Soil erosion gradient and quantitative attribution in southwest China based on karst development degree

The heterogeneity of the geographical environment determines the complexity of soil erosion patterns. Deter-mining the effects of changing gradients and combinations of environmental factors on soil erosion is the key to combating soil erosion. In this study, based on the division of the karst development degree, the revised universal soil loss equation model was optimised based on the rocky desertification factor to determine the effect of the different gradients of environmental factors on soil erosion. The geographical detector method was used to identify the dominant and interactive factors of soil erosion under different karst development degrees. The gradient attribution shows that: soil erosion is influenced by the type of bedrock assemblage and the form of the assemblage. Soil erosion is strongest at 1400-1800 m above altitude. Grassland in karst areas is prone to soil erosion and the effect of vegetation coverage on soil erosion has a critical value of 0.6-0.7. Interaction analysis shows that the interaction between land use and slope plays a dominant role in the spatial differentiation of soil erosion, but has significantly higher explanatory power (q)in sub-karst and non-karst areas than in pure-karst areas. Combined with slope and rainfall, soil erosion is obviously intensified, and the pure-karst and sub-karst areas are higher than the non-karst areas. The significant interaction between lithology and slope is a typical feature of karst areas. The findings of this study have crucial theoretical significance for the site-specific control of soil erosion in areas with different karst development degrees.