Tubercles formation depending on the prior-sowing soybean seed treatment with bacterial preparations

The aim of this work was to establish the influence of biopreparations application as prior-sowing treatment of seeds to increase the nitrogen fixing activity of soybean plants. Bacterial preparations with different doses and forms (powder - Nitrofix P, the liquid - Nitrofix G), without and together with the film formers, were tested. Results of researches on studying of influence of bacterial preparations on the preservation and viability of rhizobia during inoculation of soybean seeds in the conditions of unstable moistening of the Eastern zone of the Krasnodar region, and their impact on quantity and weight of tubercles are presented. The quantity and weight of wet tubercles varied depending on the climatic conditions during the vegetative period of the research year. The most favorable conditions for their development were in 2013, higher temperatures and lack of sufficient precipitations in 2014-2015 contributed to the lowering of nitrogen fixing activity of soybean plants. On average over three years of the research, the quantity and weight of tubercles have increased from a phase of branching to the phases of flowering and pod formation, to the phase of seeds formation they began to die. The maximal quantity of tubercles on average over the research years were in the flowering phase (2130-2046 units per sq. m) and the phase of pod formation (2397-2410 units per sq. m) in variants where bacterial preparations for soybean seeds treatment were used together with film-forming agents. Thus, the inoculation of seeds with bacterial preparations promotes to increase nitrogen fixing activity of soybean plants. The addition of film-forming agents to bacterial preparations leads to an increase of the quantity and weight of tubercles on the soybean roots.