钱塘江源头主要植被类型土壤抗剪强度研究

对钱塘江源头地区6种不同林分类型及2个对照类型（茶园、农田）不同土层深度土壤抗剪强度及土壤理化性质和土壤根系特性进行了测定。相关分析结果表明:土壤有机质含量与土壤抗剪强度、土壤粘聚力和内摩擦角呈显著的正相关关系；土壤容重与土壤粘聚力呈显著的正相关关系；粉粒/粘粒与土壤抗剪强度、土壤粘聚力呈显著的负相关关系。抗剪强度与植物根系各指标之间是显著的正相关关系，其中与根体积和根表面积相关性达到极显著水平，与根长和根质量相关性达到显著水平。通过对研究区8种植被类型抗剪强度和影响因子聚类分析得出:毛竹林和灌木林土壤抗剪性能最强；马尾松林、针阔混交林、麻栎林和杉木林次之；茶园和农田土壤抗剪性能较弱。建立了不同等级土壤抗剪强度与影响因子的回归模型，精度达80%~85%。

Research on Soil Shear Strength of the Major Forest Types in Headwaters of Qiantang River

Soil shear strength, physical and chemical properties and root system traits at different soil layers in 6 forest types and two controls (tea plantation and farmland) were determined in the headwaters of Qiantang River, Zhejiang Province. The relative analysis demonstrated that soil organic matter content had evident positive relation with soil shear strength, cohesion and internal friction angle, soil bulk density had significant relation with cohesion, and ratio of powder to viscosity had negative relation with soil shear strength and cohesion. Soil shear strength had evident positive relation with each root system trait (root length, surface area, volume and weight). Cluster analysis on soil shear strength of 8 tested forest types and influencing factors showed that soil shear strength was the highest in Phyllostachys heterocycla cv. pubescens forest and shrub, followed by Pinus massoniana plantation, coniferous and broad-leaved mixed forest, Quercus acutissima forest and Cunninghamia lanceolata forest, and it was the least in tea garden and farmland. The regression models describing the relation between soil shear strength of different forest types and influencing factors were established for different grades of soil shear strength with accuracy of 80%~85%.