冬小麦水氮配合关键期和亏缺敏感期的确定

Study on the Key and Sensitive Stage of Winter Wheat Responses to Water and Nitrogen Coordination

通过盆栽试验研究了干旱胁迫和正常供水条件下施氮对冬小麦的效应,以期确定出其水氮配合的关键期和亏缺敏感期。结果表明,干旱胁迫条件下,氮肥早施比晚施好,低量氮肥比高量氮好。而且不同施氮处理对有效穗数和穗粒数的影响差异显著,但对千粒重无明显影响。水氮配合条件下,氮素的作用得到充分发挥,产量大幅度提高,而且对有效穗数、每穗粒数和千粒重都产生显著的影响。拔节期是冬小麦对水氮配合效应的关键期和亏缺敏感期。拔节期供水供肥可以显著地提高产量,同时增加穗粒数和千粒重。分析其机制发现拔节期供水供肥可以促进作物地上部的迅速生长和发育,增强作物吸收和利用氮素的能力,同时还可延缓根系衰老,保持后期旺盛的根系活力。

Pot experiments were carried out to study the effect of nitrogen application on winter wheat under different status of soil moisture, so that the key and sensitive stage of winter wheat responses to water and nitrogen coordination were decided. The results showed that the application of N fertilizer was more effective at early stage than at late stage, and at the lower N rates than at the higher N rates under non-irrigated conditions, N treatment had greet effect on spikelet bearing number and grain number per spike, but had no effect on 1 000-grain weight. Grain yield and yield component responses to N treatment were greater under irrigated conditions than under non-irrigated conditions. The jointing stage was the key and sensitive stage of winter wheat responses to water and nitrogen coordination. The grain yield, grain number per spike and 1000-grain weight increased when water and N fertilizer were applied at this stage. The mechanism is that the growth and development, absorption and application of nitrogen, and root activities of winter wheat increased when fertilizer and water were applied at this stage.