中文摘要：

应用脉冲标记法标记富集^13C的杉木幼苗残体;采集在桔园、杉木人工林、米槠次生林和细柄阿丁枫天然林等不同土地利用方式的土壤表层样品,通过室内短期培养实验（20℃,培养90d）研究残体在〉250μm、53-250μm和〈53μm等三个水稳性团聚体粒级组中的分配。结果表明：在添加13C标记杉木残体下,不同粒级团聚体的δ13C值均显著升高,但以桔园土壤幅度最大;不同土地利用的土壤中,δ13C丰度值在〈53μm团聚体中最小,53-250μm团聚体中最高。随着外源碳输入量的增加,进入土壤的新碳含量也随之升高;C/N较大的外源有机残体在短期内更有利于新碳的积累。外源新碳在土壤团聚体中的分配比例由小到大顺序依次为〉250μm、53-250μm、〈53μm,这表明短期培养有利于微团聚体新碳的积累。

英文摘要：

The pulse labeling technique was used to label δ^13C-enriched wood residue of Cunn}nghamia lanceolata sapling, which was then mixed, separately, with soil samples collected from the tops a citrus orchard （ Citrus aurantium ） , a fir plantation （ Cunninghamia lanceolata ） , a second layers ary forest of of Castanopsis carlesii, and a natural forest of Altingia gracilipes ） . To trace dynamics of fresh carbon in soil aggregates, the mistures were incubated at 20 ℃ for 90 d and then analyzed for distribution of δ^13C-labeled wood residue carbon in the three fractions of soil aggregates, i.e. 〉 250 gin, 53- 250 μm and 〈 53 μm.Results show that in the soil samples amended with δ^13C-labeled wood residue, δ^13C value increased in all the fractions of soil aggregates, especially in the soil samples of the orchard. In all the soil samples, regardless of land use, 613C value was the lowest in the 〈 53 μm fraction of soil aggregates, and the highest in the 53 - 250 μm fraction. Once extraneous carbon was amended into the soil samples, the content of fresh carbon therein increased instantly. And the content of fresh carbon and δ^13C value was higher in the root than in the leaf, as the ratio of C/N is higher in the former. In terms of content of fresh carbon, the three fractions of soil aggregates displayed an order of 〈 53 μm 〉 53 - 250 μm 〉 〉 250 μm, which indicates that a short term of incubation facilitates accumulation of fresh carbon in micro soil aggregates.