img

Wechat

Adv search

Journal of Desert Research ›› 2022, Vol. 42 ›› Issue (4): 151-162.DOI: 10.7522/j.issn.1000-694X.2021.00157

Previous Articles    

Water sources and strategies of plant water use in desert oasis wetland of China

Ying Zhao1,2(), Bing Liu1(), Wenzhi Zhao1, Zijuan Wen3, Xiao Wang1,2   

  1. 1.Linze Inland River Basin Research Station / Key Laboratory of Ecohydrology of Inland River Basin,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
    2.University of Chinese Academy of Sciences,Beijing 100049,China
    3.Lanzhou University,Lanzhou 730000,China
  • Received:2021-09-04 Revised:2021-12-20 Online:2022-07-20 Published:2022-08-29
  • Contact: Bing Liu

Abstract:

Water is the backbone of hydraulic connection and water cycle process between different landscape in arid area, which further maintains the structure and function of wetland ecosystem in arid area. In order to quantify water source and its contribution to plant water, this paper takes riparian shrub wetland and salt-marsh grassland wetland as research objects, by measuring the δD and δ18O composition of precipitation, runoff, groundwater, soil water and plant water, to analyze the contribution rate of water sources to water use of desert plants with the linear mixed model. The results showed that: (1) annual rainfall average 104.6 mm, accounting for about 17.03% of the evapotranspiration (604.47 mm) in desert oasis wetlands in which has obvious seasonal distribution characteristics. The fluctuation of groundwater and soil water content depends on the distance from the river. The depth of groundwater and soil water content of riparian shrub wetlands near the river vary little with the seasons, while vary greatly in salt marsh grass wetlands far away from the river channel. (2) The precipitation line of local atmospheric is δD=6.33δ18O+4.04 (R2=0.931), and the slope and intercept are slightly smaller than the precipitation line of global atmospheric, which is consistent with the characteristics of less precipitation and large evapotranspiration in the wetlands of the Heihe River Basin. The mean values of δD and δ18O of Heihe River groundwater, runoff, soil waterand and plant water were -50.98‰±13.18‰ and -9.74‰±25.49‰, -43.80‰±12.09‰ and -8.65‰±23.33‰, -42.07‰±6.89‰ and -7.22‰±2.49‰, -51.84‰±14.46‰ and -8.50‰±24.13‰, respectively. (3) Surface evaporation is the main cause of soil hydrogen and oxygen isotope enrichment in desert oasis wetland. Runoff and groundwater were the main water sources of desert oasis wetlands,and the contribution rate of runoff to plant water use was about 50% in riparian shrub wetland, while the contribution rate of groundwater was about 61% in salt marsh grass wetland. However, precipitation infiltration contributed little to the water use of riparian shrub wetlands and salt marsh grass wetlands, with values of 4% and 13%, respectively. (4) Depth of root and distribution of capillary root were important determinants of plant water use strategy in desert oasis wetland.

Key words: desert oasis wetland, water sources, hydrogen and oxygen isotopes, contribution rate, water use strategy

CLC Number: