岩溶区坡耕地土壤养分空间变异及其影响因子分析

对重庆市北碚区中梁山坡耕地上的100 m×100 m标准样地进行网格取样,利用地统计学方法分析了25个土壤样品的有机质、全氮、全磷、全钾、碱解氮、速效磷和速效钾等7种土壤养分的含量。结果表明:试验样地中有机质、全磷、全钾和速效钾具有较强的空间相关性,速效磷具有中等的空间相关性,全氮和碱解氮的空间相关性较弱。在试验样地的不同坡位上,各土壤养分的空间分布具有不同的特征,其中有机质、碱解氮、全磷和速效磷在坡顶、上坡和中坡位置含量较高;全氮、全钾和速效钾在坡底含量较高,往坡顶逐步降低。对土壤养分和环境因子的相关性分析表明:全氮、全磷、全钾、碱解氮、速效磷和速效钾的空间变异主要受环境因子中地质、地貌、土层厚度等结构性因子的影响,而有机质的空间变异主要受植被种植类型、耕作程度等随机性因子的影响。

Analysis on Spatial Variation of Soil Nutrients and Its Affecting Factors in Slope Land of Karst Area

By the methods of geo-statistics,the spatial variability of soil nutrients in a slope land of karst area in Zhongliang Mountain of Beipei District in Chongqing City was studied.A sampling plot sized 100 m ×100 m was installed and 7 kinds of soil nutrients,including organic matter,total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus and available potassium,etc,were determined.The results showed that the spatial variability degrees of organic matter,total phosphorus,total potassium and available potassium were relatively higher,while that of available phosphorus was medium,and that of total nitrogen and available nitrogen were lower.The results also indicated that the spatial distribution of soil nutrients varied from the slope position.The contents of organic matter,available nitrogen,total phosphorus and available phosphorus were higher at the upper and top of the slope,while the contents of total nitrogen,total potassium and available potassium were higher at the bottom and base of the slope.Correlation analysis on soil nutrients and environmental factors showed that the spatial variabilities of total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus and available potassium were mainly affected by structural factors,such as geology,geomorphology,soil thickness,etc.The spatial variability of organic matter was mainly affected by random factors,such as vegetation type,cropping degree,etc.