Assessment of production losses due to water erosion in rainfed areas of India

Soil erosion by water has a debilitating effect on crop productivity. Though limited and scattered data is available on loss of production due to water erosion in India, no systematic effort has been made to compute the losses in crop production based upon experimental data, major soil groups, and prevailing erosion rates. The objective of this study is to estimate on-site physical and economic loss of production of major cereal, oilseed, and pulse crops cultivated on rainfed areas of India due to soil erosion by water. The estimation is done by integrating the available experimental data of a crop with the rainfed area of that crop under each erosion intensity category for each of the three major soil groups (alluvial, black and red) in a given state. Following this approach, the total production loss due to water erosion of rainfed areas under major cereal, oilseed, and pulse crops in India was observed to occur at 16%, which in actual physical terms was estimated as 13.4 million t (13.2 million tn) and in economic terms as $2.51 billion (INR 111.3 billion) (the conversion has been given in US dollars as per average conversion rate of 2005 to 2006, i.e., at INR 44.273 per US dollar). Among the six zones of India, the average production loss occurred within a range of 10% (northern) to 24% (southern). At state level, the production loss ranged from 1.4% in Punjab and Haryana states located in alluvial Indo-Gangetic Plains to 41% in the erosion-prone northeastern Himalayan state of Nagaland. In terms of production loss among major groups of crops, cereals contributed 66% to the total loss, followed by oilseeds (21%) and pulses (13%). A similar trend was observed for the monetary losses amounting to 45% for cereals, 33% for oilseeds, and 22% for pulses. Paddy was the most affected among all the crops in terms of both production (4.3 million t [4.23 million tn]) and monetary ($0.56 billion [INR 24.4 billion]) losses. Since the losses are cumulative over time, it is imperative to undertake appropriate soil and water conservation measures for rehabilitation of rainfed areas to prevent huge declines in their productivity levels, which may escalate further due to population pressures.