降水因素导致的水分亏缺对冬小麦产量影响的敏感期分析

降水是影响华北平原冬小麦产量的重要因子之一，该区域生长季降水无法满足冬小麦生长需求是造成粮食减产的主要因素。本研究设计不同降水情景，基于 CERES-Wheat 模型模拟不同水分亏缺情景下冬小麦生长发育过程，识别降水对冬小麦产量影响的关键期。研究发现: 不同持续时间的无降水对产量的影响存在较大差异，由 1 ～4 周不降水引起的水分亏缺对冬小麦造成的减产率范围为 3. 1% ～29. 7%。超过 2 周不降水引起的降水亏缺对冬小麦产量造成显著影响。播种－越冬期后期( 0～16 周) ，冬小麦不同生育阶段发生 1～4 周的无降水对减产率的影响差异较小; 从越冬期后期开始，1～4 周的的无降水造成的减产率差异显著增大。太行山山麓平原区、冀鲁豫低洼平原区、山东丘陵农林区在冬小麦生育期内存在三个较大的减产率峰值期，分别是越冬期后期、返青期前期、拔节－灌浆期。黄淮平原区在冬小麦生育期内存在两较大的减产率峰值区，分别在返青期、灌浆期周围。区域上不同持续时间的无降水造成的冬小麦减产率研究，能够为作物干旱影响评估和节水灌溉提供有益借鉴。

Analysis on the critical period of winter wheat yield impacted by water deficit caused by precipitation

Precipitation is one of the important factors affecting the yield of winter wheat in North China Plain． The main reason for grain yield reduction is that the precipitation during the growing season cannot meet the growth demand of winter wheat in this area． In this study，various precipitation scenarios are designed to simulate the growth and development process of winter wheat under different water deficit scenarios based on CERES-Wheat model，and to identify the critical period of the impact of precipitation on winter wheat yield． The results show that the effect of non-precipitation over different durations on yield is quite different． Water deficit caused by no precipitation for 1～ 4 weeks results in 3. 1% ～ 29. 7% yield reduction． No precipitation for more than two weeks leads to a significant impact on winter wheat yield． In the late seeding-wintering period ( 0～ 16 weeks) ，no precipitation for 1～ 4 weeks at different growth stages of winter wheat has little effect on yield reduction; from the late wintering period，the difference in yield reduction caused by no precipitation for 1～ 4 weeks increases significantly． There are three peaks of yield reduction during the growing season of winter wheat，namely late wintering，early returning green and the jointing-filling period，in the piedmont plain area of Taihang Mountains，the low-lying plain area of Hebei，Shandong and Henan Provinces，and the hilly agroforestry area of Shandong Province． The returning green and grain-filling period of the Huanghuai Plain are two distinct periods leading to a significant decline in yield． This study designs various and detailed precipitation deficit scenarios and analyzes deficit-induced winter wheat yield reduction，which could provide insightful references for regional drought impact assessment and water-saving irrigation．