Abstract:

[Objective] Water and soil loss on cultivated land is characterized by high erosion intensity and poor capacity of soil to retain water, conserve soil, and maintain fertility. Currently, national dynamic monitoring results on water and soil loss cannot be fully applied to the comprehensive management of water and soil loss on cultivated land. Based on existing national dynamic monitoring results on water and soil loss, this study proposes a multi-scale identification method using aggregation analysis to prioritize comprehensive management targets for cultivated land water and soil loss. Priority levels are determined for each treatment unit, providing technical support for efficient and precise evaluation and management planning. [Methods] This study selected Yuexi County in Sichuan Province as the research area. Through spatial overlay analysis of land-use raster data and soil erosion intensity raster data, the data reclassification, regional merging, and removal of small patches were performed to construct contiguous management zones. Depending on water and soil loss characteristics, cultivated land distribution patterns, and patch fragmentation degree, the study extracted cultivated land management targets of varying sizes and calculated their respective erosion grid ratios. A composite evaluation index was then derived by multiplying three graded indices: soil erosion grid ratio, management area level, and average slope level. The comprehensive management priorities were ultimately determined according to the evaluation index values. [Results] Using the proposed method, Yuexi County was classified into five comprehensive management zones for cultivated land water and soil loss, effectively covering the main severely affected cultivated areas. As the priority level increased, the land area, proportion of water and soil loss area, and erosion intensity increased. According to the zoning results of cultivated land in Yuexi County, Zone Ⅰ exhibited mild water and soil loss, with limited impact on the county’s overall loss conditions. Zone Ⅱ showed an increase in water and soil loss, with scattered distribution, suitable for decentralized strategies as a short-term comprehensive management area for cultivated land. Zone Ⅲ comprised large, contiguous areas of cultivated land and was the focus for medium- to long-term soil and water loss comprehensive management. Zone Ⅳ had large areas of high-intensity, concentrated erosion and served as the main area for reducing and mitigating soil and water loss in the county. It was a key area for planning medium- to long-term management of cultivated land. Zone Ⅴ suffered from the most severe water and soil loss, with large area, high proportion of high-intensity loss, and great difficulty in treatment. It should be treated as a priority area for intensive, long-term management efforts. [Conclusion] By comprehensively considering slope, loss area, and erosion ratio and setting appropriate thresholds for decision-making factors, the resulting comprehensive management area can effectively cover severely affected cultivated lands in the county. These zones accurately reflect the spatial distribution patterns of water and soil loss and clarify the priority levels of treatment intensity. To enhance the accuracy and applicability of this study, it is recommended to incorporate additional decision-making factors, including local topography, precipitation patterns, soil properties, and engineering measures. This multidimensional approach will enable more precise identification of representative comprehensive treatment targets, thereby providing a robust scientific basis for regional planning and formulation of optimal remediation strategies.

Key words: cultivated land, soil and water loss, dynamic monitoring, classifying priority, erosion intensity, slope, comprehensive management zones