Soil erosion rates in India

Because land degradation from water-induced soil erosion is a serious problem in India and only fragmentary information on factors affecting soil erosion is available, an attempt was made to prepare a countrywide map of soil erosion rates for land use planning. To prepare the map, available maps of soil, rainfall erosivity, slope, land use, forest vegetation, degraded land, sand dunes, and irrigation were used. Soil loss data from various research stations, watersheds, and sedimentation of reservoirs also were used. Soil losses for a number of places were estimated using the universal soil loss equation. Based on these 21 observed and 64 estimated soil loss data points spread over different land resource regions of the country and superimposing eight above-mentioned maps, iso-erosion rate lines were drawn. Annual erosion rate due to water is less than 5 Mg/ha/yr (2.2 tons/acre) for dense forest (above 40% canopy), cold desert regions, and arid regions of India. Wind erosion is also active in the Indian desert situated in the northwestern part of the country. Indo-Gangetic plains, including salt-affected lands, of Punjab, Haryana, Uttar Pradesh, Bihar, and West Bengal show moderate erosion rates (5-10 Mg/ha/yr). The areas revealing severe erosion—more than 20 Mg/ha/yr—include the Shiwalik Hills, northwestern Himalayan regions, ravines, shifting cultivation regions, Western Coastal Ghats and the black cotton soils areas of Peninsular India. Remaining parts of the country lose between 10-20 Mg/ha/yr. The map is a first approximation of soil erosion rates in India; it can be further refined as more data become available. In spite of limitations, this map will prove to be a handy tool for planners, watershed managers, and policymakers in developing appropriate land use for achieving sustained productivity.