| Summary: | Quantifying soil conservation service is critical for sustainable land management. However, the traditional algorithm includes a gap between barren land and real soil erosion (BSERef), and its paradox is that a mass of barren land rarely exists in ecologically adaptable areas with fertile soils, which might overestimate soil conservation service. This study suggests a practical algorithm to effectively evaluate soil conservation service of different ecosystems. We propose a new algorithm based on the difference between cropland without control practices and real soil erosion (CSERef), which is compared with the BSERef algorithm. Our results show that: (1) a nearly five times smaller mean soil conservation amount of cropland occurred in the CSERef algorithm (3.76×106 t·yr–1) than in the BSERef algorithm (20.04×106 t·yr–1); (2) land use has higher explanatory power for the spatial differentiation of soil conservation rate in the CSERef algorithm (15.93% – 46.34%) than in the BSERef algorithm (5.95% – 44.49%). Our results demonstrate that the BSERef algorithm overestimates the soil conservation service of cropland in ecologically adaptable areas, whereas the CSERef algorithm can effectively assess the influence of land use change induced by anthropogenic activities on soil conservation service. Furthermore, we develop an assessment framework in terms of land use classification system following the Chinese Academy of Sciences. The framework considers that for water bodies, there is no soil conservation service; for non-ecologically adaptable areas (unused land) with vast barren lands and vegetation cover below 5%, the BSERef algorithm is recommended; the CSERef algorithm is suggested to use in ecologically adaptable areas (including woodland, grassland, cropland and construction land). This assessment framework can provide scientific assistance for decision-makers to formulate strategies for sustainable land management.
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