Soil Conservation Assessment by SWAT With Improved Sediment Module and Driving Mechanism Analysis of Its Changes: A Case Study of the Jinghe River Basin, China

Abstract

Globally, the importance of soil conservation (SC) has been increasingly recognized, with a growing demand for the use of more accurate soil erosion models to assess soil conservation and investigate its driving mechanisms. This is essential to meet the requirements of land management and ecological restoration. This study developed a framework for calibrating the sediment module K, C, and P factors of the SWAT model using soil sampling data and remote sensing measurements. Taking the Jinghe River Basin as an example, the optimized model was utilized to assess the spatiotemporal characteristics of soil conservation. Furthermore, this study examined the driving mechanisms of changes in soil conservation by analyzing the relationship between potential and actual soil erosion. The findings demonstrate that calibrating the model using measured data significantly enhances its applicability. Under the combined influence of climate change and human activities, potential soil erosion markedly increased from 2000 to 2020, whereas actual erosion generally decreased, resulting in an overall increase in soil conservation. The changes in soil conservation were primarily driven by climate change‐dominated increase (CCI) and ecological restoration‐dominated increase (ERI). This study is significant for improving soil erosion mechanism models, understanding the regional baseline of soil conservation, and clarifying the driving mechanisms of soil conservation changes. It offers new insights and technical support for soil erosion research and regional management.