Changing Climatic Scenarios and Strategies for Drought Management in the Indian Arid Region

Western Rajasthan constitutes 62% of the 0.32 million km2 that make up the hot Indian arid region (Figure 1). The average annual rainfall of the area varies from less than 100 mm (coefficient of variation [CV] = 70%) in the western parts to just above 500 mm (CV = 40%) in the eastern parts of arid Rajasthan. During July and August, the eastern parts of the arid region have an assured crop growing period of 12–15 weeks, whereas the western parts mostly depend on the vagaries of the southwest monsoon. The annual potential evapotranspiration rates are 3–8 times higher than the annual rainfall, resulting in extreme water deficits and aridity conditions in the region (Figure 2). Pearl millet, which is a principal cereal crop of the arid region, needs about 90 days for its maturity, and any weather aberrations after sowing result in considerable reduction in crop yields. Agricultural droughts have been found to occur in the region in 25%–48% of the years during 1901 to 1995, with a frequency and intensity varying from one location to another, severely affecting food and fodder production