【摘要】 以海泡石、磷酸二氢钾、钙镁磷肥、钢渣、生石灰及生物炭为重金属镉钝化材料,研究钝化剂对湖南省酸性高镉(Cd)稻田土壤及水稻中Cd含量的影响。以土壤pH值和有效态镉作为评价指标,筛选出三种效果较优的钝化剂,通过正交试验进行复配,选择最优的钝化剂配方进行田间验证。结果表明,海泡石、钙镁磷肥、钢渣在施用比例为1%时均可显著提高土壤pH,pH的提升效果排序为钢渣>钙镁磷肥>海泡石;除钢渣外,其余钝化剂在施用比例为1%时均可不同程度降低土壤有效态Cd含量,钝化效果排序为磷酸二氢钾>钙镁磷肥>生物炭>海泡石>生石灰。选取海泡石、钙镁磷肥和磷酸二氢钾复配钝化剂,依据正交试验结果并综合考虑钝化效果、成本及材料易得性,确定钝化剂的最优施用量组合为海泡石500 mg kg-1、钙镁磷肥500 mg kg-1、磷酸二氢钾170 mg kg-1。大田试验结果表明,施用钝化剂后,土壤pH值提高0.5个单位,土壤有效Cd含量降低34.00%,糙米中Cd含量降低19.44%,水稻各器官Cd的富集与迁移系数明显降低,水稻产量明显升高。更多还原

【Abstract】 Five kinds of passivator material(sepiolite, monopotassium, calcium magnesium phosphate fertilizer(CMPF),steel slag, quicklime and biochar) were selected to investigate their effects on the contents of cadmium(Cd) in rice and soil of the acid and Cd paddy fields in Hunan Province. Soil pH and available Cd were used as evaluation indices to select the optimum passivator. Then the optimum formula of the passivator was selected by field verification testing and the method of orthogonal experiment. The soil pH value was significantly decreased in the order of steel slag > CMPF> sepiolite when they were applied at the ratio of 1%. Except steel slag, the other passivators applied at the ratio of1% reduced the content of available Cd. And the passivation effect was monopotassium > CMPF > biochar > sepiolite> quicklime. The optimum formula of sepiolite, CMPF and monopotassium applied was the amount of 500 mg·kg-1,500 mg·kg-1, and 170 mg·kg-1, respectively. After adding the passivators to the field, the soil pH value was increased by 0.5, and the contents of soil available Cd and Cd of brown rice were decreased by 34.79% and 19.44%,respectively. In addition, the enrichment and migration coefficients of Cd in rice organs decreased obviously. The results indicated that the passivators could increase the yield of rice slightly.更多还原