外源硅钝化稻田土壤重金属Cd有效性及降低稻谷Cd含量研究

【目的】利用两种外源硅肥材料开展试验，研究外源硅对土壤重金属Cd有效性以及稻谷Cd含量的影响。【方法】以硅胶（分子式mSiO2.nH2O，含量98%以上）、液体硅肥（SiO2浓度≥23%）作为外源硅肥材料，通过在重金属镉Cd超标稻田土壤施用硅胶，在水稻分蘖期、孕穗期喷施液体硅肥，研究硅钝化稻田土壤重金属Cd有效性及降低稻谷Cd含量。【结果】施用硅胶达到100kg/667m2对降低土壤有效Cd含量有极显著效果，表明稻田施用硅胶可以钝化土壤重金属Cd有效性；施用硅胶达到100kg/667m2对降低稻谷Cd含量有显著效果，施用硅胶再配合喷施液体硅肥时，对降低稻谷Cd含量有极显著效果；施用硅胶、液体硅肥对提高稻谷产量有显著作用。【结论】基施硅胶配合喷施液体硅肥，对钝化土壤重金属Cd有效性，降低稻谷Cd含量，提高稻谷产量具有显著效果。

Study on the effectiveness of exogenous silicon passivating heavy metal Cd in paddy soil and reducing Cd content in rice

【Objective】Two exogenous silicon fertilizer materials were used to study the effects of exogenous silicon on the availability of heavy metal Cd in soil and the content of Cd in rice.【Methods】Silica gel ( molecular formula mSiO2 · nH2O, content of more than 98 % ) and liquid silicon fertilizer ( SiO2 concentration ≥ 23 % ) were used as exogenous silicon fertilizer materials. Silica gel was applied to the paddy soil with heavy metal Cd exceeding the standard, and liquid silicon fertilizer was sprayed at the tillering stage and booting stage of rice to study the effectiveness of silicon passivation of heavy metal Cd in paddy soil and reduce the Cd content of rice.【Results】The application of silica gel to 100kg / 667m2 had a significant effect on reducing the available Cd content in soil, indicating that the application of silica gel in paddy field could passivate the availability of heavy metal Cd in soil. The application of silica gel to 100kg / 667m2 had a significant effect on reducing Cd content in rice. The application of silica gel combined with liquid silicon fertilizer had a significant effect on reducing Cd content in rice. The application of silica gel and liquid silicon fertilizer has a significant effect on increasing rice yield.【Conclusion】Base application of silica gel combined with spraying liquid silicon fertilizer has a significant effect on passivating the effectiveness of heavy metal Cd in soil, reducing the content of Cd in rice and increasing the yield of rice.