Investigation method for regional soil erosion based on the Chinese Soil Loss Equation and high-resolution spatial data: Case study on the mountainous Yunnan Province, China

Investigating soil erosion at the regional scale is challenging because of the difficulties with balancing the accuracy against the cost, especially in areas where the terrain and land use are complex. In this study, we developed a feasible approach to evaluating soil erosion at the regional scale that uses the Chinese Soil Loss Equation (CSLE) and 0.5 m high-resolution Worldview Satellite images, from which soil and water conservation (SWC) engineering practices were interpreted and included into the model as the E factor. We took the mountainous Yunnan Province of southwest China as a case study, and successfully tested this method and estimated the erosion modulus and soil erosion intensity of this region. The model was validated against with measured data derived from 47 runoff plots; the results showed that the coefficient of determination of CSLE was 0.89, which indicates high accuracy. The average erosion modulus was 12.56 t.ha(-1).a(-1 )at the provincial level, and areas with a high erosion modulus were mainly distributed in the central and northeast parts. The total soil erosion area was 104,727.74 km(2), accounting for 27.33% of the total area. More than 77% of above middle erosion occurred in farmlands. Our study is the first effort at incorporating high-precision SWC engineering measures data into regional soil erosion investigation. Our approach reduces the soil erosion estimation error caused by low data accuracy, overcomes the technical bottleneck for obtaining information on regional SWC measures, and provides a practical and low-cost method for evaluating regional soil erosion.