Influences of nitrogen forms on soil NO2 emissions and vegetable yield

A plot experiment was conducted to determine different nitrogen forms，including urea，calcium nitrate and ammonium sulfated，on N2O emissions，vegetable yield and nitrate concentration. The results showed that applying different forms of nitrogen fertilizer could increase N2O emissions，the peak of N2O emissions appeared in 2-3 days after fertilizer，the peak of N2O emissions in treatments of urea，calcium nitrate and ammonium sulfated were 0.22，0.18 and 0.14 mg/m2·h，respectively. After 6 days，N2O emissions decreased to the control level. The dry matter accumulation and vegetable nitrogen content were significantly different between the control and the treatments，but there was no remarkable difference in dry matter accumulation among different nitrogen form treatments. The results indicated that the application of ammonium nitrogen（ammonium sulfate）could effectively reduce N2O emissions，while ensure the yield of vegetable.