硒肥与钝化材料组配对土壤Cd钝化及稻米Cd消减效果

为了探讨不同硒肥施用方式联合钝化材料对土壤镉钝化和稻米镉消减的效果,采用盆栽试验的方式,选用亚硒酸钠作为硒肥,钙镁磷肥和硅藻土作为钝化材料,设置基施硒肥+钙镁磷肥+硅藻土和叶面喷施硒肥+钙镁磷肥+硅藻土2种方式,研究其不同用量对镉污染酸性稻田土壤修复与安全利用的影响。结果表明：随着施用量的增加,稻米产量增加,基施硒肥产量略高于叶面喷施硒肥,产量差为 2.115 g/pot,与对照(CK)相比,基施0.28%钙镁磷肥+0.12%硅藻土+0.004‰硒(T3)能够提高1.68倍的稻米产量;随着施用量的增加,pH升高,有效Cd降低,有机质与CEC变化不大;基施硒肥与叶面喷施硒肥处理对土壤pH、有机质与CEC差异不显著,但基施硒肥处理有效Cd含量略低于叶面喷施硒肥处理,T3对土壤Cd的钝化效果最佳;随着基施硒肥用量的增加,稻米Cd含量降低,随着叶面喷施硒肥用量的增加,稻米Cd含量先降低后升高,基施硒肥处理对稻米Cd的消减程度强于叶面喷施硒肥处理,相差 0.021 mg/kg,与对照(CK)相比,T3处理稻米Cd降低0.063 mg/kg。可见,硒对调控稻米镉累积具有重要作用,且基施硒肥强于叶面喷施。综上所述,基施0.28%钙镁磷肥+0.12%硅藻土+0.004‰硒对土壤Cd钝化与稻米Cd消减的效果最佳,值得在镉污染稻田推广应用。

Effect of Selenium and Passivator Application on Available Cadmium Passivation in Soil and Cadmium Reduction in Rice

To study the effect of different selenium fertilizer application methods combined with passivation material on soil cadmium passivation and rice cadmium reduction, a pot experiment was set up. In the study, sodium selenite was taken as selenium fertilizer, calcium magnesium phosphate fertilizer and diatomite were taken as passivation materials. The effects of basal application of selenium fertilizer + calcium magnesium phosphate fertilizer + diatomite and foliar application of selenium fertilizer + calcium magnesium phosphate fertilizer + diatomite on remediation and safe utilization of cadmium-contaminated acidic paddy field were studied. The results showed that the rice yield increased with the increase of selenium fertilizer and passivation material application. The yield of basal application of selenium fertilizer was slightly higher than that of foliar application, and the yield gap was 2.115 g/pot. Compared with the control (CK), basal application of 0.28% calcium magnesium phosphate fertilizer + 0.12% diatomite + 0.004‰ selenium (T3) could increase rice yield by 1.68 times. With the increase of selenium fertilizer and passivation material application, pH increased, available Cd decreased, while the organic matter and CEC changed a little. There was no significant difference in soil pH, organic matter and CEC between basal application and foliar application, but the available Cd content of basal application of selenium fertilizer was slightly lower than that of foliar application. T3 treatment had the best passivation effect on soil Cd than other treatments. The Cd content in rice decreased with the increase of basal application rate of Se fertilizer. The Cd content in rice decreased first and then increased with the increase of foliar application rate of Se fertilizer. The reduction of Cd in rice with basal application of Se fertilizer was stronger than that with foliar application, and the gap was 0.021 mg/kg. Compared with the control (CK), the Cd content in rice of T3 treatment was decreased by 0.063 mg/kg. It could be seen that selenium plays an important role in regulating Cd accumulation in rice, and the effect of basal application of selenium fertilizer is stronger than that of foliar application. Therefore, the effect of basal application of 0.28% calcium magnesium phosphate fertilizer + 0.12% diatomite + 0.004‰ selenium on soil Cd passivation and rice Cd reduction is the best, and the formula is worthy of popularization and application in Cd-contaminated paddy field.