How land use change contributes to reducing soil erosion in the Jialing River Basin, China

• Hydrologic modeling was done for the Lizixi watershed in Jialing River Basin, China.
• The basin suffers from serious soil erosion because of agricultural activities.
• The Soil and Water Assessment tool (SWAT) was used.
• Sediment yield and soil erosion for wheat, rice, corn, and other crops were simulated.
• A parameter named soil erosion increment measured the impacts of slope.

A lack of adequate land use planning can contribute to severe soil erosion and increased sediment yield, creating major environmental problems and threatening the sustainable development of economies and societies. The objectives of this study were to model the effects of land use change on reducing soil erosion in the Lizixi watershed, a typical agricultural area in the Jialing River Basin, China. The Soil and Water Assessment Tool (SWAT) was used to model daily runoff and sediment data from this basin collected from 1975 to 1995. First, the model was used to determine acceptable values of the coefficient of correlation (R2) and the Nash–Sutcliffe coefficient (Ens) during both the calibration and validation periods. Next, the model was used to determine which kind of crop can be grown with the least sediment yield and soil erosion. The results indicated that wheat fields caused the least soil erosion, followed by sweet potatoes, corn, and rape, the last of which was the least effective in preventing soil erosion. The entire watershed was divided into four regions with various slopes, categorized into areas with slopes of 0–5°, 5–15°, 15–25° and >25° to determine how slope influences soil erosion. The results of slope analysis showed soil erosion was the most severe in areas with slopes >25°. We recommend areas with slopes >25° should be used as forestland or grassland rather than farmland. This study will assist local governments in implementing sustainable soil conservation actions designed to reduce soil erosion.