Resource conservation technologies for soil moisture conservation in drylands

Abstract

Dry lands in India constitute 68.4 per cent of the cropped area out of the total cultivated extent of 162.03 million hectares. Due to the higher attention given to irrigated agriculture during green revolution, the care for rainfed agriculture has been considered to be minimum. To meet the growing demands for food, the scope for further addition to area under agriculture is possible only through the exploitation of dry lands. Bringing the vast stretch of dry lands under green cover is the immediate need for the ecological restoration. Rainfall is the ultimate source of water, affecting production of crops and other biomass by direct falling on the fields as well as supporting surface and ground water irrigation. However, possibilities of drought occurrence in India vary from once in 2 years in Western Rajasthan to once in 15 years in Assam. The frequency and intensity of extreme weather events like droughts, floods, heat/cold waves, cyclones, delayed or early onset, long dry spells, early withdrawal, floods in drought frequented areas and droughts in flood afflicted areas have increased during the last two decades due to global warming. Droughts in the Indian region are mainly due to various kinds of failures of rains from southwest monsoon. Also there seems to be some association between El Nino and La Nina events and weak monsoons. Over more than hundred year’s period between 1871-1988, 11 of the 21 drought years were El Nino years. During the 90 years period between 1901-1990 rainfall was sufficient in all 7 strong El Nino cases. The El Nino phase of the Southern Oscillations (ENSO) has direct impact on drought in India which causes weak or …