Chin J Plant Ecol ›› 2014, Vol. 38 ›› Issue (2): 159-166.DOI: 10.3724/SP.J.1258.2014.00014

Special Issue: 青藏高原植物生态学:群落生态学

• Research Articles • Previous Articles     Next Articles

Responses of plant community biomass to nitrogen and phosphorus additions in an alpine meadow on the Qinghai-Xizang Plateau

YANG Xiao-Xia1,2, REN Fei1,2, ZHOU Hua-Kun1, HE Jin-Sheng1,3,*()   

  1. 1Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
    3Key Laboratory for Earth Surface Processes of the Ministry of Education, Department of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
  • Received:2013-07-01 Accepted:2013-09-22 Online:2014-07-01 Published:2014-02-12
  • Contact: HE Jin-Sheng

Abstract:

Aims Rising soil temperature under the warming process stimulates microbial activity in soils on the Qinghai- Xizang Plateau. Moreover, the eastern edge of Qinghai-Xizang Plateau has been experiencing distinct atmospheric nitrogen deposition with an increasing trend. All of these have led to an increase in the available nutrients in soils. This study was aimed to determine the responses of carbon fixation in the alpine meadow to nitrogen and phosphorus additions on the Qinghai-Xizang Plateau.
Methods The study was conducted in an alpine meadow ecosystem at the Haibei National Field Research Station of Alpine Grassland Ecosystem, Northwest Institute of Plateau Biology, Chinese Academy of Sciences. Four treatments were set up in 2009, including control, nitrogen addition only (N), phosphorus addition only (P), and combined nitrogen and phosphorus additions (NP). Nutrients were added in June or July each year. The aboveground biomass of functional groups and the above- and belowground biomass of plant communities were measured by harvesting in 2012.
Important findings (1) N and P additions increased the aboveground biomass of grass, and the proportion of grass biomass in the community, but decreased the proportion of forb biomass in the community. Only P addition decreased the aboveground biomass of sedge, and the proportion of sedge biomass in the community. (2) N and P additions increased the aboveground biomass by 24% and 52%, respectively, compared with the control. (3) N addition had no effect on the belowground biomass, whereas P addition slightly increased the belowground biomass. (4) N addition had no effect on the total biomass, whereas P addition significantly increased the total biomass. Therefore, N and P additions could relieve the nutrient limitation and stimulate plant growth. Furthermore, the results suggest that the Qinghai-Xizang Plateau could be more limited by P than N on plant growth.

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Key words: alpine meadow, biomass, functional groups, nitrogen addition, phosphorus addition, Qinghai-Xizang Plateau