Nitrogen form affects nitrous oxide emission by regulating root exudates and microbial communities in constructed wetlands

The aim of this study was to investigate the followings: (1) N2O emission from CWs with NH4+-N or NO3--N influents and the conversion and removal efficiencies of different nitrogen forms; (2) nitrogen uptake by plants and its form difference affects weight of Acorus calamus L. biomass and amount of root exudates in CW; (3) response of microbial community structure and functional genes (amoA, nirS, nirK, and nosZ) in nitrogen transformation to different nitrogen forms and root exudate amount in CW.