Quantifying the Shifting Nature–Human Dynamics of Soil Erosion in the Typical Black Soil Region of Northeastern China During 1980–2020

A quantitative assessment of the characteristics and driving mechanisms of black soil erosion is essential to sustainable agricultural development. In this study, we analyzed the spatiotemporal dynamics of the soil erosion modulus (SEM) in the Typical Black Soil Region (TBSR) of Northeast China from 1980 to 2020. The SEM dataset we utilized was derived from a high-resolution dataset utilizing the Revised Universal Soil Loss Equation (RUSLE) model. The independent and interactive effects of nine driving factors, including geographic, climatic, and anthropogenic variables, were quantified. Our findings are as follows: (1) The annual average SEM exhibited a slight but non-significant increase (0.002 t·ha−1·a−1), with a notable fluctuation since 2000. (2) While most regions demonstrated persistence with stability, areas with non-significant slight degradation trends were identified in parts of the eastern Inner Mongolia, Songnen, and Sanjiang subregions. (3) Slope and altitude emerged as the dominant factors influencing SEM patterns, with their effects substantially enhanced through interactions with other variables. Temporally, from the 2000 baseline to the 2001–2010 and 2011–2020 periods, the explanatory power of GDP consistently increased, contributing to an overall rise in anthropogenic influence that surpassed climatic factors. This trend indicated that human activities had increasingly impacted SEM patterns relative to climatic effects. (4) High-risk zones were identified at slopes of 6~8° and elevations of 1230~1430 m (approximately 0.2% of the region). These zones often overlap with ecologically fragile grassland situated in areas characterized by low socio-economic development. These findings underscore the nonlinear coupling mechanisms connecting human activities, land use, and climate systems, providing a scientific basis for targeted erosion mitigation and sustainable farmland management.