Effects of short-term nitrogen and phosphorus addition on leaf stoichiometry of a dominant alpine grass

PeerJ

article

YaLan Liu¹  Bo Liu⁵  Zewei Yue⁴  Fanjiang Zeng¹  Xiangyi Li¹  Lei Li¹ 

[1] Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences;Cele National Station of Observation and Research for Desert-Grassland Ecosystem in Xinjiang;State Key Laboratory of Desert and Oasis Ecology, Chinese Academy of Sciences;University of Chinese Academy of Sciences;Shandong Provincial Key Lab. of Soil Conservation and Environmental Protection, College of Resources and Environment, Linyi University;Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences

关键词: Nutrient addition;    Leaf nutrient concentration;    Leaf stoichiometry;    Alpine grazing grassland;   

DOI  :  10.7717/peerj.12611

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

The effects of increasing nitrogen (N) and phosphorus (P) deposition on the nutrient stoichiometry of soil and plant are gaining improving recognition. However, whether and how the responses of N cycle coupled with P of the soil–plant system to external N and P deposition in alpine grassland is still unclear. A short-term external N and P addition experiment was conducted in an alpine grazing grassland in the KunLun Mountain to explore the effects of short-term N and P addition on the nutrient stoichiometry in soil and plant. Different rates of N addition (ranging from 0.5 g N m−2 yr−1 to 24 g N m−2 yr−1) and P addition (ranging from 0.05 g N m−2 yr−1 to 3.2 g P m−2 yr−1) were supplied, and the soil available N, P, leaf N and P stoichiometry of Seriphidium rhodanthum which dominant in the alpine ecosystem were measured. Results showed that N addition increased soil inorganic N, leaf C, leaf N, and leaf N:P ratio but decreased soil available P and leaf C:P. Furthermore, P addition increased soil available P, leaf P, soil inorganic N, leaf N, and leaf C and reduced leaf C:N, C:P, and N:P ratios. Leaf N:P was positively related to N addition gradient. Leaf C:P and leaf N:P were significantly negatively related to P addition gradient. Although external N and P addition changed the value of leaf N:P, the ratio was always lower than 16 in all treatments. The influences of P addition on soil and plant mainly caused the increase in soil available P concentration. In addition, the N and P cycles in the soil–plant system were tightly coupled in P addition but decoupled in N addition condition. The nutrient stoichiometry of soil and leaf responded differently to continuous N and P addition gradients. These data suggested that the alpine grazing grassland was limited by P rather than N due to long-term N deposition and uniform fertilization. Moreover, increasing P addition alleviated P limitation. Therefore, the imbalanced N and P input could change the strategy of nutrient use of the grass and then change the rates of nutrient cycling in the alpine grassland ecosystem in the future.

【 授权许可】

CC BY