轿子山自然保护区土壤理化性质垂直变异特征与环境因子关系

The Correlation between Soil Characteristics and Environmental Factors along Altitude Gradient of Jiaozi Mountain Nature Reserve

根据轿子山自然保护区的地形特点，设置东、西两条垂直样带，选取18项指标，分别代表土壤理化性质、地形和植被因子，利用主成份分析、聚类分析和典型相关分析等多元统计手段，对该保护区土壤理化性质与环境因子之间关系进行分析。结果表明：地形对土壤理化性质影响较大，海拔是影响土壤有机质、全氮、碱解氮含量、pH值、土体厚度的主要因素；坡度和坡向对土壤质地影响较大；植被类型对土壤理化性质影响不显著。土壤理化性质垂直变异水平在3个海拔段差异较大：海拔3700m以上，有机质、全氮等含量最高，pH值最小，但土体最薄，砾石含量高；海拔3000～3700m，有机质、全氮等含量较高，pH值较低，土体厚度最大，砾石含量最少；海拔3000m以下，土壤退化明显，有机质、全氮等含量最低，pH值最高，土体较厚，砾石和砂粒含量较高。

Based on the topography attributes, two transects along altitude gradient were set, which are located at eastern and western of Jiaozi Mountain Nature Reserve. In addition, 18 variables of soil physicochemical charac- ters, topography, and vegetation, were selected, the relation between Nature Reserve soil physicochemical property and the topography has been addressed by using principal components analysis （PCA）, cluster analysis, and typi- cal relevance analysis. The results indicated that topography has strongly effects on the soil physieochemical charac- ters, especially elevation is the most important affecting factor on the soil organic mater, total nitrogen, available ni- trogen,pH and soil depth and so on. Slope and aspect have stronger effects on the soil texture. However, there is not significant correlations between vegetation and soil attributes. Moreover, the soil physicochemical attributes were varied along altitude gradient. Above altitude 3 700 m, the soil organic mater and total Nitrogen were the highest, pH value was the lowest, the soil depth was the smallest, and the content of gravel is the highest. Between 3 000 m and 3 700 m, the soil organic mater and total Nitrogen were lower, pH was higher, the soil depth was lar- gest. Below 3 000 m, soil degradation was dramatic, the soil organic mater and total Nitrogen were the lowest, pH was the highest, the soil depth was large, and the contents of gravel and sand were high.