白洋淀湿地区土壤有机碳密度及储量的空间分布特征

湿地生态系统碳储量是陆地生态系统碳循环的重要组成部分，提供重要的生态系统服务功能。白洋淀湿地是国家重要生态湿地和华北平原最大的淡水湿地，同时是雄安新区的核心水系，湿地区土壤碳储量的估算研究将为湿地生态系统服务评估和湿地生态恢复提供数据支撑。研究通过对白洋淀湿地7种不同地类的105个土壤剖面进行分层取样，揭示了其湿地土壤有机碳密度及储量的空间分布特征，结果表明：（1）白洋淀湿地区土壤有机碳含量整体偏低，在各层土壤中，淹水芦苇湿地的有机碳含量均显著高于其他植被类型，约为其他类型土壤碳含量的3倍左右。（2）在各植被类型中土壤有机碳含量均以表层（0-20 cm）最高，其分配比例均集中在30%左右，随着土壤剖面深度的增加，湿地土壤的有机碳含量逐渐减少。（3）不同植被类型土壤有机碳含量与土壤有机碳密度的差异显著，具体表现为：乔木园地 < 旱地 < 常绿针叶林 < 落叶阔叶林 < 水田 < 台田芦苇 < 淹水芦苇。（4）根据估算，白洋淀湿地区的土壤有机碳储量约为5816.77×10³Mg。随着雄安新区环境治理工作的推进，白洋淀湿地区生态系统固碳将呈现持续向好态势，结合生态恢复和土地布局优化，尽量减少雄安新区建设中土地流转带来的碳排放影响，对提高区域生态效益具有重要意义。

The spatial distribution of soil organic carbon density and carbon storage in Baiyangdian wetland

Carbon storage of wetland ecosystem plays an important role in the terrestrial ecosystem carbon cycle and holds important ecosystem service functions. Baiyangdian Wetland is a national key ecological wetland and the largest freshwater wetland in the North China Plain. As the core water system in the Xiong''an New Area, it is critical to estimate the soil carbon storage in Baiyangdian Wetland, which will provide data support for ecosystem service evaluation and wetland ecosystem restoration. In this study, 105 soil profiles in seven different vegetation types in Baiyangdian wetland region were layered and sampled. The spatial distribution of soil organic carbon density and storage were clarified based on physical and chemical analysis in laboratory and statistical analysis. The results showed that: (1) the average Soil Organic Carbon (SOC) content in the surface soil (0-20 cm) in Baiyangdian wetland is 8.53-17.70 g/kg, which is relatively lower than those of the other wetlands. The SOC content varied among different vegetation types and the organic carbon content in reed marsh is about three times than that of the other land use types. (2) In terms of the vertical distribution characteristics, the SOC in Baiyangdian wetland decreased as the increase of the soil depth, and it is highest in the surface layer (0-20 cm), which account for about 30% of the total amount of the soil. (3) The dynamics of density and content of SOC is consistent and it varied according to the vegetation tapes. It showed that the garden plot < dry land < evergreen coniferous forest < deciduous broad-leaved forest < paddy field < ota reed < flooded reed. The organic carbon density of flooded reed (24.36 kg/m²) is significantly higher than that of the other vegetation types. (4) The total amount of SOC storage in this region is 5816.77×10³ Mg. With the environmental improvement in the Xiong''an New Area, Baiyangdian Wetland will continue to increase its ecosystem carbon sequestration. It is of great significance for regional ecological benefits to combine with ecological restoration and land layout optimization, and minimize the carbon emissions due to land transfer in the construction of the Xiongan New Area.