The effect of mineral matrices of loam, quartz sand, sand + 30% kaolinite, and sand + 15% bentonite on the dynamics of transformation of plant residues (PRs) of corn and red clover was studied. It is shown that the dynamics of PRs transformation has a wave pattern and depends both on the nature of mineral matrices and on the composition and properties of PRs. The kinetic parameters of corn and clover decomposition were studied, using a two-term exponential polynomial. The turnover period for the labile pool of clover and corn in all substrate (8-10 days) is typical for the organic acids and simple saccharides. The turnover time of the stable clover pool (0.95 years) and of the corn (1.60 years) corresponds to the turnover time of plant biomass.