Journal of Resources and Ecology ›› 2011, Vol. 2 ›› Issue (2): 168-174.DOI: 10.3969/j.issn.1674-764x.2011.02.010

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Modeling the Effects of Climate Change and Elevated CO2 on Soil Organic Carbon in an Alpine Steppe

LI Xiaojia1,2, ZHANG Xianzhou1, ZHANG Yangjian1   

  1. 1 Lasa Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2011-03-07 Revised:2011-04-27 Online:2011-06-30 Published:2011-06-28
  • Supported by:

    the National Key Research Program (2010CB951704).

Abstract: The objective of this study was to analyze the effects of climate change and doubled atmospheric CO2 concentrations, as well as the combined effects of climate change and doubling atmospheric CO2 concentrations on soil organic carbon (SOC) in the alpine steppe of the northern Tibetan Plateau using the CENTURY model. The results indicate that SOC loss in climate change scenarios varied from 49.77– 52.36% in the top 20 cm. The simulation results obtained for a P1T0 scenario (increased precipitation and unchanged temperature), P0T1 scenario (unchanged precipitation and increased temperature), and P1T1 scenario (increased precipitation and increased temperature) were similar. The alpine steppe in the P1T1 scenarios lost the greatest amount of SOC (844.40 g C m-2, representing the least amount of SOC) by the end of the simulation. The simulation for P0T1 scenarios resulted in a 49.77% loss of SOC. However, SOC increased 12.87% under the CO2 doubling scenario, compared with the unchanged CO2 scenario. CO2 enhancement effects on SOC were greater than the climate change effects on SOC alone. The simulation of combined climate change and doubling atmospheric CO2 led to a decrease in SOC. This result indicated a decrease of 52.39% in SOC for the P1T1 + 2 × CO2 scenario, 49.81% for the P0T1 + 2 × CO2 scenario, and 52.30% for the P1T0 + 2 × CO2 scenario over the next 50 years. Therefore, SOC content in the alpine steppe will change because of changes in precipitation, temperature and atmospheric CO2 concentrations.

Key words: soil organic carbon (SOC), modeling, CENTURY, climate change, CO2 concentration