Effects Of Different Carbon And Nitrogen Management Practices On N₂O Emissions From Spring Maize Field

[Object]A field study was conducted to investigates the effects of fertilizer application strategies onN₂O emissions from spring maize field in north of China. The experiment included seven treatments, i.e.,control（CK）, farmer’s practice（NPK）, nitrogen reduction（60%N+PK）, straw return（S+NPK）, addingmanure fertilizer to farmer’s practice（M+NPK）, adding biochar to nitrogen reduction（C+60%N+PK） andmanure（M）.[Results] N₂O emissions from spring maize field under different treatments varying from 4.91⁴46.52μg·m-2·h-1; the maximum N₂O emission with 446.52 μg·m-2·h-1was by S+NPK treatment. The N₂Oemission under different treatments all presented pulse emission characteristics. The emission peak occursafter fertilization or rainfall events, the peak discharge usually lasts 15 to 30 days.The cumulative N₂O emission was 1.37 kg N· hm-2by NPK treatment during the growth period. Whenthe N application rates is equal, the cumulative N₂O emission was 0.34 and 0.35 kg N·hm-2higher inM+NPK and S+NPK treatment than that in NPK treatment, respectively; cumulative N₂O emissions in60%N+PK treatment reduce 49.6%, and the corn yield was not significantly decreased. C+60%N+PKtreatment significant reduce cumulative N₂O emissions and the yield was quite to NPK treatment.In this study, N₂O emission factor is range from 0.04% to 0.61%, which is lower than that in the IPCCrecommended value 1%. During the entire observation period, there had no correlation between N₂Oemission fluxes and soil moisture（WFPS） when WFPS ranged from 23%⁶5%; 5 cm soil temperature andN₂O emissions of NPK, M+NPK, S+NPK, C+NPK, M and 60%N+PK treatment showed a significantpositive correlation.[Conclusion]N2O emission from the spring maize fields under different treatments had similarseasonal patterns, the N₂O emission flux got to its peaks after fertilization or rainfall. Fertilization is one ofthe most important factors to influence the N₂O emission, application of different carbon and nitrogenfertilizer had different impact on N₂O emission. In this study, we found that adding manure and strawreturn can significantly increase cumulative N₂O emissions, and appropriate to reduce nitrogen fertilizerapplication can effectively reduce N₂O emissions and will not cause reduction of output.