriculture is practiced on more than 95 percent of cropland. In temperate

regions with relatively reliable rainfall and productive soils, and in the sub humid

and humid zones of tropical regions, rainfed agriculture can have some of the

highest yields (FAO ,2002). In Sub-Saharan Africa (SSA) over 95% of the farm

land is under rain fed. Sub-Saharan Africa has vast untapped water resources.

Expansion of the irrigated area has the potential to make a substantial contribution

to agricultural development and address the problem of food insecurity (Suhas et

al., 2009).

Ethiopia is a land-locked country in the Horn of Africa, bordered by Eritrea in the

north, Sudan and South Sudan to the west, Djibouti and Somalia to the east

and Kenya in the south (Vagnat, 2013). Agriculture in Ethiopia is the foundation

of the country's economy, accounting for half of gross domestic product (GDP),

83.9% of exports, and 80% of total employment. Ethiopia's agriculture is plagued

by periodic drought, soil degradation caused by overgrazing, deforestation, high

population density, high levels of taxation and poor infrastructure (making it

difficult and expensive to get goods to market). Yet agriculture is the country's

most promising resource. A potential exists for self-sufficiency in grains and for

export development in livestock, grains, vegetables, and fruits. As many as 4.6

million people need food assistance annually. In Ethiopia, about 94% of the total

74.3 million hectare of arable land is rainfed (MARD, 2009).

In countries like Ethiopia where widespread poverty, poor health, low farm

productivity and degraded natural resources are major problems the need to

involve irrigated agricultural system in the agricultural practice of the country is

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very vital. Ethiopian agriculture is largely small-scale, subsistence-oriented, and

crucially dependent on rainfall (Girmay et al., 2010).

Mintesinot et al., (2004) reported that in tigray generally traditional surface

irrigation methods (basin, border and furrow) are used to irrigate crops. Farmers

have been producing different crops under traditional irrigation since a long time.

The diversion of perennial streams using temporary diversion structures during the

dry season has been the major means of irrigation. In addition flood spreading

using runoff water form higher altitudes and upper catchment-areas is also

practiced.

Erratic rainfall in the region over the past years has resulted wide spread crop

failure and has brought a growing awareness of the importance of irrigation.

Therefore, small-scale irrigation development for food production became of

primary interest in Tigray in view of the recurrent drought and famine condition.

Condition experienced during the 1970’s and1980’s. The previous military

government after 1984/85-famine period started the development of these small-

scale irrigation schemes. The aim was to boost food production and achieve food

self-sufficiency. From that time onwards, modern irrigation practices have been

developed in Tigray. Therefore it is dire need to adopt modern efficient irrigation

methods like drip. Drip irrigation method offers several advantages over surface

irrigation methods, including higher water use efficiency, better fertilizer

application and high yield (Mintesinot et al., 2004) .

Estimating actual crop water requirement and irrigation schedule are essential for

designing of the irrigation systems, storage construction and water conveyance

structures. In arid and semi-arid regions, water availability is a serious limitation

for crop production due to poor and irregular rainfall, high evaporative demand

and inadequate management. Planning and management of water resources have

become a very important issue in arid and semi-arid regions.

3

Understanding crop water needs is essential for irrigation scheduling and water

saving measures in an arid region because of its limited water supply. One of the

drought prone areas in Ethiopia is the Tigray region. Determination of crop water

requirement is one of the key parameters for precise irrigation scheduling,

especially in regions with limited water resources, such as Tigray. In semi-arid

regions water resources are limited. Despite the number of challenges like less

fertile soil, highly variable rainfall, and highly degraded land, designing and the

subsequent use of drip irrigation will help to save water through efficient use. As a

result, a larger area will be irrigated and this will ensure food security. However,

many of the soil and water conservation structures constructed in Tigray are non-

engineered (constructed by local communities without some technical support by

experts and fully owned by the communities) and no thorough study of the

irrigation water requirements and irrigation scheduling in the region has been

undertaken.

This research therefore seeks to recommend introduction of an affordable micro -

irrigation technology which will help local farmers increase their production levels

through irrigation. Increased productivity provides potential to accelerate poverty

alleviation within rural communities of developing countries from agricultural

sales.

1.2 .Problem Statement

In Ethiopia Small-scale irrigation recently gained importance because of its

potential to combat hunger, reducing poverty, and generating economic growth, as

well as climate adaptation of our people. Rainfall in the semi-arid Ethiopian

highlands is characterized by erratic nature and dry spells during crop growing

season is a critical problem in the rainfed production systems. One of the drought

prone areas in Ethiopia is Tigray region. Rainfed farming therefore needs to be

supported by appropriate determination of crop water requirement and irrigation

scheduling. Determination of crop water requirement is one of the key parameters

for precise irrigation scheduling, especially in regions with limited water

4

resources, such as, Tigray region. On crop water requirements is very vital in the

planning and operation of soil and water management strategies. knowledge of

crop water use is required when planning erosion control measures such are

terracing and contour building, planning and design of micro- and macro-

catchment rain/runoff water harvesting systems, surface and subsurface drainage

systems, and other soil moisture conservation techniques.

Most of the systems mentioned above are usually required to manage soil and

water in rainy season. Information on crop water requirements in literature are

largely those used for the purpose of irrigation, and were most probably developed

during the dry season. However, a thorough study of the irrigation water

requirements and irrigation scheduling in the region has not been undertaken.

Irrigation scheduling and use of drip irrigation are principal tools for striking this

balance through improving water application and water utilization efficiencies.

Despite such high investment and the lofty expectations that irrigation can shift

upward the production frontier in the region, there has been no empirical study to

investigate the efficiency of irrigated agriculture in the study area.

1.3 .Objective

A. General objective

To design a drip irrigation system for production of commonly grown vegetable

crops in semi-arid region of Tigray gereb-beati dam Ethiopia.

B. Specific objective

1. To estimate Crop Water Requirement (CWR) for commonly grown crops in the

area (tomato, onion, maize).

2. To develop irrigation regimes (when and how much to irrigate) for most market

oriented crops in the area.

3. To satisfy and fulfillments requirements of the farmer to suggest guidelines for

farming community.

5

4. Design drip irrigation method conserve water, increase crop production, and

improve crop quality.

6

2. LITERATURE REVIEW

Rain-fed agriculture dominates in Ethiopia. However, rainfall distribution and

intensity vary spatially and temporally resulting in incidents of drought every 4-5

years. These rainfall patterns affect crop and livestock production and contribute to

volatility in food price. Rainfall in Ethiopia is varying highly and erratic in time

and space (Yazew, 2005).

