华北平原双季玉米弹性种植系统水热资源高效利用及关键生育期高温避害协同机制

Traditional winter wheat – summer maize cropping system is challenged by water resource crisis and climate risk in the North China Plain. Since the consumption structure of food in China is changing, the demand for maize as feed grain is increasing. Therefore, the flexible spring maize (silage) – summer maize (grain) cropping system is more suitable in the North China Plain. However, there is a lack of in-depth study on synergetic mechanism of efficient water-heat resources use and high-temperature risk avoidance in the key growth period of this new cropping system. Aiming at this challenge regarding the new cropping system, this project will carry out field experiments of gradient seeding-dates and high-temperature stress during the period from tasseling to blooming of summer maize at the Yucheng Comprehensive Experimental Station of the Chinese Academy of Sciences. Then the synergetic mechanism of yearly efficient water-heat resources use and high-temperature risk avoidance regarding the new cropping system will be further investigated. Finally, a mechanism crop model will be improved to enhance the response capacity of the model to high temperature stress and the ability of digitally designing and optimizing the new cropping system. The expected study results will enrich the food production theory system based on the multi-objective optimization and provide scientific supports for rearranging the traditional farming layout in the North China Plain in the new period under the background of urgent water shortage and new change in food demand structure.

作为我国粮食主产区，华北平原受水资源危机和气候风险的双重制约。我国新时期食物消费结构发生改变，玉米作为饲料粮的需求日益增长。相比冬小麦-夏玉米传统种植系统，春玉米（青贮）-夏玉米（籽粒）弹性种植系统更适于华北地区水资源短缺和消费结构改变的现状和未来发展趋势，但是该新型种植系统水热资源高效利用及其关键生育期高温避害的协同机理缺少深入研究。因此，本项目拟在中科院禹城综合试验站，针对春玉米-夏玉米弹性种植系统，开展夏玉米多播期和抽雄至开花期高温胁迫交互试验，揭示水热资源年内高效利用及关键生育期高温避害的协同机制；同时改进机理模型，提高模型对高温胁迫的响应能力和弹性种植系统数字化设计与优化能力。研究结果有望发展多目标优化的粮食生产理论体系，也为水资源短缺和新时期粮食需求背景下华北平原区域农业生产的重新布局提供重要的科学依据。

依据项目计划书，首先系统分析了玉米高温胁迫的研究进展，完善优化了试验设计与观测方案，研制了田间被动增温装置；连续开展了4年（2019-2022）的双季玉米多播期与花期高温胁迫试验，获取连续、完整的试验数据，为后续科学问题研究提供了必要的数据支撑。利用中科院禹城综合试验站长期气象观测数据与本项目试验数据，比较分析了春玉米-夏玉米弹性种植系统与传统冬小麦-夏玉米种植模式的水热资源利用效率，为双季玉米弹性种植系统设计提供理论依据。利用高温胁迫试验，定量刻画了夏玉米花期高温胁迫的主要生理生态响应过程，并对目前典型作物模型中常见的4类高温响应模块进行了定量评估，为提升夏玉米花期高温胁迫响应模拟精度提供方法支撑。基于以上研究进展，采用水热资源高效利用和玉米花期高温避害的协同策略，提出了双季玉米弹性种植系统数字设计框架，并开展初步的试验验证与应用分析，初步证明了本项目提出的“气候智慧型”的弹性种植模式在黄河下游灌区种植兼具理论可行性与实践可操作性，具有较好应用推广价值。基于以上工作，截止到项目结题时限，培养人才4人，授权发明专利1个，正式发表文章2篇。