To identify nitrous oxide(N2O)emissions under greenhouse vegetable systems,a field experiment with 4 treatments was performed in a typical vegetable field in Beijing suburbs using static chamber techniques.The impacts of nitrogen fertilizer application,soil temperature and moisture on N2O fluxes were also analyzed.The results showed that N2O fluxes from vegetable tomato fields showed visible dynamic variations due to the high fertilizer nitrogen(N)and irrigation water inputs.Compared to the farmers traditional practice,the decrease of fertilization management significantly reduced the cumulative N2O emissions by 42%,while the combination of the decrease fertilization and nitrification inhibitor treatment could reduce cumulative N2O emissions by 54%.The observed emission factors of the applied N for different treatments ranged from 055% to 115%.There was a significant positive correlation between N2O emissions and soil moisture for each treatment,whereas no significant correlation was found between N2O emissions and soil temperature.