Ammonia-Oxidizing Bacteria (AOB)

Last updated: March 22, 2019

What Does Ammonia-Oxidizing Bacteria (AOB) Mean?

Ammonia-oxidizing bacteria (the Nitrosomonas genus) play an important role in the nitrification process. Their role in the garden is to convert ammonia into a usable form for plants. The oxidation of ammonia by bacteria converts it nitrites, which plants can uptake (mobilize).

Ammonia-oxidizing bacteria are a type of nitrifying bacteria, in which there are two types: ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB).

Nitrifying bacteria get their energy by the oxidation of inorganic nitrogen compounds. This is done in a two step process; first, the AOB convert ammonia into nitrite, and then the NOB turn the nitrite into nitrate.


Maximum Yield Explains Ammonia-Oxidizing Bacteria (AOB)

Nitrifying bacteria are highly concentrated in areas where there are considerable amounts of ammonia are present, especially lakes and rivers streams where sewage and wastewater are present. They are also present in freshwater due to its high ammonia content.

Ammonia-oxidizing bacteria are an essential part of an aquaponics system. This is because in an aquaponic system, ammonia (which is present in high amounts due to fish excrement) must be oxidized into nitrate to prevent toxicity to fish.

According to botanists, ammonia-oxidizing bacteria has been shown to dominate nitrification-related activities as far as semi-arid crops and agricultural soil are concerned. In some cases, soybeans are used as a nitrogen supplier since they tend to release flavonoids that enhance both bacteria and nitrogen growth around the roots of the plant.

Research carried out on Chinese agricultural landscapes showed that excessive soil nitrification can be detrimental to crops, resulting in commercial losses. In the 19th century, scientists discovered that conversion of ammonia oxidation to nitrite is often triggered by ammonia-oxidizing bacteria. According to botanists, the following soil conditions control nitrification rates:

  • Temperature: the best temperature ranges between 20 and 30 degrees C
  • PH: Near neutral
  • Drained growing soils: 60% moisture
  • Aeration: For proper oxygenation across the roots

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