Difference and evaluation model of soil anti-erodibility with different de-farming patterns

Soil anti-erodibility is one of the important parameters for evaluating the ability of soil resistance to soil erosion. Based on the comprehensive investigation on soil physical and chemical, and incorporated into bioindicator, the soil anti-erodibility was investigated with five de-farming patterns including conversion of farmland to Chinese fir plantation, conversion of farmland to eucalyptus plantation, conversion of farmland to loquat orchard, conversion of farmland to tea plantation and conversion of farmland to abandoned land by the method of field investigation and laboratory analysis on the hilly region of Western Sichuan in China. The results showed that all the 19 anti-erodibility indices could be optimized to 6 indices which were water-stable aggregates at size >0.25 mm, average weighted diameter, destructive rate of aggregates at size >0.25 mm, destructive rate of aggregates at size >0.5 mm, soil organic matter and acid phosphatase. The order of principal component analysis(PCA) comprehensive exponent of soil anti-erodibility followed that conversion of farmland to Chinese fir plantation > conversion of farmland to eucalyptus plantation > conversion of farmland to loquat orchard > conversion of farmland to tea plantation > conversion of farmland to abandoned land. Based on the 6 optimal indices of soil anti-erodibility, discriminant functions were established with different de-farming patterns. Discriminant functions included three levels of good, medium and poor soil anti-erodibility and total discriminant probability was 96.7%. So, three models could be used to evaluate soil anti-erodibility exactly in this area. The results can provide theory basis for improving index system of soil anti-erodibility and evaluating soil anti-erodibility of de-farming regions.