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.