Management in Water Stress Condition
Having finer differences between dryland and rainfed lands, it is clear that both suffer due to moisture stress or water stress. The core problem of dryland is the scarcity of water as per the requirements of the crop and soil. Therefore to conserve maximum amount of moisture in the soil from low and untimely rainfall which causes abberent weather conditions. Hence emphasis should be given on the productions of reasonable crop yields on economic and sustained basis. As water is most important in scarcity areas, conservation of soil and water are taken which is inter related and where one is tried the other is also achieved.
Management of soil
Tillage practice conserve the basic resources of soil and water also aim at complementing soil and water conservation measures such as graded bunds and land levelling. All tillage operations should be carried out at optimum soil moisture conditions when the resistance to tillage tools is low, resulting in lower draft and power requirements and better soil tilth. The ploughing of deep soils should be done once in 3-4 years. In case of light, shallow and medium soils instead of ploughing frequent hoeing should be done to receive and retain moisture.
To conserve soil moisture, temperature control, prevention of crust formation, reduction in runoff and erosion, to improve soil structure mulching is done. Using mulches particularly organic mulches e.g. jowar or bajara stubbles, paddy straw or husk, sawdust @ 5 tonnes per ha.
To reduce the loss of moisture received by the soil and soil losses through erosion,early maturing adaptable crop varieties with deep and ramified root system and having a dense canopy should be grown e.g. cereal - legumes or strip cropping or erosion permitting and erosion resisting crops.
To improved physical properties of soils,water-holding capacity and to build up the soil fertility a liberal quantity of organic matter, incorporated in combination with green manure, crop residues with inorganic fertilizers.
Dryland soils are subject to serious erosion problems. Following measures are taken which includes the break up of slopes,intercept run off ,give more time of infiltration and divert water into channels.
To retain soil from erosion and rainwater from run off ,the bund section is 1.61 m2 in vertisols and 1.05 m2 in Alfisols, vertical distance 0.9 m can be used across the slope of the land on a level that is along the contour.
Graded bunds are of 0.8 m2 cross section in vertisols and 0.5 m2 in Alfisols. The area lost should not be more than 3-5% and there would be no water stagnation. Graded bunds with grassed water ways and box type masonry drainage and outlets in arable lands. Formation of percolation tanks which leads to water in due course, find its way into subsoil and recharges the ground water.
The practice of tie ridging, where adjacent ridges are joined at regular interval by barriers of ties of the same height, allows the water to infiltrate and prevent run-off except during intense storms.
In red soils, graded bunds are preferred the contour bunds because of scope for harvesting run off water for supplementary irrigation. In black soils with their low infiltration characteristic, cultivated fields suffer from the problem of water stagnation,runoff losses can be reduced by adopting the graded bunds. Besides bunding, creating corrugations across the slope as the run off water flows along these corrugations at a safe and non-erosive velocity.
Growing a shelter belt or forage, fuel and timber trees of protect the land from wind erosion. Adopting water harvesting by inter-plot, inter-row, modified inter-row, broad-bed and furrows system for in situ conservation. Thus to utilize available moisture and water for satisfactory growth of crops, both soil management and water management measures are taken in water stress areas as soils are subject to erosion and loss of available moisture.