The Influence of River Bottom Sediments on the Biological Activity of Chernozem and Sierosand Soil

The potential agricultural uses of the Don River’s bottom sediments were assessed by analyzing the phytotoxicity of winter wheat as a test subject, the activity of enzymes (invertase and dehydrogenases), and the chemical composition of the bottom sediments. In a model experiment, river bottom sediments (RBSs) (50–1000 t/ha) were added to two soils of different genesis. It was found that the content of heavy metals in the RBSs did not exceed the soil MAC. The highest enzymatic activity in sierosands was observed in samples with the addition of 50 t RBS/ha compared to the control soil. For black soil, the optimal dose was 100 t RBS/ha. In terms of dehydrogenase activity in chernozem and sierosands, no significant differences were found between samples with a lower (50 t/ha) or higher (600 t/ha) application of RBSs. The suppression of activity relative to the control was found only in sierosands with the highest proportion of RBSs (50%). The enzymatic activity of invertase decreased with increasing RBSs in sierosands. Bottom sediments stimulated soil respiration. The highest growth rates of winter wheat were found in chernozem and sierosands 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 sierosands.