Soil Erosion Assessment in the Beiluo River Basin Based on the CSLE Model and Sampling Survey Method

Soil erosion is a global ecological and environmental issue. To improve the accuracy of regional soil erosion estimation, this study investigates the impact of different sampling densities on soil erosion estimation at the watershed scale using the CSLE model, taking the Beiluo River Basin as an example. Based on the CSLE model, the study compares the effects of four sampling densities (0.0625%, 0.25%, 1%, and 4%) on soil erosion estimation in the study area using two methods: full coverage calculation and unit interpolation extrapolation. The differences and main causes of these effects are analyzed to identify the appropriate sampling density and soil erosion estimation method for the watershed. This provides a theoretical basis for the selection of field sampling density and methods in regional soil erosion dynamic monitoring. This study extracted land use and soil and water conservation measure information through remote sensing interpretation of sampling survey units at different densities. Based on the CSLE model, soil erosion rates were calculated for the watershed. The results indicate that both the full-coverage calculation method and the sampling survey method are capable of capturing the macro-scale patterns of soil erosion within the watershed. The full-coverage calculation method provides complete spatial coverage, effectively represents the spatial distribution characteristics of regional soil erosion, and is relatively insensitive to variations in sampling density. However, due to limitations in the accuracy of model input data sources, this method tends to overestimate soil erosion rates. In contrast, the sampling survey method utilizes higher-precision input factors, resulting in more accurate soil erosion assessments. Nevertheless, its estimation results are strongly influenced by sampling density and the choice of interpolation methods. In summary, the sampling survey method better reflects soil erosion variations across different topographic conditions, making it an efficient and practical approach for regional soil erosion investigations.

Keywords：Beiluo River Basin; CSLE model; soil erosion estimation; sampling density; full coverage calculation