苗期调控对晚播小麦产量及氮素利用的影响

针对冬小麦因播期推迟造成产量损失的问题,以2个不同分蘖能力的冬小麦品种中麦8号和航麦501为供试材料,研究苗期覆膜和补施氮肥对晚播小麦产量及氮素利用的影响。试验设置3个播期：10月5日适期播种（S0,对照）、10月15日适当晚播（S1）和10月25日过晚播（S2）。结果表明：随着播期推迟,小麦产量逐渐降低。晚播条件下,苗期覆膜和补施氮肥可调控冬小麦产量构成因素、农艺性状、茎蘖生长、成穗率以及氮素的吸收利用。综合而言,晚播条件下,覆膜和补施氮肥有利于提高小麦穗长、总小穗数及冬前群体数量;同时,覆膜可显著提高2个品种晚播条件下的分蘖成穗率和过晚播条件下的植株氮素积累量（PNA）及氮肥偏生产力（PFP）,增幅分别为46.4%~89.1%、12.7%~26.5%和19.5%~20.1%;补施氮肥在过晚播条件下有利于成穗率的提高,增幅为18.5%~34.7%。2种调控措施均有利于增加晚播小麦产量,增幅达1.4%~19.5%。但不同分蘖力的小麦对2种调控措施的响应存在差异。综合考虑产量及氮素利用等各方面因素,在晚播条件下,相比于补施氮肥,苗期覆膜更有利于提高晚播小麦产量,弥补晚播造成的产量损失,但在实际操作和节约生产成本方面,前者优于后者。

Effects of Seedling Regulation on Yield and Nitrogen Utilization of Late Sowing Wheat

The experiment was conducted to solve the problem of winter wheat yield loss due to delayed sowing date. Zhongmai 8 and Hangmai 501 with different tillering abilities were used as the test materials to study the effects of plastic film mulching supplementing nitrogen fertilizer at seedling stage on the yield and nitrogen utilization of late-sowing wheat. Three sowing dates were set up in the experiment, sowing at 5th October as an appropriate date (S0, CK), 15th October as late sowing (S1), and 25th October as later sowing (S2). The results showed that the wheat yield gradually decreased with the sowing date delayed. Under the condition of late sowing, film mulching and supplementing nitrogen fertilizer at seedling stage could regulate winter wheat yield components, agronomic characteristics, stem and tiller growth, spike rate, and nitrogen absorption and utilization. Under the condition of late sowing, film mulching and supplementing nitrogen fertilizer were beneficial to increase spike length, spikelet number, and populations of wheat before winter. At the same time, mulching could significantly increase the spike rate of the tiller, plant nitrogen accumulation (PNA), and partial factor productivity (PFP) under the condition of late sowing by 46.4%-89.1%, 12.7%-26.5%, and 19.5%-20.1%, respectively. Under the condition of later sowing, supplementing nitrogen fertilizer could also increase the spike rate by 18.5%-34.7%. Both regulation measures were beneficial to increase the yield of late-sowing wheat by 1.4%-19.5%. However, there were differences between Zhongmai 8 and Hangmai 501 in response to the two regulation measures. Considering various factors such as yield and nitrogen utilization, under the condition of late sowing, film mulching at seedling stage was more effective to increase the yield and make up for the yield loss caused by late sowing compared with supplementing nitrogen fertilizer. However, in terms of practical operation and saving production costs, the former is better than the latter.