(CSA, 2007) states that Ethiopia has approximately 12 river basins with an

annual runoff of 122 billion m3 and with 2.6 billion m3 of groundwater .With all

this potential, however, it fails to produce enough food to feed its population. The

country’s perennial dependence on food aid has been attributed largely to an over-

reliance on rain-fed smallholder agriculture. For example, only 5-6% of the 4.25

million hectares of irrigable land is currently developed through traditional, small-,

medium-, and large-scale irrigation schemes (Awulachew et al., 2007).

In countries like Ethiopia where widespread poverty, poor health, low farm

productivity and degraded natural resources are major problems the need to

involve irrigated agricultural system in the agricultural practice of the country is

very vital. The importance of intervening irrigated agriculture in the economy of

developing countries results from the fact that rain fed agricultural system is not

capable of supplying the desired amount of production to feed the increasing

population. The issue of food security is a serious concern especially in arid and

semi-arid regions like Tigray, which is vulnerable to climatic instability and

frequent droughts. To see the positive effect of irrigation on livelihood, the

management aspect of irrigation must be taken in to account. Nevertheless, the

management aspect of irrigation is often neglected while priorities are given to the

construction of irrigation (Habtamu Worku, 2011).

The potential irrigable land in Ethiopia is between 3.7 and 4.3 million hectares but

the actual irrigated area is estimated at just 7-10% of this. Of this area

approximately 55% is traditional irrigation schemes, 20% is modern small-scale,

and 25% is medium- and large-scale irrigated commercial farms (private and state-

7

owned). Field assessments in small-scale irrigation projects indicate that some

irrigation schemes are not functional due to shortage of water, damaged structures

and poor water management.

Water harvesting technologies to mitigate the moisture stress during critical crop

growth stage of the main season, to increase opportunities for irrigated

horticultural production in dry land. With this aim, a wider scale of water

harvesting technology dissemination program was carried out in these areas of

Ethiopia since 2002/03. In Tigray region, on-farm level household ponds, larger

communal ponds, and a series of ponds were the three types of water harvesting

technologies promoted by the program since it initiation to store and utilize rain

water/runoff. Different soil/water conservation, water recharging, and water

harvesting structures have been constructed in Tigray. More than 80% of the

region is now covered. The whole activity is moving from soil/water conservation

to water harvesting (Habtamu Worku, 2011).

Kifle Woldearegay (2012), states that Tigray is considered as the most degraded

region in Ethiopia. Despite this, a number of positive changes have been recorded.

There is a great opportunity that the efforts made in Tigray could be scaled-up to

other regions of Ethiopia and beyond for a number of reasons: Less degraded land

better experience in the country. Other regions of Ethiopia have started massive

watershed management.

Tagar et al (2012) reported that drip irrigation generally achieves better crop yield

and balanced soil moisture in the active root zone with minimum water loses. On

the average, drip irrigation saves about 70 to 80% water as compared to

conventional flood irrigation methods, tolerance to windy atmospheric conditions,

reduced labor cost, improved diseased and pest control, feasible for undulating

sloppy lands, suitability on problem soils and improved tolerance to salinity. Many

factors influence appropriate drip irrigation management, including system design,

soil characteristics, crop and growth stage, environmental conditions, etc. The

8

influences of these factors can be integrated into a practical, efficient scheduling

system which determines quantity and timing of drip irrigation (Hartz, 1999).

2.1 Water Requirement of Crop

Water requirement of crop is the quantity of water regardless of source, needed for

normal crop growth and yield in a period of time at a place and may be supplied

by precipitation or by irrigation or by both.

Water is needed mainly to meet the demands of evaporation (E), transpiration (T)

and metabolic needs of the plants, all together is known as consumptive use (CU).

Since water used in the metabolic activities of plant is negligible, being only less

than one percent of quantity of water passing through the plant, evaporation (E)

and transpiration (T), i.e. ET is directly considered as equal to consumptive use

(CU). In addition to ET, water requirement (WR) includes losses during the

application of irrigation water to field (percolation, seepage, and run off) and water

required for special operation such as land preparation, transplanting, leaching etc.

WR = CU + application losses + water needed for special operations.

Water requirement (WR) is therefore, demand and the supply would consist of

contribution from irrigation, effective rainfall and soil profile contribution

including that from shallow water tables (S)

WR = IR + ER + S

Under field conditions, it is difficult to determine evaporation and transpiration

separately. They are estimated together as evapotranspiration (ET) (Langbein,

2013). IR is the irrigation requirement. Determination of crop water requirement is

one of the key parameters for precise irrigation scheduling, especially in regions

with limited water resources, such as Tigray region.

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2.2 .Irrigation Scheduling

Irrigation Scheduling is the process of determining when to irrigate and how much

water to apply. It depends upon design, maintenance, and operation of the

irrigation system and the availability of water. The objective of irrigation

scheduling is to apply only the water that the crop needs, taking into account

evaporation, seepage, and runoff losses, and leaching requirements. Scheduling is

especially important to pump irrigators if power costs are high. The purpose of

irrigation scheduling is to determine the exact amount of water to apply to the field

and the exact timing for application. The amount of water applied is determined by

using a criterion to determine irrigation need and a strategy to prescribe how much

water to apply in any situation. Irrigation scheduling is a planning and decision-

making process, the primary decision being: how much water to apply and when to

apply it. Providing the right amount of water at the right time results in optimal

yields and quality, saves on energy, labor, and fertilizer costs and protects ground

water quality (Broner, 2005).

Water management is a critical aspect of successful production in Tigray. This

region commonly experience drought conditions some time even during the

rainseason so supplemental water application through irrigation is necessary. In

addition, water can be a scarce resource in many areas and its efficient use must be

a high priority. Irrigation scheduling is an importat aspect of good water

management (Broner, 2005).

2.3 Irrigation Scheduling Under Drip irrigation

Drip irrigation is sometimes called trickle irrigation and involves dripping water

onto the soil at very low rates (2-20 liters/hour) from a system of small diameter

plastic pipes fitted with outlets called emitters or drippers. Water is applied close

to plants so that only part of the soil in which the roots grow is wetted unlike

surface and sprinkler irrigation, which involves wetting the whole soil profile.

With drip irrigation water, applications are more frequent (usually every 1-3 days)

10

than with other methods and this provides a very favorable high moisture level in

the soil in which plants can flourish (FAO, 2009).

Drip irrigation is the most efficient method of irrigating. While sprinkler systems

are around 75-85% efficient, drip systems typically are 90% or higher. What that

means is much less wasted water, for this reason drip is the preferred method of

irrigation in the desert regions of the United States. But drip irrigation has other

benefits which make it useful almost anywhere. It is easy to install, easy to design,

can be very inexpensive, and can reduce disease problems associated with high

levels of moisture on some plants. If you want to grow a rain forest however, drip

irrigation will work but might not be the best choice (Jess Stryker, 1997-2011).

Typical ingredentis of drip/micro system includes, pump, filters chemical

injectors, main and submainlines, laterals and emitters (Jess Stryker, 1997-2011).

