Abstract: Nitrous oxide (N2O) is an important greenhouse gas and agricultural soil is a major source of N2O emission.Effect of different fertilization treatments on N2O emissions of spring corn fields in North China plain was continuously monitored using an automatic sampling and analyzing system.Fertilizer treatments included urea (U),urea mixed with 10% and 5% by N-weight of dicyandiamide (DCD1, DCD2),sulfur coated urea (SCU),and non-fertilizer (CK).Experiment results showed that,(1) the total N2O emissions of the five treatments were U＞SCU＞DCD2＞DCD1＞CK.The emission factors ranged from 0.20% to 0.71%.In DCD treated plots, soil N2O fluxes were 59.5% (DCD1) and 47.1% (DCD2) lower than N2O fluxes in urea plots.There was no significant difference between SCU plots and U plots on N2O fluxes.The N2O fluxes of SCU plots and U plots were significantly higher than DCD plots (P＜0.01).(2)The peak of N2O emissions occurred while WFPS(Water Filled Pore Space) increased significantly，N2O fluxes of all treatments and soil WFPS correlated significantly (P＜0.01).(3)The DCD2 treatment could save about 178 yuan while reducing 1t CO2 equivalent.It can be used as a technical measure to reduce N2O emissions from spring corn field.

Key words: Spring corn, Nitrous oxide, Emission factor, Dicyandiamide, Sulfur coated urea