Abstract: A randomized complete-block design of two nitrogen fertilizers (available nitrogen and slow-release nitrogen) and different fertilization methods (fertilization periods and proportion of slow-release nitrogen) were conducted to study yield factors and nitrogen utilization efficiency of corn (Zea mays L.) in different growth stages. Results showed that both available nitrogen and slow-release nitrogen could improve corn height and stem diameter in the stage of jointing and maturity, especially in ⅠC (20% slow-release nitrogen) treatment. Available nitrogen and slow-release nitrogen had no significant effects on corn stem to leaf ratio (P>0.05). Nitrogen fertilizer could improve both fresh and hay yields of silage corn, especially the slow release nitrogen treatment of 150 kg·hm^-2 with 30% slow release component (ⅠB).The fresh and dry yields of this treatment were 10.468×10⁴ kg·hm^-2 and 2.4487×10⁴ kg·hm^-2, respectively. The dry yield had a significant increase compared with the treatment of 180 kg·hm^-2 slow-release nitrogen. Results also showed that both nitrogen apparent utilization and physiological efficiency were higher in slow-release nitrogen than in available nitrogen fertilization, and graded applied fertilization was better than only fertilizing once. In conclusion, moderate nitrogen slow release fertilizer could effectively improve silage corn yield and N use efficiency.

Key words: Slow-release nitrogen, Available nitrogen, Silage corn, Nitrogen use efficiency

摘要： 通过完全随机区组设计,研究施肥种类(180 kg·hm^-2速效氮、150和180 kg·hm^-2缓释氮)、施肥时期(1次施入和2次施入)和氮缓释比例(20%,30%和40%)对不同生长期青贮玉米(Zea mays L.)产量及其构成因素和氮素利用率的影响,以期为青贮玉米高产的氮肥管理模式提供科学依据。结果表明:施氮可以显著提高拔节与成熟期青贮玉米的株高和茎粗,以缓释氮复合肥施入量150 kg·hm^-2,缓释成分为20%(ⅠC)的处理最好;速效氮和缓释氮对青贮玉米茎叶比的影响差异不显著。对青贮玉米产量的影响,以缓释比例30%的复合肥(150 kg·hm^-2,ⅠB)产量最高,鲜草产量达到10.468×10⁴ kg·hm^-2,干草产量为2.4487×10⁴ kg·hm^-2。ⅠB处理与同缓释比例施入180 kg·hm^-2的处理相比,干重增产显著,鲜重产量无显著差异。缓释氮处理的氮表观利用率和氮素生理利用率高于速效肥;速效氮分次施入比一次施入的氮农学利用效率和氮素利用率高;总之,适度的氮缓释复合肥可有效地提高青贮玉米产量并提高其氮素利用效率。

关键词: 氮缓释复合肥, 速效复合肥, 青贮玉米, 氮素利用率