Evaluation of soil anti-erodibility at different ages of Leucaena leucocephala forests in the area with high-frequency debris flow.

Soil anti-erodibility is one of the important parameters for evaluating the ability of soil resistance to soil erosion. Aiming to understand the effect of vegetation restoration on soil erosion durability in the area with high-frequency debris flow, we determined the soil anti-erodibility at different ages of Leucaena leucocephala forests by using principal component analysis based on the data collected from the field and analyzed in the laboratory. The results showed that: 1) as the age of L. leucocephala forest increased, soil permeability, structure stability and soil nutrient decreased except for the content of fine particle; 2) the comprehensive indexes of soil anti-erodibility followed the rule as 10 a 16 a 27 a, indicating that the soil anti-erodibility decreased with forest age in Jiangjia gully; 3) according to Pearsons correlations, all the 13 anti-erodibility indicators could be simplified to 5 indicators which were soil density, maximum water-holding capacity, the content of water-stable aggregates at size 0.25 mm, clay content and silt content. Taking 5 selected indicators (X) as independent variables and soil anti-erodibility indicator (Y) as dependent variable, the soil anti-erodibility model was built by linear regression analysis as Y=－8.691X1+0.054X2+0.700X3－0.425X4－0.189X5－12.511. This result could provide a reference for the building of soil anti-erodibility assessment indicator system and its future research in the area with high-frequency debris flow.