内蒙古退化荒漠草原土壤有机碳和微生物生物量碳含量的季节变化

为探明荒漠草原土壤有机碳（SOC）和微生物生物量碳（MBC）含量特征，分别在内蒙古达茂旗、四子王旗和苏尼特右旗设置样地，依次代表轻度、中度和重度退化草地，分析了不同样地表层土壤(0～20 cm)SOC和MBC含量变化及季节动态.结果表明：退化草地SOC和MBC含量均随草地退化程度增加而减小；除2006年夏季外，轻度、中度退化荒漠草地的土壤可培养微生物总数都高于重度退化荒漠草地；MBC含量和土壤可培养微生物总数均在夏秋季较高，春冬季较低.相关分析结果显示，SOC含量与MBC含量之间呈极显著正相关（P<0.01），说明两者均可作为评价荒漠草原草地退化的敏感指标.

Seasonal variations of soil organic carbon and microbial biomass carbon in degraded desert steppes of Inner Mongolia

Sampling sites were installed in Damao Banner, Siziwang Banner, and Sunite Right Banner of Inner Mongolia, which represented lightly, moderately, and heavily degraded desert steppes, respectively, and surface (0-20 cm) soil samples were collected to analyze the quantitative characteristics and seasonal dynamics of soil organic carbon (SOC) and microbial biomass carbon (MBC) in these steppes. The SOC and MBC contents decreased with the increasing degradation degree of desert steppe. The total amount of soil culturable microbes in lightly and moderately degraded desert steppes was higher than that in heavily degraded desert steppe, except in summer 2006, and the MBC content and the quantity of soil culturable microbes were higher in summer and autumn than in spring and winter. Correlation analysis showed that there was a significant positive correlation between SOC and MBC (P<0.01), suggesting that both SOC and MBC could be used as the sensitive indicators to evaluate the degradation degree of
desert steppe.