Distribution assessment of soil erosion with revised RUSLE model in Tianshan Mountains

Soil degradation caused by soil erosion is one of the world's most critical environmental issues. Soil erosion in the Tianshan Mountains has caused various environmental problems in the surrounding areas. This study used remote sensing data to analyze the distribution of the factors influencing soil erosion, and the revised universal soil loss equation (RUSLE) to calculate the total amount and distribution characteristics of soil erosion in the Tianshan Mountains in 2019. Due to the large error of RUSLE in soil erosion estimation in mountainous areas, this study modified RUSLE equation based on the characteristics of snow cover in the Tianshan Mountains. The results show that the average soil erosion was 1690.3 t/(km²·year), of which insignificant erosion, slight erosion and moderate erosion accounted for 42, 8%, 22.4% and 9.9%, respectively. Severe erosion and above accounted for 13.3%. The accuracy of the soil erosion modulus calculated by the RUSLE was only 61.9%, with an average error of 1631.9 t/(km²·year). The average error of the double-coefficient correction method was 1259.1 t/(km²·year), and the average error of the modified formula method was reduced by 40.3% compared with the RUSLE, reaching 973.7 t/(km²·year), and its accuracy reached 76.2%. Very severe erosion and catastrophic erosion are distributed on mountain ridges with higher elevation and on the northern area with higher precipitation. Snow cover has a certain inhibitory effect on soil erosion, and snow cover in alpine mountains is a factor that cannot be ignored in soil erosion research. The improvement of the RUSLE by the modified formula method can more accurately calculate the soil erosion modulus in the Tianshan Mountains in order to provide accurate soil erosion control recommendations for different erosion areas.