水分调控和钝化剂处理对水稻土镉的钝化效应及其机理  

Immobilization of Cadmium in a Paddy Soil Using Moisture Management and Amendments

作　　者：李剑睿[1,2] 徐应明[1,2] 林大松[1,2] 梁学峰[1,2] 孙国红[3] 孙约兵[1,2] 

机构地区：[1]农业部环境保护科研监测所污染防治研究室,天津300191 [2]中国农业科学院农田重金属污染修复创新团队,天津300191 [3]天津农学院技术学院,天津300384

出　　处：《农业环境科学学报》2014年第7期1316-1321,共6页Journal of Agro-Environment Science

基　　金：国家自然科学基金项目(201107056);中国农业科学院创新团队资金项目

摘　　要：采用盆栽试验,研究了水分管理和钝化剂处理对红壤性水稻土重金属镉的钝化效应及其作用机理。结果表明,在土壤镉含量为0.75 mg·kg-1下,添加海泡石复配磷肥可以显著提高土壤pH值,长期淹水、常规管理水分条件下,土壤交换态Cd分别降低了20.4%和15.7%,碳酸盐结合态Cd分别下降了15.5%和14.1%,糙米Cd分别降低了52.3%和46.0%。未添加钝化剂条件下,长期淹水处理的根表Fe(Ⅱ)含量比常规处理增加了1.2倍,根表Cd含量则是常规处理的82.6%。土壤经钝化处理后,长期淹水和常规管理水分条件下,根表Fe(Ⅱ)分别增加了40.1%和70.0%,而根表Cd分别降低了35.3%和42.4%。糙米Cd含量与根表Fe(Ⅱ)含量呈显著负相关,与根表Cd含量呈显著正相关。土壤Fe2+和Cd2+对水稻根表吸附点位的竞争以及土壤镉较低的生物有效性是钝化处理组糙米镉含量下降的主要原因。In situ immobilization is one of remediation techniques for soil heavy metals. Here a pot experiment was conducted to study the effects and mechanisms of moisture management and amendments in Cd immobilization in a paddy soil. At 0.75 mg Cd＂·kg-1, application of sepiolite combined with phosphate fertilizer significantly increased soil pH and reduced exchangeable Cd by 20.4% and 15.7%, carbonate bound Cd by 15.5% and 14.1%, and brown rice Cd by 52.3% and 46.0%, under continuous flooding and conventional irrigation, respective- ly, compared to the control. Under no amendments, the content of Fe（ Ⅱ ） in the root coating was 1.2 times higher in continuous flooding than in conventional irrigation, but Cd content in the root coating in the continuous flooding treatment was only 82.6% of that in the conven- tional irrigation treatment. Applying amendments increased Fe（ Ⅱ ） content in the root coating by 40.1% and 70.0%, but reduced the Cd content in the root coating by 35.3% and 42.4% under continuous flooding and conventional irrigation, respectively. Cadmium in brown rice was significantly negatively conelated with Fe（ Ⅱ ） in root coating, but positively with Cd in the root coating. In conclusion, the compe- tition for sorption sites in root coating between Fe2＋ and Cd2~ and lower soil Cd bioavailability were main factors leading to lower Cd concen- trations in brown rice for the amended soils.

关 键 词：长期淹水 常规管理 土壤 镉 钝化修复 

分 类 号：S511.061[农业科学—作物学]