Study On The Characteristics Of Forest Soil’s Nutrients In Mianyang Guansi River

Forest soil is the material basis for the occurrence and development of forest vegetation, it fixed and support tree growth, while provided nutrients for tree growth. Forest soil fertility affect the health status of the stand, fertility declined will cause forest degradation, and Soil nutrients is the core of soil fertility. The survey for the characteristics of soil nutrients can provide basic basis for forest health management. Some studies suggest:there has a significant differences during Nutrient accumulation and balance of the soil under different forest vegetation cover. There has a significance for understanding the relationship between forests and soils to study the differences in soil nutrient status of different forest vegetation, such as forest regeneration, forest restoration and reconstruction, forest health management, etc. Guansi River basin is a typical basin of Sichuan hilly area. Its forest resources are the shelterbelts boiled since the eighties of the last century. There have important practical value to study the spatial differences of soil nutrients between different forest vegetation types in the Guansi River for small watershed agro forestry and land-use management and forest vegetation restoration benefit evaluation small watershed agro forestry and land-use management and forest vegetation in hilly area of Sichuan basin restoration benefit evaluation.The study of 8 nutrients of soil such as organic matter, pH, total nitrogen, available nitrogen, total phosphorus, available phosphorus, total potassium, available potassium, etc under different forest vegetation types was carried out between 5 different types of forest vegetation in hilly area of Sichuan basin Guansi River at June 2012, the distribution and variability of fattened soil and correlation between different nutrient indicators under different forest vegetation types was investigated. Through experimental analysis and statistical analysis, the main conclusions are as follows:1.Forest soil in the study area are slightly acidic soil, Soil pH of different forest vegetation types between 4.38-6.33. The coefficient of variation of soil PH in broad-leaved pure forest and bamboo pure forest between 3.17%-4.79%,The variability are weak. The coefficient of variation of soil PH in coniferous and broad-leaved mixed forest, coniferous pure forest, coniferous mixed forest is between 101.81%-154.16%, The variability are highly variable.The coefficient of variation of nutrients under other forest vegetation types nutrient between 13.86%-90.23%, The variability are moderate variability.2. The soil nutrient content under the five forest vegetation types decreased with the soil depth increasing in addition to pH, soil total potassium outside. There has differences of the decline of different nutrients during different vegetation types. The size of the order of the nutrients content was not same during different soil thickness and forest vegetation types.3. There has different correlations in different Indicators of soil nutrients under different forest types. There have a significant positive correlation between soil organic matter and total phosphorus(P<0.05), a significant negative correlation between pH and total nitrogen and available nitrogen(P<0.05), a significant positive correlation between total nitrogen, total phosphorus and available nitrogen content, available phosphorus, total potassium, available potassium(P<0.05), a significant positive correlation between total phosphorus and available phosphorus, available potassium content(P<0.01), a significant positive correlation between available phosphorus and available potassium(P<0.05).4. The study by the multivariate principal component analysis of all the index to influence the forest soil nutrients in the watershed showed that bamboo pure forest>Coniferous and broad-leaved mixed forest>coniferous pure forest>coniferous mixed forest>broad-leaved pure forest.