长江流域稻麦轮作农田水热传输机制与蒸散发模拟

Cropland is strongly affected by human activities. Deeply understanding water and heat transfer mechanism and evapotranspiration model are one of difficult and hot issues of the international research. In this study, water and heat fluxes over rice-wheat rotations field of Yangtze River basin will be observed at different time scales (from minutes to many years) and space scales (single leaf, individual plant and field). The physiological and environmental parameters will also be measured during the experimental period. Based on these, the regular mechanism of water and heat transfer at different spatial and temporal scales and their coupling mechanism with physiological and environmental parameters will be revealed. The main processes and driving factors for water and heat transfer at different spatial and temporal scales over rice and wheat field will be explicit. We will also discuss the differences and factors of water and heat transfer at different spatial and temporal scales between rice and wheat field. The rice is grown under submerged cultivated way at most of growth season. Considering the effect of evaporation from water surface and soil surface, the mechanism model will be established to estimate evapotranspiration over rice filed. The theory evapotranspiration model of wheat based on canopy development will also be established when considering canopy light distribution character and dynamic of physiological parameters to accurately simulate and predict evapotranspiration. The scientific basis will be provided for completing mater and heat cycle theory and improving efficiency of agricultural water use through this project.

农田受人类活动影响强烈，深入认识农田水热传输机制并建立蒸散发定量模型是国际研究的热点和难点问题。本研究选取长江流域轮作的单季稻和冬小麦农田为研究对象，在不同时间（分钟到多年）和空间（叶片、单株和农田）尺度的水热通量及其生理生态和环境因子综合观测的基础上，揭示不同时空尺度稻麦轮作农田水热通量传输规律及其与生理生态和环境因子的耦合机理，确定不同时空尺度水稻和小麦水热传输的主控过程和驱动因子，明晰单季稻田和冬小麦田不同时空尺度水热传输的差异及形成原因。根据水稻淹水栽培的特点，考虑水面蒸发和土壤蒸发对蒸散发估算模型结果的影响，构建水稻蒸散发估算机理模型；考虑冠层光能分布特征和生理指标变化，构建基于冠层发展的冬小麦蒸散发理论模型，以实现单季稻和冬小麦蒸散发的准确模拟和预测。通过本项目研究，为完善物质和能量理论和指导水资源高效利用提供科学依据和指导。

农田受人类活动影响强烈，深入认识农田水热传输机制并建立蒸散发估算模型是国际研究的热点和难点问题。本研究选取长江流域轮作稻麦农田为研究对象，利用多种仪器设备开展了水热通量及其生理生态和环境因子的综合观测，揭示了轮作稻麦田的水热传输规律，明晰了水稻和小麦田的水热传输差异，确定了轮作稻麦田潜热通量的主要气象控制因子，构建了适合于估算轮作稻麦蒸散发的实用模型，实现了农田蒸散发的模拟与预报。基于测定的水热通量数据，构建了水稻干物质动态模拟模型，并基于该模型对未来CO2浓度升高、气温升高等情景对干物质生产影响进行了预测。在试验研究与理论分析的基础上，受本项目资助，在《Scientific Reports》、《Journal of Arid Land》、《HortScience》、《农业工程学报》、《农业机械学报》等期刊共发表学术论文12篇（SCI、EI论文9篇），其中第一作者论文6篇，通讯作者论文1篇。项目负责人在“中国农业工程学会农业水土工程专业委员会学术研讨会”等国内外学术会议报告2次。依托本项目，项目负责人2018年晋升为副教授，并受项目部分资助赴杜克大学交流访问半年。研究结果对于准确了解轮作稻麦田水热通量、识别水热传输主要环境控制因子和定量模拟蒸散发有一定的借鉴意义，对于应用气象学和农业水利学科发展有一定的促进作用。建立的蒸散发和干物质估算模型可为水稻小麦的科学灌溉制度的制定，评估变化环境下的水分消耗和干物质生产提供一定的科学依据。