紫色土坡地尺度土壤养分的空间变异特性

利用地统计学方法,结合坡地土壤养分采样分析与G IS技术,分析紫色土坡地土壤养分空间变异特征。结果表明地块尺度上土壤养分的空间变异特性和空间相关性具有明显特征,其中土壤有机质、全氮和有效磷具有很强的空间异质性;碱解氮和pH具有中等的空间异质性;而速效钾不具有空间异质性。利用克里格法进行插值并绘制各养分属性的等值线图,表现出空间分布的类似性,但因微地形和耕作管理的影响而表现出各自的规律性,其中土壤有机质、全氮和有效磷的分布具有相似性,而碱解氮、速效钾和pH具有明显不同的分布规律。对典型地块的空间异质性分析有助于坡地和小流域尺度的土壤采样和调查分析,同时对地块水文过程分析和模型应用有重要参考价值。

Characteristics of spatial variability of nutrients in slopeland of purple soil at plot-scale

With the aid of geostatistics and GIS interface,the spatial distribution of soil properties in sloping land of purple soil in the central Sichuan basin was described and illustrated and the rational points in sampling of soil in the sloping land were further ascertained.The results indicated that the spatial correlation of organic matter,total-N,and available P at plot scale was high,so their variabilities were mainly affected by structural factors.The spatial correlation of available N and pH was moderate,so their variabilities were affected by structural and random factors.Moreover,the spatial correlation of available K was low.Based on the semi-variance and Kriging interpolation method,the isolines of soil nutrients were mapped.The spatial distributions of soil organic matter,total-N and available phosphorus were similar,while the available N,available K and pH were clearly different.The analysis of spatial variability was necessary for planning of rational sample points at field and catchment scales.