Acta Geographica Sinica ›› 2014, Vol. 69 ›› Issue (11): 1651-1660.doi: 10.11821/dlxb201411006

• Orginal Article • Previous Articles     Next Articles

Topsoil organic carbon storage and its changes in Inner Mongolia grassland from the 1980s to 2010s

Erfu DAI1(), Ruixue ZHAI1,2, Quansheng GE1, Xiuqin WU3   

  1. 1. Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
    3. School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
  • Received:2013-10-22 Revised:2014-04-18 Online:2014-11-20 Published:2014-12-26
  • Supported by:
    National Basic Research Program of China (973 Program), No.2011CB403206, No.2012CB416906;National Key Technology R&D Program, No.2013BAC03B04

Abstract:

Soil carbon sequestration and potential has been a focal issue in global carbon research. Under the background of global change, the estimation of the extent well as its change of soil organic carbon (SOC) storage is of great importance. Based on soil data from the second soil survey of China and field survey during 2011-2012, this paper studied spatial distribution and changes of topsoil (0-20 cm) organic carbon storage in Inner Mongolia grassland between the 1980s and 2010s, by using the regression relation between soil data and remote sensing data. The results showed that (1) the SOC storage values in Inner Mongolia grassland in the 1980s and 2010s were estimated to be 2.05 and 2.17 Pg C, with an average density of 3.48 and 3.69 kg C·m-2, respectively. The SOC storage was mainly distributed in the typical steppe and meadow steppe, which accounted for over 98% of the total. The spatial distribution showed a decrease trend from the meadow steppe, typical steppe to the desert steppe, corresponding to the temperature and precipitation gradient. (2) SOC variations during 1982-2012 were estimated to be 0.12 Pg C, at 7.00 g C·m-2·yr-1, which did not show a significant change. This indicates that SOC storage in grassland ecosystem of Inner Mongolia remained relatively stable over this period. However, topsoil organic carbon of different grassland ecosystems showed different trends of carbon source/sink during the past three decades. Meadow steppe and typical steppe, as a carbon sink, had sequestered at 0.15 and 0.03 Pg C, respectively, while desert steppe, as a carbon source, had lost 0.06 Pg C. It is concluded that SOC storage in grassland ecosystem may respond differently to climate change, which is related to vegetation type, regional climate type and grazing intensity. These results will provide references for decision makers to find proper resolutions to protect grassland soil resource.

Key words: surface soil, organic carbon storage, climate change, regional differences, Inner Mongolia grassland