不同化肥品种对水稻铬吸收和分配的影响

Effects of different fertilizers on Cr uptake and distribution by rice

采用盆栽试验，研究在300mg／kg铬污染水稻土中分别施加氮肥（NHnCl、NH4N03、Ca（NO3）2和CO（NH2）2）、钾肥（K2SO4和KCl）、磷肥（Ca（H2PO4）2和NaH2PO4）对水稻生长以及吸收和分配铬的影响。结果表明：（1）施肥处理虽然增加了水稻的产量，但也改变了水稻植株对土壤铬的吸收和积累。从总体上看，不同施肥处理对水稻植株总铬的影响达到显著水平（P〈0．05）；氮肥、钾肥处理的水稻植株总铬比对照处理增加了1．7％～72．9％，磷肥处理的水稻植株总铬比对照处理降低了2．1％～21．9％。（2）不同施肥处理明显影响了铬在水稻植株内的分配与迁移。受试的氮肥、钾肥不仅促进水稻根部对铬的吸收和累积，也促进了铬向地上部分迁移；而磷肥则降低了水稻根部对铬的吸收和累积以及铬向地上部分迁移。（3）受试8种不同施肥处理均显著提高了水稻糙米总铬，施肥处理后水稻成熟期糙米总铬为1．10～1．32mg／kg，均超过《食品中污染物限量》（GB2762--2005）中铬的限量（粮食1．0mg／kg），比对照处理提高了139．1％～187．0％，增加了铬通过食物链威胁人体健康的风险。

Pot experiments were conducted to study the effects of 8 fertilizers （NH4Cl,NH4NO3 ,Ca（NO2）2, CO（NH2 ）2 ,Ca（H2 PO4 ）2, Nail2 PO4, K2 SO4 and KCl） on Cr uptake and distribution by rice under the 300 mg/kg treatment. Results showed that fertilization treatment increased the biomass of rice but changed the Cr uptake and ac- cumulation in rice. The influence of fertilization on total Cr content in rice was significant （P〈0.05）. Compared with the control, the total amount of Cr in rice were increased by 1.7 %-72.9 % after nitrogen and potassium fertilizers were applied,while the phosphate fertilizers decreased the total amount of Cr in rice by 2.1 %-21.9 %. Fertilizers also had significant effect on the distribution and migration of Cr in rice. Nitrogen and potassium fertilizers could not only accel- erate the uptake of Cr in the root of rice but also promote the Cr migration from root to aerial part. While, the phos- phate fertilizer decreased the adsorption and accumulation of Cr in the root, simultaneously, the migration of Cr was also suppressed. 8 fertilizers increased the Cr concentration of grain by 139. 1%-187.0 %, the concentration of Cr in grain under maturity stage was 1.10-1.32 mg/kg after tested fertilizer were applied, which had significantly exceeded the limit Cr value （1.0 mg/kg） of national food heavy metal limits hygienic standard （GB 2762-2005）. This study sug- gested that fertilizer application significantly increased Cr accumulation in grain and potential risk to human health.