Nitrogen cycle and nitrous oxide production

The present industrial fixation of nitrogen surpasses the level of its biol ogical fixation. The increased concentration of nitrous oxide in the atmosp here is associated with the combustion of all fuels, forest fires, and the application of nitrogen-containing industrial fertilizers. The production o f nitrous oxide in the soil results from nitrification and denitrification processes. Cultivated soils are the main biological source of nitrous oxide , and the primary factor of its production is the application of mineral fe rtilizers. It was shown that about 1% of the nitrogen added with fertilizer s volatilized from the soil as N2O. The principal sources of nitrous oxide over the territory of Russia are the combustion of fossil fuels and forest fires. The contribution of the biological sources of N2O is apparently no m ore than 30-35% of its total emission. Because of the abruptly decreased us e of nitrogen fertilizers in Russia, their contribution to the total nitrou s oxide emission is evidently no more than 2-3%. The total amount of nitrou s oxide emitted in the territory of Russia is probably no more than 2.9 mil lion tons N per year.