Unlike conventional irrigation methods, drip/micro irrigation delivers frequent,

localized small doses of water. Therefore, drip/micro irrigation scheduling is

usually based on frequent replacement of the water consumed by the crop to

maintain essentially steady level of moisture content in the root zone. The

frequent water application makes the possibility of excessive soil moisture

depletion between irrigations very slim, and could improve plant nutrient-

uptake. However, due to the limited water storage in the root zone under

drip/micro irrigation and the system small application rate, it is essential to

monitor soil moisture depletion in the root zone regularly to ensure that consumed

water is timely replenished by irrigation. Irrigation scheduling and use of drip

irrigation are principal tools for striking this balance through improving water

application and water utilization efficiencies (Simonne et al., 2012).

11

2.4: Advantages of a Drip Irrigation System

A drip irrigation system results in healthy, fast-growing plants, and is very

efficient in its use of water. Little is lost to evaporation, and walkways and areas

between plants remain dry. Drip irrigation applies water only where it is needed,

with less runoff and evaporation. Studies on drip irrigation systems are show

results of up to 60% more efficiency over sprinkler systems (Jess Stryker, 1997-

2011) .

This also reduces weed growth, and makes cultivation possible during and

immediately after an irrigation cycle. Drip irrigation allows a large area to be

watered from a small water source, since it uses water more slowly than other

methods. The biggest savings for the home gardener is time: you can now garden

on a larger scale, and with an automatic timer, you can travel or deal

Drip irrigation method is not affected by high wind velocity as it applies water

directly to the root zone of plants. Its major advantages as compared to other

methods include, higher crop yields, saving in water, increased fertilizer use

efficiency, and reduced energy consumption (Jess Stryker, 1997-2011).

2.5. Disadvantages of a Drip Irrigation System

Not everything can be considered an advantage. The possible problems that can be

associated with drip irrigation are: First clogging of emitters is the most serious

problem associated with drip irrigation. To prevent blockage, care should be taken

to filter the water properly before use, depending on the particular particle size

and type of suspended material contained in the irrigation water. Second cost

conventional drip irrigation systems typically cost USD 5000–10,000 per hectare,

or more, when installed in East Africa. Third Water management when practising

drip irrigation, farmers do not see the water. This often results in over irrigation

and the loss of the benefits of high irrigation efficiency.

12

Over-irrigation will also make the soil excessively wet and therefore promote

disease, weed growth and nutrient leaching.fourth restricted root zone Plant root

activity is limited to the soil bulbs wetted by the drip emitters; a much smaller soil

volume than that wetted by full-coverage sprinkler or surface irrigation systems.

2.6 Crop Production

Rain fed crop production is the common land use practice in the study area. Agricultural

productivity is low and, the sustainability of traditional agricultural systems is threatened

by degradation of cropland. Crops like, maize, wheat, Teff are commonly grown by rain

fed, were as crops like potato, onion, tomato, pepper are grown under irrigation in the

area.

In response to change in climate, which resulted in increased moisture stress and

reduced soil fertility, the crop varieties grown in the past could not produce sufficient

yield to meet the subsistence requirement of the farming community

http://www.utviklingsfondet.noaccessed in 19 June 2013.

Some of the adaptations measures made by the farming communities, with the

support from Relief Society of Tigray (REST) within the project watersheds,

were the following: Development of irrigation structures such as check dam

ponds, underground water tankers, river diversion, hand-dug well, mini-dam,

Waterpump,treadlepump,motorizedpumps,watersavingtechnologiessuchasdripirrig

ationandwaterharvesting http://www.utviklingsfondet.noaccessed in 19 June 2013.

Early maturing and moisture stress tolerant varieties of crops have been

introduced. Because the period of rainfall is shorter a change towards a more

intensified production system was necessary. Early maturing cereals, short cycle

crops for rain fed agriculture, and new vegetables, root crops and fruits that can be

grown using irrigation has been adopted. Compost (from livestock dung), is used

to fertilize the soil) http://www.utviklingsfondet.no accessed in 19 June 2013

.Vegetable as well as livestock producers in tigray region have been strongly

linked with the Bureau of Agriculture and Rural Development (BoARD).

13

Vegetable is an edible plant or its part, intended for cooking or eating raw. In

biological terms, vegetable designates members of the kingdom. In grebe beati

districts, drip irrigation is not widely used for vegetable production, although it has

the potential to improve irrigation performance. Instated the use alternative furrow

irrigation guided by local community to produce crops most of them for

themselves and local market. Irrigation in the grebe beati districts vegetable

production has traditionally been dominated by the use of surface irrigation.

However as the area is semiarid, drip irrigation has the potential to use scarce

water resources most efficiently to produce vegetables (Locascio, 2005).

2.6.1 Tomato

Tomato (Lycopersicon esculentum) is the second most important vegetable crop

next to potato. Present world production is about 100 million tons fresh fruit from

3.7 million ha).

Tomato is a rapidly growing crop with a growing period of 90 to 150 days. It is a

day length neutral plant. Optimum mean daily temperature for growth is 18 to 25ºC

with night temperatures between 10 and 20ºC. Larger differences between day and

night temperatures, however, adversely affect yield. The crop is very sensitive to

frost. Temperatures above 25ºC, when accompanied by high humidity and strong

wind, result in reduced yield. Night temperatures above 2OºC accompanied by high

humidity and low sunshine lead to excessive vegetative growth and poor fruit

production. High humidity leads to a greater incidence of pests and diseases and

fruit rotting. Dry climates are therefore preferred for tomato production.

Tomato can be grown on a wide range of soils but a well-drained, light loam soil

with pH of 5 to 7 is preferred. Water logging increases the incidence of diseases

such as bacterial wilt. The fertilizer requirements amount, for high producing

varieties, to 100 to 150 kg/ha N, 65 to 110 kg/ha P and 160 to 240 kg/ha K.

The seed is generally sown in nursery plots and emergence is within 10 days.

Seedlings are transplanted in the field after 25 to 35 days. In the nursery the row

14

distance is about 10 cm. In the field spacing ranges from 0.3/0.6 x 0.6/1 m with a

population of about 40,000 plants per ha. The crop should be grown in a rotation

with crops such as maize, cabbage, cowpea, to reduce pests and disease

infestations.

The crop is moderately sensitive to soil salinity. Yield decrease at various ECe

values is: 0% at ECe 2.5 mmhos/cm, 10% at 3.5, 25% at 5.0, 50% at 7.6 and 100'/.

at ECe 12.5 mmhos/cm. The most sensitive period to salinity is during germination

and early plant development, and necessary leaching of salts is therefore frequently

practised during pre-irrigation or by over-watering during the initial irrigation

application.

