Assessment of soil erosion using RUSLE and GIS: a case study of the Yangou watershed in the Loess Plateau, China

Due to fragmentized terrain and physiognomy of typical loess landform, long-term anthropogenic influences, and inherent vulnerability, soil erosion is a serious problem in the Loess Plateau of China. There is a critical need to assess soil erosion and spatial distribution for achieving sustainable land use and comprehensive soil conservation management. Taking the Yangou watershed as a case and using the Landsat Thematic Mapper image (land use map), Digital Elevation Model (DEM), soil maps, and precipitation data, this study integrated the revised universal soil loss equation (RUSLE) with GIS technology to estimate soil loss and its spatial distribution. The benefits of soil conservation of land use types were analyzed and the measures for future soil conservation planning were discussed. The results show that silt-covered land and terrace have high benefits of soil conservation, indicating that building check dam, producing silt-covered land for farming, and converting sloped farmland to terrace are effective ways to control soil erosion in the Yangou watershed. Furthermore, increasing vegetation coverage on lower coverage grassland, especially on the slopes with gradients >25°, and eliminating human disturbance in barren areas are feasible and effective measures for soil conservation planning. This study reveals that the integrated RUSLE-GIS model can evaluate and map soil erosion quantitatively and spatially at watershed scale in the Loess Plateau of China. The findings suggest strategies for coping with future soil conservation planning and provide valuable references for future assessments both in the Loess Plateau of China and elsewhere.