Effects of Spartina alterniflora invasion in eastern Fujian coastal wetland on the physicochemical properties and enzyme activities of mangrove soil

Using space method instead of time, and combined with variance analysis, multiple comparison and Pearson related analysis, differential analysis in soil physicochemical properties, enzyme activity and their correlations were made in different stages of community types (Kandelia candel red wood community, Kandelia candel red wood-Spartina alterniflora symbiosis community, Spartina alterniflora community and bare beach) invaded by Spartina alterniflora in eastern Fujian coastal wetland, trying to explain the soil science mechanism of Spartina alterniflora invasion. Results showed that: Spartina alterniflora's invasion increased soil density, decreased the pH value of soil, moisture content, and reduced the concentrations of soil organic carbon, organic matter, total nitrogen and total phosphorus. It also increased the soil enzyme activities of invertase, alkaline phosphatase and catalase, and decreased urease activity. Correlation analysis showed that, there was a close relationship between soil enzyme activity and soil physicochemical factors. Among them, sucrose enzyme was very significantly positively correlated with total nitrogen, total P and water content, was very significantly negatively correlated with pH value and soil density; urea enzyme was significantly positively correlated with water content, was significantly negatively correlated with soil density; alkaline phosphate enzyme was significantly positively correlated with total P and water content, was significantly negatively correlated with soil density; hydrogen peroxide enzyme had no correlations with physicochemical factors. This study provides theoretical basis for the treatment of Spartina alterniflora.