The crop has a fairly deep root system and in deep soils roots penetrate up to some 1. 5

m. The maximum rooting depth is reached about 60 days after transplanting. Over 80

percent of the total water uptake occurs in the first 0.5 to 0.7 m and 100 per-cent of the

water uptake of a full grown crop occurs from the first 0.7 to 1.5 m (D = 0.7 - 1.5 m).

Under conditions when maximum evapotranspiration (ETm) is 5 to 6 mm/ day water

uptake to meet full crop water requirements is affected when more than 40 percent of the

total available soil water has been depleted (p = 0.4).

The crop performance is sensitive to the irrigation practices. In general a prolonged

severe water deficit limits growth and reduces yields which cannot be corrected by heavy

watering later on. Highest demand for water is during flowering. However, withholding

irrigation during this period is sometimes recommended to force less mature plants into

flowering in order to obtain uniform flowering and ripening. Care should be exercised in

this to avoid damage to the mature plants.

Excessive watering during the flowering period has been shown to increase flower drop

and reduce fruit set. Also this may cause excessive vegetative growth and a delay in

ripening. Water supply during and after fruit set must be limited to a rate which will

prevent stimulation of new growth at the expense of fruit development.

15

Surface irrigation by furrow is commonly practised. Under sprinkler irrigation the

occurrence of fungal diseases and possibly bacterial canker may become a major

problem. Further, under sprinkler, fruit set may be reduced with an increase in fruit

rotting. In the case of poor quality water, leaf burn will occur with sprinkler irrigation;

this may be reduced by sprinkling at night and shifting of sprinkler lines with the

direction of the prevailing wind. Due to the crops specific demands for high soil water

content achieved without leaf wetting, trickle or drip irrigation has been successfully

applied.

2.6.1.Onion

Onion (Allium cepa) is believed to have originated in the Near East. The crop can

be grown under a wide range of climates from temperate to tropical. Present world

production is about 46.7 million tons of bulbs from 2.7 million ha.

Under normal conditions onion forms a bulb in the first season of growth and

flowers in the second season.

The production of the bulb is controlled by daylength and the critical day length

varies from 11 to 16 hours depending on variety. The crop flourishes in mild

climates without extremes in temperature and without excessive rainfall. For the

initial growth period, cool weather and adequate water is advantageous for proper

crop establishment, whereas during ripening, warm, dry weather is beneficial for

high yield of good quality. The optimum mean daily temperature varies between

15 and 20°C. Proper crop variety selection is essential, particularly in relation to

the day length requirements; for example, a long day temperate variety in tropical

zones with short days will produce vegetative growth only without forming the

bulb. The length of the growing period varies with climate but in general 130 to

175 days are required from sowing to harvest.

The crop is usually sown in the nursery and transplanted after 30 to 35 days. Direct

seeding in the field is also practised. The crop is usually planted in rows or on

16

raised beds, with two or more rows in a bed, with spacing of 0.3 to 0.5 x 0.05 to

0.1 m. Optimum soil temperature for germination is 15 to 25°C. For bulb

production the plant should not flower since flowering adversely affects yields.

Bulbs are harvested when the tops fall: For initiation of flowering, low

temperatures (lower than 14 to 16°C) and low humidity are required. Flowering is,

however, little affected by day length.

Onion, in common with most vegetable crops, is sensitive to water deficit. For high

yield, soil water depletion should not exceed 25 percent of available soil water. When

the soil is kept relatively wet, root growth is reduced and this favours bulb

enlargement. Irrigation should be discontinued as the crop approaches maturity to

allow the tops to desiccate, and also to prevent a second flush of root growth.

The growth periods of an onion crop with a growing period of 100 to 140 days in the

field are: establishment period (from sowing to transplanting, 0) 30 to 35 days;

vegetative period 25 to 30 days; yield formation (bulb enlargement, 3) 50 to 80 days;

and ripening period (4) 25 to 30 days.

The crop is most sensitive to water deficit during the yield formation period,

particularly during the period of rapid bulb growth which occurs about 60 days after

transplanting. - The crop is equally sensitive during transplantation. For a seed crop,

the flowering period is very sensitive to water deficit. During the vegetative growth

period the crop appears to be relatively less sensitive to water deficits.

For high yield of good quality the crop needs a controlled and frequent supply of

water throughout the total growing period; however, over-irrigation leads to reduced

growth.

To achieve large bulb size and high bulb weight, water deficits, especially during the

yield formation period(bulb enlargement, should be avoided. Under limited water

supply small water savings can be made during the vegetative period and the ripening

17

period. However, under such conditions water supply should preferably be directed

toward maximizing production per hectare rather than extending the cultivated area

with limited water supply.

The crop has a shallow root system with roots concentrated in the upper 0.3m soil

depth. In general 100 percent of the water uptake occurs in the first 0.3 to 0.5rn soil

depth (D = 0.3-0. 5 m). To meet full crop water requirements (ETm) the soil should be

kept relatively moist; under an evapotranspiration rate of 5 to 6 mm/day, the rate of

water uptake starts to reduce when about 25 percent of the total available soil water

has been depleted (p = 0.25).

The crop requires frequent, light irrigations which are timed when about 25 percent of

available water in the first 0.3 m soil depth has been depleted by the crop. Irrigation

application every 2 to 4 days is commonly practised. Over-irrigation some-times cause

spreading of diseases such as mildew and white rot. Irrigation can be discontinued 15

to 25 days before harvest. Most common irrigation methods are furrow and basin.

2.6.1.Potato

Potato (Solanum tuberosum) originates in the Andes from the tropical areas of

high altitude. The crop is grown throughout the world but is of particular

importance in the temperate climates. Present world production is some 308

million tons fresh tubers from 19 million ha. (FAOSTAT, 2001).

Yields are affected by temperature and optimum mean daily temperatures are 18 to

20°C. In general a night temperature of below 15°C is required for tuber initiation.

Optimum soil temperature for normal tuber growth is 15 to 18°C. Tuber growth is

sharply inhibited when below 10°C and above 30°C. Potato varieties can be

grouped into early (90 to 120 days), medium (120 to 150 days) and late varieties

(150 to 180 days). Cool conditions at planting lead to slow emergence which may

18

extend the growing period. Early varieties bred for temperate climates require a

day length of 15 to 17 hours, while the late varieties produce good yields under

both long and short day conditions. For tropical climates, varieties which tolerate

short days are required for local adaptation.

Potato is grown in a 3 or more year rotation with other crops such as maize, beans

and alfalfa, to maintain soil productivity, to check weeds and to reduce crop loss

from insect damage and diseases, particularly soil-borne disease. Potato requires a

well-drained, well-aerated, porous soil with pH of 5 to 6. Fertilizer requirements

are relatively high and for an irrigated crop they are 80 to 120 kg/ha N, 50 to 80

kg/ha P and 125 to 160 kg/ha K. The crop is grown on ridges or on flat soil. For

rainfed production in dry conditions, flat planting tends to give higher yields due to

soil water conservation. Under irrigation the crop is mainly grown on ridges. The

sowing depth is generally 5 to 10 cm, while plant spacing is 0.75 x 0.3 m under

irrigation and 1 x 0.5 m under rainfed conditions. Cultivation during the growing

period must avoid damage to roots and tubers, and in temperate climates ridges are

earthed up to avoid greening of tubers.

