Biochemistry of nitrification in soil. 3. Nitrification of various organic nitrogen compounds

[First paragraph] It has been established (Lees & Quastel, 1946b) that nitrification of ammonium salts in soil takes place at the soil surface, at the expense of NH+4 combined or adsorbed in the form of a base-exchange complex. It has also been shown (Lees & Quastel, 1946b) that the course of nitrate formation which is autocatalytic in freshly obtained air-dried soil becomes linear, and shows no 'lag', when such soils are enriched or saturated with nitrifying bacteria by preliminary perfusion of the soil with ammonium salts