Dealing with drought, 5 August, 2002

Water is vital for agriculture. In the semi-arid tropics, where agriculture is predominantly rainfed and drought a recurring phenomenon, efficient water management practices like effective watersheds are becoming integral government policy. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) along with national agricultural system (NARS) partners has been working on technologies to manage drought for rainfed crops for the last 30 years. Rainfed agriculture, which depends on the monsoon, generally faces long dry spells during the cropping season. This year's drought is the worst in a decade.

But help is at hand. ICRISAT researchers and partners have developed and evaluated a number of options to suit various local conditions.

If crops are already planted at the onset of monsoon but drought is affecting the established crops:

• Employ soil/water conservation measures such as interculturing to loosen the surface soil, which helps break the capillary movement of water through evaporation. It also helps remove weeds and minimises competition for water. 
• Open dead furrows after every 10th crop row to increase infiltration and reduce runoff loses of rainwater. 
• Thin crops to minimise evapo-transpiration. How much thinning is required depends on the severity of soil moisture conditions. 
• Postpone fertilizer and insecticide application until the soil moisture situation improves. 
• Use available stored water efficiently for life-saving irrigation with drip or sprinkler systems.

If crops are yet to be planted and monsoon is delayed:

• Sow short-duration varieties of the desired crops - preferably legumes like green gram, black gram, cowpea, pigeonpea and soybean after monsoon rains arrive. 
• Sow on contours to reduce runoff losses and increase rainwater infiltration in soil. 
• Grow fodder crops with available soil moisture - at least fodder for livestock will be ensured. 
• Harvest rainfall water at field and community levels for use as supplemental irrigation if needed during the crop maturity. 
• If rains are very late, forgo a kharif crop and use stored soil moisture for a rabi crop. Especially in black soils sow short-duration crops like chickpea, safflower, sunflower or sorghum.

Long-term strategies to cope with drought

"The authorities should frame policy to deal with drought on a long-term basis," says Dr William D Dar, Director General of ICRISAT. "The issue of considering water efficiency and not merely availability is a recent development."

It is estimated that in the next 50 years, India's irrigation capacity requirements will increase by 50%, and the demand for domestic and industrial water will rise at an even faster rate. Now the question is - is the available water being used efficiently? Increasing usage of available water resources becomes quite significant in this context. In the 1993/94 season, about 36% of water resources were actually utilised. But experts say that a 10% improvement in this ratio would translate into 14 million additional hectares of irrigated land.

It is essential to mobilize communities to work towards implementing soil and water conservation measures developed by scientists for the rainfed areas. For example:

• Integrated watershed management should be adopted for conserving water and using it efficiently through rainwater harvesting. Diversion of rainwater into dugout ponds, mini-percolation tanks, dry wells, sunken gully silt traps, water tanks and checkdams should be taken up under watershed development programs. 
• Soil organic matter also needs to be improved in the long term. Nitrogen-fixing shrubs like Gliricidia and Leucaena can be grown on bunds to improve the water-holding capacity of the soil. 
• Vermicomposting farm residues and weeds can add valuable organic matter to the soil. Earthworms both improve fertility and increase water-holding capacity of the soil. 
• Balanced and integrated use of nutrients and environment-friendly pest management options can increase the productivity of rainfed agriculture through efficient use of conserved soil and water resources. 
• Increase green cover with suitable plants. 
• Use improved varieties that resist pests and tolerate drought. 
• Educate farmers on appropriate soil and water conservation technologies. 
• Establish community-based systems for water resources auditing and use at village level to avoid over exploitation of groundwater. 
• Desilting existing water harvesting structures to increase storage capacity. The silt can then be used as a valuable source of plant nutrition.