Actual Responses and Adaptations of Rice Cropping System to Global Warming in Northeast China
Dong Wen-jun · Zhongguo nongye Kexue · 2012
【Objective】A better understanding of global warming impacts on grain production can reduce the uncertainties of future food security projection.Rice is one of the most important grain crops in the world.Northeast China is the main region of rice cropping and the greatest warming area in China.It is significant and necessary to learn the potential impacts of warming on rice production in Northeast China for ensuring the future food security.【Method】Based on historical data analysis and three-year field warming experiment(Free air temperature increase,FATI),the actual responses and adaptations of rice cropping system to warming were investigated in Northeast China.【Result】The results showed that there were similar increasing trends between air temperature during rice cropping season and rice yield over the past decades.Significant positive relationship was found between nighttime increment and rice yield enhancement,while no significant relationship was found between rice yield and precipitation.According to the relationship between climate anomaly and rice yield anomaly over the last thirty years,1℃ increment in daily minimum temperature during rice cropping season might increase rice yield by about 6.0%.Meanwhile,field experiments showed that further 1℃ warming at nighttime might enhance rice yield by about 10.0% in future.The entire growth period of new variety approved and released in different times has been prolonged by about 3.0 d?10a-1 during the past fifty years,which is confirmed by the actual prolonging of rice growth period by 5.0 day observed in field during the last twenty years.Rice sown area in Heilongjiang province increased about 24 times in 2010 than 1970,and the cropping centre moved northward about by 110 km during the past forty years.Similar spatial change was found in ≥10℃ accumulated temperature during rice cropping season over the same years in Northeast.【Conclusion】 The above evidences indicate that warming has contributed a great to the historical increment in rice yield,and further warming will still help rice yield increase in Northeast China.Rice cropping system can progressively adapt to global warming through variety breeding,cropping technique innovation and cropping region adjustment.More efforts should be paid on the great adaptation potential of rice cropping system to warming,so as to fully explore the positive effects of warming on rice production at high latitude area and reduce the risk of yield decrease due to the unstable climate.