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Chinese Journal of Applied Ecology ›› 2021, Vol. 32 ›› Issue (6): 1943-1950.doi: 10.13287/j.1001-9332.202106.022

• Special Features of Stable Isotope Ecology • Previous Articles     Next Articles

Long-term water use characteristics and patterns of typical tree species in seasonal drought regions

WANG Xin1, JIA Guo-dong1,2*, DENG Wen-ping3, LIU Zi-qiang4, LIU Zi-he1, QIU Gui-fu5, LI Wen-li5   

  1. 1College of Water and Soil Conservation, Beijing Forestry University, Beijing 100083, China;
    2Key Laboratory of Soil and Water Conservation and Desertification Combating, Ministry of Education, Beijing 100083, China;
    3College of Forestry, Jiangxi Agricultural University, Nanchang 330045, China;
    4Nanjing Forestry University, Nanjing 210037, China;
    5Zhangjia-kou Saibei Forestry Centre (National Forestry Management Office), Zhangjiakou 075000, Hebei, China
  • Received:2020-12-21 Accepted:2021-03-31 Published:2021-12-15
  • Contact: * E-mail: jiaguodong@ bjfu.edu.cn
  • Supported by:
    National Natural Science Foundation of China (41877152, 41977149).

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Abstract: In the areas with seasonal drought, water is the key factor affecting plant growth and development. Based on long-term continuous observation data, it is of great significance to explore plant water use patterns for vegetation construction in areas with seasonal drought. Taking Platycladus orientalis in Beijing mountainous area as the research object, stable hydrogen and oxygen isotope technique was applied to measure the isotopic composition of water from the soil, plant branches, and precipitation from 2012 to 2017. The relative contribution of soil water from different soil layers to P. orientalis was quantified by the MixSIAR model. The results showed that soil water in the deep layer (40-100 cm) was more stable than that in the shallow layer (0-40 cm). The variation of soil water content and water isotope values in the shallow layer were more obvious due to the effects of evaporation and precipitation. P. orientalis mainly absorbed stable deep soil water, with a relative contribution rate of 55.7%. In the dry season, with the decreases of soil water content, the absorption depth of plants to soil water gradually shifted to the shallow layer. Under conditions of moist, natural condition, mild drought and moderate drought, the relative contribution rates of deep soil water were 59.8%, 57.9%, 54.6%, 52.7%, respectively. To maintain higher transpiration in the wet season, P. orientalis relied more on deep soil water under mild and moderate drought conditions than in the dry season. Under the conditions of moist, natural condition, mild drought and moderate drought, the relative contribution rates of deep soil water were 58.9%, 57.6%, 56.4%, and 57.1%, respectively. The adaptive characteristic of P. orientalis, which adjusts the depth of root water absorption according to soil moisture condition, is of great significance for tree species selection in ecological afforestation and long-term management planning in areas with seasonal drought.

Key words: Platycladus orientalis, water use pattern, dry season, wet season, soil moisture condition, stable hydrogen and oxygen isotopes