CLUSTER ANALYSIS OF SOME ELEMENTS IN SOILS OF TIANJIN AREA
天津地区土壤环境中若干元素的群分析

Some 15 chemical elements from 260 samples of chao soil in Tianjin region were divided into three groups by using mathematical method of cluster analysis. In the first group, there were Sr and Zr, which showed strikingly negative correlation with physical clay content<0.01mm in soils. In the second group, there were Fe, Ti, Co, Ni, Cr, Pb, As, Cu, and Mn, which showed strikingly positive correlation with content of physical clay< 0.01mm in soils. In the third group, there were Hg and Cd, which had nothing to do with soil texture. Therefore, in order to study background value for the region where the parent material is the same or where the parent material is the recent alluvium and sediment, attention must be drawn to the fact that type of soil texture has effects on the background level of some elements in soil, and it would be much significant to have the background levels of soil types with different texture.