Integrative Biology Journals

Plant Diversity ›› 2025, Vol. 47 ›› Issue (03): 479-488.DOI: 10.1016/j.pld.2025.02.006

• Articles • Previous Articles     Next Articles

Plant use of water across soil depths regulates species dominance under nitrogen addition

Fu-Qiang Huanga, Josep Peñuelasb,c, Jordi Sardansb,c, Scott L. Collinsd, Kai-Liang Yue, Man-Qiong Liua, Jiu-Ying Peia, Wen-Bin Kea, Jian-Sheng Yea   

  1. a. State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China;
    b. CSIC, Global Ecology Unit CREAF-CSIC-UAB, Barcelona 08193, Spain;
    c. CREAF, Cerdanyola del Vallès, Barcelona 08193, Spain;
    d. Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA;
    e. Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
  • Received:2024-11-08 Revised:2025-02-23 Online:2025-05-21 Published:2025-05-25
  • Contact: Jian-Sheng Ye,E-mail:yejsh@lzu.edu.cn
  • Supported by:
    This research was supported by the Natural Science Foundation of Gansu Province (Grant Number: 25JRRA749, 24JRRA515, 24JRRA527) and the Fundamental Research Funds for the Central Universities (Grant Number: lzujbky-2022-ct01). JP and JS were supported by Spanish Government grants PID2020115770RB-I, PID2022-140808NB-I00, and TED2021-132627 B-I00 funded by MCIN. SLC was supported by NSF award DEB-2423861.

Plant use of water across soil depths regulates species dominance under nitrogen addition

Fu-Qiang Huanga, Josep Peñuelasb,c, Jordi Sardansb,c, Scott L. Collinsd, Kai-Liang Yue, Man-Qiong Liua, Jiu-Ying Peia, Wen-Bin Kea, Jian-Sheng Yea   

  1. a. State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China;
    b. CSIC, Global Ecology Unit CREAF-CSIC-UAB, Barcelona 08193, Spain;
    c. CREAF, Cerdanyola del Vallès, Barcelona 08193, Spain;
    d. Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA;
    e. Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
  • 通讯作者: Jian-Sheng Ye,E-mail:yejsh@lzu.edu.cn
  • 基金资助:
    This research was supported by the Natural Science Foundation of Gansu Province (Grant Number: 25JRRA749, 24JRRA515, 24JRRA527) and the Fundamental Research Funds for the Central Universities (Grant Number: lzujbky-2022-ct01). JP and JS were supported by Spanish Government grants PID2020115770RB-I, PID2022-140808NB-I00, and TED2021-132627 B-I00 funded by MCIN. SLC was supported by NSF award DEB-2423861.

Abstract: The primary mechanism driving plant species loss after nitrogen (N) addition has been often hypothesized to be asymmetric competition for light, resulting from increased aboveground biomass. However, it is largely unknown whether plants’ access to soil water at different depths would affect their responses, fate, and community composition under nitrogen addition. In a semiarid grassland exposed to 8-years of N addition, we measured plant aboveground biomass and diversity under four nitrogen addition rates (0, 4, 10, and 16 g m-2 year-1), and evaluated plant use of water across the soil profile using oxygen isotope. Aboveground biomass increased significantly, but diversity and shallow soil-water content decreased, with increasing rate of nitrogen addition. The water isotopic signature for both plant and soil water at the high N rate indicated that Leymus secalinus (a perennial grass) absorbed 7% more water from the subsurface soil layer (20-100 cm) compared to Elymus dahuricus (a perennial grass) and Artemisia annua (an annual forb). L. secalinus thus had a significantly larger biomass and was more abundant than the other two species at the high N rate but did not differ significantly from the other two species under ambient and the low N rate. Species that could use water from deeper soil layers became dominant when water in the shallow layers was insufficient to meet the demands of increased aboveground plant biomass. Our study highlights the importance of water across soil depths as key driver of plant growth and dominance in grasslands under N addition.

Key words: Grassland, Species richness, Soil moisture, Oxygen isotope, Nitrogen enrichment

摘要: The primary mechanism driving plant species loss after nitrogen (N) addition has been often hypothesized to be asymmetric competition for light, resulting from increased aboveground biomass. However, it is largely unknown whether plants’ access to soil water at different depths would affect their responses, fate, and community composition under nitrogen addition. In a semiarid grassland exposed to 8-years of N addition, we measured plant aboveground biomass and diversity under four nitrogen addition rates (0, 4, 10, and 16 g m-2 year-1), and evaluated plant use of water across the soil profile using oxygen isotope. Aboveground biomass increased significantly, but diversity and shallow soil-water content decreased, with increasing rate of nitrogen addition. The water isotopic signature for both plant and soil water at the high N rate indicated that Leymus secalinus (a perennial grass) absorbed 7% more water from the subsurface soil layer (20-100 cm) compared to Elymus dahuricus (a perennial grass) and Artemisia annua (an annual forb). L. secalinus thus had a significantly larger biomass and was more abundant than the other two species at the high N rate but did not differ significantly from the other two species under ambient and the low N rate. Species that could use water from deeper soil layers became dominant when water in the shallow layers was insufficient to meet the demands of increased aboveground plant biomass. Our study highlights the importance of water across soil depths as key driver of plant growth and dominance in grasslands under N addition.

关键词: Grassland, Species richness, Soil moisture, Oxygen isotope, Nitrogen enrichment