氮肥追施时期及包膜控释氮肥对冬小麦产量和氮素吸收的影响

采用盆栽试验,研究了氮肥追施时期和包膜控释尿素对冬小麦产量、产量构成、氮肥利用率和土壤氮素表观损失等方面的影响。结果显示:冬小麦氮肥最佳追肥时期为拔节期;与40%普通尿素底施+60%普通尿素拔节期追施(F2)相比,30%普通尿素+35%控释期90d包膜尿素+35%控释期120d包膜尿素配合(F4、F6)一次性底施的氮素释放与冬小麦对氮素需求吻合较好,F4小麦植株总氮吸收量增加6.11%,减氮25%条件下(F6)增加8.48%;与F2相比,F4使冬小麦增产5.02%,经济系数提高6.43%,氮肥利用率提高10.22%,同时土壤氮素表观损失降低。F4通过提高千粒重和单穗重来提高产量,而F6通过维持穗粒数保证产量。

Effect of topdressing time of nitrogen fertilizer and controlled-release coated urea on winter wheat yield and apparent nitrogen recovery rate

Pot experiments were used to investigate the effect of topdressing time of nitrogen fertilizer and application of controlled-release coated urea on wheat yield, yield component, apparent nitrogen recovery rate and apparent soil nitrogen loss. The results show that jointing stage is the best time for topdressing of nitrogen fertilizer in winter wheat. Compared with 40% basal and 60% topdressing urea (F2) at jointing stage, nitrogen release trend of 30% urea, 35% coated urea with a release time of 90 d, and 35% coated urea with release time of 120 d (F4, F6) mixed basal application is more or less the same as that of plant nitrogen requirement. The total nitrogen accumulation under F4 (with normal N dose) increases by 6.11%, while under F6 (with 75% of normal N dose) increases by 8.48% compared with F2. Wheat yield, economic coefficient and apparent nitrogen recovery rate increase by 5.02%, 6.43% and 10.22% under F4 respectively. Furthermore, apparent soil nitrogen loss decreases. F4 increases yield by improving 1000-grain weight and single spike weight, F6 guarantees the yield through maintaining the grain number per spike.