南京市不同功能区城市林业土壤有机碳含量与分布

为了解城市化过程中人为活动对城市林业土壤性质及土壤碳库的影响,以南京市土壤为对象,测定了7类功能区城市林业土壤0～30 cm土层的总有机碳(SOC)、溶解有机碳(DOC)、微生物量碳(MBC)、易氧化态碳(ROC)和轻组有机碳(LFOC)的含量,分析了城市林业土壤有机碳的分布规律及其相互关系。结果表明:城市林业土壤表层(0～10 cm)活性有机碳富集特征明显,土壤活性有机碳含量随着土层加深而减小,人为干扰对土壤有机碳含量影响较大; 城郊天然林土壤积累了较高含量的ROC和MBC,道路绿化带土壤由于交通源有机物质的输入,SOC、DOC、LFOC含量较高。人类活动频繁的居民区、公园和校园的土壤活性有机碳各组分含量多处于较低水平。研究表明,土壤总有机碳与各活性有机碳之间有显著相关关系。

Content and distribution of organic carbon in urban forest soil in different function areas in Nanjing City,China

Properties of urban forest soils have been greatly altered by human activities during the progress of urbanization. The urbanization changed not only the scale of soil carbon pool, but also the composition and characteristics of organic carbon in urban forest soil. Total soil organic carbon(SOC), dissolved organic carbon(DOC), microbial biomass carbon(MBC), readily oxidation carbon(ROC)and light fraction organic carbon(LFOC)in 0-30 cm forest soil layers under seven different function areas in Nanjing were studied. The distribution of urban forest soil organic carbon and correlations between different fractions of soil organic carbon were analyzed. The results showed that all of the organic carbon fractions enriched in 0-10 cm soil layers apparently. The soil active organic carbon content in different functional areas decreased with soil depth increasing. Human disturbance exerted great influence on the content of soil organic carbon. The natural forest soil in the suburb accumulated more ROC and MBC. Due to traffic related organic matter input, urban road green belt soils had higher content of SOC, DOC and LFOC. Soils in park, campus and residence community with frequent human activities had lower level of active organic carbon content. There was a significant correlation between soil total organic carbon and the active organic carbon.