城市土壤无机碳空间分布特征及其与城市化历史的关系

城市化过程深刻影响了土壤的碳循环过程。利用城市土壤空间精细化采样,结合1900年—2010年南京城市化历史重建,分析城市土壤无机碳空间分布与城市化过程的时空关系,评估城市土壤无机碳的固碳潜力。研究表明,城市土壤无机碳密度与城市化历史具有良好的对应关系,历史老城区的无机碳库储量远高于快速城市化的新城区,揭示城市土壤无机碳具有良好的固碳潜力。随着城市化历史的增加,无机碳密度平均值表现出线性增长,研究区的城市土壤表层无机碳库为2.94Tg,其未来仍拥有的固碳潜力为1.45Tg。本研究可为阐明城市系统碳循环的机制、开展城市土壤无机碳固碳技术研究提供理论依据。

Spatial Distribution of Soil Inorganic Carbon in Urban Soil and Its Relationship with Urbanization History of the City

Urbanization has a profound impact on soil carbon recycling. Based on spatial specific sampling of the urban soil and inversion of the urbanization history of Nanjing between 1900 and 2010, spatio-temporal relationship between spatial distribution of inorganic carbon in urban soil and urbanization processes was analyzed for assessment of inorganic carbon sequestration potential of urban soil. Results show that inorganic carbon density of the urban soil is closely related to history of the city, and it much higher in historical old regions than in newly urbanized regions, which indicates that the urban soil is highly potential in sequestration of inorganic carbon. The mean inorganic carbon density in the urban soil grows linearly with the development of urbanization. The inorganic carbon pool in the topsoil of the urban area studied reached 2.94 Tg and the area still had a potential of sequestrating1.45 Tg of inorganic carbon in future. All the findings in this study may serve as theoretical basis for elaborating the mechanism of carbon recycling in the urban system and conducting research on inorganic carbon sequestration in urban soil.