中国夏玉米和冬小麦生育期对历史及未来水热条件的响应

Responses of Summer Maize and Winter Wheat to Historical and Future Hydrothermal Conditions

全球变化背景下中国区域的气候在2000年以来出现了新的时空变化特征。针对中国的夏玉米和冬小麦,该文选取2000-2013年农业物候观测站点及邻近的气象观测站点的数据,结合2021-2040年3种未来气候情景(RCP2.6、RCP4.5和RCP8.5)的模拟数据,分析夏玉米和冬小麦各物候和生育期的变化情况,以及这两种作物生育期与对应水热条件的相关性,并进一步预测未来时期夏玉米和冬小麦轮作总的生育期历时变化。结果表明:超过50%的站点显示夏玉米各主要物候期均呈一定程度的推迟,而冬小麦物候期推迟的站点数并不明显。2000-2013年对应各作物物候期的气温变化不是一般认为的升温趋势,夏玉米生育期平均气温没有明显的变化,但降水增加的站点稍多;而超过60%的站点显示冬小麦生育期的气候呈干冷化趋势。整体上,夏玉米和冬小麦各站点整个生育期与平均温呈负相关,平均温每升高1℃,生育期将缩短3.97d;在未来3种气候情景下,夏玉米和冬小麦的总生育期历时最大的缩短趋势达0.13d/a。

Climate factors,especially the hydrothermal conditions,have a range of important impacts on crops.With the global warming,a new change in the climate(warming hiatus)has been found in China since 2000.In view of the relationship of the phenology of summer maize and winter wheat with climate conditions,in this study,the phenological characteristics and the relationship between the growth periods of these crops and hydrothermal conditions were analyzed based on the historically observed data from agricultural phenological stations and meteorological stations during 2000-2013,and the simulated data for the three future climatic scenarios(RCP2.6,RCP4.5 and RCP8.5)during 2021-2040.In addition,the future lengths of the growth period(from seeding to maturity)of summer maize and winter wheat were predicted.It was found that more than 50%of the stations show a delay in the main phenological events of summer maize,while few stations show a delay for winter wheat.During 2000-2013,the temperature over the phenological periods,however,did not show a general increase as one thought.The mean temperature over the phenological events for summer maize remained rather flat,but the precipitation increased at most stations.More than 60%winter wheat stations show that the climate has a trend to be cold and dry over the whole growing period.Overall,there is a negative correlation of the total growth period of summer maize and winter wheat with the observed mean temperature.The total growth period will shorten by 3.97 days when the mean temperature increases by 1.0℃.Under the three future climate scenarios,the maximum shortening amplitude of the total growth period will be 0.13 day per year.It should be noted that the specific values must be treated carefully because of the special historical and indefinite future climatic conditions.