Climatic Potential Productivity And Climate Resources Utilization Rate Of Spring Maize In Northeast China Under Climate Change

This study was based on the daily meteorological data of101meteorological stations from1971to2000and the0.25°×0.25°grid data from1951to2100simulated by RegCM3underA1B scenario given by National Climate Center, in combination with the demand of climaticcondition for maize growth in Northeast China. The trajectory of agricultural climaticresources and the effects of climate change on variety distribution and climatic potentialproductivity of spring maize in Northeast China under future climate change were analyzed.And through selecting test points in Liaoning province to determine the suitable sowing datethat could improve the climatic potential productivity and climate resources utilization rate.The study will provide theoretical foundation for maize production using agriculturalclimatic resources efficiently and reasonably in Northeast China. The main conclusions are asfollows:⑴Northeast China was affected by climate change obviously as follows:(a) The dailyaverage temperature had a significant rise trend in Northeast China since1981, and thewarming rate in four periods(1981-2010s，2011-2040s，2041-2070s，2071-2100s) are0.42℃/10a，0.64℃/10a，0.61℃/10a&0.42℃/10a，higher than that of China in nearly54years(0.25℃/10a) and the global in nearly50years (0.13℃/10a). Trends of maximum andminimum air temperature are similar to daily average temperature.(b)The spatial tendency ofthe precipitation was different and the increase trend was not obviously but the change isremarkable among years.(c)The total radiation increased obviously since2011, and theincrease rate became bigger from west to east.⑵The agricultural climatic resources of maize would change significantly due to climatechange. Compared to the benchmark period, the initial date daily average temperature stablypassing10℃would be significantly advanced, and the first frost date would be delayed. Thedays of growing period would be extended, the≥10℃accumulated temperature and the totalradiation would be significantly increased since2010. Due to the increase of climaticresources, the early-maturing varieties would be gradually replaced by late-maturing varietiesin Northeast China, and the planting boundaries of several maize varieties would be extendednorthward and eastward, especially since2011. In theory the late-maturing varieties (with22laminas) could be planted in northeast except Xiaoxing’an Mountains and ChangbaiMountain from2071s to2100s.⑶There would be a significant change in the climatic potential productivity of maize onspatio-temporal scales because of the change of maize variety. As the constant climatewarming, the climatic potential productivity would decrease significantly since2010due tohigh temperature in Liaoning Province. As to Jilin and Heilongjiang Province where werelack of heat resources, the climatic potential productivity would increase since2000with theincrease of heat resources and the change of variety. There would be a significant change inthe climatic potential productivity of maize in Northeast China with the high-value graduallymoving towards northeast.⑷By establishing subordinate functions of radiation, temperature and rainfall, theresources utilization rate was studied. The result showed that the resources utilization ratehad an obvious downtrend of three provinces, and it was very significant in LiaoningProvince since2011. The resources utilization rate of Liaoning Province became lower than Jilin and Heilongjiang Province after2065. The resources utilization rate was different indifferent periods, and on the whole the areas with high-value would move northeast.⑸It was an effective way to increase the climatic potential productivity and resourcesutilization rate of maize by appropriate adjustment of sowing date in order to avoid hightemperature, but it would vary from place to place. The effect was more obvious in areas withlow height, low latitude and high temperature in Liaoning, and the sowing date could bedelayed by about40days. But in areas with high height, high latitude and low temperature,the sowing date should not be delayed too long. However, due to the different climaticresources in different years over different regions, how to determine an appropriate delayingsowing data was a complicated issue, needing to consider the effects of many factors andfurther study.