Estimation of Soil Loss Under Changing Climatic Scenarios in Semi-Arid Watersheds

Abstract

Spatial and temporal estimation of soil loss is very essential for the sustainable planning and management of watersheds. In the present study, an attempt was made to estimate the soil loss spatially and temporally using RUSLE from a dry semi-arid watershed (Goparajpalli in Warangal District) and a wet semi-arid watershed (Seethagondi in Adilabad District) under changing climatic scenarios using PRECIS data. In the dry semi-arid watershed, the annual rainfall varied from 390 to 1181 mm with a mean value of 735 mm and a mean erosivity of 6260 MJ mm/ha/h/y. The mean annual rainfall during the base line period (1961–1990), mid (2021–2050) and end centuries (2071–2098) in this watershed were 738, 835 and 777 mm, respectively. The mean erosivity during these periods were 5657, 9253 and 7170 MJ mm/ha/h/y and soil loss from crop land were 2.39, 4.02 and 3.14 t/ha/y, respectively. In the wet semi-arid watershed, the annual rainfall varied from 508 to 1351 mm with a mean value of 950 mm and a mean erosivity of 6789 MJ mm/ha/h/y. The mean annual rainfall during base line, mid and end centuries in this wet semi-arid watershed were 956, 1088 and 1124 mm and erosivities were 10547, 14437 and 14755 MJ mm/ha/h/y, respectively. Similarly, the soil loss from crop land during these periods were 9.18, 13.11 and 14.11 t/ha/y. Even though, the soil loss from the dry semi-arid watershed was relatively lower than the wet semi-arid watershed, it showed an increasing trend in the mid century and a decreasing trend in the end century whereas, in the wet semi-arid watershed, it showed an increasing trend in both mid and end centuries. Considerable spatial variation in the mean annual soil loss was observed in both the wet and dry semi-arid watersheds during base line period, mid and end centuries.