Effects Of Understory Vegetation Coverage On Soil Quality Of Aerial Seeding Pinus Massoniana Plantation

Understory vegetation is an important part of forest ecosystem, and it plays animportant role in maintaining the soil fertility, improving soil, conserving water and soil.Three types of aerial seeding Pinus massoniana plantation understory vegetation wereselected to analyze the effects of understory vegetation in Xingguo county of Jiangxiprovince on soil physical and chemical and quality based on the filed investigation andindoor analysis methods.The three types were understory vegetation＞70%(type A)，30%-70%(type B) and＜30%(type C). It provided theory and practice foundation for therecovery of the understory vegetation and scientific reference for reasonable managementaerial seeding Pinus massoniana plantation and ecological restoration. The main resultsshowed that:(1) Among the different understory vegetation displayed significant difference in thesoil water content, saturated moisture capacity, capillary water holding capacity, fieldwater holding capacity, soil bulk density, capillary porosity, total porosity and pH valueof0-10cm and10-20cm and in total nitrogen and available phosphorus of10-20cm, andno significant difference in the non-capillary porosity, soil organic matter, totalphosphorus, total potassium, available nitrogen and available potassium of0-10cm and10-20cm and total nitrogen and available phosphorus of0-10cm.(2) In addition to the non-capillary porosity with other physical properties of soil0-10cm and10-20cm as well as soil water content with soil bulk density, saturatedmoisture capacity, capillary water holding capacity of0-10cm soil, significant or verysignificant correlation between other physical properties. Significant or very significantcorrelation between soil organic matter with total nitrogen, available potassium, pH withsoil organic matter, total phosphorus, available nitrogen, total phosphorus with availablenitrogen of0-10cm soil as well as soil organic matter with total nitrogen, availablephosphorus, pH with total nitrogen, available phosphorus, total nitrogen with availablephosphorus of10-20cm soil. Significant or very significant correlation between pH withsoil bulk density, saturated moisture capacity, capillary water holding capacity, fieldwater holding capacity, total porosity, capillary porosity, available phosphorus with soilwater content, field water holding capacity of0-10cm soil as well as soil organic matterwith soil water content, saturated moisture capacity, total porosity, pH with soil watercontent, soil bulk density, saturated moisture capacity, field water holding capacity, totalnitrogen and available phosphorus respectively with soil water content, soil bulk density,saturated moisture capacity, capillary water holding capacity, field water holding capacity,total porosity, capillary porosity of10-20cm soil.(3) The mean comprehensive score were calculated by principal component analysis (PCA) of SPSS statistical software which showed A (1.005)＞B (0.012)＞C(-0.523),among soil quality of three types exists significant difference. Soil bulk density, field waterholding capacity, soil organic matter, available phosphorus and pH value were selected intothe minimum data set by PCA and correlation analysis, the soil physical and chemicalcomprehensive indexs showed A(0.620)＞B(0.354)＞C(0.295), among CI of three typesexists significant difference. The soil physical and chemical comprehensive index which iscalculated by selected indicators is consistent with the result of PCA.It illustrates theselection of indicators is appropriate, so the selected indexs were suitable to reflect the soilquality. The result of soil quality evaluation showed that the soil quality rises with theincrease of understory vegetation, especially when the understory vegetation reached70%.