Transformation of Low-Molecular Nitrogen-Containing Compounds in Soil

A simple model is proposed to show the decomposition of low-molecular organic compounds in soil. The model permits us to estimate the rate of oxidation of different carbon atoms in amino acid molecules, the share of their use by microorganisms for anabolism, and the inclusion in humus, as well as the number of cycles oriented to microorganism renewal in the soil during the vegetation period. At initial stages of soil evo- lution, passive mechanisms (natural selection of heavily decomposed high-molecular components of plant res- idues) play an essential role in accumulation of humus substances. In the course of soil evolution, active mech- anisms assume ever greater importance (inclusion of low-molecular labile N-containing compounds). Changes in the mechanisms may be considered as an additional factor in the microorganism strategy to be adopted for succession in the ecosystem and as one of the indicators of soil transition from an inert to a bioinert system.