Screening And Validation And Evaluation Of Cadmium Pollution Remediation Agent In Acidic Rice Soil

Cadmium(Cd)is a primary focus on farmland and the control of pollutants,hunan Xiangtan,guangxi hechi and guangdong shaoguan,etc for the development of the non-ferrous metals industry surrounding farmland cadmium pollution is more serious.In this paper,the effects of 10 different remediation agents on rice cadmium,soil p H,soil effective cadmium and rice yield were studied.Three remediation agents suitable for field application were obtained through screening test,and field validation tests were conducted in five areas of guangdong shaoguan,guangxi hechi,hubei daye,jiangxi pingxiang and anhui tongling;To study the effects of remediation agents on cadmium,soil p H,soil effective cadmium,rice yield and nutrient elements in rice.Selecting rice production growth rate,the effective state content reduction rate of soil Cd,the increase rate of soil p H value,repair material input cost and extra labor input cost,etc six indexes are used as the evaluation indexes of the restoration effect of the restoration materials.The effects of three remediation agents on cadmium pollution i n acid paddy soil were evaluated.Cadmium pollution in paddy soil in 10 kinds of repair materials,including clay mineral A,calcium silicate material B F H I,microbial agent C E,nano-ceramic material D,organic material G,humic acid J.Except that E only increased the p H of the soil at low doses,the other 9 remediation agents all increased the p H of the soil at different doses.Effects of increasing soil p H: I>A>C>J>D>B>G>H>F>E.10 remediation agents all reduced the effective cadmium in the soil to varying degrees,and the cadmium reducing effect was as follows: J>C>B>A>G>F>I>H>D>E.After the addition of 10 different remediation agents to the soil of the cd-polluted paddy field,except that C did not significantly reduce the cadmium in rice,the othe r 9 remediation agents all significantly reduced the cadmium in rice,reducing the cadmium effect :G>A>J>H>B>I>F>E>C.The rice yield was increased by applying different doses of D,G and H.Rice yields were also increased by applying low doses of C and high doses of E and low and medium doses of F.After applying the three remediation agents G,B and D,at five verification points,namely,daye in hubei,pingxiang in jiangxi,shaoguan in guangdong,hechi in guangxi and tongling in anhui,the p H of soil increased to varying degrees,ranging from 0.15 to 0.98.After applying three remediation agents at hubei daye,The effective cadmium content in soil decreased by 0.77%~48.86%;Cadmium content in rice decreased by 0.99%~70.55%;The rice yield increased by 4.24%~21.43 in pingxiang of jiangxi and hechi of guangxi.The yield of rice increased by 1.33%~20.26% after the application of organic material G,nano-ceramic material D at the verification points of daye in hubei province and shao guan in guangdong province and nano-ceramic material D at the verification points of tongling in anhui province.After applying G,B,D at the verification point of hubei daye,the content of Ca,Zn in rice increased to varying degrees.Compared with the control group,the content of Ca,Zn increased by 4.7%~15.36%,0.83%~4.9%,respectively;The content of Ca in rice increased by 0.77%~4.44% compared with the control group in jiangxi.The application of G,D in guangdong shaoguan increased the content of Fe in rice.Compared with the control group,the content of Fe increased by 6.3%~39.59%.The application of B increased the content of Ca and Se in rice.After the application of B,D in guangxi hechi,the content of Ca Se in rice increased by 0.79% and 25.9 3%,respectively.The content of Ca Fe Zn in rice increased by 5.83%,25.37% and 1.63%,respectively after the application of B,D in anhui.By calculating the comprehensive evaluation index,the comprehensive index of the restoration effect of the three materials in five different areas was compared.Shaoguan,guangdong: silica calcium material B>nano ceramic material D>organic material G;Pingxiang,jiangxi: silica calcium material B>nano-ceramic material D>organic material G;Hechi,guangxi: silica calcium material B>organic material G>nano-ceramic material D;Hubei daye: organic material G>silica calcium material B>nano-ceramic material D;Tongling,anhui: silica calcium material B>organic material G>nano-ceramic material D.The calcium silicate B was the best remediation agent in shaoguan,guangxi,hechi,hubei,daye,pingxiang,jiangxi and tongling,anhui.