BACKGROUND: Generally, nitrogen (N) fertilization higher than the recommended dose is applied during vegetable cultivation to increase productivity. But higher N fertilization also increases the concentrations of nitrate ions and nitrous oxide in soil. In this experiment, the impact of N fertilization was studied on nitrous oxide (N2O) emission to standardize the optimum fertilization level for minimizing N2O emission as well as increasing crop productivity. Herein, we developed N2O emission inventory for upland soil region during red pepper and Chinese milk vetch cultivation. METHODS AND RESULTS: Nitrogen fertilizers were applied at different rates to study their effect on N2O emission during red pepper and Chinese milk vetch cultivation. The gas samples were collected by static closed chamber method and N2O concentration was measured by gas chromatography. The total N2O flux was steadily increased due to increasing N fertilization level, though the overall pattern of N2O emission dynamics was same. Application of N fertilization higher than the recommended dose increased the values of both seasonal N2O flux (94.5% for Chinese cabbage and 30.7% for red pepper) and N2O emission per unit crop yield (77.9% for Chinese cabbage and 23.2% for red pepper). Nitrous oxide inventory revealed that the N2O emission due to unit amount of N application from short-duration vegetable field in fall (autumn) season (6.36 kg/ ha) was almost 70% higher than that during summer season. CONCLUSION: Application of excess N-fertilizers increased seasonal N2O flux especially the N2O flux per unit yield during both Chinese cabbage and red pepper cultivation. This suggested that the higher N fertilization than the recommended dose actually facilitates N2O emission than boosting plant productivity. The N2O inventory for upland farming in temperate region like Korea revealed that N2O flux due to unit amount of N-fertilizer application for Chinese cabbage in fall (autumn) season was comparatively higher than that of summer vegetables like red pepper. Therefore, the judicious N fertilization following recommended dose is required to suppress N2O emission with high vegetable productivity in upland soils.