Abstract: The mean N₂O emission from paddy field under continuously flooding, alternately flooding and soil draining, and drying was 1.02, 23.87 and 47.99μg·m^-2·h^-1,respectively. Application of chemical N fertilizers could increase N₂O emission, and ammonium sulphate seemed to emit more N₂O than urea. The fertilizer induced N₂O Nloss from ammonium sulfate was 0.04% at the application rate of 100kg·hm^-2, and 0.26% at the rate of 300kg·hm^-2. The corresponding loss was 0.03% and 0.15% from urea.

Key words: Paddy field, Nitrous oxide, Flux, Water regime, N fertilizer forms, high-throughput sequencing, bacterial community, nitrogen deposition, Lefse analysis