磷硅肥配施抑制华南地区水稻籽粒砷积累的效果

选取华南地区广泛种植的杂交水稻品种“培杂泰丰”，利用外源添加砷（50 mg·kg-1）的土壤盆栽试验，研究不同施用量的磷硅肥对水稻生长特性和砷积累的影响。结果表明，施用磷硅肥的处理，水稻糙米中砷含量为0.504~0.586 mg·kg-1，低于农业部颁布的粮食中砷限量标准（NY 861—2004）中大米砷限值。相关性分析表明，水稻糙米砷含量与水稻植株的生物量、稻谷千粒重和秸秆中硅/砷摩尔比呈显著负相关，与秸秆中磷/砷摩尔比呈极显著负相关；糙米的砷含量随磷、硅肥的施加而降低。综合分析表明，在华南地区同类中度砷污染土壤中可有效控制砷向水稻籽粒运输累积的磷、硅肥最优施加量及配比为40 mg P·kg-1土、50 mg Si·kg-1土。

Effects of phosphorus and silicon applications on arsenic accumulation in rice grains in South China

Phosphorus(P)and silicon(Si)have showed the ability to reduce arsenic(As)uptake by plants from soils. Here a pot experiment was conducted in a soil spiked with 50 mg·kg-1 arsenic to study the effects of different rates of phosphorus and silicon fertilizers on growth and arsenic accumulation of a hybrid rice cultivar, PeizaTaifeng, which is widely planted in South China. Results showed that after applica-tions of phosphorus and silicon fertilizers,arsenic content in rice grains ranged from 0.504 to 0.586 mg·kg-1, lower than the limit of arsenic in rice grains(NY 861—2004)enacted by the China Ministry of Agriculture. Correlation analyses showed that arsenic content in rice grains had significantly negative correlation with rice plant biomass, thousand seed weight, Si/As molar ratio in straw, and extremely significant negative correlation with P/As molar ratio in straw. Arsenic concentrations in grains decreased with increasing rates of phosphorus and sili-con fertilizers. The present findings suggest that the optimum application rates of phosphorus and silicon fertilizers for rice grown in arsenic polluted soil would be 40 mg P·kg-1 soil and 50 mg Si·kg-1 soil in the South China area.