摘要：SOC “fractionation” in soil aggregates are the key scientific issues to assess the dynamics and sequestration potential of soil organic carbon.However,the changes in content of soil organic carbon fractions in soil aggregates under different land uses are still unclear.Soil samples were collected from paddy land and upland in Northeast China to study the changes in contents of soil organic carbon and organic carbon fractions in different soil aggregates of mollisols under different land-use types.Results showed that: land-uses and soil aggregate sizes significantly influenced the content of total SOC and oxidizable SOC fractions with varying magnitude.Compared with the paddy land,the SOC content under upland increased by 13%.The SOC contents in different soil aggregates followed the order regardless of the land use treatment: micro aggregates < silt-clay < large aggregates.The FI had the biggest variation among land uses.The lability index of large aggregate was lower than that of micro aggregate and silt-clay,indicating the large aggregates had more stable organic carbon fractions and had higher stability.Results are helpful to promote the overall level of soil organic carbon dynamics and stability studies and have a great means to evaluate the role of soil in the terrestrial ecosystems carbon cycling.
