[Effects of nitrogen application on N2O flux from fluvo-aquic soil subject to freezing and thawing process].

The experiment was conducted to investigate the effects of different forms of nitrogen application (ammonium, NH4(+) -N; nitrate, NO3(-) -N; and amide-N, NH2-N) and different concentrations (40, 200 and 800 mg/L) on N2O flux from the fluvo-aquic soil in a lab-simulated freezing and thawing process. N2O flux slowly decreased with soil freezing, and then increased slowly with soil thawing, reaching a peak at the initial thawing stage. The average N2O fluxes with addition of NH4(+) -N, NO3(-) -N and NH2 -N are 119.