固沙植被吸水源解析及其对干旱胁迫和地下水波动响应研究

金山银山不如绿水青山，内蒙古位于我国正北方，为建设亮丽北方风景线，沙地生态系统植被建设尤为重要，本项目以浑善达克沙地为研究区，通过对不同自然地理条件生态系统下的气象、水文、植被生理生态等要素和大气、植物、土壤环境同位素的测定，利用环境同位素示踪技术，分析大气—植物—土壤界面水分及物质传输规律；利用能量平衡原理建立多涌源模型研究植被蒸腾机理，用植被蒸散发模型和土壤水热均衡模型的耦合模型研究浑善达克沙地生态系统耗水机理，将干旱区沙地生态系统固沙植被耗水量计算模型与基于环境同位素的大气—植物—土壤—地表水—地下水水循环模型、多源线性混合模型、贝叶斯模型、深度吸水模型、地下水模拟模型相互耦合，计算沙地生态系统固沙植被耗水量，揭示沙地生态系统植被根系吸水水分来源分布规律及水分利用效率，研究固沙植被根系吸水潜在水源对干旱胁迫和地下水水位波动的响应规律，确定满足固沙植被生长的地下水位的生态阈值。

Lucid waters and lush mountains are invaluable assets. Inner Mongolia is located in the north of China. In order to build a beautiful northern landscape, the construction of vegetation in sandy land ecosystem is particularly important. In this project observation of meteorology, hydrology, vegetation physiology and ecology under different natural and geographical conditions and the environmental isotopes of atmosphere, plant and soil in Hunshandake sandy land will be performed. Environmental isotope tracing techniques are used to analysis the regular pattern of the atmosphere-plant-soil interface moisture and material. Multi-source model based on energy balance principle is going to be established to study vegetation transpiration mechanism. Coupling model of vegetation evapotranspiration and soil hydrothermal equilibrium model will be used to study the water consumption mechanism. This project will couple the water consumption calculation model of sand-fixing vegetation, environmental isotope based atmosphere-plant-soil-surface water-groundwater circulation model, multi-source linear mixed model, Bayesian model, deep water absorption model and groundwater simulation model to calculate the water consumption of sand-fixing vegetation in sandy land ecosystem. The water source distribution patterns and water use efficiency in the root system of sandy ecosystem supposed to be reveal. The response rules of potential water source of sand-fixing vegetation to drought stress and fluctuation of groundwater level is going to be study as well. Ultimately, the ecological threshold of groundwater level to meet the growth of sand-fixing vegetation will be determined.