Soil erosion prediction in multiple scenarios based on climate change and land use regulation policies in context of sustainable agriculture

It remains a great challenge to develop feasible land use regulation strategies to control soil erosion under environmental constraints and agricultural demands. This study aims to explore the future outcomes of soil erosion under different land use regulation strategies and the impacts of climate change, while trying to incorporate regional differences in agricultural system development into these strategies. Based on historical data from 2000 to 2020 in 69 cities in South China, this study revealed the reciprocal cross-regulation patterns between soil and water conservation (SWC) and agricultural system development (ASD), highlighting the dynamic and evolving nature of their bidirectional interaction. Taking this historical experience into account, we designed an explorative scenario called discriminatory regulation with regional characteristics (DRC). This scenario assigned different sustainable regulation priorities to regions at different stages of agricultural system development based on the strength of the interaction between SWC and ASD. We also designed two reference scenarios: business as usual (BAU) and ecological and economic balance (EEB), to compare with the exploratory DRC scenario. The DRC scenario involved no additional interventions and continued the land use change trends of the past five years, while the EEB scenario implements uniform sustainable land use regulation across all regions. Ultimately, we used the CSLE model to project soil erosion outcomes under three scenarios and discussed the influencing factors. The SSP2-RCP4.5 scenario from the CMIP6 archive was chosen to provide the climate change background for the soil erosion predictions. The results of the BAU scenario show that the soil erosion modulus is predicted to be 975.75 t·km⁻²·a⁻¹ by the year 2050, exhibiting a significant increase relative to the average value of 729.03 t·km⁻²·a⁻¹ over the period 2000–2020. By 2050, climate change is projected to increase rainfall erosivity by 46.80 %, indicating that climate change will be the major driver of increased soil erosion in the future. In the EEB scenario, soil erosion will be reduced by 11.59 % compared to the BAU scenario when sustainable management is applied region-wide without discrimination. In the DRC scenario, soil erosion will be reduced by 15.68 % compared to the BAU scenario via promoting ecological restoration and encouraging conservation agriculture practices. Comparison of the three scenarios establishes that the DRC scenario is a meaningful attempt to integrate regional disparities in agricultural system development into land use regulation strategies. This study provides valuable references for policy makers to develop a holistic approach to soil resource management and coordinated regional development.