Abstract: To clarify the indication and response of soil and plant stoichiometric ratios of natural coastal wetlands in the abandoned course of Yellow River to the development process of coastal wetlands, we selected bare tidal flats (BF), Suaeda salsa dominated wetlands (SW), Tamarix chinensis dominated wetlands (TW), and Phragmites australis dominated wetlands (PW) as the objects. We analyzed the carbon (C), nitrogen (N), and phosphorus (P) contents and their stoichiometric ratios of soils and plants of natural coastal wetlands to examine the nutrient limitation status. The results showed that there were significant differences in soil nutrient contents among different types of natural coastal wetlands. The total carbon (TC) and total nitrogen (TN) contents of soils generally followed the order of PW>TW>SW>BF. The TC and TN contents in the surface layer of soils were higher than those in the deep layer of soils, while the total phosphorus (TP) content did not show a clear pattern of change in vertical profiles. Soil TC content was significantly positively correlated with C∶P and N∶P, while TN content was significantly correlated with C∶N and N∶P. Considering the relatively stable contents of soil TP, the soil was limited by N in the study area. The utilization of soil nutrients by different plant communities was different. The TC, C∶N, C∶P, and N∶P of P. australis community were significantly higher than those of other plant communities. Though the S. salsa community had the highest TN and TP contents, C∶N, C∶P and N∶P were lower than those of other plant communities. The N∶P values of plant communities were higher than the national average level in China, and P utilization rate was low, indicating that the growth and development of typical plant communities in this area were mainly limited by P. Our results will provide reliable data support for the restoration and conservation of wetland vegetation in the abandoned Yellow River course.

Key words: coastal wetland, stoichiometric ratio, carbon, nitrogen, and phosphorus, vegetation type, abandoned Yellow River course