The article highlights the results of the research to study the action of the microbial preparation Melanoriz (1.0, 1.25, 1.5 l/t)
and plant growth regulator Agrolight (seed treatment before sowing – 0.26 l/t, spraying crops – 1, 0 l/ha) for the development
of certain groups of microorganisms in the rhizosphere of hulless oat.
The research was performed in the field and laboratory conditions of the Department of Biology of Uman National University
of Horticulture during 2019–2021. Field experiments were established by a systematic method. The experiment was repeated
three times.
The number of microorganisms in the rhizosphere of hulless oat was estimated in the flowering phase of the culture. Soil
samples from the rhizosphere of hulless oat were taken in accordance with generally accepted methods described by V.V.
Volkogon et al. The total number of rhizosphere microorganisms that use mainly organic forms of nitrogen as a food source
(ammonification group) was determined by sowing a soil suspension of appropriate dilutions on agar medium meat-peptone
agar, nitrifying bacteria – on a selective medium environment of
S.M. Vinogradskyi, cellulosolytic microorganisms on the environment of
O.O. Imshenetskyi and L.I. Solntseva. The number of microorganisms was expressed in colony-forming units per thousand
cells in 1 g of absolutely dry soil, depending on the method of determination.
On average over three years, the highest number of rhizosphere bacteria was observed in the variants of the experiment using
Melanoriz 1.0–1.5 l/t and Agrolight 0.26 l/t for seed treatment before sowing, followed by treatment of crops with Agrolight
at the rate of 1.0 l/ha, which exceeded the control by 273–346 thousand CFU/g of absolutely dry soil and by 83–87 thousand
CFU/g of absolutely dry soil was higher than the indicators of the same options, but without treatment of vegetative plants by
Agrolight.
The highest number of nitrifying bacteria was observed for the combination of pre-sowing seed treatment with a mixture of
Melanoriz and Agrolight followed by spraying of vegetative plants with Agrolight. Thus, in the variant Melanoriz 1.5 l/ha +
Agrolight 0.26 l/t + Agrolight 1.0 l/ha the number of nitrifying microorganisms exceeded the control indicators by 66 thousand
cells / g of soil, and in comparison with the variant Melanoriz + Agrolight (seed treatment before sowing) – 27–44 thousand
cells/g of soil. Using a mixture of Melanoriz (1.0; 1.25; 1.5 l/t) with Agrolight (0.26 l/t) the number of cellulosolytic bacteria increased by
31–52 thousand cells/g of soil according to the control, but was the highest for pre-sowing treatment of seeds with a mixture
of Melanoriz at a rate of 1.5 l/t and Agrolight at a rate of 0.26 l/t, followed by spraying crops with Agrolight at a rate of 1.0 l/
ha, where the number of cellulolytic bacteria exceeded the control by 78 thousand cells/g of soil.