Efficiency of introduction of ACC-utilizing rhizobacteria in soybean agrocenoses in the Orel region

Resource-saving technologies contribute to the reproduction of the soil fertility and increase sustainability of agrocenoses. Legumes are most relevant to the modern requirements for formation of ecological balance. They form a multicomponent symbiosis with various groups of useful soil microflora, which not only improves soil properties and increase the yield and its quality, but also makes them a valuable precursor in the rotation. In this regard, promising search and practical use of new microorganisms with multifunctional properties that will improve the economic efficiency of legume cropcultivation. Of particular interest is the use of ACC-utilizing bacteria having a versatile anti-stress effect on plants.We have carried out a study on the impact of the introduction of promising strains ACC utilizing rhizobacteria ( Pseudomonas oryzihabitans Ep4 and Variovorax paradoxus 3P-4) and nodule bacteria ( Bradyrhizobium japonicum 634b) on efficiency of cultivation of the northern soybean ecotype Svapa in the Orel region depending on mineral nutrition (NPK 100 % and NPK 70 %). The strain of nodule bacteria was used for inoculation of seeds in the amount of 200 g per hectare seed rate. Strains of associative ACC utilizing microorganisms were added to the rows in the seedling stage (10 % solution). NPK was applied to the soil before planting in the form of fertilizer mixture with the percentage of mineral nutrients 10:26:26. Biochemical assessment of the quality of soybean was performed in the laboratory conditions. In forming symbioses with introduced microflora the soybean agrocenoses were more environmentally adaptable, which was reflected in increasing the productivity in drought years by 35-98 %. The positive effect of the bacteria was evident in increasing the grain protein content by 34 %. Getting a high yield and high yield quality of the studied soybean variety due to formation of effective plant-microbe system leaded to the increase of total protein up to 1.05-1.30 t/ha. The introduction of microorganisms was the most effective at lowering the dose of mineral fertilizers by 30 %. It was found that the use of rhizobacteria Pseudomonas oryzihabitans together with nodule bacteria ensured maximum economic benefit and allowed to obtain cheaper and high-quality protein with high profitability. This will reduce the costs associated with the application of mineral fertilizers without crop losses.