气候变化领域集成服务门户

Soil erosion occurs extensively across China, leading to severe degradation of the land and ecosystem services. However, the spatial and temporal variations in soil erodibility (k) and the distribution of soil erosion across land use types and slopes remain unclear. We synthesized the results from 325 sites published in 152 literatures to analyze the factors affecting the k, such as land use type, climate, topography, soil, and vegetation restoration age. The results showed that areas with slopes >25 degrees had a larger k factor (k=0.1047) than did those with slope <6 degrees (k=0.0637) or 6-25 degrees (k=0.0832). The k from 2006 to 2011 (k=0.0725) was higher than that from 1999 to 2005 (k=0.058) and that from 2012 to 2016 (k=0.0631). The k value initially increased with vegetation restoration age and then gradually decreased. Land use also had an impact on the k factor, with the k factor of cropland (k=0.0697) being higher than that of grassland (k=0.0663) but lower than that of forest (k=0.0967). Across China, North Shaanxi, Heilongjiang, and South Guizhou, which are located in the Loess Plateau in Northwest China, the Black Soil region of Northeast China, and the Karst areas in Southwest China, respectively, were the three most severely eroded regions due to hydraulic erosion, frost-thaw erosion, and high-intensity erosion, respectively. Overall, the most important factors affecting the k were soil characteristics, followed by topography and climate. Among them, soil nitrogen and precipitation were the two most critical factors influencing the k.