Nitrification

Nitrification. When organic nitrogenous matter, such as animal refuse, decayed vegetation, manure, etc., is exposed to the air, a portion of the nitrogen becomes converted into nitric and nitrous acids; and then, by combination with bases such as lime or potash, into the salts nitrates and nitrites. This change is termed nitrification, and, by the experiments of Warrington, Winogradsky, and others, has been shown to be due to the vital activity of certain micro-organisms (bacteria} present in the soil. In soils where these are absent nitrification is not effected. The action proceeds best at a moderately high temperature, and in moist porous soils. It is of the utmost importance agriculturally, as plants are unable to obtain their supply of nitrogen directly from the nitrogenous organic matter present in the manure, but can obtain it from the nitrates and nitrites produced from it. Nitrification has also been employed as a source of nitre; heaps of dung, etc., being well watered with urine and exposed to the sun until the action has proceeded far enough, when the nitre is extracted with water. The vast beds of nitre and Chili saltpetre existing in many localities, as e.g. Chili and Peru, are believed to have been produced by this fermentative action of similar bacteria.