Distribution Characteristics of labile organic carbon in soil aggregates in different stages of vegetation restoration of grassland in Yunwu Mountain
云雾山草原区不同植被恢复阶段土壤团聚体活性有机碳分布特征

Labile organic carbon (LOC) in soil aggregetes plays an important role in carbon fixation. We analized content of labile organic carbon(LOC) in soil aggregates from 0 to 20 cm during vegetation restoration in Yunwu Mountain. The results showed that:(1) content of LOC in soil aggregates followed the order of abandoned grassland 0.25 mm). Furthermore, Content of LOC in fraction of 0.5-0.25 mm was higher than other size fraction and the content was lowest in micro-aggregate (<0.25 mm). (3)The effecs of soil depths on content of LOC in soil aggregetes was different. Content of LOC in depth of 0-10 cm in size of >0.5 mm was higher than the depth of 10-20 cm in prophase of vegetation restoration (abandoned grassland-Artemisia gmelinit community ) while content of LOC in size of <0.5 mm showed similar community in the late of vegetation restoration (Stipa bungeana community ). (4)The linearly positive correlation was found between content of LOC and total organic carbon in soil aggregates. The correlation coefficient reached 0.9493 which was extreamly significant. This showed that content of labila organic carbon in soil aggregates could be a sensitive index to indicate dynamic of soil organic carbon.