RUSLE model coupled with RS-GIS for soil erosion evaluation compared with T value in Southwest Iran

Evaluation of soil loss tolerance and of erosion risk is vital to sustain agricultural productivity and to manage natural resources. In the present study, we attempted to evaluate soil erosion risk of the Dorudzan watershed in Southwest Iran by using the RUSLE model coupled with RS-GIS. The soil erosion risk was compared with the measured soil loss tolerance (T value). To derive the RUSLE factors, we used a digital elevation map with a 10-m resolution, a 10-year rainfall data set, and a digital land use map with soil data obtained from 60 profiles plus Landsat-8 images. The thickness method was employed for determining the T value. The results revealed that the average of the T value was 10.4 t ha−1year−1, ranging from 3.5 to 22.5 t ha−1 year−1. The T value in Inceptisols with significantly deeper soils and a higher SOM percentage was noticeably higher than that of in Entisols. Regarding the T value, the SOM and permeability with correlation coefficients of 0.77 and 0.59, respectively, were the best-correlated properties. The annual soil loss (24.6 t ha−1 year−1), varying from zero in the flat areas up to 153.5 t ha−1 year−1 in the hilly areas, was more than twice the T value. Erosion classes of very high, severe, and very severe cover 25.07% (6983.2 ha) of the site. The LS factor has been identified as the most influential linked to soil erosion.