FeSO_(4)对水稻根表铁膜及污染稻田土中镉迁移转运影响研究

Effects of FeSO_(4) on Root Iron Plaque and Migration and Transportation of Cd in Contaminated Paddy Soil

选取湖南某污染稻田耕作层土壤,通过盆栽实验外源施加硫酸亚铁(FeSO_(4)),研究FeSO_(4)对水稻根表铁膜及污染稻田土中镉(Cd)迁移转运的影响。结果表明,随着FeSO_(4)施加量增加(0~320 mg/kg),水稻根际土壤pH值呈下降趋势,最高下降了0.70;水稻盆栽土壤TCLP-Cd含量与对照组相比出现一定程度上升;施加FeSO_(4),降低了水稻茎叶、谷壳、糙米中Cd含量,增加了水稻植株根表铁膜的数量,一定程度上控制了水稻对土壤中Cd的吸收。但施加外源铁影响了土壤pH值及Cd的生物有效性,在实际稻田施加FeSO_(4)时建议与石灰等其他碱性修复材料进行组配,以获得更好的阻控效果。

A kind of contaminated paddy soil was taken for pot experiment by adding FeSO_(4) to investigate the impact of FeSO_(4) on the formation of iron plaques on the root surface and the migration of the Cd from Cd⁃contaminated paddy soil.Results show that with the addition of FeSO_(4) increased from 0 to 320 mg/kg,the pH value of the paddy soil tends to decline,maximally by 0.70.The TCLP⁃Cd content in the potting soil rises to a certain extent compared to the control group.The addition of FeSO_(4) significantly reduces the Cd content in leaves,husks,and brown rice,as well as effectively increases the amount of root iron plaque,thus the absorption of Cd in the soil by rice is moderately controlled.However,the addition of external iron resource can bring impact to the pH of soil and bioavailability of Cd,so it is recommended that in practical operation,FeSO_(4) should be added with some alkaline restorative materials such as lime to contaminated paddy fields for enhancing the control.