The crop is moderately sensitive to soil salinity with yield decrease at different

levels of ECe: 0% at 1.7, 10% at 2.5, 25% at 3.8, and 50% at 5.9 and 100° / at ECe

10 mmhos/cm.

Potato is relatively sensitive to soil water deficits. To optimize yields the total

available soil water should not be depleted by more than 30 to 50 percent.

Depletion of the total available soil water during the growing period of more than

50 percent results in lower yields. Water deficit during the period of stolonization

and tuber initiation and yield formation have the greatest adverse effect on yield,

whereas ripening and the early vegetative periods are less sensitive. In general,

water deficits in the middle to late part of the growing period thus tend to reduce

yield more than in the early part. To maximize yield, the soil should be

maintained at relatively high moisture content. This, however, can have an

19

Water supply and scheduling are important in terms of quality. Water deficit in the early

part of the yield formation period increases the occurrence of spindled tubers, which is

more noticeable in cylindrical than in round tubered varieties. Water deficit during this

period followed by irrigation may result in tuber cracking or tubers with black hearts. Dry

matter content may increase slightly with limited water supply during the ripening period.

Frequent irrigation does reduce occurrence of tuber malformation.

Good yields under irrigation of a crop of about 120 days in the temperate and subtropical

climates are 25 to 35 ton/ha fresh tubers and in tropical climates yields are 15 to 25

ton/ha. The water utilization efficiency for harvested yield (Ey) for tubers containing 70 to

75 percent moisture is 4 to 7 kg/m3.

adverse effect when frequent irrigation with relatively cold water may decrease

the soil temperature below the optimum value of 15 to 18°C for tuber formation.

Also, soil aeration problems can sometimes occur in wet, heavy soils.

Since the potato is a relatively sensitive crop in terms of both yield and quality,

under conditions of limited water supply the available supply should preferably be

directed towards maximizing yield per ha rather than spreading the limited water

over a larger area. Savings in water can be made mainly through improved timing

and depth of irrigation application.

20

3. METHODOLOGY AND SOURCE OF DATA

3.1 Location and physiographic

The study area is found in small micro earth dam, called grebe Beat Dam in the

Southern zone of Tigray region. It lies between latitude of 13°44 '67” E and 39°47

'70 "N longitude about 3.14 km, west Aynalem town. The elevation of the area

ranges from 2144 to 2155 m ASL. The topography of the area is not uniform. The

catchment area of the study consists; gentle slope, considerably plain and hilly

slopes. The gentle and hilly slope areas are mainly used for agricultural

production. The reservoirs is constructed on a gentle slope and situated on

farmlands causing displacement of a number of farmers. The irrigation and

drainage infrastructure in the dam is open canals made of earth.

Figure 1: location of Gereb Beati

21

3 .2 Methodology

3.2. 1 Collection of agro-climatic data

Tigray is located at the northern limit of the central highlands of Ethiopia. The

landform is complex composed of highlands (in the range of 2300 to 3200 meters

above sea level, (masl), lowland plains (with an altitude range of <500.to 1500

masl), mountain peaks (as high as 3935 masl) and high to moderate relief hills

(1600 to 2200 masl). The climate condition in the study area can be described as

dry and hot typical of subtropical Regions.

3.2.2 Geology and Soil

The soils of this site are Liptosoils, consist 50 of clay and sand 20%, 31 volume

gravel, having small amount of salt around 0.1%. This type of soil a very

shallow over hard or highly calcareous material or a deeper soil that is

extremely gravelly or stony. It is graduàùally transported from the surrounding

mountainous area. Leptosols are unattractive soils for rain fed agriculture because

of their inability to hold water.

22

Sources: Soil water character

Table 1: soil mapping unit

23

3.2.3 Water source

Reliable water source is essential for sustainable production and the amount of

water that is available determines the area to be irrigated. Its gets water from the

Gereb Beati Dam found in Aynalem city. Gereb-Beati present reservoir capacity

is 85000m³ the source of water utilize rain water/runoff, diversion of floods from

the highland and two rivers, there is 90 ha planned command area but the actual

command area under irrigation is 36 ha and 440 actual beneficiaries (Aster et al.,

2007).

3.2.4. Climate

The area has a monomodal rainfall pattern that the main rainy season is during

summer from June to August. The remaining months are dry. A shorter rainy

season and such climate variability represent major challenges for the population.

The temperature and rainfall data was obtained from CLIMWAT 2.0

The annual rainfall data were obtained directly by the software

New_LocClim_1.10 from the interpolation done on the basis of data from

meteorological stations nearby.

Figure 2: Vegetation period of Gereb beati

Source: New-LocClim analysis

24

3.3. Determination of tomato, onion, pepper) grown crops water

requirement

Water requirement of tomato, onion, pepper) grown crops were determined using

the software CROPWAT 8.0developed by FAO. The crop coefficient Kc,

however, was adjusted to bring them closer to tropical conditions.

3.3.1 The crop coefficient Kc

The Kc integrates the characteristics of the crop that distinguish it from the

reference crop (usually a short, green, well-watered crop that completely shades

the ground) used to estimate reference ET .

Table 2: Tomato Growth Stages and Crop Coefficient Kc

Crop Init.

(Lini)

Dev.

(Ldev)

Mid

(Lmid)

Late

(Llate)

Total Plant

Date

Region

Tomato 30 40 40 25 135 January Arid Region

35 40 50 30 155 Apr/May Calif., USA

25 40 60 30 155 Jan Calif.

Desert, USA

35 45 70 30 180 Oct/Nov Arid Region

30 40 45 30 145 April/May Mediterrane

an

Crop

Coefficient,

Kc

0.6 >> 1.15 0.7-0.9

Source: http://www.fao.org/nr/water/cropinfo_tomato.html

25

Table 3: onion Growth Stages and Crop Coefficient Kc

Source: FAO, 2009

Table 4 : Potato Growth Stages and Crop Coefficient Kc

Source: http://www.fao.org/nr/water/cropinfo_potato.html

Init.

(Lini)

Dev.

(Ldev)

Mid

(Lmid)

Late

(Llate)

Total Plant

Date

Crop Region

15 25 70 40 150 April Onion (dry) Mediterranean

20 35 110 45 210 Oct; Jan. Arid Region;

Calif.

0.7 >> 1.05 0.75- Crop

Coefficient,

Kc

Crop Init.

(Lini)

Dev.

