Nitrification in agricultural soils: impact, actors and mitigation

• Published in: Current opinion in biotechnology Vol. 50; pp. 166 - 173
• Main Authors: Beeckman, Fabian, Motte, Hans, Beeckman, Tom
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2018
• Subjects: Agriculture; Ammonia - metabolism; Bacteria - metabolism; Nitrification; Oxidation-Reduction; Soil
• ISSN: 0958-1669; 1879-0429
• DOI: 10.1016/j.copbio.2018.01.014

[Display omitted] •Nitrification causes nitrogen losses with impact on crop yield and environment.•Newly discovered microbes can be important for nitrification in agricultural soils.•Recent studies revealed distinctly evolved ammonia oxidation pathways.•Current nitrification inhibitors show no or limited efficiency on the novel players. Nitrogen is one of the most important nutrients for plant growth and hence heavily applied in agricultural systems via fertilization. Nitrification, that is, the conversion of ammonium via nitrite to nitrate by soil microorganisms, however, leads to nitrate leaching and gaseous nitrous oxide production and as such to an up to 50% loss of nitrogen availability for the plant. Nitrate leaching also results in eutrophication of groundwater, drinking water and recreational waters, toxic algal blooms and biodiversity loss, while nitrous oxide is a greenhouse gas with a global warming potential 300× greater than carbon dioxide. Logically, inhibition of nitrification is an important strategy used in agriculture to reduce nitrogen losses, and contributes to a more environmental-friendly practice. However, recently identified and crucial players in nitrification, that is, ammonia-oxidizing archaea and comammox bacteria, seem to be under-investigated in this respect. In this review, we give an update on the different pathways in ammonia oxidation, the relevance for agriculture and the interaction with nitrification inhibitors. As such, we hope to pinpoint possible strategies to optimize the efficiency of nitrification inhibition.