nitrogen fixation

noun

: the conversion of atmospheric nitrogen into a combined form (such as ammonia) through chemical and especially biological action (such as that of soil rhizobia)

Examples of nitrogen fixation in a Sentence

Recent Examples on the Web
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When two became one Until this discovery, the ability to transform nitrogen from a gas into a usable form — something called nitrogen fixation — was a feat that scientists thought only certain kinds of bacteria and other simple microbes could pull off. Ari Daniel, NPR, 18 Mar. 2025 Consider inoculating pea seeds before planting to increase nitrogen fixation rates. Lauren Landers, Better Homes & Gardens, 20 Feb. 2025 But if they are grown in soil that is too acidic, nitrogen fixation is reduced and pea plants won’t grow well.1 To keep pea crops healthy, grow these plants in rich, well-draining soils with a pH between 6.0 and 7.5. Lauren Landers, Better Homes & Gardens, 20 Feb. 2025 At present, nitrogen fixation—the chemical process required to produce ammonia from nitrogen gas—is hugely energy intensive, accounting for as much as two percent of the world’s annual energy budget. Charina Chou, Foreign Affairs, 7 Jan. 2025 Clearly, this is a recurring theme in the world of nitrogen fixation. Quanta Magazine, 17 July 2024 Legume seeds can be inoculated with rhizobia bacteria before planting to enhance nitrogen fixation even further. Lauren Landers, Better Homes & Gardens, 1 Aug. 2024 The relationship appears to represent a significant chunk of nitrogen fixation on Earth. Quanta Magazine, 17 July 2024 There are other approaches to possibly increasing nitrogen fixation on cropland. Matthew Hutson, The New Yorker, 6 Feb. 2024

Word History

First Known Use

1893, in the meaning defined above

Time Traveler
The first known use of nitrogen fixation was in 1893

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Cite this Entry

“Nitrogen fixation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/nitrogen%20fixation. Accessed 25 Mar. 2025.

Kids Definition

nitrogen fixation

noun
: the changing of free nitrogen in the air into a combined form (as ammonia) especially by bacteria in the soil and in roots

Medical Definition

nitrogen fixation

noun
1
: the industrial conversion of free nitrogen into combined forms useful especially as starting materials for fertilizers or explosives
2
: the metabolic assimilation of atmospheric nitrogen by soil microorganisms and especially rhizobia and its release for plant use by nitrification in the soil on the death of the microorganisms

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