长柄扁桃根系吸水与耗水的试验研究

The sustainable construction of desert vegetation with limited water resources is critical for the desertification control in the arid region of Northwest China. Increasing water-use efficiency based on the improved understanding of root water uptake and depletion by the desert vegetation is crucially important for solving this problem. This project aims to study the root water uptake and depletion by the endangered desert plant—Amygdalus pedunculata Pall., through a combination of plot experiments, field observations, laboratory analysis and isotope techniques. The objectives are (i) to investigate the growth and distribution of roots in soils with different textures and water stresses; (ii) to analyze the temporal variations and vertical changes in the rates of water uptake and depletion; and (iii) to quantify the relative contribution of different water sources to the root water uptake. This research will be conducive to understand the mechanism of root water uptake and depletion by Amygdalus pedunculata Pall., and would provide a scientific basis for enhancing water-use efficiency in the arid region that experiences severe water scarcity. The research results will also contribute to the development of strategies for optimizing water management, promote the extensive construction of Amygdalus pedunculata Pall., and explore the new way of sustainable control of desertification in the arid region of Northwest China.

如何利用有限的水资源建立具有一定盖度又可持续生长的治沙植被是当前西北旱区沙漠化防治面临的重要科学与实践问题。而解决这一问题的关键在于深入理解治沙植被根系吸水过程与耗水规律，并在此基础上提高西北旱区水分利用效率。基于此，本项目选取沙地濒危植物长柄扁桃为研究对象，通过小区控制试验、田间定位观测、室内理化分析和同位素技术手段相结合的方法，研究长柄扁桃在不同质地土壤和水分胁迫下根系生长状况与剖面分布特征，分析根系吸水速率与耗水量随不同生育期和土壤深度的变化规律及其影响因素，明确田间自然状况下根系对不同水源吸收利用的比例和效率。研究结果一方面对深入认识长柄扁桃根系吸水机制与耗水规律，提高旱区严重缺水情况下水分利用效率具有重要的科学意义；另一方面可为优化西北旱区水分管理，推进长柄扁桃大面积种植和探索可持续治沙新途径提供理论依据。

本项目按照计划任务书开展相关研究工作，以陕北六道沟流域和圪丑沟流域不同质地土壤（壤土和砂土）和典型植被（樟子松、长柄扁桃和沙柳）为研究对象，通过盆栽实验、土柱控水试验、田间小区试验和室内理化分析，揭示了坡面尺度不同植被类型下土壤碳、水分布特征及其影响因素，阐明了不同土质条件下土壤水分对长柄扁桃和沙柳幼苗生理特征与土壤水分有效性的影响，定量解析了不同类型植物（樟子松、长柄扁桃和沙柳）对降水、土壤水和地下水吸收利用比例及其季节变化特征，探讨了不同土质和植被类型下溶质运移过程及其影响因素。研究结果一方面对深入认识典型植物对水分胁迫的响应特征与耗水规律，提高旱区严重缺水情况下植物水分利用效率具有重要意义；另一方面可为优化西北旱区水分管理，推进不同类型治沙植物可持续建设提供理论依据。在该项目的支持下，发表论文12篇（含SCI论文7篇和CSCD论文5篇）。项目执行期间，协助培养硕士研究生1名。