(Ldev)

Mid

(Lmid)

Late

(Llate)

Total Plant

Date

Region

Potato 25 30 30/45 30 115/130 Jan/Nov (Semi)

Arid

Climate

25 30 45 30 130 May Continental

Climate

30 35 50 30 145 April Europe

45 30 70 20 165 Apr/May Idaho,

USA

30 35 50 25 140 Dec Calif.

Desert,

USA

Crop

Coefficient,

Kc

0.5 >> 1.15 -0.5

26

Table 5: Climate data

Source: cropwat analysis

Table 6: monthly Rainfall

Source: cropwat analysis

27

3.4. Design Software

9 programs were used to design the irrigation system:

1.Google Earth is a virtual globe, map and geographical information program that

was originally called Earth Viewer 3D, and was created byKeyhole, Inc, a Central

Intelligence Agency (CIA) funded company acquired by Google in 2004 (see In-

Q-Tel).

It maps the Earth by the superimposition of images obtained from satellite

imagery, aerialphotography and GIS 3D globe

https://en.wikipedia.org/wiki/Google_Earthacessed 6/17/2013.

2.Harmonized World Soil Database is a 30 arc-second raster database with over

16000 different soil mapping units that combines existing regional and national

updates of soil information worldwide. The HWSD contributes sound scientific

knowledge for planning sustainable expansion of agricultural production to

achieve food security and provides information for national and international

policymakers in addressing emerging problems of land competition for food

production, bio-energy demand and threats to biodiversity (FAO, 2009). Soil

3.water characteristics program estimates soil water tension, conductivity and

28

water holding capability based on the soil texture, organic matter, gravel content,

salinity, and compaction. The result analysis from this gives very low infiltration

rate and used the associated soil for the analysis because this is not the actual data

from local the software may not give me perfect results of actual area.

4 Cropwat is a decision support system developed by the Land and Water

Development Division of FAO for planning and management of irrigation.

CROPWAT is meant as a practical tool to carry out standard calculations for

reference evapotranspiration, crop water requirements and crop irrigation

requirements, and more specifically the design and management of irrigation

schemes. It allows the development of recommendations for improved irrigation

practices, the planning of irrigation schedules under varying water supply

conditions, and the assessment of production under rainfed conditions or deficit

irrigation (FAO, 2013).

6. CLIMWAT 2.0 is an extensive climatic database of more than 5,000 stations

worldwide which is directly linked to the irrigation model AQUACROP. The

combination of both allows users to calculate crop water requirements, irrigation

supply and irrigation scheduling for various crops for a range of climatologically

stations. Climate data: maximum and minimum temperature, mean daily relative

humidity, sunshine hours, wind speed, precipitation and calculated values for

reference evapotranspiration and effective rainfall as input data for cropwat

7. EPANET is software that models water distribution piping systems. EPANET

is public domain software that may be freely copied and distributed. It is a

Windows 95/98/NT/XP program. EPANET performs extended period simulation

of the water movement and quality behavior within pressurized pipe networks.

EPANET was developed by the Water Supply and Water Resources Division

(formerly the Drinking Water Research Division) of the U.S. Environmental

Protection Agency’s National Risk Management Research

29

Laboratoryhttp://www.epa.gov/nrmrl/wswrd/dw/epanet.htmlacessed in 19 June

2013.

8 Ve.pro.LG.s is application software that performs the operation checks

dimensioning and design of systems of drip irrigation, with the aim to increase the

uniformity of distribution of irrigation, to save water and reduce energy

consumption. For the design of the distribution network at the sub-plot level,

namely drip lines system. The software Ve.Pro.L.G. s., name derived from the

initials of "Verification and Design of drip lines and areas of plant stems from

Ve.Pro.LG.s first version, released in 2003 and represents a substantial evolution,

being able to assess the functioning of entire planting areas and also extend the

application range of the horticultural industry and tree crops, even when grown on

sloping ground elevation along the line.

3.4.1. Choice of Plot

An area of 90 ha square shape was arbitrarily defined on the undeveloped area of

the plain of served as plot type. The choice was made on the agricultural area

which could potentially be attributed to farmers. This division is designed to

enable simultaneous operation or not of these three sub-plots, Allowing to vary the

crop pattern.

30

Figure 3: Plot division

Source: Google earth

Table 7: Felid measurements

Column Field 3 Field 2 Field 1

Tomato

(m)

Onion

(m)

Potato

(m)

Quote upstream 2136 2136 2136

Quote

downstream

2131 2131 2132

Length 270 200 160

Width 50 50 45

Slope 1.9 12.5 3.1

Area 7200 10000 13500

Total Area 30,700 m2

Area 44% 33% 23%

Source: Google Earth

31

4. Result and Discussion

4.1 Crop Water Requirements of Each Crop

Tomato crop has large area coverage than the other vegetable crops produce in

study area. Total water requirements (ETm ) after transplanting, of a tomato crop

grown in the field for 90 to 120 days is 525.8 mm, depending on the climate of the

study area. The average crop evapotranspiration under standard conditions,

denoted as Etc and average effective rainfall are 586.5 and 59.5 respectively.

Irrigation of tomatoes can result in higher and more consistent yields, better

quality, larger fruit, less blossom-end rot and less cracking. The use of drip

irrigation will to reduce the Phytophthora problems caused by furrow irrigation.

Table 8: Tomato crop water requirement

Month Decade Stage Kc Etc ETc Eff rain Irr. Req.

Coeff mm/day mm/dec mm/dec mm/dec

Dec 1 Init 0.6 2.14 21.4 0.7 20.7

Dec 2 Init 0.6 2.07 20.7 0.1 20.7

Dec 3 Deve 0.6 2.14 23.5 0.3 23.2

Jan 1 Deve 0.69 2.52 25.2 0.5 24.7

Jan 2 Deve 0.83 3.12 31.2 0.6 30.6

Jan 3 Deve 0.98 3.84 42.3 1 41.2

Feb 1 Mid 1.13 4.6 46 1.2 44.7

Feb 2 Mid 1.16 4.96 49.6 1.5 48.1

Feb 3 Mid 1.16 5.16 41.3 3.3 38

Mar 1 Mid 1.16 5.36 53.6 5.1 48.5

Mar 2 Mid 1.16 5.56 55.6 6.7 49

Mar 3 Late 1.14 5.58 61.4 8.6 52.8

Apr 1 Late 1.03 5.13 51.3 11.3 39.9

Apr 2 Late 0.91 4.63 46.3 13.6 32.6

Apr 3 Late 0.82 4.29 17.1 4.9 11

586.5 59.5 525.8

Source : cropwat analysis

Total water requirements (ETm ) after transplanting, of a potato crop grown in the

field for 90 to 120 days is 461.3 mm, depending on the climate station of the study

32

area. The average crop evapotranspiration under standard conditions, denoted as

Etc and average effective rainfall are 502.9 and 39.8 respectively.

