Efficient Resource Management Systems for Drylands of India

Abstract

India is a vast country with different agro-climatic regions. About 70% of the 143.8 Mha of arable land depends entirely on natural precipitation for crop production. Much of this land is best described as dryland. It is important to distinguish between dryland agriculture in particular and rain-fed agriculture in general. Clearly, they both exclude irrigation. The emphasis for rain-fed agriculture, however, is often on disposal of excess water, maximum crop yields, high levels of fertilizer inputs, and water erosion constraints. In dryland agriculture, emphasis is on water conservation, sustainable crop yields, limited inputs of fertilizer, and both wind and water erosion constraints (Burnett, 1985). Drylands generally receive less than 750 mm of rainfall annually and are arid to semiarid. However, an absolute value cannot be stated because seasonal rainfall distribution and temperature affect crop water requirements and thus the kinds of soil and water management practices. Thus a region with annual rainfall of 750 mm with good monthly distribution in a cool climate might utilize rain-fed agriculture-type management systems, whereas in a hot climate a region with poorly distributed rainfall of less than 750 mm per year might appropriately require dryland farming techniques (Stewart and Burnett, 1985). Both dryland agriculture and rain-fed agriculture are considered in this review, but attention is focused on drylands.