Chin J Plant Ecol ›› 2014, Vol. 38 ›› Issue (2): 209-218.DOI: 10.3724/SP.J.1258.2014.00018

Special Issue: 青藏高原植物生态学:植物-土壤-微生物 土壤呼吸

• Research Articles • Previous Articles    

Characteristics of soil respiration in different degraded alpine grassland in the source region of Three-River

WEN Jun1,2,*(), ZHOU Hua-Kun2,**(), YAO Bu-Qing2, LI Yi-Kang2, ZHAO Xin-Quan2, CHEN Zhe2,3, LIAN Li-Ye1, GUO Kai-Xian1   

  1. 1Qinghai Institute of Water Resources and Hydropower, Xining 810001, China
    2Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
    3University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2013-01-11 Accepted:2013-05-24 Online:2014-01-11 Published:2014-02-12
  • Contact: ZHOU Hua-Kun


Aims Soil respiration is a major way that CO2 is emitted into the atmosphere, and it is important in global change research. Our objective was to examine the effects of degradation on carbon flux in alpine grassland.
Methods We measured soil respiration rates in alpine grassland under four degrees of degradation (no, light, moderate, and heavy degradation) using a LI-8100A open-circuit soil carbon flux measuring system. We analyzed the relationship between soil respiration and soil temperature, as well as between soil respiration and soil moisture.
Important findings Soil respiration under each level of degradation showed a monthly dynamic, but it varied by degree of degradation. With an increase of degradation, average soil respiration of the growing season first increased and then decreased. The highest soil respiration occurred under the moderate level ((2.46 ± 0.27) μmol·m-2·s-1), which was significantly higher than under no degradation ((1.92 ± 0.11) μmol·m-2·s-1) and heavy degradation ((1.30 ± 0.16) μmol·m-2·s-1) (p < 0.01). There was no significant difference between the moderate degradation and the light degradation (p > 0.05). The respiration under heavy degradation was significantly lower than under the other degradation levels (p < 0.01). There was a significant positive linear correlation between aboveground biomass and soil respiration (p = 0.004), but not between soil respiration and underground biomass (p = 0.056). There was a significant positive correlation between soil respiration and soil temperature at each level except heavy degradation. There were correlations between soil respiration and soil moisture (binomial fitting) with no degradation as well as moderate and heavy degradation (p < 0.05), and it was significantly correlated with light degradation (p < 0.01).

Key words: alpine grassland, grassland degradation, soil moisture, soil respiration, source region of Three-River, temperature