江苏滨海湿地不同植被演替阶段土壤有机碳分布特征

对江苏滨海湿地土壤有机碳的分布特征进行研究,阐明了植被演替和土壤理化性质对土壤有机碳分布的影响,对探讨今后如何增加滨海湿地的"碳汇"能力具有重要的意义。结果表明,水平方向上,有机碳的分布特征表现为:光滩米草群落芦苇群落刺槐群落碱蓬群落。在0~10 cm层,土壤有机碳平均含量为20.84 g·kg-1,其中米草群落土壤有机碳含量显著高于其他几种类型;10~25 cm和25~40 cm土层,土壤有机碳平均含量分别为18.66 g·kg-1和19.15 g·kg-1,光滩含量最高。垂直方向上,0~10 cm层土壤有机碳含量均最高,光滩土壤有机碳含量随土层深度增加而增加;碱蓬和米草群落湿地土壤有机碳含量的垂直分布特征则相反;刺槐群落和芦苇群落湿地土壤有机碳含量分布表现为,表层含量最高,中间土层含量最低。土壤有机碳含量与土壤容重具有极显著的负相关关系,而与C/N和盐分呈显著的正相关关系。虽然研究结果中土壤有机碳含量与其他因子的相关性不显著,但是土壤各理化性质间的相互作用会间接影响有机碳含量的分布。

Distribution of soil organic carbon under different vegetation successions in the coastal wetland of Jiangsu

The horizontal and vertical distribution of soil organic carbon (SOC) in the coastal wetland of Jiangsu was studied. The influence of vegetation succession and soil physic-chemical properties on SOC distribution was analyzed in order to explore how to increase the potential carbon sink of coastal wetland. The results showed that the SOC content at different succession stages was mudflats > Spartina auglica wetland > Phragmites australis wetland > Robinia pseucdoacacia forest > Suaeda glauca wetland. The average content of the SOC at the five succession stages was 20.84 g·kg^-1 in the 0-10 cm soil layer and the SOC content in mudflats was significantly higher than the others. In the 10-25 cm and 25-40 cm deep soils, the average values of the SOC contents were 18.66 g·kg^-1 and 19.15 g·kg^-1, respectively, with the greatest value in mudflats. The SOC content at all five succession stages in the soil exhibited that the SOC content was the highest in the 0-10 cm soil layer. The distribution of SOC content along the soil profile in mudflats was increased with an increase of the soil depth, while the Suaeda glauca wetland and Spartina auglica wetland showed an opposite trend. The highest content of SOC in Phragmites australis wetland and Robinia pseucdoacacia forest was observed in the 0-10 cm soil layer, while the lowest value was observed in the 10-25 cm soil layer. Correlation analysis indicated that the SOC content was positively correlated with the soil C/N and salinity, while a significant negative relationship was observed between SOC and bulk density. Although there were no significant correlations between the SOC content and other soil factors in this study, the interaction of soil factors could indirectly influence SOC distribution.