Research on the spatiotemporal distribution and control degree of soil erosion in Dali River Basin

The Dali River basin as the representative areas of the middle reaches of the Yellow River. Accurately evaluating the degree of soil erosion control is very important for soil erosion control. In response to the problems existing in the current research on soil erosion control degree (SECD) methods, the maximum possible soil erosion modulus is introduced into the evaluation model. Thereby eliminating the uncertainty of the assumed state of the original model. This paper calculates the SECD for 2020 based on this method. The results show: (1) From the soil erosion modulus spatial distribution, it can be seen that the soil erosion intensity is stronger in the eastern and southwestern parts. (2) Based on the SECD spatial distribution, it was found that eastern and southwestern regions were well controlled. This is consistent with the actual situation. (3) As the slope increases, the area proportion of SECD within the 0.2-0.3 range in each slope zone shows an increasing trend, while that of SECD within the 0.5-1 range gradually decreases; (4) In the case of vegetation coverage greater than 80%, SECD is still concentrated between 0.3-0.5, which indicates that vegetation coverage is not the only factor affecting soil erosion control. This research provided a new perspective for the evaluation of SECD.