北方冬小麦冬季冻害及播期延迟应对

Freezing Injury of Winter Wheat in Northern China and Delaying Sowing Date to Adapt

全球变暖背景下,我国北方冬麦区冬季冻害是否仍是主要气象灾害,冬小麦播期延迟是否能作为应对气候变化的措施,成为当前亟待解决的科学问题。研究表明:1981—2000年北方冬麦区偏北地区冬季冻害指数与冬小麦减产率相关系数为0.62(达到0.001显著性水平),即2000年前冬季冻害是冬小麦减产的主要气象灾害之一;2000年后冻害与冬小麦减产率相关不显著,即冬季冻害已不再是冬小麦减产的主要影响因子。2018—2021年的冬小麦分期播种试验分析表明:山东泰安和陕西咸阳主栽的冬小麦品种播期推迟,冬前积温和生长季积温明显减少,导致冬小麦植株高度、地上总干重和叶面积指数减小;播期推迟对产量结构造成不利影响,有效穗数、穗粒数和千粒重均分别减少,导致减产,播期推迟10 d平均减产22%,推迟20 d平均减产40%。因此,冬小麦推迟播期并未产生积极效应,可能原因是当前冬小麦播期和主栽的冬小麦品种已适应当地气候变化。

Under the background of global warming,whether freezing injury is still the main meteorological disaster in northern winter wheat growing region of China becomes uncertain,and whether delaying sowing date is an effective measurement to adapt to climate change becomes an urgent scientific problem to solve.It is found that the correlation coefficient between winter freezing injury index and winter wheat yield reduction rate is 0.62 in the northern winter wheat region from 1981 to 2000,which indicates that winter freezing injury is one of the main disasters before the year of 2000.However,this correlation becomes very low after the year of 2000,indicating that winter freezing injury is no longer the main factor for yield reduction of winter wheat.Experiments are carried out at Taian and Xianyang stations,showing that the accumulated temperature before winter and the accumulated temperature of the whole growth season of winter wheat are significantly reduced.The plant height,total aboveground dry weight and leaf area index will decrease when sowing date of winter wheat is delayed for 10 days and 20 days.Furthermore,the delay of sowing date has an adverse impact on the yield structure,the effective panicles and grains per panicle are decreased by 5%and 10.2%respectively when the sowing date of winter wheat is delayed for 10 days from2018 to 2021 at Taian Station,and they are decreased by 17.2%and 11.9%respectively when the sowing date is delayed for 10 days at Xianyang Station.Overall,the average yield of winter wheat is reduced by22%and 40%when sowing dates are delayed for 10 days and 20 days respectively,which indicates that the delayed sowing date of winter wheat have no positive effects.The possible cause is that the local winter wheat varieties have changed at Xianyang and Taian,and farmers have appropriately adjusted the sowing date according to experience.The current winter wheat sowing date and the main winter wheat varieties have adapted to local climate change.