On the complex formation between soil humus and polyvalent cations

Abstract

Abstract In 1946 BREMNER et al.(1) suggested a theory that, in soils, polyvalent metals are combined with organic matter as metal-organic matter complexes, and that these complexes are insoluble in solvents that do not themselves form complexes with metals. The principle of one of the most prevailing methods for humus extraction, the neutral sodium pyrophosphate extraction proposed by BREMNER and LEES (2), is a corollary of the theory.