Institute of Grassland Science, College of Animal Science and Technology, China Agricultural University, Beijing, People's Republic of China.
PLoS One. 2012;7(5):e36434. doi: 10.1371/journal.pone.0036434. Epub 2012 May 4.
The potential of grazing lands to sequester carbon must be understood to develop effective soil conservation measures and sustain livestock production. Our objective was to evaluate the effects of grazing on soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC) in Typical steppe and Desert steppe ecosystems, which are both important grassland resources for animal grazing and ecological conservation in China, and to derive region-specific soil C changes associated with different stocking rates (ungrazed, UG; lightly grazed, LG; moderately grazed, MG; heavily grazed, HG). This study substantiated that significant higher SOC, TN and MBC appeared with the treatment of LG in typical steppe. From 2004 to 2010, grazing treatments increased soil carbon storage in desert steppe, which was partly due to the grazing history. The higher MBC concentration and MBC/SOC suggest a great potential for carbon sequestration in the desert steppe ecosystem. The greater MBC in desert steppe than typical steppe was mainly the result of higher precipitation and temperature, instead of soil substrate. The change of MBC and the strong positive relationships between MBC and SOC indicated that MBC in the soil was a sensitive index to indicate the dynamics of soil organic carbon in both steppes in Inner Mongolia of China.
为了开发有效的土壤保持措施和维持畜牧业生产，必须了解放牧地固碳的潜力。本研究的目的是评估放牧对中国重要的草地资源——典型草原和荒漠草原生态系统中土壤有机碳（SOC）、总氮（TN）和微生物生物量碳（MBC）的影响，并得出与不同载畜率（未放牧、轻度放牧、中度放牧和重度放牧）相关的特定区域的土壤 C 变化。本研究证实，在典型草原中，轻度放牧处理显著提高了 SOC、TN 和 MBC。从 2004 年到 2010 年，放牧处理增加了荒漠草原的土壤碳储量，这部分是由于放牧历史。MBC 浓度和 MBC/SOC 较高表明荒漠草原生态系统具有很大的碳固存潜力。荒漠草原的 MBC 高于典型草原，主要是由于较高的降水和温度，而不是土壤基质。MBC 的变化以及 MBC 与 SOC 之间的强正相关关系表明，土壤中的 MBC 是中国内蒙古两个草原土壤有机碳动态的敏感指标。
