A device is suggested for the determination of the total and carbonate carbon, the nitrogen content, and the oxidizability (chemical consumption of oxygen) of soil organic matter. This device permits us to analyze rather precisely the amount of CO₂ released upon carbonate decomposition and the oxidation of organic substances, as well as the degree of molecular oxidation-reduction of organic matter, which is an important diagnostic feature of soils. It is shown that data on the organic carbon content obtained by the Tyurin method differ significantly from the actual content of carbon of organic substances, which may lead to incorrect estimation of the humus reserve in soil.