Water quality and water scarcity issues and may lead some growers to adopt drip

irrigation for potato production. It’s part of the solution to being as conservative

and efficient with the water. Study in Drip irrigation of potato in arid farmlands

of China also sates that a feasible eco-technological and economically viable

technology Use of scarce water resources, in a sustainable way, in potato

cultivation to spread over a larger area. Higher productivity, quality tubers, food

security and increased income to farmers. The risk of foliar diseases is lower with

drip systems, and they can apply fertilizers and some pesticides effectively.

Table 9: Potato crop water requirements

From: Cropwat analysis

Month Decade Stage Kc ETc ETc Eff rain Irr.

Req.

Coeff mm/day mm/dec mm/dec mm/dec

Dec 1 Init 0.5 1.78 17.8 0.7 17.1

Dec 2 Init 0.5 1.73 17.3 0.1 17.2

Dec 3 Deve 0.54 1.93 21.2 0.3 20.9

Jan 1 Deve 0.76 2.76 27.6 0.5 27.1

Jan 2 Deve 0.98 3.66 36.6 0.6 36

Jan 3 Mid 1.15 4.52 49.7 1 48.7

Feb 1 Mid 1.17 4.77 47.7 1.2 46.4

Feb 2 Mid 1.17 4.97 49.7 1.5 48.1

Feb 3 Mid 1.17 5.17 41.4 3.3 38.1

Mar 1 Mid 1.17 5.37 53.7 5.1 48.6

Mar 2 Late 1.09 5.21 52.1 6.7 45.5

Mar 3 Late 0.95 4.64 51 8.6 42.4

Apr 1 Late 0.81 4.06 36.5 10.2 25.2

502.3 39.8 461.3

Total water requirements (ETm) after transplanting, of onion crop grown in the field for

100 to 140 days is 461.3 mm, depending on the climate station of the study area.

33

The average crop evapotranspiration under standard conditions, denoted as Etc and

average effective rainfall are 331.7 and 11.8 mm respectively.

Mohammad Quadir ,et al (2005 ) also state design drip irrigation for onion

production in arid regions allows very littile evaporation and runn off, save water by

directing it more precisely ,reduce the transmission of pathogens and produce fewer

weeds ,also has the ablity to meet crop requirements ,this is particular as the crop

matures as over watering on onon crop near harvest can damages the bulbs and reduce

shelf life , occur with furrow irrigations and also help can apply water uniformly

,alternative method for crop need high demand .

Table 10: crop water requirements of onion

Source: cropwat analysis

Month Decade Stage Kc ETc ETc Eff

rain

Irr.

Req.

coeff mm/day mm/dec mm/dec mm/dec

Dec 1 Init 0.7 2.5 25 0.7 24.3

Dec 2 Init 0.7 2.42 24.2 0.1 24.1

Dec 3 Deve 0.77 2.74 30.2 0.3 29.9

Jan 1 Deve 0.9 3.28 32.8 0.5 32.3

Jan 2 Mid 1.02 3.82 38.2 0.6 37.6

Jan 3 Mid 1.06 4.16 45.8 1 44.8

Feb 1 Mid 1.06 4.35 43.5 1.2 42.2

Feb 2 Late 1.06 4.52 45.2 1.5 43.7

Feb 3 Late 1.02 4.52 36.2 3.3 32.9

Mar 1 Late 0.98 4.5 22.5 2.6 19.9

343.5 11.8 331.7

34

4.2 Cropping pattern

Cropping pattern means the proportion of area under various crops at a point of time

in a unit area or it indicated the yearly sequence and spatial arrangements of crops and

follows in an area. Land resources being limited emphasis have to be placed for

increasing production from unit area of land in a year. Cropping systems based on

climate soil and water availability have to be evolved for realizing the potential

production levels through efficient use of availability use of available resources. The

cropping pattern, or cropping schedule of an irrigation area provides information, for a

period of at least one season, on three important elements, which crops are grown,

when are they cultivated, how many hectares of each crop are grown (FAO,1992).

Figure 4:area cropping pattern

44%

33%

23%

Area of crooping pattern %

Tomato

Onion

Potato

35

4.3. Schemes supply

Water supply networks usually represent the majority of assets of a water utility. One

of the most important factors that affect service delivery and the continued use of rural

water schemes is the quality of water the schemes deliver to users. The net scheme

irrigation need, is the amount of water needed to meet crop water needs of an entire

scheme minus the effective rainfall. Water supply schemes coverage has maxima net

irrigation requirement of 4.3 mm/day and minimum is 1.3 mm/day.

Table 11: scheme supply

From: Cropwat analysis

Lines available in the study area, 11 provide a uniform distribution over 93.5 (90%

being the acceptable threshold in drip irrigation). The first 11 drip lines ranking are

self-compensating, i.e. drip line whose discharge varies very little or not in case of

change of pressure (Emitter discharge exponent x close to zero). Another

characteristic of self-compensating drip lines is their relatively high cost due to

this particular characteristic. The area uniformity is 93.5 % and the area flow rate

is 15.3 l/s = 55.08 m3/hour and the inlet pressure is 8 mH2o.

36

Figure 5 :drip line for potato

Figure 6: checking drip

Having identified and ranked the drip lines available with the software

Ve.Pro.LG, the drip line best drip line from select 11 drip lines is stream line

,having uniformity of 93.6 ,spacing 0.4 inlet pressure 8 and discharge of 2.04l/hm

and irrigation intensity of 4.1mm/h .

37

Figure 7: pressure compensating

Pressure compensating drippers adjusted to provide a continuous wetting pattern

along a line. The use of pressure compensating dripline can simplify the design of

the entire irrigation system. With pressure compensating dripline water can be

applied uniformly on long rows and on uneven terrain.

38

Figure 8 :onion drip line

The emission uniformity is 92.5 % and the area flow rate is 11.2 l/s = 40.03

m3/hour and the inlet pressure is 8 mH2o, having annual water loss of 374m3/ha

and Considering that the system operates by rotational distribution of irrigation

water within the four sub-plots irrigation intensity is 4m3/ha .

39

Figure 9: Tomato

The area uniformity is 87.8 % and the area flow rate is 7.6 l/s = 27.36 m3/hour and

the inlet pressure is 8 mH2o, having annwater loss of 538m3/ha.

4.3 Network of the design

Figure 10: Network of the design

40

4.5 System in operation

Figure 11: system watering of field one

The system delivers to the field one a flow rate of 28.44m3/h and pressure of 4.4

mH2o and flow velocity of 0.46 m/s (figure 11).

Figure 12 : system watering of field two

The system delivers to the field two a flow rate of 40.32 m3/h and pressure of 8

mH2o and flow velocity of 0.66 m/s figure (12).

