Study On The Transformation Of Cd Forms In Different Paddy Soil By Soil Conditioner

As the overall pattern of economic development in China,the industrial structure and layout is still not reasonable,the total amount of pollutants discharged,the soil as the final recipient of most of the pollutants,the soil environment suffered heavy pollution of heavy metals.At the same time,heavy metal pollution has a direct impact on food safety,through the food chain transmission and danger human health.Application of regulators is one of the effective ways to repair heavy soil contaminated soil.In this paper,the content of available Cd?1.0?5.0?10.0?20.0mg/kg?and the distribution of Cd in the soil after the application of pH adjusting agent and bio-organic fertilizer were studied by indoor culture test.The results showed that the content of Cd in soil was higher than that in paddy soil the effects of different regulators on the Cd growth and decline of paddy soil and the remediation effect of Cd contaminated rice paddy field were studied.The following conclusions were obtained.?1?After the application of the pH meter,increasing of the dynamic time,the pH value of the two kinds of paddy soils in the sand and the muddy mud field showed different degrees of rise.After application of time,the soil pH value of amalgam mud was 5.91⁶.99,and the pH value of soil in the muddy mud was 6.70⁷.83.After application of calcium and calcium fertilizer,the pH value of the sandy soil was 5.59⁶.56,and the pH value of the mud in the mud was 6.46⁷.35.?2?After the application of organic manure,the content of organic matter in the two kinds of paddy soils of Amomum villosum and Huangni Tian was fluctuating or basically flat with the increase of dynamic time.After application of 25%organic fertilizer,the soil organic matter content was 17.42²9.73g/kg,and the soil organic matter content in the muddy mud was 13.02¹8.67g/kg.After application of 40%organic fertilizer,the soil organic matter content was 17.76²8.59g/kg,and the soil organic matter content in the muddy mud was 14.82¹8.08g/kg.?3?Under the dynamic culture time of 90 days,the contents of TCLP extract and CaCl₂exchangeable heavy metal cadmium in the soil were different from the soil pH and organic matter in different concentrations of sand and mud,and the correlation coefficient was:PH>organic matter.?4?During the dynamic culture time of 90 days,the treatment of four kinds of pH adjusting agent could significantly improve the p H value of Cd and reduce the effectiveness of Cd in soil.The content of extracted Cd in TCLP was decreased by 19.83⁴2.58%and2.70¹3.95%,respectively,with the addition of 1,5,10 and 20 mg/kg of exogenous Cd pollution in the soil of sand and mud in the soil.SH-3g/kg treatment,TCLP extract Cd content decreased by 19.10³4.51%,6.91¹5.66%;application of GG-1.5g/kg treatment,TCLP extract Cd content decreased by 18.38³5.42%,3.90¹4.40%;GG-3g/kg treatment,TCLP extractive Cd content decreased by 23.25³3.93%,6.31¹7.51%.?5?During the dynamic culture time of 90 days,the treatment of four kinds of pH adjusting agent could significantly improve the p H value of the two Cd contaminated soils and reduce the effectiveness of Cd in soil.The contents of CaCl₂ exchangeable Cd were reduced by 52.80⁶5.52%and 83.21⁹1.26%,respectively,after the addition of 1,5,10 and20 mg/kg of exogenous Cd pollution in the soil of sand and mud in the soil.The CaCl₂exchangeable Cd content decreased by 81.29⁸6.84%and 93.00⁹5.66%respectively.The content of CaCl2 exchangeable Cd decreased by 42.87⁶2.90%and 77.53⁸4.14%respectively after treatment with GG-1.5g/kg.The content of CaCl₂ exchangeable Cd decreased by 40.29⁷0.43%and 83.72⁸8.19%respectively after GG-3g/kg treatment.?6?During the 90-day dynamic culture,the treatment of four organic manure agents could significantly reduce the effectiveness of Cd in soil.The content of extracted Cd in TCLP was decreased by 28.38³5.68%and 7.54¹9.02%,respectively,with the addition of1,5,10 and 20 mg/kg of exogenous Cd pollution in the soil of sand and mud.TCLP extracted Cd content decreased by 29.38³8.41%,13.87²0.08%respectively.After treatment with 40%organic fertilizer 2g/kg,the extracted Cd content of TCLP was decreased24.18³3.33%and 7.77¹7.64%respectively.The content of extracted Cd in TCLP decreased by 23.19³6.20%and 4.19¹9.52%,respectively,with 40%organic fertilizer4g/kg.?7?During the 90-day dynamic culture,the treatment of four organic manure agents could significantly reduce the effectiveness of Cd in soil.The addition of 1,5,10 and 20mg/kg of exogenous Cd pollution in the soil of the sand and the muddy mud was 25%organic fertilizer 2g/kg,and the CaCl₂ exchangeable Cd content decreased by 49.51⁷1.79%,71.59⁸6.82%CaCl₂ exchangeable Cd content decreased by 61.98⁷6.64%and72.23⁸2.17%respectively.The Cd content of CaCl₂ was decreased by 40%organic fertilizer 2g/kg 41.17⁶9.86%and 68.41⁷6.67%respectively.The Cd content of CaCl₂ was decreased by 44.22⁷5.06%and 73.16⁷8.96%respectively with 40%organic fertilizer4g/kg.?8?After the application of pH and conditioning fertilizer,with the extension of the culture time,the content of Cd in the extracted and weak acid extracted from the four Cd concentration decreased first and then increased,and the content of Cd in the soil was decreased slightly,Cd content in the residual state is increased first and then slowly decreased,with time,content is flat,the final content is generally increased,the reduced and oxidizable state Cd content is little change,was fluctuating or basically flat trend.