Study of the effect of antibiotics on the urease activity of sod-podzolic and gray forest soils

Environmental pollution with antibacterial drugs is associated with their massive use, and can affect the microbial communities of ecosystems and their functions, which determines the relevance of the study of such effects. Urease participates in the nitrogen cycle, promotes the breakdown of urea to ammonia. Ammonia, in turn, is a source of nitrogen nutrition for plants and microorganisms. The objects of research were sod-podzolic (Umbric Albeluvisols Abruptic) and gray forest (Greyic Phaeozems Albic) agricultural soils. Antibiotics of various groups were used as pollutants, differing in the spectrum of action and physicochemical characteristics: tylosin, benzylpenicillin, oxytetracycline. The urease activity of the sod-podzolic soil without antibiotics was 0.951 g NH3/10 g soil/24 hours, gray forest soil - 1.178 g NH3/10 g soil/24 hours. The results of the study demonstrate the predominantly toxic effect of antibiotics on urease activity. The effect of drugs depends both on their concentrations and properties, and on the properties and type of soil. The urease activity of gray forest soil is higher than that of sod-podzolic soil, and is more resistant to the effects of antibacterial drugs. A triple mixture of antibiotics had the greatest toxic effect on the urease activity of the sod-podzolic soil. Tylosin had the greatest toxic effect on the urease activity of the gray forest soil. However, these effects were not dose-dependent (p > 0.05). Significant negative correlations were established for dependences of the urease activity of sod-podzolic soil on the concentration of oxytetracycline and its mixture with tylosin, and the urease activity of gray forest soil on the concentration of benzylpenicillin and a mixture of oxytetracycline with tylosin (p < 0.05).