Analysis on Forest Soil Nutrient of Qilu Lake Watershed in Yunnan Plateau

The relationship between the fertility of forest soil in the Qilu Lake watershed in Tonghai County, Yunnan Province and the nutrient indices of the forest soil under natural status was analyzed. The following conclusions were drawn:The organic matter content in the soil of the valley was commonly low or very low. The total N content of the soil was comparatively high, while the available P content was quite low. The principal component analysis of the soil fertility showed that the contents of organic matter, the available N, available P and the pH value of the soil could basically represent the natural fertility of the soil, showing the positive load to the soil fertility. Whereas the available K and C/N ratio would also affect the soil fertility, showing the reverse load to the soil fertility.