SPATIAL DISTRIBUTION CHARACTERISTICS OF SOIL ORGANIC MATTER AND NITROGEN UNDER NATURAL CONDITIONS IN YANCHENG COASTAL WETLANDS

SOM (soil organic matter) and N (nitrogen) are important ecological factors in coastal wetland ecosystems. A specific area in Yancheng coastal wetlands was chosen and monitored on the spot in April 2012, spatial distribution characteristics of SOM and N and the relationship between them were analysed. The results showed that the content of SOM and N differs significantly in various vegetation types, their content in Spartina marshes is the highest, followed by Reed marshes, Suaeda marshes and the mudflat. The average content of SOM and N in them were 1.138%, 1.103%, 0.851%, 0.399% and the average value of total nitrogen were 489.935 mg/kg, 369.811 mg/kg, 365.491 mg/kg, and 95.542 mg/kg respectively. Furthermore, SOM and TN (total nitrogen), TN and ammonia nitrogen (NH3-N) in the coastal wetlands are closely related and fit perfectly for linear regression equation, however, the correlation coefficient for OM (organic matter)and NH3-N is low and fits well for the cubic curve equation. The specific value of carbon and nitrogen are the highest in the mudflat, followed by Reed marshes, Spartina marshes and Suaeda marshes. The specific value of NH3-N and TN are the highest in the mudflat and in Spartina marshes, Reed marshes and Suaeda marshes are close to it. Vegetation coverage conditions and physiological characteristics of plants are important factors affecting spatial distribution of SOM/N in coastal wetlands.