INFLUENCE OF SINGLE AND MIXED CROPS OF PERMANENT GRASS ON SOIL ENZYMIC ACTIVITY IN THE CONDITIONS OF FOREST-STEPPE OF THE MIDDLE VOLGA REGION

The research is aimed at the development of effective methods to restore soil fertility under intensive agrogenic loads. The studies were conducted in the fields of the Department of Plant Cultivation and Agriculture from 2016 to 2018. The following variants of single-species and mixed crops of perennial grasses were studied: 1. awnless brome; 2. crested wheat grass; 3. awnless brome + smooth brome; 4. crested wheat grass + Agropyron; 5 awnless brome + smooth brome + Hungarian sainfoin; 6. crested wheat grass + Agropyron + Hungarian sainfoin. Medium soil samples were taken from the experimental field from all variants of single-species and mixed crops of perennial grasses in triplicate in three periods: beginning, middle, and end of the growing season. Samples were taken from depth of 0-20 cm and 20-40 cm. Bacteria number was assessed by sowing special soil mixture on the solid sterile MPA media according to the method of J. Sega. Enzyme activity was determined by the method of A. Sh. Galstyan. When studying the activity of PPO, a high activity of this enzyme was observed in the soil layer of 20-40 cm. The analysis of the activity of the enzyme peroxidase has various indicators both between the studied variants and in the soil section. The high activity of the enzymes was noted in the variants «awnless brome + smooth brome» and «crested wheat grass + Agropyron + Hungarian sainfoin». In the process of research, a correlation was found between peroxidase activity and the number of bacteria. The highest coefficient of humification was noted in the «awnless brome», the lowest – «crested wheat grass + Agropyron + Hungarian sainfoin». From 2016 to 2018, in the first variant, a decrease in the coefficient of humification is observed. Thus, of the above options, with the optimal species composition, the following options turned out to be: « awnless brome», «awnless brome +smooth brome», «awnless brome +smooth brome + Hungarian sainfoin». Research data were processed by the dispersion method.