Presentation Topic: water logging

Course instructor

Dr Nassir sb

Registration number

SP15-BES-001 (AMNA ZIA )

Page no 1 Water logging?Page no 4 When and why it

causePage no 5 Water logging and

salinityPage no 6 Water logging in

Pakistan

Page no 7 Affected areas of Pakistan

Page no 12 Impact on agriculture

Page no 14 Impact on landPage no 18 Control on water

logging

WATER LOGGING

Water logging is presents the situation whereby the underground water comes on the surface of land and in certain cases it gathers on the ground level of lands it may assume the shape of streams

When and why it cause? Waterlogging may be a natural condition of

the soil, but can worsen with deterioration in soil structure

It occurs when rainfall exceeds the ability of some soils to drain surplus water away

It is often perceived that waterlogging is a surface water problem that surface drains

will overcome. However, in many situations waterlogging is due to the soil profile (soil below the ground surface) being saturated and some type of subsurface drainage may be necessary to overcome this problem

Unfortunately, some soils and areas, due to their location, cannot be economically or feasibly drained by any means

Susceptibility maps indicate that waterlogging is high to very high over more than 50% of the Corangamite region and is:

o usually a seasonal problemo caused by a relatively impermeable

layer through which water moves only very slowly

o due to soil compaction, sodic soils, high rainfall

Water logging and salinity

As a result, the lands become uncultivated. In same case underground water does not reached the upper surface it remains slightly low on land so different salts accumulated near the roots of plants this situation is called salinity. So water is not sufficient water available for plant growth (irrigation).

These salts are not absorbed in land.

These salt is gather in the form of layers on land, they leads decrease in the productivity of land and finely it become uncultivated

Water logging in Pakistan

38% of Pakistan irrigated land was damaged by water logged

14% saline Only 45% are cultivated at present

time Accumulation on Indus basin

Affected areas of Pakistan

Water logging mainly affect agricultural sector it is estimated that 50% land was affected by water logging in Pakistan

While 30 lace of acres became uncultivated

In case of Punjab 70,000 acres of land affected by water logging every year

Graph show the level of water logging

Impact of water logging on agriculture

Effect of water logging on framer

Waterlogging is currently a significant land degradation threat across much of south-west Victoria

Vast areas including the Heytesbury Soldier Settlement and the Victorian Volcanic Plains represent landscapes significantly affected by waterlogging

Is a significant problem for dairy farmers during winter and early spring where soils can remain waterlogged for considerable periods

Causes poorer pastures, both in growth and quality

Water logging and Stalinization are major impediment to the sustainability of irrigated lands and livelihoods of the

farmers, especially the smallholders, in the affected areas of the Indus Basin. These problems are the result of a multitude of factors, including seepage from unlined earthen canals system, inadequate provision of surface and subsurface drainage, poor water management practices, insufficient water supplies and use of poor quality groundwater for irrigation. About 6.3 million ha are affected by different levels and types of salinity, out of which nearly half are under irrigated agriculture. Since the early 1960s, several efforts have been made to improve the management of salt-affected and waterlogged soils. These include lowering groundwater levels through deep tu

bewells, leaching of salts by excess irrigation, application of chemical amendments (e.g. gypsum, acids, organic matter), and the use of biological and physical methods. However, in spite of huge investments, the results have in general been disappointing and the problems of water logging and salinity persist. Water logging force farmer to sell him land.

Effect on plants

Waterlogging occurs when there is too much water in the plant’s root zone, which results in the roots not being able to access enough

oxygen for respiration. Waterlogging, when it occurs, is a major constraint to production. Plant growth is affected, and under certain conditions will even lead to premature plant death

Seeding ratesIncrease sowing rates in areas susceptible to waterlogging to give some insurance against uneven germination, and to reduce the dependence of cereal crops on tillering to produce grain. Waterlogging depresses tillering. High sowing rates will also increase the competitiveness of the crop against weeds, which take advantage of stressed crops

. Waterlogged seedlings can die before emergence or show symptoms similar to nitrogen deficiency.

Lower leaves turn purple-red to yellow, then die.

Prolonged waterlogging causes root death and eventually death of the whole plant. Plants are more susceptible to root disease.

Waterlogging of adult plants causes yellowing of lower leaves.

Salinity magnifies waterlogging effects, with more marked stunting and oldest leaf marginal necrosis and death

Signs of waterlogging include:

yellowing of crops and pastures; the presence of weeds such as toad rush,

copula, dock and Yorkshire n fog grass; dark, wet, slimy, usually with algae on the

topsoil grey or greenish colored subsoil (permanent

waterlogging creating reducing conditions); The presence of orange mottles in soil

profiles (although some mottles may have been caused by waterlogging in previous climates).

Effect of water logging on land Areas affected by water logging

Germination and early growth can be much worse on saline areas after waterlogging events

Water accumulating or poorly drained areas such as valleys, at the change of slope or below rocks Duplex soils, particularly sandy duplexes with less than 30 cm sand over clay

Low nitrogen status crops In very warm conditions when oxygen is

more rapidly depleted in the soil Deeper so wn crops

Figure 1 Hole in the ground filling with water

observe where soils are boggy and crops are yellow;

mark out the areas that are affected, either with posts laid on the ground or on an accurate map;

at harvest time observe where the crops are poor and check this against earlier observations;

survey seepage interceptor drains, placing them immediately above affected sites or consider raised beds;

install drains when the soils are moist (for example, after summer or autumn rains);

Effects of water logging

Cause of water looging

Control of water logging

Biological control

Water logging is contrl by planting trees bushes plants on water table and control water logging

Drainage

Proper drainage system also help to control water logging and choice of crop,seedling ,fertilization and weed control aslo control the water logging

Best way to control water logging

Remove excess water (drainage options)

o Surface drainage – start with the perimeter

o Subsurface drainageo Raised beds (cropping areas) - to

reduce soil compaction and improve soil structure

Minimize compaction (non-drainage options)

o Controlled traffic flat beds (cropping areas) - to reduce soil compaction and improve soil structure

o Stock management - graze and spell (rotation) based on understanding of plant and soil needs

o Land class fencingo

Improve water storage in profile

Removal of excess water through drainage options

Surface and sub-surface drainage is commonly used to rehabilitate waterlogged land and improve soil structure

Currently, over 80% of dairy land has some form of surface drainage and up to 20% has sub-surface drainage (MacEwan 1998)

- Surface drains- Subsurface drains

Surface drainage - Is very useful in removing excess water from land in a controlled manner and as quickly as possible, to an artificial drainage system or a natural watercourse. This should be done with no damage to the environment. 

Types of surface drainage include: 

Ditches or open drains: 

o These vary in size and length and can be formed by spinner cuts or excavators

o Must be very wary of constructing open drains in dispersive soil as they are highly prone to erosion

Grassed Waterways: 

o These are usually shallow, varying in width from narrow to meters wide, but are constructed such that they are often grazed as part of the paddock

o They are sometimes used to bring drain outflows down slopes to prevent erosion without considerable expense

Humps and hollows (bedding): 

o Hump and hollowing is the practice of forming (usually while renovating pastures) the ground surface into parallel convex (humps) surfaces separated by hollows. The humped shape sheds excess moisture relatively quickly while the hollows act as shallow surface drains

o Humps and hollows are useful in areas or on soil types that are not suitable for tile or mole drainage

o