THE INFLUENCE OF FIRE CULTIVATION ON THE SOIL MICROORGANISMS

An increase in the pesticide load in agro-cenoses leads to a decrease in the number of the main ecological and trophic groups of microorganisms, which causes a disruption of connections in agro-ecosystems and soil biological activity. For example, more than 95% of applied pesticides have a greater impact on soil microorganisms than on their target objects, as they are sprayed proportionally all over the field, regardless of the affected areas. In this case, fire treatment has the main benefit of a more targeted treatment, which is more focused on its main object of impact. But, as you know, fire can also cause significant damage to both soil and microorganisms living there. Soil microbiota is very sensitive to environmental changes, but it is completely killed only at soil temperatures above +120°C, so treatment with a fire cultivator that can work at both +100°C and +70°C has a high chance of becoming the safest way to control weeds. Despite the known negative effect of fires and flames on soils, to fully assess the impact of this method on soil and its fertility, it is necessary to investigate the impact of this treatment primarily on changes in the microbiological characteristics of the surface soil layer. The treatment was carried out using two modes of the fire cultivator (+70°C and +100°C). Microbiological analyzes of the soil were carried out according to generally accepted methods. The content of total biomass of microorganisms in the soil was determined by the rehydration method. Thus, to study the impact of fire cultivation on the direction of processes in the soil and the main ecological and trophic groups of microorganisms, we determined the content of total biomass of microorganisms, coefficients of mineralization-immobilization and oligotrophicity, cellulolytic activity, the number of bacteria, micromycetes, etc. Our analysis of the total microbial biomass of the selected soil samples allows us to assert the safety of the applied fire method of weed control. In the study of soil fouling lumps (Ashby's medium), 100% presence of bacteria of the genus Azotobacter was noted in all variants with temperature treatment. The analysis of soil samples on Ashby's medium showed that oligotrophs do not significantly change under fire treatment at 70°C, but some negative impact on the vital activity of these microorganisms is still observed under 100°C treatment. The obtained ecological coefficients of the direction of microbiological processes indicate the decreasing intensity of decomposition of soil organic matter, in particular humus compounds and reducing soil oligotrophicity indicates an increase in the content of nutrients in the soil. For the most environmental benefits, we recommend to use a milder fire treatment of 70°C, wich allows not only to control the weeds, but also stimulates and directs microbiological processes in a positive directio.