| nitrogen fixation n. 1. The conversion of atmospheric nitrogen into compounds, such as ammonia, by natural agencies or various industrial processes. 2. The conversion by certain soil microorganisms, such as rhizobia, of atmospheric nitrogen into compounds that plants and other organisms can assimilate. ni  tro·gen-fix er (n tr -jn-f ksr) n.ni tro·gen-fixing adj. |
nitrogen fixation
n
1. (Life Sciences & Allied Applications / Biology) the conversion of atmospheric nitrogen into nitrogen compounds by certain bacteria, such as Rhizobium in the root nodules of legumes
2. (Chemistry) a process, such as the Haber process, in which atmospheric nitrogen is converted into a nitrogen compound, used esp for the manufacture of fertilizer
nitrogen-fixing adj
| nitrogen fixation The process by which free nitrogen from the air is combined with other elements to form inorganic compounds, such as ammonium ions, which can then be converted by nitrification into nutrients that can be readily absorbed by plants and other organisms for incorporation into more complex organic compounds. During lighting strikes, the atmosphere's free nitrogen molecules (N2) are broken apart and combine with oxygen to form nitrogen oxides that dissolve in rain to form nitric acid; atmospheric nitrogen is also fixed industrially under high pressure and heat to form ammonia, as in the production of fertilizers. Many species of cyanobacteria and certain other forms of bacteria, especially those that live in the roots of legumes, conduct nitrogen fixation as part of their metabolism, using the enzyme nitrogenase to combine nitrogen with hydrogen as ammonia. All living organisms are dependent on nitrogen fixation and would ultimately die without it. See more at nitrogen cycle. |
ThesaurusLegend: Synonyms Related Words Antonyms
| Noun | 1. |  nitrogen fixation - the assimilation of atmospheric nitrogen by soil bacteria and its release for plant use on the death of the bacteriabiological process, organic process - a process occurring in living organisms |
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