不同铁肥及其施用方法对水稻籽粒镉吸收的影响

针对四川省稻田生态系统中镉(Cd)污染突出的问题,以轻度Cd超标稻田治理为目标,开展阻控稻米积累Cd的施肥技术研究。通过大田试验采用裂区设计,研究不同铁肥种类及施用方法对水稻籽粒Cd吸收的影响。结果表明,不同铁肥处理均增加了四个不同类型水稻品种的产量,其中硫酸亚铁追肥喷施显著增加了Y两优的产量(6.67%,P0.05),EDDHA-Fe底肥土施及追肥喷施显著增加了德粳1号的产量(13.33%～14.32%,P0.05)。不同铁肥施用方式中,EDDHA-Fe喷施处理对四个水稻品种的稻米Cd含量降低幅度最大(20.87%,P0.05)。不同时期喷施铁肥结果来看,以孕穗期、扬花期和灌浆期各喷施一次EDDHA-Fe处理的稻米Cd含量最低。四个水稻品种的秸秆Fe含量与稻米Cd含量呈直线性负相关。扬花期喷施铁肥稻米中Fe含量增加最多,稻米/秸秆Fe含量比值远高于稻米/秸秆Cd含量比值,这表明水稻中Fe由植株向稻米转移的速率远高于Cd。水稻稻米Fe含量与稻米Cd含量呈二元函数关系(P0.05),在较低含量时,水稻籽粒中Cd的含量随着Fe含量的上升而上升,当到达一定程度时,水稻籽粒中Cd的含量随着Fe含量的上升而下降。研究表明,水稻籽粒中的Cd受秸秆中Cd和铁肥施用方式和类型的影响,通过合理施用铁肥可以降低镉轻度污染土壤中稻米Cd含量。

Effects of different iron fertilizers and application times on cadmium absorption in rice

In researching Cd pollution control in rice fields of Sichuan Province, we used Fe fertilizers during the rice growing period. The results showed that the yields of four rice varieties were increased by ferrous sulfate and ethylenediamine-N,N''-bis(2-hydroxy-phenyl) acetic acid-Fe(EDDHA-Fe)application. Application of Fe fertilizer increased rice yield by 6.67% in Y Liangyou(P<0.05), while EDDHA-Fe increased rice yield by 13.33%~14.32% in Dejing 1(P<0.05). Among the different Fe fertilizer applications, foliar EDDHA-Fe application showed the most significant Cd reduction. The application of Fe fertilizer had significant influence on rice Cd content. EDDHAFe spraying treatment significantly reduced Cd content, with the average rice Cd content decreasing by 20.87%(P>0.05). Iron content was negatively correlated with Cd content in the four rice varieties tested. The Fe content increased most in the flowering stage, and the ratio of rice/straw Fe content was far higher than the ratio of rice/straw Cd content, which showed that the Fe transfer rate from plant to rice was much higher than that of Cd. The Fe and Cd rice content showed a quadratic function relationship(P<0.05). At lower concentration levels, the content of Cd in rice grains increased with the Fe content, and then decreased as the increased Fe content reached a certain level. In summary, it has been found that the Cd level in rice grains was affected by the amount of shoot Cd, and by the method and type of Fe fertilizer application, and that, in soil that was slightly Cd polluted, the Cd content of rice could be reduced by controlled use of Fe fertilizer.