Chin J Plant Ecol ›› 2006, Vol. 30 ›› Issue (4): 545-552.DOI: 10.17521/cjpe.2006.0072

• Research Articles • Previous Articles     Next Articles

CARBON CONTENTS AND ITS VERTICAL DISTRIBUTION IN ALPINE GRASSLANDS IN BAYINBULAK, MIDDLE STRETCH OF THE TIANSHAN MOUTAINS OF XINJIANG

MOHAMMAT Anwar1,2(), YANG Yuan-He1, GUO Zhao-Di1, FANG Jing-Yun1   

  1. 1 Department of Ecology, College of Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
    2 Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
  • Received:2005-06-01 Online:2006-06-01 Published:2006-07-30

Abstract:

Background and Aims Accurate estimates on the size of terrestrial organic carbon stocks are necessary for understanding their importance in regulating atmospheric CO2 concentrations. In this paper, biomass and SOC contents in alpine grasslands (alpine steppe and alpine meadow) in Bayinbulak were estimated. In addition, the vertical distribution of belowground carbon was discussed. Our objectives were to (a) estimate biomass and SOC contents of two different alpine grasslands, (b) investigate the root distribution of two alpine grasslands, and (c) explore the vertical distribution of SOC of two alpine grasslands.
Methods SOC content was estimated by an improved method (integral arithmetic method). Based on continuous decrease of SOC density with soil depth, integral arithmetic method could estimate SOC content to a given soil depth.
Key Results There were significant differences in the biomass between the alpine steppe and alpine meadow; aboveground biomass of the alpine steppe was 71.4 g C·m-2, whereas aboveground biomass of the alpine meadow was 94.9 g C·m-2; belowground biomass of the two alpine grasslands was 1 033.5 and 1 285.2 g C·m-2, respectively. No significant differences were found between integral arithmetic and traditional methods of estimating SOC contents. SOC contents of the alpine meadow was higher than in the alpine steppe; SOC contents in the two alpine grasslands was 25.7 and 38.8 kg·m-2, respectively. Most of the root biomass of the two alpine grasslands was in the upper 40 cm of the soil profile, while SOC was concentrated in the top 60 cm. The two alpine grasslands had different root distributions; the percentage of root biomass in the top 20 cm averaged 76%-80% for the alpine steppe and alpine meadow. Alpine meadows had a deeper root profile with only 49% of the SOC in the upper 20 cm, whereas the alpine steppe had 55% of the total SOC in the top 20 cm.
Conclusions This study suggests that vegetation determines the vertical distribution of SOC through root: shoot ratio and its vertical root distribution.

Key words: Alpine steppe, Alpine meadow, Biomass, Soil organic carbon