INFLUENCE OF OIL POLLUTION ON ACTIVITY OF SOIL ENZYMES OF OXIDOREDUCTASE AND HYDROLASE CLASSES

Abstract

Soil enzymatic activity is the most important biochemical parameter of soil fertility and it is determined by chemical composition, species and quantitative diversity of soil microbiota and plants, and the set and degree of activity of soil enzymes. The article shows the dynamics of enzymatic activity of the soil contaminated with oil from Vishenskoyedeposit in Melekesskiy district of Ulyanovsk region before and after spring wheatcultivation, as well as using biohumus, zeolite and diatomite sorbents. To assess the biological state of the soil contaminated with oil products, the activity of the main enzymes of the soil pool of the class of oxidoreductases (polyphenol oxidase), peroxidase, catalase) and the class of hydrolases (phosphatase, invertase) was determined. As a result of the studies, it was found that oil pollution reduces activity of oxidoreductase and part of hydrolytic enzymes. The inhibitiondegree correlates with oilconcentration in the soil. A direct dependence of inhibitiondegree of polyphenol oxidase, catalase, phosphatase and invertase on oil concentration was found. It was found that introduction of diatomite increased the activity of peroxidase and invertase, zeolite and biohumus - phosphatase. To assess the state of soil fertility, humus accumulation coefficient (humification coefficient) is used, which is defined as the ratio of polyphenol oxidase activity to peroxidase activity. This coefficient allowsto assess the tendencies of humus formation processes: humification or mineralization. It was determined that the introduction of low doses of oil (2-3%) increases humification coefficient, and high concentrations (8%) reduce it. To diagnose the state of oil-contaminated soils, it is recommended to determine the activity of basic enzymes: polyphenol oxidase, peroxidase, catalase, phosphatase, and invertase.