Influence of river bottom sediments on the biological activity of chernozem and sandy soil

The potential use of bottom sediments of the Don River in agriculture was assessed by analyzing the phytotoxicity of winter wheat for the test object, the activity of enzymes (invertase and dehydrogenase), and the chemical composition of bottom sediments. In the conducted model experiment, river bottom sediments (RBS) (50–1000 t/ha) were introduced into 2 soils of different genesis. It was found that the content of heavy metals in the RBS did not exceed the soil maximum permissible concentration. The highest enzymatic activity in the seropesks was observed in samples with an application of 50 t RBS/ha compared with the control soil. The optimal dose for chernozem was 100 t RBS/ha. No significant differences were found in the activity of dehydrogenases in chernozem and sulfur sands between samples with a lower (50 t/ha) and a higher (600 t/ha) RBS content. Suppression of activity relative to the control was found in seropesques with only the highest proportion of RBS (50%). The enzymatic activity of invertase decreased with an increase in RBS in seropesques. Bottom sediments stimulated soil respiration. The highest growth rates of winter wheat were found in chernozem and gray soils with the addition of a dose of 50 t RBS/ha. The results of the correlation analysis confirmed the relationship between the content of organic carbon and the activity of enzymes in sulfur mixtures.