Figure 2. Distribution map of K factor(a), LS factor(b), and T factor (c) in the Jiuyuangou watershed,spatial distribution of R factors(d–f), B factors (g–i) and E factors(j–l) in 2010, 2015, and 2020

Temporal and spatial evolution of soil erosion (2010–2020)

We calculated the soil erosion modulus of the Jiuyuangou watershed in 2010, 2015, and 2020 using the CSLE model. According to the Soil Erosion Classification Standard (SL190-2007) issued by the Ministry of Water Resources of the People’s Republic of China, the soil erosion modulus is divided into six grades: weak (0–10 t ha–1yr–1), slight (10–25 t ha–1yr–1), moderate (25–50 t ha–1yr–1), intensive (50–80 t ha–1yr–1), very intensive (80–150 t ha–1 yr–1), and severe (>150 t ha–1 yr–1) (Figure 3). The average soil erosion modulus in the watershed was 10.85 t ha–1 yr–1 in 2010, 8.03 t ha–1 yr–1 in, and 10.57 t ha–1 yr–1 in 2020.