毛乌素沙地长柄扁桃土壤水分植被承载力的试验研究

Artificial forest is one of the important ways of sand control and ecological restoration. The rational use of limited soil water resources are important scientific and practical issues for the sustainable construction of artificial forests. Due to the insufficient understanding of the relationship between vegetation water consumption and soil water supply capacity, some of artificial forests for sand control continue to degrade. Selecting reasonable tree species with strong water stress resistance and economic benefits for artificial forest and meanwhile, clarifying the soil water vegetation carrying capacity for the selected forest is an important guarantee for the sustainable performance of ecological and economic benefits. This project aims to study the soil eco-hydrological processes in the Amygdalus pedunculata Pall. forest land by combining of the plot experiment, field observation and model simulation as the research method. The objectives are (i) to determine the water stress threshold of the Amygdalus pedunculata Pall. and the soil water use characteristics in the soil profile; (ii) to understand the soil water replenishment-consumption process of the studied forest land; and (iii) to obtain the relationship between soil moisture and vegetation density and the soil water carrying capacity for Amygdalus pedunculata Pall. under field condition in the Mu Us Sand Land. The results of this project will be conductive to understand the ecological and hydrological processes of artificial forests lands in sandy area. Meanwhile, this research will also provide important practical significances for the promotion and cultivation of Amygdalus pedunculata Pall. in the sandy area, which in turn will benefit the regional social and economic development.

人工林是沙地治理和生态修复的重要途径之一，有限土壤水资源的合理利用是治沙人工林可持续建设所面临的重要科学与实践问题。由于缺乏对植被耗水特征与土壤供水能力间关系的深入认识，部分地区人工林持续退化。选择抗逆性强且兼具经济效益的树种，确定治沙人工林地土壤水分植被承载能力，是人工林地生态和经济效益持续稳定发挥的重要保障。基于此，项目选取长柄扁桃林地土壤水文过程为研究对象，通过小区控制试验、田间定位观测和模型模拟相结合的方法，在科学确定长柄扁桃水分胁迫阈值及剖面土壤水分利用特征的基础上，分析林地土壤水分的补给-消耗过程，对林地土壤水分与植被密度的关系进行模拟，获得自然条件下毛乌素沙地土壤水分对长柄扁桃的承载能力。研究结果一方面有助于深化认识沙区人工林地生态水文过程；另一方面对于长柄扁桃在沙化地区的推广种植以及该区社会经济发展具有重要的实践意义。

本项目按照计划任务书开展相关研究工作，以陕西省神木市毛乌素治沙造林基地的长柄扁桃林地为研究对象，通过野外原位监测、小区控制实验和模型模拟等方法，获取了长柄扁桃林地土壤基本理化性质的剖面分布特征，定量解析了长柄扁桃对降水的再分配过程及其与降雨特征的关系，阐明了林地土壤水分时空变异特征，明确了长柄扁桃对水分胁迫的响应特征及其水分胁迫阈值，在此基础上，利用Biome-BGC模型确定了不同气候情景下，毛乌素沙地长柄扁桃土壤水分植被承载力的阈值。研究结果对于长柄扁桃在沙化地区的推广种植以及该区社会经济发展具有重要的实践意义，为荒漠化防治工作的可持续推进提供科学依据。在该项目的支持下，发表论文5篇SCI论文，在项目的资助下，有2名研究生开展了相关的研究工作。