The effects and mechanism of fertilizer additives on reduction of N₂O emission

It is of global scientific concern to increase both crop production and nitrogen use efficiency and meanwhile controlling environmental pollutions of nitrogen fertilizer application, such as greenhouse gas N2O emissions. The use of various fertilizer additives is one of the effective ways to achieve this goal. In this study, the effects and mechanism of different fertilizer additives on N2O emission in a typical agricultural soil on the North China Plain was investigated in laboratory by static incubation method under giving soil moisture and temperature. The results showed that the peak of N2O flux occurred within 2-4 days after fertilization, with earlier N2O emission by mixed application of urea than that by surface application. Interestingly, addition of nitrification inhibitor DMPP or DCD could significantly reduce total N2O emission by 99.2% and 97.1% respectively comparing with sole urea application, while there was no effect of copper sulfate on the inhibition of N2O emission. The total N2O emission increased by 60.7% after incorporation of straw with urea, and this increase of N2O emission could be eliminated completely to background level again after addition of nitrification inhibitor DMPP. The results indicated that the N2O production of investigated soil was driven by nitrification process and that nitrification inhibitor could be an effective measure to reduce N2O emissions.