干旱区典型流域土壤微量元素的空间变异特征研究

采用地统计方法,以新疆三工河流域为例,研究了干旱区流域土壤微量元素的空间异质性特征。结果表明,四种微量元素为对数正态分布;流域内土壤微量元素的空间异质性明显,微量元素含量绿洲区普遍高于荒漠区;其中,有效铁和有效锌含量基本属正常范围,有效锰含量处于普遍缺乏状态,有效铜含量较高;微量元素变异系数在42.28%~83.24%;四种微量元素含量空间变异具有各向异性特征,为中等强度的空间自相关性,表现为二阶趋势效应。用简单克立格法进行最优内插,考虑各向异性及趋势效应,制作研究区土壤微量元素含量的等值线图,分析结果表明其具有明显的空间分布规律。利用地统计学方法,对认识本区土壤微量元素的空间变异结构,流域农业生产合理布局、土壤资源综合治理都具有重要的意义。

Spatial variability of Characters of soil trace elements in a watershed of arid area

In this paper,with the supporting of geo-statistics,semivariance,and the sufer software,the spatial heterogeneity of soil trace elements in Sangong River valley was studied.Soil samples representing several soil quality characters were collected from 57 sites in Sangong River valley.The 4 trace elements,namely Fe,Mn,Cu and Zn were measured with atomic adsorption spectrophotometry.Preliminary data analysis showed that the concentration of each element conforms to logarithmic normal distribution.Therefore,logarithmic transformation was performed in order to reduce the possible scale effect.As general statistical analysis showed that the soil trace elements have the evident spatial heterogeneity.In oasis,the content of trace elements is higher than it's in desert.The content of available Fe and available Zn are inside the normal scope,the content of available Mn is generally deficient and the content of available Cu is relatively enrich.The variation coefficient of trace elements fluctuated between 42.28% and 83.24%. Simple Kriging Analysis was applied to analyze the spatial correlation pattern among several trace element contents.All trace elements satisfied the Gauss model by analysis.The spatial distribution of soil trace elements showed evident trend effect and anisotropic distribution by soil parent material.The results indicated that the soil trace elements present secondary trend effect.Spatial correlation analysis was preformed to examine the relative correlation among the trace elements at various scales by the variogram models.The result demonstrated that the concentrations of Fe,Mn,Cu and Zn showed moderate spatial relativity. At last,The Semi-variogram and the Simple Kriging were used to make the contour map of soil trace element,at the same time taking into account anisotropy and trend effect.In the research area,the total spatial variation of the trace elements does not only show impact of natural causes,but also those of human activities or random factors.The analysis is useful to know the spatial variability structure of soil trace element.The research on the statistical characters and the semivariance structure of the trace elements can provide land use programming with scientific basis,and overall management of soil nutrients,soil amelioration and cultivation with guidelines.