Water is the key factor limiting the improvement of wheat yield and quality. In order to explore the effects of irrigation in different periods on winter wheat yield, agronomic characteristics, grain quality and photosynthetic performance, four water treatments were set under conditions of automatic rain-proof shelter that water and fertilizer were controlled: no watering（control treatment, W1）, water 1050m~3/ha at jointing stage（W2）, water 1050m~3/ha at flowering stage（W3）, and water 525m~3/ha at jointing stage + 525m~3/ha at flowering stage（W4）. The results showed that, the grain protein content of W1 treatment, the protein yield of W2 treatment and the grain yield of W3 treatment were the highest. W4 treatment had the most stable photosynthetic performance. Compared with W1 treatment, irrigation affected the photosynthetic performance of wheat flag leaves, increased its net photosynthetic rate, stomatal conductance, intercellular CO 2 concentration and transpiration rate. Irrigation at jointing stage increased leaf chlorophyll content, dry matter accumulation and grain protein yield, and increased biological yield by increasing the number of spikes and grains per spike. Irrigation at flowering stage could increase grain length and width, increase sink capacity, and increase grain yield by increasing weight. By comparing W1, W4 and W2 treatments after irrigation at jointing stage and before irrigation at flowering stage, it was found that irrigation increased the maximum net photosynthetic rate and light saturation point, decreased the dark respiration rate, and the flag leaf was more adapted to strong light, but could not further increase the photosynthetic efficiency, and the weakening range of flag leaf adaptation to strong light increased with time. With the same amount of irrigation, irrigation only once at flowering stage or twice at jointing stage and flowering stage could prevent the decline of photosynthetic performance and the earlysenescence of leaves at the later stage. Therefore, attention should be paid to the role of water in different growth periods in production, and irrigation should be carried out in time according to the actual precipitation and production demand.

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.

本试验在宽幅播种条件下,以大穗型冬小麦品种‘泰农18’为材料,设计常规播期10月10日和适期晚播10月20日2个播期处理,各播期下分别设置225、375、525万株/hm2 3个种植密度,研究了播期和密度互作对冬小麦产量及产量形成、茎秆重心高度、基部节间机械强度和茎秆抗倒指数的影响,以期明确适期晚播对密植高产冬小麦产量和茎秆抗倒性能的调控效应.研究结果表明:播期和种植密度显著影响冬小麦的产量和抗倒性能.各播期间适度密植(375万株/hm2)可通过提高穗数获得高产,且在两播期间无显著差异.适度晚播显著提高各密度冬小麦抗倒指数;在晚播条件下,随种植密度增加,小麦重心高度提高的幅度、基部节间机械强度降低的幅度显著低于常规播期,从而使得适期晚播密植小麦的抗倒能力仍可维持在较高水平.适度密植小麦可通过适期晚播平衡其产量和抗倒能力,本试验条件下,采用375万株/hm2的种植密度,在10月20日播种,可协同实现高产、稳产.