气候变化对河南省灌溉小麦的影响及对策初探

Possible Impacts of Future Climate Change on Irrigated Winter Wheat and Adaptive Strategies in Henan Province

灌溉是河南省冬小麦最重要的种植管理模式。在DSSAT-CERES小麦模型参数调试和区域适用性验证的基础上,利用区域气候模式PRECIS输出的未来气候情景资料,量化分析了2021—2050年河南省灌溉条件下冬小麦产量的可能变化,结果表明:若不采取其他措施,未来A2,B2两种温室气体排放情景下,河南省冬小麦产量平均减少5%左右,A2情景减产率略高于B2;随着产量降低,产量波动区间略有缩小,但25%～75%的稳产区间也相应缩小,且B2情景下更容易出现极端低产的年份;冬小麦水分利用效率相应降低。采取适当应对措施,如延迟播种期、减小种植密度等有利于提高产量或缓解减产趋势。

Henan Province is one of the most important growing areas for winter wheat in China, and irrigation is the main planting and managing mode for winter wheat. Traditionally, winter wheat is watered three times during the whole growing season, namely, irrigating before overwintering, at green turning stage and jointing to grain filling stage respectively. As to the impact of climate warming, how the irrigated wheat would be influenced in the future has been concerned. DSSAT-CERES Wheat Model is widely used in China and has been proved feasible in future influence simulating. Based on parameters debugging and regional validation of the DSSAT-CERES Wheat Model, two different climatic scenarios data which is outputted by regional climate model PRECIS is combined to study the possible yield variation of winter wheat in the future 30 years of 2021--2050 in Henan Province. The reduction rate of yield and the reduction distribution as well as the changing of water use efficient （WUE） are shown. By drawing quartile graph, the fluctuation of the yield in the future is analyzed. In case of two kinds of greenhouse gas emission scenarios A2 and B2, on the assumption that the tra- ditional irrigation mode doesn＇t change, the average rate of yield reduction is 5~ approximately, and the reduction in A2 scenario is more obvious than B2. Generally speaking, the final yield reduction on the east and southwest plain is relatively less, and the largest reduction rate appears in different decade for different scenarios. With the yield reduction, the variability of yield decreases a little, but 25^--75% interval which means stable yield also shrinks. Extreme low yield is more likely to occur in B2 scenario than A2. During 2021--2050, with the decrease of final yield and increase of water consumption, the WUE for irri- gated winter wheat will decrease by 9 G averagely for two scenarios. Taking the advantage of crop model experiment, sowing date, planting density and irrigating method are adjusted, respectively. Results show that postponing the planting date has an effect on increasing yield and yield stability,subtracting the plant- ing density to some extent achieves more yield than increasing the density, and changing the watering method from ditch irrigation to trickle could save water resource and enhance final yield.