Simulation of changes in some soil properties as affected by water level fluctuation in an inland salt marsh

Abstract

Abstract An 87-day simulation experiment was conducted to test the effects of water level fluctuation on soil properties of an inland salt marsh. The simulated wetland was periodically flooded for 15 days with consistent water levels of 10 cm above the wetland surface soil and then drained to 0 cm for 9 days. Soil samples were collected from the 0 to 30 cm depth with 10 cm intervals at days of 0, 39 and 72 after a 15-day pre-incubation. Total nitrogen (TN), total phosphorus (TP), soil organic matter (SOM) and pH were determined during the experimental period. Results showed that TN content was much higher in surface soils than other soil layers during the whole incubation period, especially at the second inundation period (54 days), and TN greatly increased in the soil layers above 20 cm with increasing incubation time. However, the SOM content in each soil layer showed a consistent tendency of “decreasing followed increasing” with increasing incubation time. Compared to other soil layers, SOM content in surface soils were generally higher during the simulation periods. TP content in upper soils (0-20 cm) consistently increased over the course of incubation time, while those in deeper soils (20-30 cm) decreased. Soil pH values showed similar changing tendencies to SOM content over the incubation experiment, while they generally increased with depth.