Ammonia(NH3)volatilization is a major path of N losses from applied nitrogen fertilizers, which not only results in economic loss-es, but also poses risks to the environment. A field experiment was set up in Yutian county, Hebei Province, to evaluate the NH3 volatiliza-tion in fluvo-aquic clay soil under applications of different fertilizers. There were four treatments with four replicates per treatment:fresh cow manure+urea(RAW), composted cow manure+urea(COM), NPK fertilizer(NPK), and control with no N fertilizer(CK). The manures and chemical fertilizer were applied at a rate of 225 kg N·hm-2, with half mixed into the soil as basal fertilization before planting and the other half applied to the soil as a top dressing after plant emergence. A continuous air-flow enclosure method was used to monitor NH3 volatilization rates during a winter wheat growing season. The highest cumulative amount of NH3 volatilization during the wheat growing sea-son was measured in the RAW treatment with a net loss through NH3 volatilization of 1.97%of the N applied, which was significantly higher than that in the COM and NPK treatments. Up to 80%of the total NH3 volatilization occurred after top-dressing. Soil temperature was iden-tified as a key factor affecting NH3 volatilization during the basal fertilization period and the flux of NH3 volatilization was significantly cor-related with soil moisture and NH+4-N contents after top-dressing.