Assessment of runoff and sediment losses under different slope gradients and crop covers in semi-arid watersheds

Soil erosion is a serious threat to counter global population growth with increased and sustainable agricultural production. Torrential rains in sub- mountainous areas of Pakistan yields tremendous amount of runoff which is a major limiting factor to obtain maximum benefits of land use in sloppy areas. A study was planned to estimate the runoff and soil loss under different vegetation covers and slope. For this purpose, three slope gradients, i. e., 1, 5 and 10% were established having four plots of each slope gradient. Three crops, i. e., groundnut, mungbean and millet were sown with a fallow plot (bare soil), on each slope gradient. Runoff and sediment produced after every rainfall (>= 20 mm) was collected and runoff and sediment losses under each crop cover and slope gradient, were calculated. The results showed that groundnut, mungbean and millet has decreased the accumulative soil sediment loss upto 40, 28 and 38% and runoff loss was decreased by 31, 30 and 24%, respectively, comparing with the bare soil. The highest soil and water losses were monitored at 10% slope gradient following 5 and 1% slope gradients, respectively under all vegetation covers. However, under the same topographic condition, different crops runoff and soil loss show obvious disparity. Topographic gradient has shown significant variation on soil and water loss. It was concluded that crop cover is the best option for appropriate soil and water conservation and profitable crop husbandry.