Halophyte Plant Communities Affecting Enzyme Activity and Microbes in Saline Soils of the Yellow River Delta in China

The Yellow River Delta covers a large area of saline soil, which needs to be recovered urgently. As the main local halophytes Suaeda salsa, Phragmites australis, and Tamarix chinensis communities play an important role in the improvement of the soil microenvironment. Therefore, we investigated the effect of these three salt-tolerant plant communities on soil enzyme activity in the Yellow River Delta in China. Halophyte plant communities influence the soil micro-ecosystem in the wetland by exerting effects on the physicochemical properties of the soil, and on enzymes andmicrobial community. In the soil these enzymes affect the redox potential (catalase) and cycling of carbon (dehydrogenase), nitrogen (protease, urease), and phosphorus (acid phosphatase). We analyzed enzyme activity and the relations between the activity of different enzymes, the physicochemical properties of the soil, and the microbial composition. The activity of five enzymes differed significantly between the plant communities. Soil salinity and microbial community composition all influenced enzyme activity. Catalase, protease and urease activity in the soil of the T. chinensis community was significantly higher than in the other two plant communities. Dehydrogenase and acid phosphatase activity were significantly higher in the soil of the P. australis community than in the other two communities. In the succession of the plant community from herbs to woody plants with different salt tolerance mechanisms, a large aboveground biomassmay support the growth of soil enzyme activity and soilmicroorganism diversity. This study showed that the belowground processes were strongly related with plant community succession in salt marsh ecosystem.