Topsoil and Deep Soil Organic Carbon Concentration and Stability Vary with Aggregate Size and Vegetation Type in Subtropical China.

摘要: The impact of reforestation on soil organic carbon (OC), especially in deep layer, is poorly understood and OC stabilization relation with aggregation vegetation type afforested area unknown. Here, we collected topsoil (0-15 cm) (30-45 from six paired coniferous forests (CF) broad-leaved (BF) reforested the early 1990s subtropical China. Soil aggregates were separated by size dry sieving stability was measured closed-jar alkali-absorption 71 incubation days. concentration mean weight diameter higher BF than CF. cumulative mineralization (Cmin, mg CO2-C kg-1 soil) varied aggregate CF topsoils, soil, it larger smaller BF, but not percentage mineralized (SOCmin, % SOC) general aggregates. Meanwhile, SOCmin greater at In comparison to topsoil, generally exhibited a lower Cmin, SOCmin. Total nitrogen (N) ratio phosphorus (C/P) aggregates, while same trend N/P only found Moreover, negatively correlated OC, total N, C/P N/P. This work suggests that might play an important role storage through internal nutrient cycling. depth influenced stability, could be altered about 20 years.