Characteristics of soil nutrient in karst rocky regions with heavy desertification under different land-use patterns

This study used the principal component analysis(PCA) method to analyze the variation characteristics of soil nutrient under different land uses in the karst rocky desertification regions of Bisezhai village, Mengzi City, Yunnan Province. The results show that，(1) the variation coefficient of nutrient content in soil is between 0.14 and 1.76, indicating the relatively great differences in soil nutrients among different land uses；(2) Twelve soil nutrient indexes could be reduced to three principal components, which provide information accounting for 90.69% of the total. Among them, PC1 contains total P, effective P, rapidly effective K and available Mn. PC2 includes total organic carbon, total N, total Ca and available Zn. The contribution of available Fe to PC3 is the greatest；(3) The comprehensive score of principal components of soil nutrients in different land uses are ranked as follows， Pitaya > Plantation > undisturbed grass > Corn. The ranking result shows that forestation and Pitaya plantation can effectively improve soil nutrient status in rocky desertification areas. Collectively, the rocky desertification control in the study area should be on the premise of forestation to ecological restoration. We suggest that planting pitaya or eucalyputs is conducted to improve the soil conditions in the sampled area , thus gradually forming the integrated management system of rocky desertification, which is beneficial to the coordinated development of the ecological environment and social economy