东祁连山区高寒灌丛土壤水文效应研究

Land surface hydrological processes not only has a very important role of regional and global climate change, but also closely associated with people's life and the development of the society. The alpine regions of Eastern Qilian Mountains is an important water source conservation areas of shiyang river. Alpine shrub is a typical vegetation community in Eastern Qilian Mountains, the soil hydrological effects of which play an important role in regional hydrological processes, hydrological cycle as well as the maintenance of the ecological environment in the Eastern Qilian Mountains. Therefore, further integrated experimental researches are crucial for improving our understanding of the hydrological effects of alpine shrub soil in the Eastern Qilian Mountains. However, till now, the responding mechanisms of soil hydrological effects to spatial distribution pattern and soil preferential flow are still uncertain. Therefore, four types of alpine shrub will be selected in the altitude 3200m-3800m on Eastern Qilian Mountains, by means of artificial rainfall experiments, runoff plot observations, and blue dye tracer technique, the hydrological characteristics and regularity of alpine shrubs will be observed in this project. The law of hydrological effects of alpine soil then will be revealed and the dominant factors of hydrological effects and response rule will be clarified. The aims of this project are to provide scientific basic data and information for the water resources evaluation and sustainable utilization to Eastern Qilian Mountains.

陆面水文过程不仅对区域乃至全球气候变化有重要作用，也与人们生活和社会发展密切相关。祁连山东段高寒山区是石羊河的重要水源涵养区，高寒灌丛作为区内的典型植被，其土壤水文效应对该区域的陆面水文过程、水文循环、石羊河水资源和生态环境维持等作用巨大。因此，深入开展祁连山东段高寒灌丛土壤水文效应研究有重要的科学意义。但高寒灌丛土壤水文效应对灌丛分布特征和土壤优先流的响应机制还不明确。为此，本研究拟在祁连山东段海拔3200m-3800m的区域选取4类高寒灌丛，借助室外人工降雨，径流小区，染色剂示踪等实验方法，阐明高寒灌丛景观分布特征对土壤水分空间分布格局的影响；揭示高寒灌丛土壤优先流过程；探讨优先流对土壤水文过程的影响；通过以上实验结果揭示东祁连山高寒灌丛的土壤水文效应机制，为东祁连山高寒生态区的水文循环和水资源评价及高寒灌丛可持续利用提供重要科学依据。

高寒灌丛是东祁连山的典型植被，其土壤水文效应对高寒生态区的陆面水文过程、动态平衡、水土保持及生态环境维持等具有重要作用。项目采用室内外观测和实验，研究了高寒灌丛植物群落特征、优先流、枯落物及土壤性状等特征，分析了高寒灌丛土壤水分空间分布规律与影响因素，探讨了祁连山东段高寒灌丛土壤水文效应规律，揭示了不同高寒灌丛土壤水文效应的异质性。结果表明：高寒灌丛斑块的灌木植物物种6种，隶属于3科4属；高寒草地斑块的草本植物物种86种，隶属于21科53属。不同高寒灌丛斑块植物群落的密度、盖度、物种数和地上、地下生物量等特征间有显著差异(P<0.05)；高寒灌丛的茎干流量、穿透雨量和截留量分别占降雨总量的3.7%-5.9%，70.2%-79.7%和16.4%-26.1%；高寒灌丛的茎干流量、穿透雨量和截留量均与降雨量呈显著线性正相关(P<0.01)。高寒灌丛在40~60cm土层达到土壤最大持水量的最大值，土壤初渗透率、平均渗透速率和稳渗透率数分别在0.58～2.81mm•min-1、0.05～1.26mm•min-1和0.04～1.31mm•min-1之间变化。高寒灌丛平均日蒸散量在年间无显著差异(P<0.05)；7月是高寒灌丛蒸散量最高，日蒸散量在白天14:00时最高。高寒灌丛的蒸散发主要受植物蒸腾的控制，降水是影响灌丛蒸散的主要因素。高寒灌丛和高寒草地在土层0-5cm是优先流的主要发生区域。通过上述研究明确了祁连山东段高寒灌丛和高寒草地群落生物学特征和土壤理化属性，明晰了高寒灌丛降雨再分配特征及其与降雨量之间的关系，探讨了不同高寒灌丛冠层水文效应的异质性，揭示了高寒灌丛土壤水文动态规律与影响机制，为改善祁连山东段植物和水资源利用与生态环境治理提供基础资料。项目完成论文8篇；国家新型实用专利5项，培养硕士研究生3人。