Figure 13: system watering of field 3 part lot 1

41

The system delivers to the felid d three part one a flow rate of 27.56 m3/h and

pressure of 8 mH2o and flow velocity of 0.45 m/s (figure 13).

Figure 14: system watering of field 3 part lot

The system delivers to the field one a flow rate of 27.56 m3/h and pressure of 8

MH2o and flow velocity of 0.45 m/s (figure 14).

The pipe line system was fully designed with pipe of 110.2 mm of diameter. The

diameter of the pipe was kept constant because the delivery system will be by

rotation among the 4 plots. Then all the water from the pump will be used by a

single sub-plot at a time.

Valves (PRV) with loss coefficient to obtain the desired pressure head at each plot

level have been also used. Indeed the 4 sub-plot receive a head pressure a little bit

higher than they need then the need to decrease this pressure to the desired

pressure.

42

4.2 Characteristics of system components Table 12: system components

Pipe

number

19

Diameter 110.2

roughness 140

43

6. Conclusion and recommendation

The efficient use of water is seen as a key to crop production in arid and semi-arid

areas in subSahara Africa. This is increasingly true because of ever-increasing

populations and demand for food production, coupled with growing competition

for water. For smallholder farmers, drip irrigation provides a means of maximizing

returns on their cropland by increasing the agricultural production per unit of land

and water and increasing cropping intensity by growing a crop during the dry

season.

Drip irrigation can help you use water efficiently. A well-designed drip irrigation

system loses practically no water to runoff, deep percolation, or evaporation.

Irrigated desert soils are commonly used for the production of high value

horticultural crops.

The study shows that the dam can conveniently supply the water required for

irrigation in the area used at present and also in the entire land area. The results

obtained from the study can be used as a guide by farmers for selecting the amount

and frequency of irrigation water for the crops studied under consideration but the

climate in the study was characterized shorter rainy season and climate variability

represent major challenges for the population , the water supply in the study area is

low due to a drought and water restrictions are applied, the inefficiencies of a

poorly designed and installed irrigation system quickly become apparent. For an

irrigation system to be successful, it must include proper design, correct

installation, the right component selection, the proper layout, and equally

important, appropriate maintenance, for this reason the software’s like Google

earth, CLIMWAT2.0, SPAW, the CROPWAT Ve.pro.LG.s, and EPANET was

44

used to evaluate field and coordinates, get climatic data, determine soil

characteristics, the crop water requirements, determine efficiency of the irrigation

system ,proper design of drip irrigation are used respectively in the selected

agricultural district in the study area. This technology could help a farmer to

overcome the worst conditions would have a substantial impact on crop yields,

improve food security, and increase the farmer’s potential for income.

The final system has an efficiency of 92 % and works without pumping, only by

gravity. This performance increases substantially water saving in irrigation,

therefore, allows extension of irrigated areas with the same resource and also its

sustainable use. Google Earth allows users to perform some basic measurements

(latitude and longitude, elevation, and size) but this all measurements do not mean

it is perfect. Some place marks or place mark collections are dynamic, in that they

contain information that changes through time.

45

5. Reference

A. Tagar, F. A. Chandio, I. A. Mari, B. Wagan, 2012, Comparative Study of Drip

Adeniran K.A Amodu M.F1, Amodu M. and Adeniji F.A, (2010), Water

requirements of some selected crops in Kampe dam irrigation project,

AJAE 1(4):119-125 ISSN:1836-9448

FAO, 2013, Crop Water Information, Potato water development and management

unit.

FAO,1992, Irrigation Water Management: Scheme irrigation water needs and

supply

FAO,2013,WaterDevelopmentAndManagementUnit,http://www.fao.org/nr/water/i

nfores_databases_cropwat.html accessed in June 19, 2013

FAO/IIASA/ISRIC/ISSCAS/JRC, 2009. Harmonized World Soil Database

(version 1.1). FAO, Rome, Italy and IIASA, Laxenburg, Austria

Furrow Irrigation Methods at Farmer’s Field in Umarkot, World Academy of

Science, Engineering and Technology

Girmay Tesfaye, Mitiku Haile, Berhanu Gebremedhin, J. Pender

and Eyasu

Yazew.2010. Small-scale irrigation in Tigray: Management and

institutional considerations

http://www.epa.gov/nrmrl/wswrd/dw/epanet.htmlacessed in 19 June 2013.

Jess Stryker, 2011 Drip Irrigation Design Guidelines

Kifle Woldearegay Woldemariam, 2012, Regreening Tigray - Up scaling 3R

Catchments

Langbein W. B. and Kathleen T.Iseri ,2013 General Introduction and Hydrologic

Definitions PAPER 1541

46

Locascio, J.S. (2005) Management of irrigation for vegetables: past, present,

future, Hort Technology 15(3): 482–485.

Management in Ethiopia, world water in week in Stockholm

MARD, 2009. Agricultural Investment Potential of Ethiopia. Review rt. March,

2009, Addis Ababa

Mintesinot Behailu, Mohammed Abdulkedir., Atinkut Mezgebu, Mustefa Yasin,

2004.Community Based Irrigation Management in the Tekeze Basin:

Impact Assessment A case study on three small-scale irrigation schemes

(micro dams).

Mofoke, A. L. E., Adewumi, J. K., Mudiare, O. J. and A. A. Ramalan, 2004,

Design, construction and evaluation of an affordable continuous-flow drip

irrigation system, Journal of Applied Irrigation Science, Vol. 39. No

2/2004, pp. 253-269

Pascal Vagnat, 2013, Federal Democratic Republic of Ethiopia.

Seleshi Bekele Awulachew, Aster Denekew Yilma , Makonnen Loulseged

Willibald Loiskandl ,Mekonnen Ayana, Tena Alamirew, 2007 . Water

Resources and Irrigation Development in Ethiopia, Paper 123

Simonne Eric ,Hochmuth Robert, Brem Jacque an , Lamont William , Treadwell

Danielle , and Gazula Aparna , 2012 Drip Irrigation System for Small

Conventional Vegetable Farms And Organic Vegetable Farms

Suat Irmak, 2007, Drip Irrigation Design and Management Considerations for Windbreaks

Suhas P Wani ICRISAT, Johan Rockström SEI, n and Theib Oweis ICARDA,

2009 . Rainfed Agriculture

T.K. Hartz, 1999 Water Management in Drip-Irrigated Vegetable Production

University of California, Davis, CA 95616

47

Yazewe (2005) Development and management of irrigated lands in Tigray,

Ethiopia PhD thesis UNESCO IHE Institute for Water E ducation. Delft,

the Netherlands: 265 p.

48

Appendix

Annex 1:Soil mapping unit

Annex 2: Soil water character

49

Annex 3 Networki table of field one

Anex 4: Networki table of field two

50

Anex 5 : Networki table of field 3 part one

51

Anex 6: Networki table of field 3 part 2