Quantitative analysis of driving factors in soil erosion using geographic detectors in Qiantang River catchment, Southeast China

Abstract

Soil erosion has received enormous attention from the scientific community and government across the world. This study aims to detect those important driving factors and their potential interactions on soil erosion. Findings would facilitate the rational development of soil and water conservation. Here, soil erosion was simulated using the Revised Universal Soil Loss Equation (RUSLE) in the Qiantang River catchment, southeast China, for the period of 2006–2015. Contributions to soil erosion by six driving factors including land cover type, annual rainfall, elevation, slope, soil type, and vegetation coverage were quantitatively analyzed via Qiantang River Catchment geographic detectors. The results suggest that vegetation coverage explains 7.28% of soil erosion distribution, and the impact of vegetation coverage on soil erosion is significantly larger than that of the other five driving factors (p < 0.05). In recent years, the explanatory power of vegetation coverage to soil erosion has experienced a change from increasing to decreasing trend. The interaction between vegetation coverage and slope explains up to 32.69% of soil erosion distribution, and an increasing trend has been detected in the explanatory power of this interaction. The spatial heterogeneity of soil erosion can be well understood by vegetation coverage and elevation. The high-risk areas are featured by elevation ranging from 1135 to 1777 m or vegetation coverage between 50 and 62%. Changes in vegetation coverage and its spatial distribution at different elevations are the main causes of the variations in the explanatory power. The spatial analysis and quantitative analysis of six driving factors in soil erosion have improved the understanding of the heterogeneity in soil erosion. Measures in soil and water conservation should be strengthened in high-risk areas. The interaction between vegetation coverage and slope is the dominating contributor to soil erosion. The study provides a scientific basis for rational prevention of soil erosion in the Qiantang River catchment.