Nitrogen and phosphorous removal efficiency of Deyeuxia angustifolia wetland ecosystem in Sanjiang Plain.

An area(about 1 600 m~2) of Deyeuxia angustifolia wetland in Sanjiang Plain was selected to study the function of wetland ecosystems purifying environmental N and P pollutants.Results show that the N and P removal rates presented a rather steady trend during the vegetation growth and maturation periods,and the average removal rate was 85.62% and(85.94)%,respectively.The accumulated concentration of NH~+_4-N was significantly correlated with TN in the water body of the wetland.Input concentration,mowing and runoff all affected the purification function of the wetland and distribution of N and P.The removal rate decreased with the increase of input concentration and also with mowing.Limited runoff played little role in removing N and P.In a word,the purification efficiency of the Deyeuxia angustifolia wetland ecosystem in Sanjiang Plain was remarkable.The total removal rate of N and P reached 97.97% and 99.05%,respectively.