黄土丘陵区植被恢复中不同粒级土壤团聚体有机碳分布特征

Distribution of Organic Carbon in Different Soil Aggregates Size During Revegetation in Hilly-Gully Region of Loess Plateau

对黄土丘陵区土壤有机碳在不同粒级团聚体中的分布特征及其对植被恢复的响应进行了研究。结果表明：（1）黄土丘陵区不同植被覆盖条件下,土壤有机碳的分布具有一定的表聚性,0～20 cm土层中有机碳的含量均高于20～40 cm中有机碳的含量,不同植被群落下有机碳的含量大小为：大针茅群落〉长芒草群落〉铁杆蒿群落〉百里香群落;（2）同一深度土壤各粒级团聚体中有机碳的分布特征是：0.5～0.25 mm与1～0.5 mm两个粒级中有机碳的含量最高,〉1 mm的团聚体中有机碳的含量有随粒级增大而减小的趋势;（3）恢复年限对不同粒级土壤团聚体中有机碳的含量影响很大,有机碳的含量随恢复年限的增加总体呈上升趋势。黄土高原沟壑区土壤有机碳的积累与土壤团聚体的粒级和植被恢复的类型、年限等有明显的关系。

The distribution of organic carbon in different size soil aggregates was studied in hilly-gully region on the Loess Plateau,and also the relationship among soil aggregates,organic carbon and vegetation restoration was analyzed. The results showed that：（1） The organic carbon content in the 0～20 cm soil layer was higher than that in the 20～40 cm layer under different vegetation covering.The organic carbon content in different plant communities were Stipa grandis P.smirn community 〉 Stipa bungeana Trin.community〉 Artemisia sacrorum Ledeb.community 〉 Thymus mongolicus Ronn.community;（2） There were obvious relations between the organic carbon content and the soil aggregates size,the higher of soil carbon content were in 0.5～0.25 mm and the 1～0.5 mm two size in soil aggregates,organic carbon content decreased along with the soil aggregates size increases;（3） The revegetaion years also had a certain influence to the organic carbon content in different size soil aggregates.The organic carbon content assumed the trend of escalation along with the increasing of revegetation years returning back from agricultural land to grassland.The vegetation worked on the soil organic carbon quality and quantity by the withered leaves and other matters,meanwhile they ameliorate soil structure,especially the contents of water stable aggregates.The accumulation of soil organic was affected by vegetation types,revegetation years and also aggregates sizes in loess hilly-gully region.