中国北方气候暖干化对粮食作物的影响及应对措施

Impact of climate warming and drying on food crops in northern China and the countermeasures

东北、华北和西北50a来的平均气温增幅高于全国平均水平,气候变暖明显,尤其冬季增温最显著。区域增暖的极端最低气温远比极端最高气温的贡献大。东北、华北大部、西北东部降水量明显减少,平均每10a减少20—40mm,尤其春夏季减少最明显。这种趋势一直延续到20世纪90年代以后,干旱化趋势非常突出。在综述我国北方现代气候变化基本特征是暖干化的基础上,重点阐述了喜凉作物冬小麦、春小麦、马铃薯和喜温作物水稻、玉米、谷子、糜子等7种主要粮食作物的生长发育、品种熟性、种植区域与面积、产量与品质等对气候暖干化的响应特征。揭示了气候暖干化使春播作物播期提早,苗期生长发育速度加快,营养生长期提前,生殖生长期和全生育期延长;秋作物发育期推迟,生殖生长期和全生长期延长;越冬作物播期推迟,越冬死亡率降低,种植风险减少,春初提前返青,生殖生长期提早,全生育期缩短。使作物适宜种植区域向高纬度高海拔扩展;品种熟性向偏中晚熟高产品种发展;喜温作物和越冬作物以及冷凉气候区的作物种植面积迅速扩大;在旱作区种植不较耐旱的玉米、春小麦等作物种植面积受到制约。对雨养农业区的作物气候产量影响严重,尤其对不够耐旱的小麦和玉米的气候产量受影响最大;对较耐旱的谷子、糜子、马铃薯等影响较轻。从作物属性而言,对喜温作物水稻、玉米和越冬作物冬小麦有利于气候产量提高;对喜凉作物春小麦和马铃薯的气候产量将产生不利影响。同时,提出了从5个方面应对气候暖干化的技术措施,调整作物种植结构,确保粮食生产安全;根据不同气候年型调整各种作物种植比例;针对不同气候区域发展优势作物和配置作物种植格局;采取不同栽培技术和管理模式应对气候变化;采取综合配套技术提髙抵御灾害能力。为粮食作物安全生产和种植结构调整与布局提供科学依据。

Global warming and drying are the most prominent changes among all climate changes. It is reported that the range of rising temperature in northern China is above the average in the whole country and the climate warming in these areas are dramatic. The contribution of minimum temperature to region warming is greater than that of maximum temperature. The precipitation in the northeast, north and east part of northwest of China decreased significantly at a rate of 20 to 40 mm per ten years, especially in spring and summer. The drying and warming are prominent trends that lasted to the later 1990s. Global climate warming puts a constant pressure on crop growth and production. In northern China, climate warming is compounded with climate drying, resulting in a condition that dramatically affects crop growth. To delineate the impact and the response of crops to such changes, we analyzed the growth/development, planting region and area, cereal production and quality of seven major cereal crops that include both thermo-philic （rice, maize, millet and prosomillet） and cool-philic （winter wheat, spring wheat and potato） crops. The results showed that climate warming and drying caused early sowing of spring crops, accelerated seedling growth and development, early arrival of the vegetative growth phase, extended reproductive growth phase, and hence extended whole growth periods. To fall crops, climate warming and drying caused delayed growth and development, extended reproductive growth phase, and extended whole growth periods. To winter crops, it caused delayed sowing, reduced winter mortality, early greening, and shortened entire growth periods. As a consequence, this change led to an expansion of crop suitable growth regions towards north and high altitude, a gradual adaptation of high yield crops with midto late maturation, a quick increase in planting areas for thermo-philic crops and winter crops in low temperature areas, a restrained planting areas for drought sensitive crops such as maize and spring wheat in dry areas. It also indicated that climatic yields of crops were seriously affected by warming and drying in rain-dependent areas. The climatic yields of drought sensitive crops such as wheat and maize were influenced seriously by warming and drying, but the climatic yields of drought-tolerant crops such as millet, prosomilet and potato were influenced slightly. The trend of warming and drying appeared to be advantageous to climatic yield of rice, maize and winter and disadvantageous to spring wheat and potato. We provided the technical measures in dealing with the climate drying and warming in adjusting structure of planting to ensure grain production safety, adjusting the percentage of different type of annual climate accordingly, breeding for more suitable crop varieties and measuring optimum crop planting pattern, adopting different planting techniques and management model and different climatic condition, s and taking integrated technology to improve the ability to fend off disasters. Countermeasures in dealing with climate warming and drying were also provided and discussed in this context.