Soil erosion associated with an upland farming system under population pressure in northeast India.

摘要

Rapid increase in population and growing demand for agricultural products has generated changes in land use and upland farming systems and resulted in erosion and land degradation over large tracts of northeast India. The spatial variation of soil erosion rates was studied, in a small catchment under a modified form of shifting cultivation on the hilly Meghalaya Plateau, using the 137Cs technique. Soil erosion and deposition patterns are much influenced by land use. The estimated annual soil loss from cultivated fields ranged from 32 to 79 Mg ha-1 y-1 and reached only 0.5 Mg ha-1 y-1 from degraded grassland. Calculated soil erosion rates from cultivated fields exceed that which can be produced by weathering of new soil from parent materials. Observed intensification of agricultural production will lead to progressive conversion of cultivated fields into degraded grasslands and other changes to land use in the upper part of the Meghalaya Plateau.