Study On The Regulation Measure Of Heavy Metal Pb Bioavailability With The Yellow Graden Soil

The production and growth of Chinese cabbage ,Pb absorption, uptake coefficient of Pb etc were studied through pot culture experiment,which used yellow Graden Soil is widespread distribution in Guizhou province,followed by adding different level of Pb solution into soil,after three fortnight's equilibrium, adding different fertilizer and modifiers.the affect of morphoiogy of soil Pb and soil PH on Pb bioavaillability were analyzed,at last discuss how to prevent and control Chinese cabbage absorption Pb.The results show that:1 .The soil Pb contaminated decrease the production of Chinese cabbage,and more production is decreased ,as the concentration of Pb is higher.However , applying the different kinds of nitrogenous,phosphorus and potassium ,the best highest production of cabbage are ammonium bicarbonate, calcium superphosphate and plant ash,adding organic fertilizer, Calcium magnesium phosphate, lime and pyretic can increase the production singnificantly compared with the contrast,the order of production of cabbage from high to low is organic fertilizer> Calcium magnesium phosphate > lime > pyretic,the production of cabbage is increase 13.02%—18.75% compared with the contrast with mixed modifiers.2.The Pb contaminated soil increase the contents of Pb in the body of Chinese cabbage,the more contaminant are,the more contents of them absorbed by the Chinese cabbage, applying the different kinds of nitrogenous,phosphorus and potassium, the best low contents of Pb in the body of Chinese cabbage are ammonium bicarbonate, Calcium magnesium phosphate and plant ash. adding organic fertilizer, Calcium magnesium phosphate, lime and pyretic can decrease the contents of Pb in the body of Chinese cabbage singnificantly compared the contrast, the more density are,the less contents of them absorbed by the Chinese cabbag.the organic fertilizer+Calcium magnesium phosphate+lime+ pyretic can best reduce the contents of Pb in the body of Chinese cabbage.3.The main fractions are bound to carbonates ,bound to Fe-Mn oxid and bound to organic matter when esextraneous source Pb enter into soil, applying the different kinds of nitrogenous,phosphorus and potassium ,the contents best low of exchangeable, bound to carbonates ,bound to Fe-Mn oxid and bset hight of bound to organic matter and residual are ammonium bicarbonate, Calcium magnesium phosphate and plant ash. Modifiers can reduce the content of exchangeable and bound to carbonates and increase the content of bound to Fe-Mn oxid and bound to organic matter,the more density are,the more obvious of changing.mixed modifiers can singnificantly reduce the content of exchangeable and bound to carbonates and increase the content of bound to Fe-Mn oxid and bound to organic matter compared the contrast.4.Ammonium bicarbonate, Calcium magnesium phosphate, phosphate rock, plant ash can enhance soil pH,but urea,ammonium nitrate, potassium suifate and potassium chioride can decrease soil Ph. All the modifiers can increase soil pH compared the compariom, and the ability is lime > organic fertilizer > Calcium magnesium phosphate > pyretic, the more density are,the more ability of them increase the soil pH.All the mixed can increase soil pH (0.76～1.45units).5. The uptake coefficient of Pb in Chinese cabbage roots is higher than leaves and the uptake of Pb in Chinese cabbage is increased significantly on Pb pollution soil,and significantly decrease with the intensifies of soil Pb pollution,while decreased by adding the different modifiers.At the same shows that the accumulation of Pb adsorbed by Plants is mainly in roots, and the amounts of contaminants translated from roots to leaves are lower than that from soils to roots.6.The content of Pb adsorbed by Chinese cabbage is related not only to the content of Pb in soil,but also positively to the content and rate of Pb each fractions.The soil Pb pollution ,different kinds fertilizers,different kinds modifiers with different density and the change of soil pH can affect the change of Pb fractions,so causes difference of the Chinese cabbage absorption to Pb.7.Therefore, preventing soil Pb pollution can decrease bioavailability of Pb , reduces effect of Pb to the Chinese cabbage , promotion product of Chinese cabbage and reduces the cabbage absorption Pb. Choosing ammonium bicarbonate, Calcium magnesium phosphate and plant ash can promotion product of Chinese cabbage and reduces the cabbage absorption Pb. Lime,organic fertilizer, Calcium magnesium phosphate and pyretic were used in the agricultural can promotion product of Chinese cabbage and reduces the cabbage absorption Pb.