氮肥运筹对稻田田面水氮素动态变化及氮素吸收利用效率影响

通过大田试验,设计3个不同氮肥水平（0、150、240kgN·hm-2）和两种不同施肥比例（基肥：分蘖肥：穗粒肥=40%：30%：30%、基肥：分蘖肥：穗粒肥=30%：20%：50%）,研究了氮肥运筹对稻田田面水氮素动态变化特征和氮素吸收利用效率的影响。结果表明,稻田田面水NH4＋-N和总N浓度在施肥后第1d达到最大值,随后降低,在施肥后的第7d,分别降为峰值的7.88%～17.84%和29.71%～45.55%。施氮水平介于0～240Nkg·hm-2时,水稻产量随着氮素水平的提高而显著增加,氮素的吸收利用率和偏生产力却随之降低。在高氮水平（240kgN·hm-2）下,与氮肥前移相比（基肥：分蘖肥：穗粒肥=40%：30%：30%）,采用氮肥后移（基肥：分蘖肥：穗粒肥=30%：20%：50%）的施肥比例,水稻产量增加了6.2%、氮素吸收利用率和农学利用率分别提高了30.49%和23.72%,而氮素生理利用率和偏生产力差异不显著,说明适宜的氮肥运筹可以增加水稻的产量,提高氮素的吸收利用率和农学利用率,减少氮素损失。

Effects of Nitrogen Management on Dynamics of Nitrogen in Surface Water from Rice Field and Nitrogen Use Efficiency

Effects of nitrogen management on nitrogen use efficiency and nitrogen concentration in the surface water from rice field were examined by a field experiment.In this study,the nitrogen was applied in three splits as 40% basal,30% at 10 days after transplanting（DAT）,30% 36 DAT and 30% basal,20% 10 DAT,50% 36 DAT at three N rates as 0,150,240 kg N·hm-2.The results showed that two N concentrations（NH4＋-N and total N） in the surface water reached the highest on the first day after fertilizer application,and thereafter decreased.NH4＋-N and total N concentrations at 7th day were separately in ranges of 7.88%～17.84% and 29.71%～45.55%.Grain yield was significantly increased as the N rates increased from 0 to 240 kg N·hm-2,however,nitrogen recovery efficiency and partial factor productivity were decreased.At the N rate of 240 kg N·hm-2,grain yield,nitrogen recovery efficiency and agronomic efficiency were 6.2%,30.49% and 23.72% higher when the nitrogen was applied in three splits as 30% basal,20% 10 DAT,50% 36 DAT,compared with that of the N splits as 40% basal,30% 10 DAT,30% 36 DAT.However,no obvious differences in the nitrogen physiological efficiency and partial factor productivity were observed among different N splits.The results revealed that appropriate fertilizer application in three splits as 30% basal,20%10 DAT,50% 36 DAT could increase grain yield,improve nitrogen recovery efficiency and agronomic efficiency,and decrease nitrogen loss.