土壤调控剂与硅肥配施对镉污染土壤的改良效果及水稻吸收镉的影响

Remediation Effects of Regulating Agents and Silicon Application on Cd Contaminated Soil and Cd Uptake of Rice

【目的】本研究为稻米Cd污染阻控技术提供理论依据和技术支撑。【方法】通过田间试验,研究了土壤调控剂T1(纳米活性炭+硅钾钙镁肥)、T2(火山石+钙镁磷肥)和Si(叶面硅肥)单一及组合共5种不同调控措施(T1、T2、Si、T1+Si、T2+Si)对云南个旧矿区稻田镉污染土壤的修复效应及对稻米镉累积的影响。【结果】土壤调控措施均能提高土壤pH,T2处理调控效果最好,较对照提高0.80个单位;调控剂处理后,土壤酸可提取态Cd都有不同程度的降低,残渣态有不同程度的增加,T1+Si处理对土壤酸可提取态调控效果最好,较对照降低了31.6%。经调控措施处理后水稻产量有不同程度的提高,组合调控处理的增产效果优于单一调控措施,T1+Si、T2+Si组合处理较对照分别增加27.2%、29.7%。不同处理水稻根系Cd含量有不同程度的降低,但茎叶中Cd含量有不同程度的上升,糙米中Cd含量均有不同程度的降低,符合国家食品污染物限量标准(GB 2762-2012),其中T1+Si处理糙米中Cd含量较对照降低45.3%。【结论】采用纳米活性炭+硅钾钙镁肥基施以及在水稻灌浆期和抽穗期分别喷施叶面硅肥不仅可以有效修复个旧矿区镉污染土壤,而且可以明显降低糙米中镉的含量,提高矿区稻米安全质量。

[ Objective ] The present study aimed to provide the theoretical basis and technical support for the prevention and control of Rice Cd pollution. [ Method] Field experiments were carried out to investigate the effects of composite passivator T1 （ activated carbon nanop-article and silicon-potassium-calcium-magnesium fertilizer） , T2 （volcanic rock and calcium-magnesia phosphate fertilize）and their compound treat- ments with silicon fertilizer Si （T1, T2, Si, T1 ＋ Si, T2 ＋ Si） on cadmium （Cd）remediation in paddy soil and Cd accumulation in Gejiu mining area of Yunnan Province. [ Result] Application of soil regulator could increase soil pH values, and it was quite obvious in T2 treat- ment. Compared to the control treatment, soil pH values had been increased by 0.8 units. The acid extractable fraction of Cd decreased, but the residue fraction of Cd increased in different treatments in soil. T1 ＋ Si was the best treatment to decrease the acid extractable fraction of Cd in soil, and compared to the control treatment, the acid extractable fraction of Cd decreased by 31.6 %. Application of above amend-merits could increase the yield of rice, and soil regulator supplemented with silicon fertilizer treatments appeared more effective than the single treatments in increasing yield of rice.Compared to the control treatment, the yield of rice increased by 27.2 % and 29.7 % in T1 ＋ Si and T2 ＋ Si, respectively.The Cd content of rice roots in different treatments decreased in different degree, but the Cd content of stems and leaves in-creased in different degree. The Cd content of brown rice de-creased in different degree and lower than the maximum levels permitted by Chinese standard of pollutants in foods （ GB2762- 2012）. T1 ＋ Si was the best treatment to decrease Cd content in brown rice, and compared to the control treatment, the Cd content in brown rice decreased by 45.3 %. [ Conclusion] Composite passivator T1 （ activated carbon nanop-article and silicon-potassium -calcium -magnesimn fertilizer） combined with silicon fertilizer not only decrease available Cd in contaminated soil, but also can obviously reduce the content of Cd in rice and improve the safety of rice.