The effect of different flooding duration on soil organic carbon and its labile fraction in the riparian zone of Three Gorges Reservoir Area

摘要

The labile fractions of organic carbon (OC) in soil can respond rapidly to changes in C supply and have been suggested as a sensitive indicator of soil quality. The object is to determine soil organic C and its labile fractions at the duration of different flooding. Three elevation gradient sites were chose: below 145m (permanently flooding site), 145-175m (seasonal flooding site), and above 175m (never flooding site) in the riparian zone of Three Gorges reservoir Area. The results showed that soil OC, dissolved organic C (DOC) and water-soluble carbohydrate (WSCh) were lower under seasonal flooding sites than those of never flooding upland and permanently flooding sites, whereas microbial biomass C (MBC) decreased with the flooding duration. Correlation analysis showed that soil OC and MBC had significantly positive relationship with DOC. The results suggested that seasonal flooding significantly affected soil OC and its labile fractions in the riparian zone of Three Gorges reservoir Area.