Effects of Postponing N application on yield and n absorption and utilization of summer maize in later harvest time | 氮肥后移对晚收夏玉米产量及氮素吸收利用的影响

صينى. 摘　　要：采用田间试验研究氮肥后移对晚收夏玉米产量、氮素吸收分配和氮肥利用效率的影响。结果表明，氮肥后移使夏玉米产量和氮素积累量增加，在农民习惯收获和晚收条件下分别较正常施氮增产2．11％～2．91％和7．23％～9．52％。晚收较农民习惯收获增产2．12％-6．42％，氮积累量增加1．10％～3．18％；晚收夏玉米茎和子粒氮积累量增加，而叶和其他器官中积累量减少。氮肥后移提高了夏玉米氮肥利用率和农学效率，晚收条件下氮肥利用率提高了3．52％～6．87％，氮肥农学效率提高了0．82～1．60kg／kg。氮肥按“30％苗肥＋30％大喇叭口肥＋40％吐丝肥”方式施用在晚收条件下产量和氮肥利用效率最高。

إنجليزي. Field experiment was carried out to study the effects of postponing N application on yield and N absorption, allocation and N fertilizer utilization efficiency of summer maize in later harvest time. The results showed that postponing N fertilizer application could increase grain yield and N accumulation, increased yield by 2.11% - 2.91% in accustomed harvest time and 7.23% - 9.52% in later harvest time. Compared with accustomed harvest, later harvest＇s yield increased by 2.12% - 6.42%, N accumulation increased by 1.10% - 3.18%. The stem and grain N accu- mulation increased in later harvest time, while the leaves and other organs were reduced. Postponing N application increased apparent N recovery by 3.52% - 6.87% and N agronomic efficiency by 0.82 - 1.60 kg/kg in later harvest time. Based on results from this experiment, it was recommended that 30% of N fertilizer should be applied as seeding fertilizer, 30% should be applied as trumpeting stage and 40% should be applied as silking stage, the yield and N utilization efficiency were the highest in later harvest time.