覆盖滴灌农田微气候特征与作物耗水机制

The efficient irrigation characterized by the combination of agronomy and engineering measures, will be the long-term research direction in the field of agricultural water saving in China. The project aiming at studying mutual feeding mechanism and response characteristics among field microclimate environment, crop water consumption mechanism and crop growth, for main food crops, such as Wheat and Corn in typical areas of northern China, under drip irrigation with different mulching modes. The main researching contents for this project will consist of three parts. Firstly, the process of energy redistribution and water and heat balance in field under mulching drip irrigation would be studied, in order to reveal the quantitative influence and characterization mechanism of different mulching drip irrigation models on the changes of key factors of farmland microclimate. Secondly, the evapotranspiration mechanism of main grain crops under different mulching drip irrigation modes would be systematically explained, and the water consumption process of main grain crops under drip irrigation would be quantitatively described, and the related crop water consumption models would be constructed at the same time. Finally, the relationship between crop growth and field microclimate response under different mulching drip irrigation patterns would be explored simultaneously. The expected research results will contribute to reveal the inherent mechanism of water saving and increasing efficiency of main grain crops under mulched drip irrigation, and it is of great scientific significance and practical value for the construction of high efficient and accurate water use management system in China.

以“农艺节水+工程节水”为典型特征的高效灌溉集成技术模式将是我国农业节水领域长时段内需重点跟踪和研究的方向。项目拟针对北方典型区主要粮食作物（小麦和玉米），基于不同覆盖类型（白膜、黑膜和秸秆覆盖）和滴灌制度条件下，以“田间微气候－作物耗水－作物生长”之间的互馈机制和响应特征为研究主线，研究覆盖滴灌下田间能量再分配与水热平衡过程，揭示不同覆盖滴灌模式对农田微气候关键因子变化的定量影响与表征机制；系统阐晰不同覆盖滴灌模式下主要粮食作物蒸散发机理，定量刻画覆盖滴灌下主要粮食作物耗水过程并构建相应作物耗水模型；同步探索不同覆盖滴灌模式下作物生长与田间微气候环境响应关系。预期研究成果对系统科学揭示覆盖滴灌下主要粮食作物节水增效的内在机理，对于我国区域高效精量用水管理技术体系构建具有重要的科学意义和实用价值。

推广以“农艺节水+工程节水”为特征的高效灌溉技术模式是破解我国农业水资源短缺和保障国家粮食安全的重要抓手。项目针对北方主要粮食作物（小麦和玉米），基于不同覆盖类型（白膜、黑膜和秸秆覆盖）和滴灌制度，研究覆盖滴灌下田间能量再分配与水热平衡过程，定量刻画覆盖滴灌下主要粮食作物耗水过程和光合生理响应机理。取得的主要结果有：.1）量化了覆盖滴灌下田间微气象因子的动态变化特征，黑膜和白膜相比秸秆覆盖可提高0~40 cm土壤的含水率5%~16%；白膜和黑膜处理0~30cm土层土壤积温比不覆盖处理提高5.2%-10%和2.0%-6.2%；阐明了覆盖滴灌下田间能量分配的变化特征，白膜和黑膜覆盖增加玉米田冠层净辐射累积值，而秸秆覆盖降低了该值; 2）阐明了覆盖滴灌农田作物生长调控机理，厘清了不同覆盖滴灌处理光合参数的变化规律并确定了其变异来源，玉米季，覆盖处理比不覆盖处理提高平均光合能力8.3%~17.3%，小麦季，白膜处理下的最大羧化速率显著增加22.0%~39.4%；揭示了不同覆盖滴灌模式对产量和水分利用效率的影响，玉米季，白膜和黑膜处理的产量较不覆盖处理分别提高4.9%~13.4%和4.8%~12.5%，覆膜处理的WUE较不覆盖处理提高11.7~17.0%；3）确定了玉米和小麦田全生育期的蒸散量及覆盖处理对其分量的影响，全生育期春玉米、夏玉米和冬小麦各处理的耗水量分别在425.3-444.6 mm、373.0-398.3 mm和277.5-385.6 mm之间；构建了基于作物生长天数和LAI的基础作物系数Kcb估算模型，确定了覆盖滴灌下作物节水增产的蒸发蒸腾量阈值，其中玉米为400 mm左右，冬小麦为280 mm-300 mm之间。.项目研究成果对系统科学揭示覆盖滴灌下主要粮食作物节水增效的内在机理，对于我国区域高效精量用水管理技术体系构建具有重要的科学意义和实用价值。