Calculation of soil conservation physical quantity in Sanjiangyuan National Park: based on CSLE model

Soil conservation ability is an integral part of the value of ecosystem products, which plays a vital role in soil erosion control and ecological environment improvement. Since the development of the national park system in China, its influence on soil erosion modulus and soil conservation capacity in the Sanjiangyuan area still needs to be clarified. This paper compares the differences between the CSLE and USLE models and their factors. CSLE was selected to conduct a comparative study of soil erosion modules in 2000 and 2020. The total amount of soil conservation in Maduo County, the source area of the Yellow River, in the past 20 years was calculated. The results showed as follows: 1) In the study area, the CSLE model was significantly better than the USLE model in distinguishing different soil erosion modulus intensities, and its optimization calculation method for slope length factor and biological measure factor could more accurately evaluate soil erosion modulus. 2) From 2000 to 2020, the soil erosion intensity of Maduo County has been dramatically improved. The soil erosion modulus of about 75% of the regions has decreased significantly. However, a small part of the regions still have increased soil erosion modulus, and the soil erosion intensity has intensified. 3) The total amount of soil conservation in Madao County in the past 20 years was 1.683×10⁶ t. When calculating the soil conservation amount in the value of ecosystem products, the calculation should be carried out with the area where the soil erosion modulus decreased by 75% rather than using the USLE formula, which assumes that the soil in the whole area is effectively maintained.