不同发育期干旱对冬小麦灌浆和产量影响的模拟

为探明不同强度干旱对农作物生长过程所产生的影响,本文基于作物生长模型WOFOST,采用数值模拟方法,模拟分析了河南省郑州地区冬小麦在拔节期、抽穗期和灌浆期分别发生不同程度干旱、两个发育期以及3个发育期都发生不同程度干旱对冬小麦灌浆过程和产量的影响。结果表明,当单一发育期供水减少10~30 mm时,干旱导致小麦灌浆强度在正常灌浆后的第14~18 d下降,可使小麦减产1.34%~12.5%,且以抽穗期干旱影响最大,其次是灌浆期干旱,拔节期干旱影响最小;当两个发育期供水都减少10~20 mm时,干旱导致小麦灌浆强度在正常灌浆后的第10~17 d下降,可使小麦减产4.94%~21.88%,且以抽穗期和灌浆期干旱影响为最大,其次是拔节期和灌浆期干旱,拔节期和抽穗期干旱影响最小;当3个发育期供水都减少5~15 mm时,干旱导致小麦灌浆强度在正常灌浆后的第11~16 d下降,可使小麦减产3.93%~24.84%。可见,干旱致使土壤水分亏缺,影响了作物正常的灌浆强度,进而导致作物减产。干旱发生时段与程度不同,造成作物的减产率也不尽相同,多个发育期干旱导致小麦的减产率往往大于单一发育期干旱相叠加的效应。

Impact simulation of drought disaster at different developmentalstages on winter wheat grain-filling and yield

Based on WOFOST crop growth model, this study analyzed the impact of different drought intensities during one, two or three combination of jointing, heading and grain-filling stages on the grain-filling and yield of winter wheat in Zhengzhou, Henan Province. The simulation results showed that when water supply was reduced by 10~30 mm during single development stage, grain-filling intensity began decreasing on 14~18 days after normal grain-filling date, which reduced yield by 1.34%~12.5%. While the highest impact on winter wheat yield was when drought occurred at heading stage and then at grain-filling stage, the lowest impact was when drought occurred at jointing stage. When water supply was reduced by 10~20 mm at two developmental stages, grain-filling intensity began decreasing on 10~17 days after normal grain-filling date, which reduced yield by 4.94%~21.88%. The highest effect on winter wheat yield was when drought occurred at both heading and grain-filling stages and then at jointing and grain-filling stages. The lowest impact was when drought occurred at both jointing and heading stages. When water supply was reduced by 5~15 mm during the three developmental stages, grain-filling intensity began decreasing on 11~16 days after normal grain-filling date, which reduced yield by 3.93%~24.84%. The above results showed that drought reduced winter wheat yield by affecting grain-filling intensity due to soil water deficit. The reduction in yield was significantly different when drought occurred at different developmental stages. There was higher impact on winter wheat when drought occurred at several developmental stages than at a single developmental stage.