ABSTRACT
Nitrification ƒ Let us point out that nitrification is, unlike what we have discussed above, the set of reactions that results in the manufacture of nitrates in presence of oxygen by strictly aerobic autotrophic bacteria. The process starts with organic nitrogen or ammonium ions in the soil (Fig. 12.8). Organic nitrogen, ammonium and nitrite act as electron donors and also as sources of energy of which bacteria utilize a few per cent, the rest being dissipated as heat. In these conditions, they accomplish their biosyntheses by utilizing the ambient carbon dioxide. They make much more nitrate than they need.
