摘要
通过室内培养实验,研究了45%WHC(饱和田间持水量)和110%WHC两种水分条件下,施用腐植酸矿粉钝化红沙泥中外源镉(10 mg Cd/kg)的效应及其作用机理。结果表明:红沙泥中外源镉经陈化后约80%以交换态镉形态存在,施用腐植酸矿粉,能有效降低红沙泥中DTPA提取镉的含量,其降幅为4.8%-25.8%,并促使土壤中对植物有效性高的交换态镉向有效性低的碳酸盐结合态镉和铁锰氧化物结合态镉的转化,其效果是随着腐植酸矿粉用量的增加而显著增强,且45%WHC水分条件下的效果更好。其作用机理是:腐植酸矿粉中含有的大量活性基团与土壤镉直接发生了各种物理或化学反应,从而降低了土壤中镉的活性;同时,施用腐植酸矿粉改变了土壤的DOC、Eh和CEC等基本性质,进而改变了土壤中镉的赋存形态。研究结果还表明,在110%WHC水分条件下,降低DTPA提取态镉含量的主要影响因子是土壤的DOC与Eh,而45%WHC水分条件下,降低DTPA提取态镉含量的主要影响因子则是土壤的CEC。
To study the immobilization effect and its possible mechanism of humic acid slag on additional Cd in red-sandy paddy soil,an incubation experiment with three levels of humic acid slag addition and two moisture conditions（110% WHC and 45% WHC） was conducted.The results indicated that after 2 weeks aging the exchangeable Cd in soil occupied about 80% in total additional Cd.The addition of humic acid slag induced the decrease of exchangeable Cd with relevant increase of Fe/Mn oxide bound Cd and carbonate bound Cd in soil and significantly decreased DTPA extractable Cd in soil by 4.8%-25.8%.The immobilization effect was enhanced with the increase of added humic acid slag and the effect was obviously better in 45%WHC than in 110% WHC.The humic acid slag contains large number of reactive groups which could complex with Cd in soil to decrease the availability of Cd in soil.Moreover,application of humic acid slag significantly changed the content of DOC,soil Eh and CEC and lead to redistribution of Cd in soil.The regression analysis indicated that the significantly decrease of DTPA extractable Cd in soil was related to the change of soil DOC content and Eh for 110% WHC moisture condition and related to change of CEC for 45% WHC moisture condition,respectively.
出处
《农业现代化研究》
CSCD
北大核心
2011年第4期497-501,共5页
Research of Agricultural Modernization
基金
国家水体污染控制与治理重大科技专项(编号:2009ZX07212-001-05)"
十二五"国家支撑计划课题(编号:2011BAD04B01)
中国科学院知识创新工程重要方向项目(编号:KZCX2-YW-437)
国家现代农业产业技术体系建设项目(编号:CARS-19-E18)
关键词
腐植酸矿粉
镉污染
DTPA提取态镉
镉形态
红沙泥
humic acid slag
Cd pollution
DTPA extracted Cd
Cd fraction
red-sandy paddy soil
