Impacts of climate warming on growth period and yield of rice in Northeast China during recent two decades

By using rice growth period,yield and climate observation data during the recent two decades,the impact of climate warming on rice in Northeast China was investigated by mathematical statistics methods. The results indicated that in the three provinces of Northeast China,the average,maximum and minimum temperatures in rice growing season were on the rise,and the rainfall pre-sented a downward trend during 1989-2009. Compared to 1990 s,the rice whole growth periods of Heilongjiang,Jilin and Liaoning provinces in 2000 s were prolonged 14 d,4. 5 d and 5. 1 d,respectively. The increase of temperature in May,June and September could extend the rice growth period,while that in July would shorten the growth duration. The rice growth duration of registered varieties and experiment sites had a similar increasing trend in Northeast China except for the Heilongjiang Province,and the extension of registered varieties growth period was the main factor causing the prolonged growth period of rice at experiment sites. The change in daily average,minimum and maximum temperatures all could affect the rice yield in Northeast China. The increasing temperature significantly increased the rice yield in Heilongjiang Province,especially in the west region of Sanjiang Plain. Except for the south of Liaoning Province,rice yields in other regions of Northeast China were promoted by increasing temperature. Proper measures for breeding,cultivation and farming,could be adopted to fully improve the adaptation of rice to climate warming in Northeast China.