以华北落叶松〔Larix gmelinii var. principis-rupprechtii （Mayr） Pilg.〕、青杨（Populus cathayana Rehd.）、青海云杉（Picea crassifolia Kom.）和白桦（Betula platyphylla Suk.）组成的青海高寒区6类水源涵养林为研究对象，比较了不同类型林分土壤的机械组成、理化性质、饱和导水率和田间持水量的差异，并采用统计分析方法对影响土壤饱和导水率和田间持水量的主要因子进行分析。结果显示：6类水源涵养林土壤的大多数机械组成和理化指标有显著差异，仅黏粒含量无显著差异。土壤的粉粒含量、总孔隙度、毛管孔隙度、有机质含量、全氮含量、全磷含量、饱和导水率和田间持水量在白桦天然次生阔叶林中均最大，但在青杨人工阔叶林中均最小；而土壤的砂粒含量、容重和非毛管孔隙度均在白桦天然次生阔叶林中均最小，但在青杨人工阔叶林中均最大。表明天然次生阔叶林土壤的水分渗透性和持水能力较强。相关性分析和多元逐步回归分析结果显示：土壤的砂粒含量和粉粒含量与多数土壤理化指标存在显著或极显著的相关性，仅黏粒含量与各理化指标均无显著相关性。土壤的饱和导水率和田间持水量与多数土壤机械组成和理化指标存在显著或极显著的相关性，但土壤饱和导水率与砂粒含量和粉粒含量无显著相关性，土壤田间持水量与黏粒含量无显著相关性。土壤的毛管孔隙度和有机质含量是影响土壤饱和导水率和田间持水量的主要因子。通径分析结果显示：土壤毛管孔隙度的直接通径系数大于土壤有机质含量的直接通径系数，毛管孔隙度的间接通径系数小于其直接通径系数，而有机质含量的直接通径系数小于其间接通径系数。综合分析结果表明：在青海高寒区6类水源涵养林土壤中，影响土壤饱和导水率和田间持水量的主要因子是毛管孔隙度和有机质含量，其中，毛管孔隙度具有直接影响效应，而有机质含量则主要通过毛管孔隙度的改变产生间接影响。

Taking six types of water conservation forests composed of Larix gmelinii var. principis-rupprechtii （Mayr） Pilg.， Populus cathayana Rehd.， Picea crassifolia Kom. and Betula platyphylla Suk. in cold highland area of Qinghai as research objects， the differences in mechanical components， physical and chemical properties， saturated hydraulic conductivity and field capacity of soil in different types of forests were compared， and the main factors affecting saturated hydraulic conductivity and field capacity were analyzed by statistical analysis method. The results show that there are significant differences in most mechanical components and physical and chemical indexes of soil in six types of water conservation forests， only no significant difference in clay content. Silt content， total porosity， capillary porosity， organic matter content， total nitrogen content， total phosphorus content， saturated hydraulic conductivity and field capacity of soil in natural secondary broad-leaved forest of B. platyphylla are the largest， but those in artificial broad-leaved forest of P. cathayana are the smallest； while sand content， bulk density and non capillary porosity of soil in natural secondary broad-leaved forest of B. platyphylla are the smallest， but those in artificial broad-leaved forest of P. cathayana are the largest. It is indicating that water permeability and water holding capacity of soil in natural secondary broad-leaved forest are stronger. Correlation analysis and multiple stepwise regression analysis results show that there are significant or extremely significant correlations of sand and silt contents of soil with most physical and chemical indexes of soil， only no significant correlation of clay content with each physical and chemical index. There are significant or extremely significant correlations of saturated hydraulic conductivity and field capacity of soil with most mechanical components and physical and chemical indexes of soil， but no significant correlation of saturated hydraulic conductivity of soil with sand and silt contents， that of field capacity of soil with clay content. The capillary porosity and organic matter content of soil are the main factors affecting saturated hydraulic conductivity and field capacity of soil. The result of path analysis shows that direct path coefficient of soil capillary porosity is greater than that of soil organic matter content， indirect path coefficient of capillary porosity is less than its direct path coefficient， and direct path coefficient of organic matter content is less than its indirect path coefficient. The result of comprehensive analysis shows that in six types of water conservation forests in cold highland area of Qinghai， the main factors affecting saturated hydraulic conductivity and field capacity of soil are capillary porosity and organic matter content， in which， capillary porosity has a direct effect， while organic matter content has an indirect effect through the change of capillary porosity.