Natural chemical degradation of soils in the Indian semi-arid tropics and remedial measures

Most published research on soil degradation in general emphasizes the role of anthropogenic factors. Even among the natural soil degradation processes the regressive pedogenic processes that lead to the formation of CaCO3 and concomitant development of subsoil sodicity and the adverse effects of palygorskite on the soils of the semi-arid tropics (SAT), have received little global attention as the natural processes of chemical degradation of soils. Studies in India during the last two decades, however, have demonstrated the important role of regressive pedogenic processes in natural degradation of major soil types in the Indian SAT regions. The present article summarizes the research on natural degradation of soils in the Indian SAT. The management practices to reclaim the degraded soils are also discussed with examples.