Quantifying the contributions of driving factors and analyzing dynamic changes of water erosion in mountain areas are crucial for water erosion control and sustainable soil resource utilization. In this study, the Revised Universal Soil Loss Equation (RUSLE) and Sediment Delivery Ratio (SDR) model were integrated, and the Geographically Weighted Regression (GWR) and path analysis models were used to explore the contributions and interactions of key influencing factors (precipitation, NDVI, slope, soil moisture) on water erosion in Longnan City. The results showed that the RUSLE-SDR model could simulate the water erosion process effectively in Longnan City from 2000 to 2020 (R2 = 0.821, NSE = 0.67). The spatial and seasonal distribution of water erosion intensity was consistent with precipitation, showing the characteristics of weak in northwest and strong in southeast, and summer is the most serious period of water erosion. The GWR and path analysis models revealed that vegetation and slope were the main influencing factors of water erosion, and they had a strong interaction. When NDVI was below 0.67, slope had a direct impact on water erosion; when NDVI was between 0.67 and 0.82, slope and vegetation jointly influenced water erosion; and when NDVI was above 0.82, vegetation became the dominant factor, while slope indirectly affected erosion by regulating vegetation cover. Precipitation was the main factor that influenced erosion when the rainfall was less than 550 mm, but when the rainfall exceeded 550 mm, it exhibited a strong inhibitory effect on erosion through vegetation. This study reveals water erosion’s driving mechanisms in mountain areas and provides soil erosion control measures’ implementation with a scientific basis and theoretical support.

中文翻译：

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基于RUSLE-SDR的山区水土流失时空分布特征及驱动因素探究


量化驱动因素的贡献并分析山区水土流失的动态变化对于水土流失控制和土壤资源的可持续利用至关重要。本研究整合了修正的通用土壤流失方程 （RUSLE） 和泥沙输送比 （SDR） 模型，并采用地理加权回归 （GWR） 和路径分析模型探讨了关键影响因素（降水、NDVI、坡度、土壤水分）对龙南市水土流失的贡献和交互作用。结果表明，RUSLE-SDR模型能够有效模拟2000—2020年龙南市水土流失过程（R2 = 0.821，NSE = 0.67）。水土流失强度的空间和季节分布与降水一致，表现出西北弱、东南强的特点，夏季是水土流失最严重的时期。GWR 和路径分析模型显示，植被和坡度是水土流失的主要影响因素，两者具有很强的交互作用。当 NDVI 低于 0.67 时，坡度对水蚀有直接影响;当 NDVI 在 0.67 和 0.82 之间时，坡度和植被共同影响水土流失;当 NDVI 高于 0.82 时，植被成为主导因子，而坡度通过调节植被覆盖间接影响侵蚀。当降雨量小于 550 mm 时，降水是影响侵蚀的主要因素，但当降雨量超过 550 mm 时，对植被侵蚀表现出较强的抑制作用。本研究揭示了山区水土流失的驱动机制，为水土流失防治措施的实施提供了科学依据和理论支持。