Vegetation greening partly offsets the water erosion risk in China from 1999 to 2018

Abstract

Soil erosion by water is a major threat to land degradation. The United Nations Decade on Ecosystem Restoration 2021–2030 calls for massive ecosystem restoration to address land degradation impacts. Due to the implementation of large-scale soil and water conservation programs in China (i.e., the Grain for Green Program), the area covered by vegetation has increased. Climate change may exacerbate soil erosion risk, while vegetation greening may alleviate this risk. This work aims to assess China's water erosion risk over the past two decades since the implementation of the Grain for Green Program (1999–2018) and explore the relative importance of precipitation and vegetation on erosion risk dynamics. An integrated method was developed using the Revised Universal Soil Loss Equation and the Pressure-State-Response model. An indicator contribution index was applied to detect the impacts of soil cover and management (C) and rainfall erosivity (R) on risk changes. The results showed that China's water erosion risk had a decreasing trend (23% between 1999 and 2018), especially in areas with middle and high state indicator values. R contributed more than C in northern China, whereas the opposite occurred in southern China. The contribution of R decreased while that of C increased. Vegetation greening partly offset the pressure from climate change. Overall, this work highlights the importance of vegetation recovery in reducing water erosion.