Study On In Situ Passivation Remediation Technology Of Mild Cadmium Pollution In Farmland Soil

In this study,four kinds of passivating agents such as lime,biological carbon,bio organic fertilizer and porous ceramic nanomaterials were selected to explore the effect of insitu remediation technology in the field of mild Cd polluted farmland by using four kinds of small Cd Contaminated Farmland in the lower reaches of a pyrite in the lower reaches of a pyrite.1.Single lime treatment,biological charcoal lime treatment,bio organic fertilizer with lime treatment and lime treatment with porous ceramic nanomaterials can increase the soil pH value by 0.17 to 0.44 units,and the soil pH value tends to be neutral after the test.2.Single lime treatment,bio carbon lime treatment,bio organic fertilizer with lime treatment and lime treatment with porous ceramic nanomaterials can reduce the content of DTPA in soil Cd by 1.08%-45.81%,and decrease the activation rate of soil Cd by 7.08%-28.86%.3.The application of lime,biological carbon,bio organic manure and porous ceramic nanomaterials to farmland soil can change the distribution of different forms of Cd in soil.The acid soluble and reducible content of Cd in soil can be reduced,and the content of oxidizing and residue can be increased,and the soil Cd has an acid soluble and reducible state.The trend of the oxidizable state and the transformation of the residue state.4.Lime,biological carbon,bio organic fertilizer and porous ceramic nanomaterials can reduce the Cd content of crop seeds to a certain extent.In situ passivation and low accumulation of low accumulation varieties can make the Cd content of rice grain reach the requirements of national food safety standard.Single lime treatment,biological carbon combined lime treatment,bio organic fertilizer with lime treatment and lime treatment with porous ceramic nanomaterials can make rice grain Cd content decreased by 10.51%-35.56% and 45.14%-53.94%,respectively,in rice season in situ passivation and low accumulation of low accumulation varieties.The Cd content of wheat grain decreased by 8.02%-39.86% in routine routine test.The Cd content of rice seeds under four treatments was 0.14-0.16 mg/kg in the rice season in situ passivation and low accumulation of low accumulative varieties.All of them met the requirements of national food safety and health standards(the content of Cd in brown rice is not more than 0.2 mg/kg).5.The content of soil organic matter can be improved to a certain extent by applying lime,biological carbon,bio organic fertilizer and porous ceramic nanomaterials to farmland soil.Biochar combined with lime treatment and bio organic fertilizer combined with lime treatment can increase soil organic matter content by4.01%-37.22%.6.The application of lime,biochar,bio organic fertilizer,porous ceramic nanomaterials and other passivating agents to the farmland soil can increase crop yield to a certain extent.7.There was a positive correlation between the content of DTPA extraction state of soil Cd and the content of acid soluble and reducible Cd in soil,and there was a negative correlation with the oxidizable content and residue content of soil Cd.There was a positive correlation between the Cd content of crop grain and the content of DTPA extraction state of soil Cd,the acid soluble content of soil and the content of reducible state,and a certain negative correlation with the oxidizable content and residue content of the soil Cd.There was a negative correlation between crop yield and the content of DTPA extraction state of soil Cd,acid soluble content of soil Cd,reducible content and Cd content of crop grains,and there was a positive correlation with the oxidizable content and residue content of soil Cd.