黄土丘陵区典型草地土壤有机碳及微生物量碳的分布特征

对黄土丘陵区植被恢复中柳枝稷、长芒草和白羊草这3种典型草地土壤有机碳、微生物量碳以及团聚体中有机碳的含量变化和分布特征进行了研究。结果表明,土壤中有机碳、微生物量碳以及不同粒级团聚体中有机碳均集中分布在土壤的表层;不同草地类型下有机碳的含量大小顺序为:柳枝稷草地>长芒草草地>白羊草草地;相同土层深度土壤各粒级团聚体中有机碳的分布表现为2～1mm粒级团聚体中有机碳含量明显高于其它粒级中有机碳的含量;在3种典型草地中,柳枝稷草地土壤中有机碳含量和团聚体中有机碳含量高于长芒草和白羊草草地的含量,柳枝稷草地土壤微生物量碳的含量仅低于长芒草中的含量。

Distribution Characteristics of Soil Organic Carbon and Microbial Biomass Carbon in Loess Hilly Regain

A study was conducted to investigate the distribution of total soil organic carbon,soil microbial biomass carbon and organic carbon in different size soil aggregates in three typical grasslands that were dominated by Panicum virgatum,Bothriochia ischaemum,Stipa bungeana in hilly-gully region on the Loess Plateau.The results showed that total soil organic carbon,soil microbial biomass carbon and organic carbon content in soil aggregates was higher in the soil surface than in other layers.The organic carbon contents of different grasslands in a descending order were Panicum virgatumBothriochia ischaemumStipa bungeana.A clear relationship was found between the organic carbon contents and the sizes of soil aggregates.2-1 mm aggregates had the highest soil carbon content.The total organic carbon content and organic carbon content in soil aggregates in Panicum virgatum grassland were higher than those in Bothriochia ischaemum grassland and Stipa bungeana grassland,while the microbial biomass carbon content was lower than that in Bothriochia ischaemum but higher than that in Stipa bungeana grassland.