黄淮海地区冬小麦关键生育期不同灌溉水平对产量影响的模拟

研究黄淮海地区不同灌溉水平下冬小麦产量的变化规律，对于识别干旱对冬小麦产量的影响和制定合理的节水灌溉措施具有指导意义。基于DSSAT作物模型，参考各生育阶段的水分亏缺量以及当地的灌溉习惯，制定模型输入的不同处理的灌溉量，模拟分析近30年黄淮海灌溉冬麦区4个典型站点冬小麦关键生育期不同灌溉水平下，产量及产量构成的相对变化规律，并且以典型处理为例，探讨2个关键生育阶段减产的累积概率。结果表明，拔节至抽穗期的水分胁迫对冬小麦的产量影响最大，产量相对变化主要由水分胁迫引起单位面积粒数的相对变化引起。在重度干旱条件下，拔节至抽穗期胁迫造成中等程度减产概率约为灌浆期胁迫的2倍(山东兖州点除外)；在河北石家庄和天津点，轻度和重度减产主要由拔节至抽穗期胁迫引起，而在山东兖州和河南新乡点，拔节至抽穗期及灌浆期胁迫造成轻度减产概率差别不大，但灌浆期重度干旱导致一定概率的重度减产。因此，在黄淮海冬小麦灌区偏南部，不但要加强拔节至抽穗期的灌溉措施，还应该注重灌浆期的干旱风险。

Simulation of Winter Wheat Yield in Response to Irrigation Level at Critical Growing Stages in the Huang-Huai-Hai Plain

Water deficiency is recognized as a major problem in winter wheat production in the Huang-Huai-Hai Plain. This study aimed to assess the impact of drought stress on winter wheat yield and raise irrigation proposals for water-saving production in this area. With reference to the fact of water deficits in major growth stages of wheat and the local irrigation practice, we input different irrigation levels (volumes) required by the DSSAT crop model to simulate yield variations in response to irrigation levels at critical growing stages in four typical sites during the past three decades. The cumulative probability for yield reduction was concluded based on irrigation at jointing–heading and filling stages. The greatest yield reduction was found under jointing–heading drought stress, and the relative change rate in yield was two folds to that under drought stress at filling stage. This relative yield change was primarily attributed to the relative change in grain number per square meter caused by water deficiency during jointing–heading stage. Under high-strength drought stress, medium yield reduction dominantly resulted from water deficiency during jointing–heading, with a two-fold probability to that under drought stress at filling stage (except for Yanzhou site); whereas, slight and severe yield reductions at Shijiazhuang and Tianjin sites resulted from early (jointing–heading) drought stress and those at Yanzhou and Xinxiang sites were attributed to either early (jointing–heading) or late (filling stage) drought stress. At Yanzhou and Xinxiang sites, the probabilities of slight yield reduction were similar under early and later drought stressed; however, water deficiency at filling stage resulted in severe yield reduction. These results indicate that irrigation is important not only from jointing to heading but also at filling stage of winter wheat in the southern area of the Huang-Huai-Hai Plain.