Unformatted text preview: Nitrogen Fixation by Combustion and Lightning The NZ molecule is relatively inert and unreactive. Tvvo sources of N oxides are internal combustion engines
and lightning. lntemal combustion engines produce NO and N01 because
the high internal temperatures and pressures cause
atmospheric N3 and O: to react. Lightning provides similar energy. Nitrogen Fixation by Combustion and Lightning Lightning produces approximately 9.4 million metric tons
of N oxides each year. 20 million metric tons of N/yr released by combustion. Estimates of other global anthropogenic fixation of N1: 50 - 80 million metric tons/yr of chemical N fertilizer. 35 million metric tons of N/yr fixed by agricultural
plantrngs of N-frxrng legumes. 25 million tons of N recycled in non-agricultural
anthropogemc \vastes. N Mineralization and Immobilization Mineralization is the release of inorganic nitrogen (NH 4*) from organic residues by decay organisms.
Mineralization is accomplished by a variety of microbes that
convert complex proteins into amine groups (R-NHZ) Which are then hydrolyzed to ammonium (NH 4+). xi; of Soil N mineralizes annually. ...
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- Spring '08