东北稻作系统对气候变暖的实际响应与适应

【目的】明确气候变暖对作物生产的实际影响，降低对未来粮食安全预测的不确定性。【方法】依据东北水稻生产和气候变化的长期观测数据，并结合田间开放式增温试验（free air temperature increase，FATI），系统研究稻作系统对气候变暖的实际响应与适应。【结果】历史数据分析发现，近几十年来东北水稻单产与其生长季的气温呈明显递增趋势，相关显著，但与降水量变化相关不显著。理论推算表明，水稻生长季最低气温升高1℃，水稻单产可提高6.0%以上。田间试验发现，在目前的气温背景下，水稻冠层气温升高1℃，单产可提高10%左右。近四十年来东北水稻新品种的生育期每10年约延长3 d，与近二十年来田间观测到的水稻实际生育期延长幅度基本一致，达5 d左右；与1970年相比，2010年黑龙江省的水稻种植面积扩大了24倍，种植重心向北位移了近110 km，与东北水稻生长季≥10℃有效积温带北移的幅度一致。【结论】气候变暖对东北水稻的直接增产效应显著，稻作系统可以通过品种改良、栽培改进和区域调整等策略来逐步适应气候变化的趋势。在应对气候变化的稻作制度调整上，应充分挖掘增温的增产效应及作物系统的适应潜力，调整时机和幅度应适当迟后于预测的气候变化进程。在气候变暖的大趋势下，要注意因水稻生育期延长和种植区域北扩而可能遭遇的低温冷害等极端性天气。

Actual Responses and Adaptations of Rice Cropping System to Global Warming in Northeast China

【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.