钾硅肥施用对水稻吸收铅、镉的影响

为探讨钾硅肥施用对水稻铅、镉吸收及土壤中铅、镉生物有效性的影响,将施肥和重金属钝化修复良好结合在一起提供依据,采用盆栽试验,研究了钾硅肥施用对水稻生物量、钾素积累量、铅/镉含量和土壤中有效态铅/镉含量及其变化的影响。结果表明,钾硅肥施用可以显著提高水稻植株各部位生物量和钾素累积量,与不施钾处理相比,水稻生物量和钾素积累量分别增加了40.4%~47.0%和170.0%~252.0%;钾硅肥的施用显著降低了水稻茎、叶和籽粒中铅和镉的含量,与施用硫酸钾处理相比,水稻茎、叶、籽粒中铅和镉的含量分别降低了23.6%、35.6%、28.7%和15.6%、29.7%、26.8%,且随着钾硅肥用量的增加,水稻地上各部位铅和镉的含量显著降低,但水稻根部重金属含量并无显著差异。土壤中有效态铅、镉经过一季水稻种植后均有不同程度降低,钾硅肥处理和硫酸钾处理土壤有效铅、镉含量并无明显差异。钾硅肥的施用既满足了水稻对钾素的需求,又降低了水稻地上各部位对土壤重金属的吸收。

Effects of Potassium-silicon Fertilizer Application on Lead and Cadmium Uptake by Rice

Potassium-silicon fertilizer contains potassium and other elements(silicon, calcium and managesium) and may be used as a potential metal-immobilizer. Here a pot experiment was conducted to study the effects of potassium-silicon fertilizer applications on growth and potassium(K), lead(Pb) and cadmium(Cd) uptake of rice, and soil Pb and Cd availability. Applying potassium-silicon fertilizer increased plant biomass and K accumulation by 40.4%~47.0% and 170.0%~252.0%, respectively, compared with no K fertilization. However, Pb and Cd content in stems, leaves and grains of rice was decreased significantly by adding potassium-silicon fertilizer. Compared with treatments with K₂SO₄, applying potassium-silicon fertilizer decreased Pb and Cd content in stems, leaves and grains of rice by 23.6%, 35.6%, and 28.7%, and 15.6%, 29.7%, and 26.8%, respectively. Increasing K fertilizer rates significantly decreased Pb and Cd content in aboveground part of rice. However, there were no significant differences in Pb and Cd content in roots among different treatments. Soil available Pb and Cd content decreased at rice harvest, but they did not show differences between K₂SO₄ and potassium-silicon fertilizer treatments. The present results show that applying potassium-silicon fertilizer meets rice needs for K while inhibiting the uptake of heavy metals by rice aboveground parts.