Research On Modern Soil Spatial Variability And Influence Factors Of Soil Formation

Soil is connected to the human life,and is an important part of earth's crucial zone.The characteristics and mechanism about different areas and different soil types are one of the focus at home and abroad.This paper investigated and analyzed magnetic parameters?magnetic susceptibility,frequency-dependent magnetic susceptibility and percentage of frequency-dependent magnetic susceptibility?in the topsoil?5cm?and subsoil?20cm?,soil granularity,pH,organic matter?OM?,water content,total iron?Fet?,Fed/Fet,Feo/Fed and heavy metals?Cu,Zn,Ni,As,Pb,Cr,Cd,Hg?in the subsoil by multivariate statistics and geo-statistics,SangGan River Basin of Yangyuan county of HeBei province.This study was aimed at understanding soil pedogenesis,and reveal interaction and spatial distribution characteristics in this study.The results showed that soil wasn't polluted severely.The eight heavy metals were divided into four classes by multivariate statistics analyses?principle component analysis,cluster analysis and correlation analysis?,Cu,Zn,Ni,As were grouped into PC1,Pb and Cr were classed into PC2,these six heavy metals were from parent rock,which were affected by natural factor,however,PC1 was different from PC2 because the physical and chemical properties of heavy metals elements;Cd and Hg were divided into PC3 and PC4,respectively.PC3 was influenced by traffic vehicles and factories,PC4 was influenced by fertilization in agricultural land.The results showed that topography was the main factor for soil pedogenesis in contrast to parent rock,time et al.The spatial characteristics of?_fd20,?_fd20%,pH,organic matter,clay contents,silt contents,sand contents,heavy metals?Cu,Zn,Ni,As,Pb,Cr,Hg?are basically similar to elevation,these elements are higher in north and south of the study area,while they are lower in the central area,however,pH and sand concentrations are relative lower in north and south than the center of the study area,so the analysis imply that elevation is crucial factor for the differences of pedogenesis,inferred that hydrodynamics influence soil development.In addition,the spatial characteristics of water content,free iron oxide and active iron are similar to aspect,so the analysis imply that aspect is important factor for the differences of pedogenesis,it was inferred that southeasternwind about rainy season passed in October,soil had a strong water content in northwestern area compared with southeastern area.