Soil water migration in the unsaturated zone of semiarid region in China from isotope evidence

CORC > 生态环境研究中心 > 中国科学院生态环境研究中心 > 城市与区域生态国家重点实验室

	Soil water migration in the unsaturated zone of semiarid region in China from isotope evidence
	Yang, Yonggang; Fu, Bojie
刊名	HYDROLOGY AND EARTH SYSTEM SCIENCES
	2017-03-24
卷号	21 期号:3 页码:1757-1767
关键词	Urban Green Space Spatial Configuration Urban Heat Island Solar Radiation High-rise Building Area Numerical Modeling
英文摘要	Soil water is an important driving force of the ecosystems, especially in the semiarid hill and gully region of the northwestern Loess Plateau in China. The mechanism of soil water migration in the reconstruction and restoration of Loess Plateau is a key scientific problem that must be solved. Isotopic tracers can provide valuable information associated with complex hydrological problems, difficult to obtain using other methods. In this study, the oxygen and hydrogen isotopes are used as tracers to investigate the migration processes of soil water in the unsaturated zone in an arid region of China's Loess Plateau. Samples of precipitation, soil water, plant xylems and plant roots are collected and analysed. The conservative elements deuterium (D) and oxygen (O-18) are used as tracers to identify variable source and mixing processes. The mixing model is used to quantify the contribution of each end member and calculate mixing amounts. The results show that the isotopic composition of precipitation in the Anjiagou River basin is affected by isotopic fractionation due to evaporation. The isotopic compositions of soil waters are plotted between or near the local meteoric water lines, indicating that soil waters are recharged by precipitation. The soil water migration is dominated by piston-type flow in the study area and rarely preferential flow. Water migration exhibited a transformation pathway from precipitation to soil water to plant water. delta O-18 and delta D are enriched in the shallow (< 20 cm depth) soil water in most soil profiles due to evaporation. The isotopic composition of xylem water is close to that of soil water at the depth of 40-60 cm. These values reflect soil water signatures associated with Caragana korshinskii Kom. uptake at the depth of 40-60 cm. Soil water from the surface soil layer (20-40 cm) comprised 6-12% of plant xylem water, while soil water at the depth of 40-60 cm is the largest component of plant xylem water (ranging from 60 to 66 %), soil water below 60 cm depth comprised 8-14% of plant xylem water and only 5-8% is derived directly from precipitation. This study investigates the migration process of soil water, identifies the source of plant water and finally provides a scientific basis for identification of model structures and parameters. It can provide a scientific basis for ecological water demand, ecological restoration, and management of water resources.
内容类型	期刊论文
源URL	[http://ir.rcees.ac.cn/handle/311016/39110]
专题	生态环境研究中心_城市与区域生态国家重点实验室
推荐引用方式 GB/T 7714	Yang, Yonggang,Fu, Bojie. Soil water migration in the unsaturated zone of semiarid region in China from isotope evidence[J]. HYDROLOGY AND EARTH SYSTEM SCIENCES,2017,21(3):1757-1767.
APA	Yang, Yonggang,&Fu, Bojie.(2017).Soil water migration in the unsaturated zone of semiarid region in China from isotope evidence.HYDROLOGY AND EARTH SYSTEM SCIENCES,21(3),1757-1767.
MLA	Yang, Yonggang,et al."Soil water migration in the unsaturated zone of semiarid region in China from isotope evidence".HYDROLOGY AND EARTH SYSTEM SCIENCES 21.3(2017):1757-1767.