Soil carbon dioxide efflux responds to land-use changes in the sub-urban regions of Nanjing, China

Abstract

The aim of this study was to assess the influence of urbanization on soil carbon dioxide efflux. We investigated how the soil environment affects the soil carbon dioxide efflux in native grassland, residential lawns and agricultural land. Continuous measurements of the soil carbon dioxide efflux were made once a week for a 10-week period during July-September 2013 in Nanjing China. Our results demonstrated that the soil carbon dioxide efflux significantly decreased during the10-week period in the three land-use types. Soil carbon dioxide efflux in urban lawns was the highest among the three land-use types in the following order: residential land > agricultural land > native grassland. The soil water-soluble organic carbon (WSOC), the labile organic carbon (LOC), and the basal respiration, as covariates, did not significantly influence the soil carbon dioxide efflux. The soil temperature and land-use type had significant contributions to the carbon efflux. A higher soil temperature in the lawns was attributed to the urban heat island effect. Our data suggest that human-induced land-use changes, such as urbanization and agricultural practice, could enhance the local soil carbon dioxide emissions, especially when urban development increased the local soil temperature.