Effects of fresh water restoration on dynamics of water and salt information in salt marsh soils of the Yellow River Estuary, China

Information of spatial distribution of water and salt in wetland soil helps to understand adaptation mechanisms of plant communities in saline habitats， and to elucidate the physical, chemical and biological processes of soil ecosystems. Surface soil samples were collected in the present work from salt marshes and freshwater restoration wetland in the Yellow River estuary in plant growing season typical soil profiles were collected in spring, summer and autumn. Soil water and salt information was analyzed to elucidate vertical distributions and seasonal variations in soil water and salt information in both wetland types and their correlationship. Data showed that salt marsh soils had higher electrical conductivity (EC) than freshwater restoration wetland soils but decreased gradually in the growing season, while soil EC values first decreased then increased after water and sediment regulation in freshwater restoration wetland. Soil water contents (WC) of both wetland types increased slowly in the growing period, soil WC increased significantly after water and sediment regulation in freshwater restoration wetland. WC and EC values of salt marsh soils fluctuated with increasing soil depth. WC in the freshwater restoration wetland was: upper layer>bottom layer>middle layer before and after water and sediment regulation. EC in the freshwater restoration wetland showed the opposite trend. There was a significant positive correlation between EC and SO2-4／Cl-(P<001) in surface soil of salt marshes and freshwater restoration wetland, while soil EC only exhibited positive correlation with Cl-(P<005) in freshwater restoration wetland. The dynamic changes in soil water and salt information in wetland of the Yellow River estuary are therefore affected by heterogeneity of resources under different flooding conditions.