New 30-m resolution dataset reveals declining soil erosion with regional increases across Chinese mainland (1990–2022)

Abstract

Hydraulic erosion-induced soil loss critically undermines soil fertility, leading to vegetation degradation, reduced crop yields, and increased flood and pollution risks, thereby threatening food security, ecological integrity, and economic stability. Existing soil erosion estimations using the Revised Universal Soil Loss Equation (RUSLE) model are constrained by the absence of high-resolution (30 $m$) nationwide rainfall data, significant spatial and temporal inconsistencies among multi-source data, and limited regional adaptability of empirical RUSLE parameters. To address these challenges, we developed the first 30-$m$ resolution Hydraulic Soil Erosion Dataset (CSWED) for Chinese mainland, spanning from 1990 to 2022. This was achieved by implementing a Random Forest (RF) interpolation method to generate 30-$m$ annual rainfall data and designing a multi-equation combined vegetation cover management factor tailored to China’s diverse soil characteristics. The mean absolute error (MAE) compared to the China Soil and Water Conservation Bulletin was 9.48%, and the CSWED illustrates good consistency with collected runoff plot observation data, significantly surpassing the accuracy of existing publicly available datasets. Our analysis reveals a predominant influence of slope length, steepness, and support practice factors on soil erosion, coupled with a synergistic effect of vegetation cover and topography. Notably, soil erosion in Chinese mainland has exhibited an overall decreasing trend from 1990 to 2022, with significant reductions in light, moderate, and severe erosion categories by 31.70%, 22.24%, and 44.74%, respectively. Also, the sensitivity of soil erosion in 2022 was dominated by strong sensitivity and moderate sensitivity, accounting for 74.149 % and 14.072 %. Then, the decrease in cropland area creates a decrease in soil erosion of 123.54 ${\mathrm{t/hm}}^2$ from 1990 to 2022, while for every additional hectare of forested area, soil erosion was reduced by 58.67 $t$. Special attention should be given to the substantial expansion of soil erosion brought on by extreme rainfall in the Middle and Lower Yangtze River (MLYR) and Southwest China (SWC), where mean soil erosion was 11.71 $t/\left({\mathrm{hm}}^{2}a\right)$ and 15.79 $t/\left({\mathrm{hm}}^{2}a\right)$, respectively, accounting for 60% of the national total.