Nitrous oxide flux in constructed wetland with/without plant

To investigate the effect of plant presence on the nitrous oxide flux, we established constructed wetland using two common plant species. Results showed that nitrous oxide emissions have significant difference between constructed wetlands with and without plants, 7567.64 ug N2O m−2 d−1 and 492.67 ug N2O m−2 d−1 respectively (P < 0.001), contrary to microbial biomass nitrogen and total nitrogen content (P > 0.05). The nitrous oxide emissions in constructed wetlands planted with Phragmites australis and Lythrum salicaria had significant differences, 13328.72 ug N2O m−2 d−1 and 1806.56 ug N2O m−2 d−1 respectively (P < 0.001), and they were significantly higher than in constructed wetlands without plant (P < 0.001). The total nitrogen content in constructed wetlands planted with Phragmites australis and Lythrum salicaria had no significant differences (P > 0.05). Hence, plant presence and plant species are important factors in regulating nitrous oxide emissions and total nitrogen removal in constructed wetlands.