Effects of emerged plant on soil methane emission and nitrogen content in constructed wetland

To find the effects of emerged plant on soil methane (CH4) emission and nitrogen content in constructed wetland, we constructed the constructed wetland microcosms with 3 treatments through 2 emerged plants (Typha orientalis and Phragmites australis). Results showed that soil CH4 flux have no different (2.0, 2.4, 2.5 mg m⁻² d⁻¹, P > 0.05), but soil nitrogen contents and microbial biomass nitrogen were significantly different (P < 0. 01) among the 3 treatments. The soil ammonium nitrogen (P < 0.001) and nitrate nitrogen (P < 0.01) contents in the planted constructed wetland were lower than in those unplanted constructed wetland, but microbial biomass nitrogen (MBN) were higher (P < 0.01). The soil CH4 flux, microbial biomass, organic matter and nitrogen content had no different between those constructed wetlands planted with Typha orientalis and Phragmites australis (P > 0.05). As total plant biomass in the constructed wetlands planted with Typha orientalis (P < 0.001) were higher than that in the constructed wetlands planted with Phragmites australis (P < 0.05). Hence, emerged plant regulate soil nitrogen removal but not affect soil CH4 emission in these systems.