Влияние гербицидов на численность микроорганизмов и биологическую активность почвы в агроценозах сои

Abstract

THE INFLUENCE OF HERBICIDES ON THE NUMBER OF MICROORGANISMS AND THE BIOLOGICAL ACTIVITY OF THE SOIL IN THE SOYBEAN AGROCENOSIS I. S. Brovko , V. U. Jashchuk , Y. V. Chabaniuk The use of pesticides and agrochemicals in agriculture affects not only the productivity of crops and the quality of their crops, but also the ecological state of the soil, and as a consequence the quantity and diversity of vegetation cover and soil biota, which is an indicator of the safety of the use of substances in agriculture. Each species of organisms in the biogeocenosis (even insignificant) has multiple connections with a significant number of other species. The disappearance of any species of animals or plants can cause unpredictable consequences and even the destruction of the entire biogeocenosis. Biodiversity can be attributed to objective factors of assessing the state of the environment and the stability of ecosystems. Biological diversity is the basis of the structural and functional organization of living matter of the biosphere, determines the stability and sustainability of ecosystems. It fulfills a regulating function in the implementation of all biogeochemical, climatic and other processes on Earth. Pesticides can influence plant-microbial interactions through their effect on the pathogen or on other soil biota. For soil microorganisms, a certain selective sensitivity to herbicides and pesticides in general is characteristic. Chemical treatments mainly lead to the death of sensitive species and genera of microorganisms, the activation of resistant mutants, and the herbicide used as an energy material. As a consequence, there is a disturbance in the state of equilibrium of the soil ecosystem and, accordingly, the soil self-purification conditions resulting from the activity of successive successive microbial races, the narrowing of the spectrum of microbiological activity due to both the direct microbicidal action of herbicides and through changes in the ecological environment. Purpose of the study. Establish the dependence of changes in the numbers of microorganisms of different ecological-trophic groups on the use of herbicides, the phase of development of soybean plants and the sampling period for the natural ecosystem. In view of the fact that biological diversity, being the basis of living matter of the biosphere, determines the sustainability of ecosystems on the Earth, it is relevant to monitor and evaluate all factors that can influence the state of the agrosphere, identify risk factors, and identify links between them. In the work, generally accepted methods of conducting field experiments, methods of soil microbiology, methods of biochemistry were used. In the field experiments, the effect of herbicides imazamox and clomazone on the number of microorganisms of the main ecology-trophic and taxonomic groups in the soy rhizosphere was studied. The regular effect of preparations in the V2 phase of soybean plants as compared to the soil of the natural ecosystem has been established. It has been suggested that bacteria belonging to the clomazone preparation can use the mineral nitrogen of the soil. The number of mycelial microorganisms (streptomycetes and micromycetes) increased in the phases V 2 and R 2 for soybean plants by 30-40% and 10-15%, respectively. More sensitive to the effects of herbicides were indicators of biological activity of the soil. Thus, the influence of herbicides imazamox and clomazone was significant at the initial stages of plant development, since the R 2 phase, the effect on the indices of the number of microorganisms, the biological activity of the soil and the activity of the symbiotic system was significantly reduced and leveled at the end of the vegetation. A representative index is the phytotoxicity of the soil when using the drugs under study. Thus, the influence of herbicides imazamox and clomazone was significant at the initial stages of plant development, since the R 2 phase, the effect on the indices of the number of microorganisms, the biological activity of the soil and the activity of the symbiotic system was significantly reduced and leveled at the end of the vegetation. A representative index is the phytotoxicity of the soil when using the drugs under study. So, for ecological rationing and ecological expertise of growing technologies, it is necessary to search for and develop more sensitive methods for assessing the impact of pesticides on soil biota. Keywords: soil microbiota, soil biological activity, herbicides, imazamox, clomazone