Nitrification in Agricultural Soils, Microbial Players and Their Interactions with Management.

Nitrification in Agricultural Soils, Microbial Players and Their Interactions with Management.

Jeanette Norton

Nitrification changes the form of nitrogen (converting ammonium/ammonia to nitrite and nitrate) and thereby alters the fate of N in agricultural soils. Since many of the soil nitrifiers are difficult to culture, molecular tools are used extensively to characterize the community responsible for nitrification in soils. Although nitrifying bacteria have been investigated for more than a century, recent metagenomic surveys revealed that the genetic potential for ammonia oxidation was also present in members of the Crenarchaeota phylum. The complete genomes of Nitrosomonas europaea ATCC 19718, Nitrosomonas eutropha C71, Nitrosospira multiformis ATCC 25196, Nitrobacter hamburgensis X14, Nitrobacter sp. Nb-311A, Nitrobacter winogradskyi Nb-255, Nitrococcus mobilis Nb-231, Nitrosococcus oceani ATCC 19707, and Candidatus Nitrosopumilus maritimus SCM1 have added to our knowledge of the metabolism of these important organisms.  Methods for determining the rates and kinetics of the nitrification process are progressing simultaneously. Summaries of the known interactions of nitrification with agricultural management will also be presented. Advances in all these areas have moved us closer to the goal of linking the capable organisms to the process rate and extent in the environment.