不同生育期施用硅肥对水稻吸收积累镉硅的影响

为探明硅肥对镉污染稻田降低稻米镉的作用机理,完善稻米镉消减的硅肥施用技术,采用田间试验,研究水稻不同生育期(基肥、分蘖期和孕穗期)施用硅肥对水稻吸收积累镉、硅的影响。结果表明:施用硅肥能够提高土壤0.160~0.290个pH单位,降低镉生物有效性,同时,显著增加土壤有效硅含量,增幅为295.3%~399.2%(P0.05);不同生育期施用硅肥中,基施硅肥能够显著增加9.7%的水稻产量,高于其他处理,基施硅肥显著降低了水稻茎秆、叶片、稻壳和稻米中的镉含量,降幅分别为31.9%(P0.05)、65.8%(P0.05)、46.1%(P0.05)和25.3%(P0.05),施硅降低了镉由茎秆向叶片和稻壳的转运,从而降低了稻米镉的积累,同时显著增加茎秆、叶片和稻壳硅含量,增加幅度分别为44.1%(P0.05)、71.5%(P0.05)和28.8%(P0.05)。综上表明,镉污染稻田基施硅肥能够显著增加水稻产量,降低土壤镉生物有效性,阻止镉的迁移转运,减少稻米镉积累,是镉污染稻田修复中推荐的硅肥施用技术。

Effects of silicon fertilizer application on the cadmium and silicon content of rice at different growth stages

This aim of this research was to study the reduction mechanism of cadmium and improve the silicon fertilizer application process to inhibit cadmium(Cd) accumulation in rice, according to field trials. The results showed that silicon increased the pH of soil(0.160~0.290) and reduced the availability of cadmium. In contrast, basal application enhanced crop yield by 9.7%(P<0.05); and cadmium levels in rice stem, leaf, husk, and grain were significantly lowered, by 31.9%,65.8%,46.1%, and 25.3%, respectively(P<0.05). Meanwhile, silicon effectively inhibited cadmium transport from the stem to the leaf and husk, which reduced the Cd accumulation in grain. In addition, silicon fertilizer significantly increased the silica content in the stem, leaf, and husk to 44.1%, 71.5% and 28.8%, respectively(P<0.05). Our study suggested that basal silicon fertilizer could reduce the availability of Cd, prevent Cd migration and accumulation, and increase rice production simultaneously. Basal dressing is recommended as a method of silicon fertilizer application in Cd-polluted paddy fields.