Objective This study aims to systematically evaluate the cultivability of sloping farmland in Hunan province, where extensive hilly terrain and a high risk of soil erosion constrain the sustainable use of farmland.

Methods A province-wide sloping farmland database was constructed using sloping farmland polygons identified from the 2024 National Land Survey. Seven indicators were selected for the evaluation: slope gradient, soil erosion severity, soil layer thickness, soil texture as represented by gravel content, soil pH, cation exchange capacity (CEC), and soil organic matter content. The limiting factor method was applied to evaluate the cultivability of sloping farmland.

Results 1) Sloping farmland in Hunan province covered 3 754.51 km², accounting for 10.08% of the total farmland area. Farmland on gentle slopes of ≥ 6° –15° accounted for 65.07% of the total sloping farmland area. Farmland on steep slopes of ≥ 25° covered 311.77 km² and was mainly distributed in Huaihua, Xiangxi prefecture, and Shaoyang. The mean sloping farmland characteristic index for the province was 0.19. Changsha (0.35), Zhuzhou (0.32), and Huaihua (0.31) had relatively high index values, indicating greater difficulty in the development, utilization, and management of sloping farmland. 2) Very slight and slight erosion were the predominant soil erosion classes across the province. The mean values of the comprehensive index of soil erosion on sloping farmland in Yongzhou, Loudi, and Hengyang were 11.83, 11.69, and 11.64, respectively, identifying these cities as priority areas for soil and water conservation. 3) The areas of sloping farmland classified as suitable and unsuitable for cultivation were 2 251.86 and 1 502.66 km², respectively. The proportions of sloping farmland classified as suitable for cultivation exceeded 80% in both Zhuzhou and Hengyang, while areas unsuitable for cultivation were concentrated mainly in Shaoyang, Huaihua, and Loudi. The main limiting factors included low CEC, high gravel content, and excessive slope gradient, corresponding to areas of 824.08, 400.01, and 311.77 km², respectively.

Conclusions Sloping farmland in Hunan province exhibits pronounced spatial heterogeneity, and soil erosion risk increases with slope gradient. Unsuitability for cultivation is jointly constrained by topographic conditions and soil physicochemical properties. Management measures should be tailored to cultivability grades and dominant limiting factors and should include category-specific protection, soil improvement, soil and water conservation, and the ecological conversion of unsuitable sloping farmland.