季节性冻土区农田全年水热传输规律及水分高效调控

For cropland in seasonal frost region, the processes of water and heat transfer in frost period and crop growing period are closely related. The annual pattern of water and heat transfer in cropland and its impact on crop yield are the base for high-efficient use of water resources. Taking the North China Plain that suffers from serious water shortage as the representative region, experiment on soil, crop and meteorology factors will be carried out in winter wheat - summer maize field on annual basis. Based on experiment results, mechanism of water and heat transfer in both frost period and crop growing period will be analyzed, and models for simultaneous water and heat transfer in frozen soil-atmosphere system (FSAS) and soil-plant-atmosphere continuum (SPAC) will be developed. In the SPAC model, the hybrid dual source model will be used to describe water and heat exchange among soil, plant canopy and atmosphere so as to reflect the significant differences of plant coverage and its uniformity in crop growing period. Models for water and heat transfer in FSAS and SPAC will be integrated to a coupled water and heat transfer model in a whole year for cropland in seasonal frost region. Then the model will be used to simulate processes of water transform and consumption in cropland for a whole year at different conditions, so as to reveal the pattern of water transform and consumption in cropland and its response to irrigation. A simulation based multi-objective optimization model will be proposed for optimal irrigation scheduling of winter wheat - summer maize field, and high-efficient regulation mode of water resources in a whole year will be proposed. The results will provide support for high-efficient use of agricultural water resources in the study region.

在季节性冻土区，冻融期与作物生长期的农田水热传输过程密切相关，以年为周期的农田水热传输及其对作物产量的影响是水分高效利用的基础。以水资源严重短缺的华北平原为典型区，在冬小麦-夏玉米农田进行全年土壤、作物、气象等要素动态观测。根据试验结果分析冻融期、作物生长期农田水热传输机理，分别建立冻土-大气系统（FSAS）、土壤-植物-大气连续体（SPAC）水热传输模型。SPAC水热传输模型采用混合双源模型描述土壤、冠层与大气间的水热交换过程，能适应一年内作物覆盖度及其均匀性的巨大变化。综合SPAC、FSAS水热传输机理与模型，建立季节性冻土区农田全年水热耦合传输模型。利用模型模拟不同条件下农田全年水分转化与消耗过程，揭示以年为周期的农田水分转化与消耗规律及其对灌溉的响应特性。建立冬小麦-夏玉米农田灌溉制度的多目标模拟-优化模型，提出以年为周期的研究区农田水分高效调控模式，为农田水分高效利用提供依据。

由于水文、气象、农业生产等的年周期特性，以年为周期的农田水热动态变化及其对作物生长和产量的影响是农田水分高效利用的基础。以水资源严重短缺的华北（以北京永乐店试验站为代表）、西北（以甘肃石羊河试验站为代表）季节性冻土区为研究区，进行了农田全年土壤水热、作物生长及产量、气象等要素动态观测。根据试验结果，建立了农田土壤水分的2参数指数消退模型，结果表明该模型可以较好地描述农田水分动态变化过程。建立了基于双作物系数的覆膜农田水量平衡模型及日尺度非充分灌溉制度模拟-优化模型，模拟分析了石羊河流域春小麦农田覆膜对蒸发、蒸腾及蒸散发的影响和不同灌溉定额下的优化灌溉制度。对比分析了计算潜在蒸发、潜在蒸腾的3个双源模型，结果表明混合双源模型较层状模型和块状模型具有更好的模拟效果，能够适用于更广的下垫面植被覆盖状况。将陆面水热传输的混合双源模式与土壤水热动态模拟模型相结合，建立了基于混合双源模式的土壤—植被—大气连续体水热传输模型（HDS-SPAC），结果表明该模型可以很好地适用于不同水分条件下的冬小麦农田生态系统的水热通量模拟，同时能更好地区分土壤蒸发与植被蒸腾过程。利用AquaCrop模型对华北季节性冻土区冬小麦—夏玉米轮作农田全年的水分动态及作物生长过程进行了模拟分析；建立了轮作农田灌溉制度的多目标模拟—优化模型，分析了以年为周期的轮作农田优化灌溉制度。.本项研究建立了农田水分动态变化的系列模型，揭示了季节性冻土区农田全年水、热动态变化规律，发展了季节性冻土区农田水文学理论；建立了以年为周期的华北冬小麦—夏玉米轮作农田灌溉制度多目标模拟—优化模型和覆膜农田灌溉制度模拟—优化模型，提出研究区农田水分高效调控模式，为农田水分高效利用提供依据。结合本项目研究，发表论文14篇（其中SCI收录8篇、EI 收录5篇），出版英文专著1本（Springer）；培养培养博士后1人（已出站），博士生4人（毕业2人），硕士生1人（已毕业）。