极端干旱绿洲农田生态系统土壤-植被-大气连续体水分传输机制与模拟研究

By comprehensively applying the long-term in situ observations which include the eddy covariance system, sap flow technique, leaf-scale gas exchange method and isotope technique and laboratory experiments as well as model simulations, this project aimed to reveal the water movement and transport mechanisms over extreme arid crop ecosystems in northwest China. Here, we will systemically study: (1) the mechanism of soil water movement in arid crop ecosystems, to reveal the soil water movement satisfies the translatory flow hypothesis or the “two water world” theory; (2) the characteristics of crop root active layer to reveal the water usage sources and its influence on soil water distribution during its different growing stages; (3) the responses of stomatal conductance to the environmental factors at different soil water conditions, to develop the stomatal conductance models based on optimal stomatal behavior theory; (4) the dynamic characteristics of the total ET and its components as well as their relationship with environmental factors. Based on these researches, we will develop a water movement and transport model based on the SPAC theory, and simultaneously estimate the model parameters by assimilating multi-datasets using the Bayes’ theorem. It is excepted that this study will enrich and develop the contents of hydrology, crop physiology, soil science, agricultural microclimate and agronomy in theory; in practice, it will be important to to guarantee the food, water and ecosystem securities and the social and economic sustainable developments of our country.

针对干旱绿洲农田生态系统水分运移和传输过程的重要性和复杂性，以西北干旱区主要经济作物葡萄为研究对象，综合应用涡度相关、树干液流、叶片气体交换和稳定同位素技术，通过野外定位监测、室内试验和理论建模，系统研究：(1)极端干旱条件下土壤水分的运动运移机制，揭示土壤水分运移满足平移流假设还是“二水世界”理论；(2)作物根系活动层的分布及其对土壤水分分布的影响，揭示其水分利用策略；(3)气孔导度对环境影子的响应机制，构建气孔导度机理模型；(4)作物总蒸散发及其组分的动态特征及其与环境因子的关系。在此基础上，建立基于SPAC理论的干旱绿洲农田生态系统水分传输模型，并以贝叶斯定理为框架融合多源数据进行模型参数同步估计，提高模型模拟的精度和一致性。其预期成果将在理论上丰富和发展水文学、作物生理学、土壤学、农田气象学和农学等的理论；在实践上，对保障我国粮食安全、水安全和生态安全具有重要的战略意义。

针对干旱绿洲农田生态系统水分运移和传输过程的重要性和复杂性，以西北干旱区主要经济作物葡萄为研究对象，综合应用涡度相关、树干液流、叶片气体交换和稳定同位素技术，通过野外定位监测、室内试验和理论建模，系统研究：(1)极端干旱条件下土壤水分的运动运移机制，揭示土壤水分运移满足平移流假设还是“二水世界”理论；(2)作物根系活动层的分布及其对土壤水分分布的影响，揭示其水分利用策略；(3)气孔导度对环境影子的响应机制，构建气孔导度机理模型；(4)作物总蒸散发及其组分的动态特征及其与环境因子的关系。在此基础上，建立基于SPAC理论的干旱绿洲农田生态系统水分传输模型，并以贝叶斯定理为框架融合多源数据进行模型参数同步估计，提高模型模拟的精度和一致性。其预期成果将在理论上丰富和发展水文学、作物生理学、土壤学、农田气象学和农学等的理论；在实践上，对保障我国粮食安全、水安全和生态安全具有重要的战略意义.。