Chin J Plan Ecolo ›› 2017, Vol. 41 ›› Issue (12): 1262-1272.DOI: 10.17521/cjpe.2017.0219

Special Issue: 稳定同位素生态学

• Research Articles • Previous Articles     Next Articles

Water-use process of two desert shrubs along a precipitation gradient in Horqin Sandy Land

CHEN Ding-Shuai2,3,*, DONG Zheng-Wu1,*, GAO Lei2, CHEN Xiao-Min3, PENG Xin-Hua2, SI Bing-Cheng4, ZHAO Ying1,4,**()   

  1. 1Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, ürümqi 830011, China;

    2State Key Laboratory of Soil and Sustainable Agriculture, Nanjing Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China

    3College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
    and
    4Institute of Water Saving Agriculture in Arid Areas of China, Northwest A & F University, Yangling, Shaanxi 712100, China;
  • Online:2017-12-10 Published:2018-02-23
  • Contact: CHEN Ding-Shuai,DONG Zheng-Wu,ZHAO Ying

Abstract: Aims The determination of the source of plant water is an important research on the plant-water relationship in arid and semiarid regions and helps to understand the adaptation strategy of desert species to the dry environment. Plant water use pattern affects plant community composition and ecosystem water budget. This study aims to investigate the water use patterns of Caragana microphylla and Artemisia halodendron, two typical shrub species, under altered rainfall conditions in Horqin Sandy Land. Methods Water treatments include ambient rainfall (natural rainfall), 50% increase in rainfall (enhanced rainfall) and 50% decrease in rainfall (reduced rainfall) by artificially intercepting and redistributing natural rainfall. Stable hydrogen and oxygen isotope ratios (δD and δ18O) were measured for xylem water, rainfall, and soil water in different soil layers (0-120 cm depth). The possible ranges of potential water sources used by C. microphylla and A. halodendron were calculated using the IsoSource model. Important findings 1) Alteration of ambient rainfall mainly affected the soil water condition in the shallow soil (0-30 cm). Increase in rainfall significantly increased the above- and below-ground biomass, and δ18O values of soil water declined with soil depth. 2) Under the enhanced rainfall treatment, A. halodendron mainly used the soil water in the shallow soil (0-40 cm) and C. microphylla was able to extract water from multiple soil layers. Under the reduced rainfall treatment, both species increasingly relied on extracting water from deeper soil layers, 60-80 cm for A. halodendron and 60-120 cm for C. microphylla. 3) For the natural rainfall treatment, in the wet season, the upper soil water was recharged by rainfall, C. microphylla and A. halodendron extract the shallow soil water (0-60 cm). However, in the dry season, soil water content was dramatically reduced, and main water sources for C. microphylla shifted from topsoil to deeper soil, and A. halodendron can use multiple layers of soil water. In summary, A. halodendron is more capable of exploring deeper soil moisture under reduced rainfall in comparison with C. microphylla, and is likely to be more adaptive to this water-limiting desert environment.

Key words: Caragana microphylla, Artemisia halodendron, water sources, simulated rainfall