黄土高原冬小麦田土壤水分与小麦产量对降水和气温变化响应的模拟研究

明确黄土高原地区降水和气温变化对冬小麦田土壤水分和产量的影响,对探索适应气候变化的冬小麦田间管理措施具有重要的现实意义。论文在验证EPIC模型对冬小麦田土壤水分模拟精度的基础上,以历史气象数据为基础,设置TR1、TR2和TR3三个气候情景,采用作物模型模拟的方法,研究黄土高原冬小麦田土壤水分和冬小麦产量对降水和气温变化的响应。结果显示：1）1961—2010年黄土高原降水呈降低趋势,其年际间变化幅度和频率均有所增加。与1961—1970年相比,洛川、长武、运城和延安的年均降水量在2001—2010年间分别降低了18.1%、13.6%、18.8%和24.9%,其变差系数分别增加了0.029、0.087、0.02和0.057。1961—2010年黄土高原气温呈波动性增加趋势,其中日最低气温增加幅度大于日最高气温增加幅度。与1961—1970年相比,日最高气温在2001—2010年间增加了0.30~0.84 ℃,而日最低气温增加了1.00~1.55 ℃。2）EPIC模型能够较好地模拟黄土高原冬小麦田土壤水分动态变化规律,0~2.0 m土层土壤湿度观测值与模拟值间的相对均方根误差RRMSE值为6.0%~14.0%,R²和模型效率ME值分别为0.824和0.815。3）黄土高原地区降水的减少和最高气温的增加均不利于冬小麦生产,而最低气温的提高对冬小麦生产较为有利。洛川、长武、运城和延安冬小麦产量因年降水量的降低而分别减产了8.5%、7.6%、11.7%和12.3%;因日最高气温的升高分别减产了6.4%、6.8%、7.2%和-3.0%;因日最低气温的提高而分别增加了8.8%、10.2%、1.5%和12.0%。因此,为适应降水减少和日最低气温升高的趋势,黄土高原冬小麦生产区应适当调整冬小麦播期,研究并推广保水节水技术措施,充分利用气候变化对冬小麦生产的有利因素,克服不利因素,确保冬小麦的可持续生产。

Simulation of the Response of Soil Water in Winter Wheat Field and Winter Wheat Yield to Rainfall and Temperature Change on the Loess Plateau

There is great meaning to research the impacts of rainfall and temperature changes on soil water and grain yield of winter wheat on the Loess Plateau of China, with the objective of ensuring the safety of grain production in China. EPIC model was used to simulate the response of soil water and winter wheat yield to rainfall and temperature changes in different regions on the Loess Plateau of China. The results are: 1) The EPIC model simulated soil water content well in the 0-2 m soil layer, the RRMSE value between the simulated values and measured values being 6.0%-14.0%; the mean value of R² was 0.824 which was close to the value of ME (0.815). 2) There was a descending trend of rainfall and an ascending trend of temperature from 1976 to 2010 on the Loess Plateau of China. Compared with those during 1961-2000, rainfall decreased 13.6%-24.9% in Luochuan, Changwu, Yuncheng and Yan’an during 2001-2010, the maximum temperature increased 0.30-0.84 ℃, while the minimum temperature increased 1.00-1.55 ℃ during 2001-2010. 3) Both the increasing of maximum temperature and the decreasing of rainfall were harmful to the production of winter wheat, while the increasing of minimum temperature was good to the production of winter wheat on the Loess Plateau. Due to the descending of rainfall, winter wheat yield in Luochuan, Changwu, Yuncheng and Yan’an decreased 8.5%, 7.6%, 11.7% and 12.3% respectively. The increasing of the highest temperature made winter wheat yield decrease 6.4%, 6.8%, 7.2% and -3.0% respectively in Luochuan, Changwu, Yuncheng and Yan’an; while the ascending minimum temperature increased the winter wheat yield by 8.8%, 10.2%, 1.5% and 12.0% respectively in Luochuan, Changwu, Yuncheng and Yan’an. In conclusion, considering sustainable use of soil water and sustainable production of winter wheat, adjusting planting time properly and developing water conserving and saving technologies are two of the best ways to adapt the climate change and to ensure the sustainable production of winter wheat on the Loess Plateau of China.