Abstract: To identify the effect of salinity on dissolved organic carbon (DOC) concentration and the rate of carbon dioxide (CO₂) production of soil, we collected soils from reed wetland in Liaohe estuary at different depths (0-10, 10-20, 20-30 and 30-40 cm). After washed to different salinity levels (CK, 2.5, 5, 10 mS·cm^-1) with synthesized saline solution, soil samples were incubated for 56 days at 28 ℃. The results showed that salt treatment had no significant effect on the DOC concentration in the topsoil layer (0-10 cm) during the 56d incubation period, but significantly affected the DOC concentrations in the subsoil layers (10-20, 20-30 and 30-40 cm), and elevated salinity decreased the DOC concentration. However, salt treatment had no significant effect on the rate of CO₂ production in any soil layers. The DOC concentration and CO₂ production rate were significantly different among different soil layers, and the mean values were significantly higher in the topsoil layer than in the subsoil layers. The results provide a basis for understanding the response of carbon cycles to salt changes in estuary wetlands.

Key words: MaxEnt model, Chongqing, climate change, Brassica juncea var tumida, dominant factor