Background As one of the three major inland river basins in Hexi Corridor, Shule River Basin is the main ecological protection barrier in inland arid areas of northwest China. However, due to arid climate, low vegetation coverage, wide distribution of bare land and sandy land, and high terrain in the upper reaches, soil erosion is serious, and soil conservation is one of the important ecosystem services in the basin, which is crucial to the ecological sustainable development of the basin.

Methods Based on land use, DEM, precipitation, soil and other data, this paper used the soil conservation module in the InVEST model to conduct spatio-temporal analysis and quantitative evaluation of soil erosion and soil conservation in the Shule River Basin from 2000 to 2018, and analyzed the spatio-temporal variation characteristics and trends of supply and demand risks by establishing the supply and demand risk framework of soil conservation services. The main conclusions are as follows.

Results 1) From 2000 to 2018, the total amount of soil erosion showed a fluctuating decreasing trend, from 3.73×10⁸ t in 2000 to 3.30×10⁸ t in 2018; the watershed was dominated by slight and mild erosion, accounting for about 85% of the watershed area. From the perspective of change, the erosion degree was generally improved, and the areas of extremely strong erosion and severe erosion were reduced by 14%. 2) The total amount of soil conservation showed an increasing-decreasing-increasing trend. Among them, the decline in 2010—2015 was the largest, which decreased by 1.01×10⁸ t, and the decline was 29%. The soil conservation in the upper reaches of the basin changed significantly, mainly affected by vegetation, topography and climate. The ecological background in the middle and lower reaches was poor, and the soil conservation was less and the change was not obvious. 3) In terms of supply and demand risks, the risk level was clominated by danger and insufficient supply. In 2000-2018, the area of highly endangered and endangered high-risk areas decreased from 33% to 12%, while the area at risk level of safety changed slightly.

Conclusions Overall, the situation of soil erosion in Shule River Basin has been reduced, the amount of soil conservation has increased, the risk level of supply and demand of soil conservation services has been reduced, and the supply and demand situation has improved, indicating that the local ecological policy has been reasonably implemented, and the ecological environment has been optimized.