nitrogen fixation


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ni·tro·gen fix·a·tion

process in which atmospheric nitrogen is converted to ammonia.

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 (-fĭk′sər) n.
ni′tro·gen-fix′ing adj.

nitrogen fixation

the utilization of atmospheric nitrogen in the synthesis of AMINO ACIDS by some bacteria. Such bacteria can be free-living (e.g. Azotobacter, an aerobe; Clostridium, an obligate anaerobe) while others (e.g. Rhizobium) live in association with plants, occupying swellings in the root called root nodules. The latter relationship is one of SYMBIOSIS, in that the plant gains nutrients and thus can live in nitrogen-poor soils, while the nitrogen-fixer obtains a supply of carbohydrates from the plant. The nitrogen is reduced to ammonia in the microbes by action of the enzyme nitrogenase: N2 + 3 H22 NH3, the ammonia then reacting with keto acids to form amino acids.
References in periodicals archive ?
Because the medium was essentially devoid of the natural isotope of nitrogen, organic [14N] that was found in the cyanobacterial cells would have come from nitrogen fixation because [15N] was the only available source of reduced nitrogen supplied.
The Overproduction of Indole-3-Acetic Acid (IAA) in Endophytes Upregulates Nitrogen Fixation in Both Bacterial Cultures and Inoculated Rice Plants.
Good estimation of biological nitrogen fixation (BNF) by cowpea genotypes can be obtained from N-accumulated by using the proposed model: Y = 0.0127[X.sup.2] - 0.5354X + 17.441, where Y and X represent N dfa-ID (kg N [ha.sup.-1]) and total N-accumulated (kg N [ha.sup.-1]), respectively.
Siddique & Bal (1991) reported that peanut is privileged by BNF, since plants are able to maintain nitrogen fixation even with poor supply of photosynthates.
Symbiotic Nitrogen Fixation; Prospects for Enhanced Application in Tropical Agriculture.
For example, to assist a joint USDA and N2Africa project to improve soybean production in Ghana in 2014, Elia carefully selected a mix of several strains from the collection that he thought could provide excellent nitrogen fixation, work well in an agricultural system that does not use mechanized farming equipment, and survive the area's harsh climate.
Excess amount of nitrogen in the solution may be utilized for cell metabolism of the bacteria rather than nitrogen fixation process.
The second edition contains 12 all-new chapters on topics like biological nitrogen fixation, case studies of cropping systems in China, Africa, and South America, and the impact of climate change.
(...) My gas will break the deadlock, make the war much shorter And therefore save millions from the slaughter." Harrison has Haber (who versified in real life) further say: "After the mental struggle of nitrogen fixation I turn to verse as an effortless relaxation."