Effects of Vegetation Restoration on Soil Erodibility and Nutrients at Different Slope Sites in Northern Hebei Mountains

[Objective] To understand the variations in soil erodibility and nutrient content caused by different slope positions and land uses, and to discuss the influence of various factors on soil erodibility and nutrient status. [Methods] Soil and root samples were collected, and the Comprehensive Soil Erodibility Index (CSEI) and Comprehensive Soil Nutrient Index (CSNI) were calculated using a weighted sum method under different slope positions and land uses. [Results] (1) There were differences in both CSEI and CSNI among different slope positions. The highest value of CSEI was recorded on the slope crest (0.653) and the lowest value was at the bottom of the slope (0.275), while the highest value of CSNI was found on the slope crest (0.715) and the lowest value was at the top of the slope (0.341). (2) Differences in both CSEI and CSNI were observed among different land uses. The highest value of CSEI was observed in fallow land (0.617) and the lowest value was in forests (0.252), while the highest value of CSNI was found in forests (0.793) and the lowest value was in fallow land (0.322). (3) CSEI was significantly negatively correlated with clay content, sand content, root length density and aboveground biomass. It was also significantly positively correlated with silt content and soil bulk density. Soil bulk density had the greatest direct impact (0.26). CSNI was significantly positively correlated with clay content, sand content, root length density and aboveground biomass. It was also significantly negatively correlated with silt content and soil bulk density. Clay content had the greatest direct impact (0.45). There was a significant negative correlation between CSEI and CSNI. [Conclusion] Slope position significantly influences both CSEI and CSNI, emphasizing the importance of focusing on slope crests and mid-slopes in vegetation restoration efforts. Vegetation restoration in various geomorphic positions effectively reduces CSEI and enhances CSNI, with trees being more effective in controlling soil erosion.