The spatial distribution of the nitrogen could reflect the course of the environmental change in the wetland to a certain extent.The content of the organic matter and the total nitrogen in the sediment

pore water and overlying water were analyzed for the three typical areas in Baiyangdian wetland.Results showed that the vertical distribution of the organic matter and the total nitrogen in sediment were all gradually decreases from upper to the lower

and the horizontal distribution of them in surface soil were distinctly different.There was a lower content of the total nitrogen and a higher content of the NH 4-N at 6 cm in sediment.It showed that 6 cm in sediment was an activity area of degradation organic nitrogen in Baiyangdian wetland.The content of NH 4-N and NO-3-N in upper water of bulrush area was higher than openness lakeland.The results implied that the hydrophyte in wetland could accelerate nitrogen liberation and increase nitrogen settling.At the same time

the metabolite and relict from hydrophyte could increase the nitrogenous concentration in water.So

the harvesting and refloatation was a necessary measure to reduce the nitrogen input.