Abstract: In order to investigate the effects of N fertiliser reduction and N application period on the growth and development,yield components and photosynthetic characteristics of oats(Avena L.) in alpine region,four N fertilizer treatments:N1(conventional N application,69 kg·hm^-2),N2(20% reduction,55.2 kg·hm^-2),N3 (40% reduction,41.4 kg·hm^-2),N4 (60% reduction,27.6 kg·hm^-2) and N0 (0 kg·hm^-2),and three nitrogen application periods:T1 (all basal application),T2 (follow-up application at the jointing stage),and T3 (follow-up application at the heading stage),were set up in this study to compare the effects of the treatments on the growth and development indexes of oats,the yield constituting factors and the photosynthetic characteristics. The results showed that N fertilization promoted the growth and development of oats,significantly increased the stem thickness,plant height,spike length and flag leaf height of oats,and also improved the yield and constitutive factors,the number of spikelet per plant,the number of grains per spike per plant,the grain weight per spike per plant,the length of grains,the width of grains,and the weight of 1000 grains of oats,improved the net photosynthetic rate,the rate of transpiration and the stomatal conductance,and lowered the inter-cellular CO₂ concentration of oats. The correlation analysis indicated that the N fertilization at the spike stage improved the growth and development indexes,the yield constitutive factors,and the photosynthetic characteristics of oats. The correlation analysis showed that N fertiliser application at the heading stage was better than at the jointing stage. Through comprehensive analysis,N1T3 treatment was the best. Therefore,the best fertilizer application period for oats in the alpine region was the heading stage under the appropriate N application rate.

Key words: Nitrogen fertilizer, Oat, Yield, Photosynthetic characteristics, Nitrogen application period

摘要： 为探究氮肥减施与施氮时期对高寒区燕麦(Avena L.)生长发育、产量构成因素及光合特性的影响，本研究共设置4个氮肥处理：N1(常规施氮量：69 kg·hm^-2)、N2(减施20%：55.2 kg·hm^-2)、N3(减施40%：41.4 kg·hm^-2)、N4(减施60%：27.6 kg·hm^-2)和全生育期不施氮处理N0(0 kg·hm^-2)，3个施氮时期：T1(全部基施)、T2(拔节期追施)、T3(孕穗期追施)，比较各处理对燕麦生长发育指标、产量构成因素及光合特性的影响进行研究。结果表明，氮肥后移促进了燕麦的生长发育，显著增加了燕麦的茎粗、株高、穗长和旗叶高度，同时也提高了产量及构成因素，燕麦单株小穗数、单株穗粒数、单株穗粒重、粒长、粒宽和千粒重显著增加，氮肥后移改善了燕麦的净光合速率、蒸腾速率和气孔导度，降低了胞间CO₂浓度，相关性分析表明，燕麦孕穗期追施氮肥优于拔节期追施。通过综合分析，N1T3处理最好。因此，在适宜的施氮量下，高寒区燕麦最佳追肥时期为孕穗期。

关键词: 氮肥, 燕麦, 产量, 光合特性, 施氮时期