Study On The Distribution And Bioavailability Of Heavy Metals In The Soil Of Rizhao Green Tea Garden

Soil is the basis for the survival of tea trees.The quality of soil directly affects the yield and quality of tea.For a long time,the research on the soil quality of tea gardens mainly focused on the basic physical and chemical properties of soil,the characteristics of soil fertility and the influence of beneficial trace elements on tea quality.With the increasing pollution of the agricultural environment,especially the heavy metal pollution in the soil,the problem of heavy metal pollution in the tea garden soil has received increasing attention.This article takes Rizhao green tea tea garden as the research object,through field survey sampling and indoor analysis,to study the total amount and morphological characteristics of heavy metals(Cu,Zn,Pb,Cd,Cr,Ni)in Rizhao green tea tea garden soil and tea leaves,with the help of heavy metal bioavailability coefficient.(MF),migration coefficient(M),conversion factor(TF)and other indicators were used to analyze the bioavailability of heavy metals in tea garden soils.At the same time,the effects of soil physical and chemical properties,planting years,and other factors on the distribution and bioavailability of heavy metals in tea garden soils were analyzed.Research indicates:(1)The average contents of Cr,Ni,Cu,Zn,Cd,and Pb in surface soil of Rizhao tea garden were 62.61 mg/kg,27.13 mg/kg,43.21 mg/kg,94.94 mg/kg,and 0.26 mg/kg,respectively.,27.18 mg/kg;According to the national secondary standards for soil environment,except for Cd and Pb,the over-standard rates of Cr,Ni,Cu,and Zn were 12.77%,26.24%,2.13%,and 61.70%,respectively.The distributions of Cr and Ni in surface soil of Rizhao tea garden are as follows: residue state> oxidizable state> reducible state> weak acid-soluble state;the distribution of Cu and Pb is: residual state> reducible state> oxidizable state> weak acid dissolution The morphological distribution of Zn and Cd is: Residue state> Weak acid soluble state> Reducible state> Oxidizable state.(2)The average contents of Cr,Ni,Cu,Zn,Cd,and Pb in the tea garden profile of Rizhao City were 61.97 mg/kg,25.50 mg/kg,37.59 mg/kg,85.21 mg/kg,and 0.45 mg/kg,respectively.At 30.48 mg/kg,with the exception of Cd,the peaks of other elements were found at the surface layer;the distribution of Cr,Ni,Cu,and Pb in the profile soil was the same as that of the surface layer,and the distribution of Zn and Cd was: residue state> oxidizable state> Reducible state > Weak acid soluble state.(3)The activity and migration coefficients of Cd in the tea garden soil of Rizhao City were the highest,and the activity and migration coefficients of Cr were the smallest.The order of the transfer coefficients was: Ni> Zn> Cu> Cd> Pb> Cr.Obviously,the weakest is Cr,and the conversion coefficients of Zn,Cu,and Ni are close to each other.(4)There is a correlation between the total amount of heavy metals in soil,various forms of distribution,and the bioavailability of soil in tea gardens,and the physicochemical properties of the soil and the planting years.Among them,pH and organic matter have a greater influence.