Abstract: To explore the effects of waterlogging and salt condition on soil water and salt transportation of estuary wetlands in the Yellow River Delta, we examined the infiltration process and water/salt redistribution process in the soils of three plant communities dominated by Tamarix chinensis, Phragmites australis and Suaeda salsa, respectively, by soil column experiments in laboratory. The Hydrus-1D model was used to simulate the distribution of water content and salt in soil profile after water infiltration and redistribution. The results showed that water depth significantlyaffected soil water transportation. Under different water depth conditions, the infiltration rates of three soil types showed a similar trend of rising first and then falling. The infiltration rates were decayed and tended to stabilize with the prolongation of infiltration time. At the end of the infiltration experiment, soil salt contents of 0-30 cm layer were similar to those of the infiltration water, while those of the water and salt transportation bottom (100 cm soil depth) were close to the salt contents in original experiment soils. After the water and salt redistribution experiment, the differences of soil water content of each soil layer were decreased, and salt contents of each layer basically unchanged compared with those at the end of the infiltration experiment. Our results indicated that Hydrus-1D model could well simulate the infiltration processes of soil water and salt, as well as the whole change trend of soil profile, providing a theoretical basis for the regulation of water and salt in estuarine wetlands and the restoration of wetland hydrological connectivity.

Key words: Hydrus-1D model, water and salt transportation, estuarine wetland, Yellow River Delta.