Spatial Autocorrelation Analysis of Cr Content in Cultivated Soil at Different Scales*

Abstract

A case study done in Yucheng,Shandong,China was presented.Using Moran' s I statistics,the spatial autocorrelation coefficients,correlation distances and spatial patterns of heavy metal Cr contents in cultivated topsoil were compared at different scales(county scale and town scale).The following results were obtained: 1) At the higher scale,the variation coefficient of Cr content increased,while C0/Sill decreased,indicating spatially structure enhanced;2) Moran indexes of Cr content of the two scales were greater than 0,suggesting that the Cr contents at the two scales possessed spatial autocorrelation,and the Moran's I indexes became larger at higher scale;3) Lisa cluster maps showed that there were spatial aggregation areas and spacial isolated areas of the Cr contents at two scales,and in "high – high" spatial aggregation areas and "low – high" spatial isolation areas potential Cr pollution risks existed.This study showed that at town scale minor differences could be observed,but they would not be observed at country scale,which provided useful basis to assessment of soil environmental quality and prevention of soil pollution.Fig 4,Tab 2,Ref 23