灌水时间对冬小麦生长发育及水肥利用效率的影响

研究秸秆还田后不同越冬前灌水时间(11月10日、11月25日、12月10日)和春季灌水时间(3月5日，返青期；4月5日，拔节期)对冬小麦生长发育、干物质运转及水肥利用效率的影响.结果表明： 越冬前灌水时间主要影响冬前和拔节期群体大小，而春灌时间对冬小麦成穗数、产量、干物质运转和水肥利用效率的影响较大，而且越冬前灌水时间对冬小麦产量构成的影响与春灌时间密切相关.在春季返青期灌水条件下，越冬前灌水时间越早，成穗数和产量越高；在拔节期灌水条件下，随越冬前灌水时间的推迟，成穗数和产量呈先升高再降低的趋势，而穗粒数逐渐增加，千粒重受影响较小.水分利用效率、养分吸收量和肥料利用率均随越冬前灌水时间的推迟而降低，随春季灌水时间的推迟而升高.因此，在秸秆还田足墒播种条件下，将越冬前灌水时间适当提前，可以塌实土壤，促进冬小麦冬前分蘖，增加群体大小；配合拔节期增量灌水，可以控制早春无效分蘖，提高成穗率，稳定粒重，提高水肥利用效率，实现节水高产高效栽培.

Effects of irrigation time on the growth and water-and fertilizer use efficiencies of winter wheat

A field experiment was conducted to study the effects of irrigation time before wintering (November 10th, November 25th, and December 10th) and in spring (March 5th, re-greening stage; and April 5th, jointing stage) on the growth, dry matter translocation, water use efficiency (WUE), and fertilizer use efficiency (FUE) of winter wheat after returning corn straw into soil. The irrigation time before wintering mainly affected the wheat population size before wintering and at jointing stage, whereas the irrigation time in spring mainly affected the spike number, grain yield, dry matter translocation, WUE, and FUE. The effects of irrigation time before wintering to the yield formation of winter wheat were closely related to the irrigation time in spring. When the irrigation time in spring was at re-greening stage, the earlier the irrigation time before wintering, the larger the spike number and the higher the grain yield; when the irrigation time in spring was at jointing stage, the delay of the irrigation time before wintering made the spike number and grain yield decreased after an initial increase, the kernel number per plant increased, while the 1000-kernel mass was less affected. The WUE, nutrition uptake, and FUE all decreased with the delay of the irrigation time before wintering, but increased with the delay of the irrigation time in spring. Therefore, under the conditions of returning corn straw into soil and sowing when the soil had enough moisture, to properly advance the irrigation time before wintering could make the soil more compacted, promote the tillering and increase the population size before winter, and in combining the increased irrigation at jointing stage, could control the invalid tillering in early spring, increase the spiking rate, obtain stable kernel mass, and thus, increase the WUE and FUE, realizing water-saving and high efficiency for winter wheat cultivation.