Study On Effect Of Cadmium Reduction And Mechanism Of VIP Technology In Different Soil Environment In Rice

In order to explore the and influencing factors of comprehensive cadmium reduction technology(VIP),the double-season rice experiments of 194 test spots in cadmium-polluted areas in Hunan province were conducted from 2015 to 2016.Two treatments were contrast(CK)and VIP treatment,testing the brown rice cadmium content,the whole cadmium content in soil,available cadmium content,pH,soil cation exchange capacity(CEC)and organic matter content.The main results were as follows:VIP treatment could reduce the content of cadmium in brown rice in different soil environment.Under the condition of different pollution degree,VIP had the most significant effect on brown rice cadmium content in heavily cadmium polluted areas,the cadmium content in brown rice of VIP was lower than CK by 24.13%-48.86%.In different soil pH areas,the most significant reduction effect were acidic and light acidic areas,and the range of reduction was12.28%-37.59%.Under the condition of different soil cation exchange capacity,VIP treatment had the best effect on cadmium reduction in the first grade area with the lowest CEC content,and the range of reduction was 33.87%-61.26%.VIP treatment had the best effect on the area that had lowest organic matter content,and the range of reduction was36.62%-58.91%.Under the condition of different pollution degree,VIP treatment had significant reduction on the available cadmium content in heavily polluted areas,and the maximum available cadmium reduction was 10.96%.In different soil pH areas,VIP treatment in acid and alkaline areas of cadmium reduction effect was the most significant with a drop of 10.76%.Under the condition of different CEC,VIP treatment reduced the available cadmium content of early rice in the first and third grades in 2015,and decreased by 10% and 9.25% respectively.VIP could significantly reduce the available cadmium content in the soil in class A area with the highest content of organic matter,and reduced the available cadmium content of soil in early season of 2016 by 30.98%.Combining soil Cd content in brown rice,the RCD(cadmium content in brown rice)and SCD(whole cadmium content in soil),pH and CEC to set a multiple regression analysis to explore the correlation between environmental factors,and the regression equation was as follows:Early rice:CK :y=0.598+0.62SCD-0.067pH-0.005CECVIP:y=0.357+0.053SCD-0.47pHLate rice:CK :y=0.63+0.16SCD-0.07pHVIP:y=0.408+0.1SCD-0.05pHAs for early rice,VIP treatment reduced the influence of soil whole cadmium content(SCD)to brown rice cadmium,and improved the correlation of pH to brown rice cadmium.And as for late rice,VIP treatment only reduced the whole cadmium content of soil,and other factors had no obvious change.