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Related to Nitrification: Nitrifying bacteria, nitrogen cycle


Formation of nitrous and nitric acids or salts by oxidation of the nitrogen in ammonia; specifically, oxidation of ammonium salts to nitrites and oxidation of nitrites to nitrates by certain bacteria.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



the microbiological conversion of ammonium salts to nitrates, the main form of nutrient nitrogen for plants. Nitrification takes place in the soil and in bodies of water. It is the final stage of the mineralization of organic nitrogen compounds, which begins with ammonification, and it is an index of soil fertility. The process is caused by chemosynthesizing nitrifying bacteria.

Nitrification proceeds in two stages. An ammonium ion is oxidized to a nitrite ion by bacteria of the first stage, and then the nitrite ion is oxidized to a nitrate ion by bacteria of the second stage. Nitrification takes place at a soil pH of 5–9 and is carried out by aerobic organisms. An insufficiency of air in the soil leads to cessation of nitrification. Proper soil management improves aeration, thus intensifying nitrification.

As a result of the increasing combustion of fuel in industrial plants and internal-combustion engines, nitrogen oxides are formed in the atmosphere and are deposited in large amounts in the soil and in the water of reservoirs with rainfall. They are then converted to nitrates by the action of nitrifying bacteria. The excess concentration of nitrates in water makes it unsuitable for drinking. To prevent large-scale formation of nitrates in water, chemical preparations that prevent nitrification in the soil are sometimes used.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
One major problem is that nitrifiers with low growth rate can be washed out in the conventional activated sludge process, resulting in a reduction in the nitrification performance.
Furthermore, the alkalinity of the influent was increased to meet the nitrification demand.
Inactivation kinetics and mechanisms of viral and bacterial pathogen surrogates during urine nitrification. Environmental Science: Water Research & Technology 1/1: 65-76.
An HFBR with 55 sheets and surface plan area of 0.17[m.sup.2]/person, operated at the ambient temperature (20-35[degrees]C), could achieve BOD removal reached 95%; 70% nitrification and 78% total nitrogen removal.
The ratio of [BOD.sub.5] to T-N was around 2.1 which had too low carbon content to obtain effective biological nitrogen removal via nitrification and denitrification.
The crops which could not release these BNI compounds from their roots e.g., crucifers (Bending and Lincoln, 2000), their residues could be incorporated into soil for nitrification inhibition to improve crops N use (Subbarao et al., 2012).
Identification of bacterial morphology and analysis of colonies A set of culture plates with heterotrophic nitrification medium was prepared.
Many synthetic compounds have been commercialized for nitrification inhibition but few of them have been considered and patented as nitrification inhibitors (NIs).
Nitrification inhibitors at a glance: A number of compounds like dicyandiamide (DCD), nitrapyrin and 3,4-dimethylpyrazole phosphate (DMPP) have been reported to inhibit the nitrification process in soils (Zerulla et al., 2001; Gioacchini et al., 2002; Majumdar et al., 2002; Irigoyen et al., 2003) andreduce nitrous oxide emissions and nitrate leaching (Zaman andBlennerhassett, 2010).
The enzymatic potential of nitrification was measured according to Lensi et al.