Effects of Carbon Addition and Biochemical Control on N2O Emission from Facility Vegetable Soil

The experiment was carried out with soil of greenhouse in Yongqing, Hebei Province, under constant temperature(25±1)℃ and soil moisture (70% WFPS), using the static incubation method to study the effect of different management controls, i.e. urea, controlled release urea, straw, biochar, dicyandiamide (DCD), CaCN2, straw and CaCN2 while covering the shed, organic fertilizer, on N2O emission and nitrogen transformation. The results showed that the N2O emission peaks reached 644.11 μg N·kg-1·d-1 with the addition of urea in soil, while the ad-dition of DCD or CaCN2 not only reduced the N2O emission to 101.47 μg N·kg-1·d-1 or 36.74 μg N·kg-1·d-1 relatively, but also inhibited the production of nitrite nitrogen effectively. Controlled release urea, biochar or organic fertilizer could play a role to reduce N2O emission, while adding CaCN2 and covering the shed significantly increased the N2O emission. Controlled release urea, straw, biochar, DCD and CaCN2 inhib-ited the transformation from ammonium to nitrate nitrogen. CaCN2 and organic fertilizer could reduce the transformation from nitrate to nitrite. Correlation analysis showed that the increase of the content of nitrate or nitrite in soil contributed to the process of denitrification and N2O e-missions