Climate Change Impacts On Wheat And Maize Phenology In China

The study of crop phenology is of great meaning for investing the crop response and adaption to ongoing climate change.The purpose of this study is to investigate the phenplogy change as well as its relationship with the change of climate for the main crops in China.The materials and methods as bellow: the theis includes the study of main crops’ phenology in the past 14 years and future.Tirst of all,we process the datas of the ariculrural sites and the meteorological stations.Then,calculate and analysis the change of crop phenology and the ralationship between the period of crop growing and the change of meterological factors.Third,we pick up the winter wheat and summer maize rotation stations to investate the variation trend for the growth period in these rotation ststions using the calculated multiple regression equations with the future meteorological date in the model of ECHAM.Based on the above analysis, following conclusions are made:1.The start date of the main phenologis shows the trend of delay for the for kind of crops: spring maize,summer maize,spring wheat and winter wheat in 2000-2013.The trend of average temperature and precipitation in the crop growing period is raised for the researched crops expect the winter wheat.The study for the change of crop growing period showed that it is shorten in the stations of spring maize and summer maize,and the growing period of spring wheat in not of great change,well in the winter wheat stations the length of vegetative growing period decreased but the length of reproductive growing period increased.We calculated that spring maize growth is negatively correlated with the average temperature,the growth period of spring maize decreased 4.58 days when ever the average temperature increased by 1 ℃.The summer maize growth is negatively correlated with the average temperature,when ever the average temperature increased 1℃,the summer maize growth length decreased 2.74 days. The spring wheat growth is negatively correlated with the average temperature,when ever the average temperature increased 1℃,the spring wheat growth length decreased 3.14 days. The winter wheat growth is positively correlated with the average temperature,when ever the average temperature increased 1℃,the winter wheat growth length increased 1.11 days.All the crops we investigated were less obviously effacted by the precipitation change.2. The study of correlation analysis between the historical meteorological and meteorological datas showed that the correlation is poor, especially the average temperature data.In the stations selected,there are only 8 stations that the historical meteorological and meteorological datas are positively correlation in tha all 16 stations. Therefore, analyzing the correlation between the crop phenology changes and meteorological factors can not simply adopt the annual value data instead of growing data.3. Calculated the growth length change in winter wheat and summer maize rotation stations under the three scenarios simulated by ECHAM in the future 2021-2040. The resulate under every three scenarios shows that there are respectively 35,35 and 38 stations that the growth length are decreased in the totally 56 rotation stations.The study showed that the mean growth length decreased in the three scenarios respectively 0.11day/year,0.13day/year and 0.13 day/year.However,the simulated resulate under every three scenarios in the phase 2021-2030 and 2031-2040 are different.Also,the mean growth length decreased in the main region for wheat and summer maize rotation, but the resulate in the phase 2021-2030 and 2031-2040 are different.