The aim of this study was to determine the influence of microbial biostimulants on wheat and oat growth, grain yield, and grain quality and to evaluate the influence of these probiotics on some soil agrochemical traits in the open field. Active concentrations of ProbioHumus and NaturGel and their mixtures were selected under laboratory conditions using winter wheat as a reference plant. Probiotics had a biostimulating effect on the development of the underground and aboveground part of winter wheat when 2 µL/g was used for seed priming and 2 mL/100 mL for seedling spraying. Under field conditions, after treatment of soil (2 L/ha), wheat and oat seeds (2 L/t), and plants (2 L/ha) with ProbioHumus and NaturGel, it was found that the yield of the studied cereals increased, on average, by 0.50 t/ha to 1.09 t/ha. ProbioHumus promoted protein accumulation in the investigated cereal grains. The level of microelements in wheat and oat grains increased after treatment of plants with NaturGel. Probiotics improved soil agrochemical properties, such as total and nitrate nitrogen, total and available phosphorus, organic carbon, humic acid, and humus content. In conclusion, plant probiotics can be used as an ecological alternative for growing cereals and improving the agrochemical properties of the soil.
Keywords: Avena sativa; Triticum aestivum; humus; microelements; organic carbon; phosphorus; plant microbial biostimulants; protein content; soil nitrogen.