Effect Of Sulphur And Mineral Modifiers On Behavior Of Cadmium And Lead In Soil-Bo Chrysanthemum System

Sulfur and natural minerals(dolomite,attapulgite,bentonite)were employed to investigate the effect of chemical characteristics of cadmium and lead in contamination soil,and of influence to the growth of Bo Chrysanthemum,by a pot experimental method, using soil-plant system of yellow fluvo-aquic soil - Bo Chrysanthemum as a test sample. The main results of the study were as follows:The soil pH value had reduced about 0.3 units at a high amount of sulfur-treated soil during various growth stages of Bo Chrysanthemum.Form transformation of cadmium and lead in yellow fluvo-aquic soil was produced from the low bio-availability to the high one,ether in the intact or the contamination soil,and this tendency in soil was corresponding with the change of pH value caused by sulfur-treating.It would promote growth of Bo Chrysanthemum by application of 130 mg/kg of sulfur to the intact soil,and enhanced 21.2%of yields compared to CK sample.No significant influence,by application of 530 mg/kg of sulfur to the growth of Bo Chrysanthemum,was observed in the experiment.However,in contamination soil,it was found that application of 530 mg/kg of sulfur not only inhibiting the growth of Bo Chrysanthemum,but also reducing the biomass and yield,in which the amount of blossom almost reduced of 36.6%.In the high sulfur-treated contamination soil,it obviously increased the amount of cadmium and lead absorbed into Bo Chrysanthemum, of which,for cadmium,increased of 19.14%,and for lead,of 16.8%,to the blossom. While in the low sulfur-treated contamination soil,no significant difference was found comparing to CK.It was difficult to find a change rule for Bo Chrysanthemum to absorb phosphorus and potassium element in soil applied with sulfur.However,it would enhance absorption amount of nitrogen in both the intact and the contamination soil as application of proper amount of sulfur,up from 2.04%to 2.12%for the blossom in intact soil,and 1.80%to 1.96%in contamination soil.It is hard to find difference for absorption of nutrition element in high sulfur-treated soil.The soil pH value was obviously affected by application of material modifiers of dolomite,attapulgite and bentonite,and ascending with increasing of the amount,up of 0.2-0.4 unit for high amount applied,of which dolomite was the greatest one.All of the modifiers,at high level application,could deactivate cadmium and lead in soil,and reduce the amount of cadmium and lead in tissues of Bo Chrysanthemum during development,for cadmium,reduced of 59.6%,68.7%and 48.2%at application of high amount of dolomite, attapulgite and bentonite,and for lead,of 29.1%,25.4%and 47.6%,respectively.Soil environment conditions were greatly improved by application of modifiers of dolomite,attapulgite and bentonite,consequently,biomass of Bo Chrysanthemum was increased significantly,the yield of blossom increasing of 81.7%,108.4%and 72.8% comparing to CK,respectively.Absorption ability of nitrogen,phosphorus and potassium was also enhanced,for nitrogen,from 1.80%to 2.05%,2.11%and 2.12%respectively, and for phosphorus,from 0.283%to 0.325%,0.326%and 0.314%,and potassium,2.41% to 2.58%,2.66%and 2.58%,respectively.When planted Bo Chrysanthemum in contamination soil,the three modifiers can reduce adsorption of cadmium and lead,and for cadmium,the effective sequence is attapulgite＞dolomite＞bentonite and,for lead,sequence is bentonite＞dolomite＞attapulgite.The modifiers can also enhance the yield of blossom,especially in cadmium and lead-contaminated soil,in which sequence is attapulgite＞dolomite＞bentonite.