A year maize -wheat rotation field e xperiment with 4treatments was conducted to measure
denitrification lo sses and N
2 O emission from fertilizer nitrogen a pplied to fluvo -aquic soil by acetylene -inhibition soil -core incubation method.The results showed that during the whole year N 2 Oemission fromthe applied Nwas 1.77～2.82kg N·hm -2 ,accounting for 0.49%～0.76%of the applied N;while the correspon ding figures of
denitrification loss were 3～3.18kg N·hm -2 and 0.81%～0.86%of the applied N.The denitrification loss rates from maize and wheat fields were resembled i.e 0.7%～0.99%and 0.77%～0.88%,respectively.Both Denitrificatio n and
N 2 O emission were closely related to th e soil water contents.Application o f organic manure mixed with urea increased N 2 O emission in comparison with applic ation of urea alone.The results indi cated that denitrification was not an important pathway of Nloss in t he rotation system.However,N 2 Oemission was greatly increased by a pplication of Nfertilizer,which might affect environmental qu ality.