RELATIONSHIP BETWEEN Pb CONTENT IN TEA LEAVES AND Pb SPECIES DISTRIBUTION IN TEA GARDEN SOILS

On the basis of Pb content at different layers of soil in tea garden from 0 to 100 cm,and total Pb content in tea leaves,the content and distribution of Pb in different forms in various soil layers,and correlation between Pb content in different forms in soil and total Pb content in tea leaves were investigated by using grey scale correlation analysis.Results show that in the studied soil profile,averaged Pb content in different forms was: residual leadoxide leadorganic combined leadcarbonate leadexchangeable lead.Pb distribution characteristics in the same profile was: exchangeable lead,organic combined lead and residual lead had higher content in the surface layer than that in the substrate,while the content of carbonate lead and oxide lead were higher in the bottom layer.The proportion of different forms of Pb varies along with their content in different layers.Therefore,the content of exchangeable lead had the lowest proportion in various layers while that for residual lead had the highest proportion(except in substratum).Grey scale correlation analysis revealed that Pb content in tea leaves had positive correlation with Pb content in each soil profiles,exchangeable lead showed maximum correlation while organic combined lead showed the second,especially Pb content in surface layer of soil has the greatest effect on Pb content in tea leaves.