Quantitative analysis of soil erosion spatiotemporal variation and contributing factors in the eastern region of the Agro pastoral Transition Zone in Northern China based on RUSLE

[Objective] This study investigates the spatiotemporal variations of soil water erosion in the eastern region of the agro-pastoral ecotone in northern China, and firstly quantifies the interactive effects of multiple factors on water erosion dynamics, providing decision-making bases and methodological references for soil erosion control and ecological environment restoration in this region. [Methods] Based on the RUSLE model, an attribution analysis was conducted on the spatiotemporal differentiation characteristics of soil water erosion in the eastern region of the agro-pastoral ecotone in northern China from 2000 to 2023, and a quantitative analysis was performed on the main contributing factors to dynamic changes in soil water erosion. [Results] (1) The multi-year average soil water erosion modulus in the eastern region of the agro-pastoral ecotone is 777.94 t·km⁻²·a⁻¹, with most areas experiencing slight and mild erosion, accounting for 69.3% and 22.9% of the total eroded area, respectively. (2) From 2000 to 2023, the soil water erosion intensity in the study area showed a slight upward trend, with an increase rate of 0.90 t·km⁻²·a⁻¹. Soil erosion alleviated in the southeastern and northwestern regions, while intensified in the western region. (3) Areas prone to soil water erosion in the eastern region of the agro-pastoral ecotone are mainly distributed in Chifeng City in the central part, and Zhangjiakou City and Xilin Hot in the southwestern part of the study area. (4) The main contributing factor to dynamic changes in soil water erosion in the eastern region of the agro-pastoral ecotone from 2000 to 2023 is the vegetation cover management factor, with an average contribution rate of 64.18%. The combined influence of three factors(vegetation cover management factor, soil and water conservation practice factor, and rainfall erosivity factor) accounts for 23.12%, the soil and water conservation practice factor contributes 10.57% on average, and the rainfall erosivity factor contributes 2.13% on average. There are strong interactions between parameters of the RUSLE model, and the combined influence of multiple factors has a significant contribution to the dynamic changes of water erosion in the study area. [Conclusion] From 2000 to 2023, the soil water erosion situation in the eastern region of the agro-pastoral ecotone in northern China was generally stable. During the study period, with the improvement of vegetation coverage and the effective adoption of soil and water conservation measures, the aggravating effect of increased rainfall erosivity on water erosion intensity was alleviated to a certain extent. However, the soil water erosion situation in this region remains severe, and areas with low vegetation coverage and without soil and water conservation measures should be prioritized in soil erosion control efforts.