Nitrogen fixation

The conversion of atmospheric nitrogen to biologically usable nitrates.

The conversion of atmospheric nitrogen gas to oxidized forms that can be assimilated by plants, particularly by blue-green algae and some genera of bacteria (e.g. Rhizobium spp.; Azotobacter spp.). An important source of nitrogen in unfertilized soils. See: nif gene cluster.

The transformation of atmospheric nitrogen into nitrogen compounds that can be used by growing plants.

Conversion of atmospheric nitrogen gas into forms useful to plants and other organisms by lightning, bacteria, and blue-green algae; it is part of the nitrogen cycle.