Background The Karst region of Southwest China is characterized with the fragile ecological environment. Guizhou province is suffering from high intensity of soil erosion and sloping cropland is the most vulnerable to soil erosion in this region. Soil erosion of sloping cropland in Guizhou province had been studied on a provincial scale, and the results are beneficial to providing a basis for promoting soil and water conservation in this region. The spatial distribution and erosion intensity of cropland are greatly affected by regional divisions by geomorphy and topographic factors; therefore, it is necessary to take regional divisions and topographic factors into consideration to determine key areas for ecological restoration in this region.

Methods 1) The digital map of regional divisions by geomorphy was created in ArcGIS 10.2 software according to related articles. 2) By using SPSS 19.0 software (Statistical Product and Service Solutions 19.0), we explored the proportion of cropland area and the cropland soil erosion intensity in Guizhou province. 3) By using ArcGIS 10.2 software, we built spatial distribution map of the proportion of cropland area and the cropland soil erosion intensity in Guizhou province.

Results 1) The spatial distribution pattern of cropland area proportion in Guizhou province was obvious, which decreased from west to east. The proportion of cropland in non-karst plateau was the lowest, on the contrary, it was the highest in western Karst plateau. 2) The cropland with slope gradient of 8-35° accounted for 91.28% of the total cropland, and cropland with slope length >25 m accounted for 97.81%. With the increase of slope gradient, the soil erosion modulus increased correspondingly, especially in karst area; however, with the increase of slope length, the soil erosion modulus showed no obvious trend. 3) 71.17% of the total cropland area in Guizhou province belonged to middle erosion (< 200 t/km²). The soil erosion in Peak-cluster depression and Karst fractured basin region were more serious with the acute erosion areas accounting for 34.97% and 15.16% of the total cropland, respectively.

Conculsions On the whole, the Peak-cluster depression region and the Karst fractured basin region are the key areas for soil erosion control. These findings hold important implications for agricultural management, regional soil and water conservation and ecological management in Guizhou province.