Microbial preparations on the basis of endophytic and rhizobacteria to increase the productivity in vegetable crops and spring barley (Hordeum vulgare L.), and the mineral fertilizer use efficiency

We use an approach involving a combination of endophytic and rhizobacteria in the development of microbial preparations for crop production, which allows to create self sufficient plant-microbe systems, enhancing agricultural production and reducing the environmental burden. The article presents data on the properties of promising strains of endophytic and rhizobacteria and their efficiency in pot and field experiments. Rhizobacteria were isolated from the roots of tomato plants ( Solanum lycopersicum L.) cultivar Bella, endophytic bacteria from internal tissues of hogweed ( Heracleum sphondylium L.) stem. Identification of the studied bacterial strains was determined by nucleotide sequences of the 16S rRNA gene, and on cultural and biochemical properties. Middle grade lettuce ( Lactuca sativa L.) variety Eralash and early maturing variety Duro of radish ( Raphanus sativus L.) were used in pot experiments. It was shown that the Bacillus subtilis strain TR6 was active against all tested phytopathogenic fungi. Zones of inhibition varied from 17.4 to 48.2 mm. Almost all of the studied strains were capable of producing auxins, except strain TR7. Highest auxin production was observed in strains TR1 and TR9 - 12.3 and 20.1 µg/ml of medium respectively. Three of the five studied strains ( B. subtilis НС8, B. subtilis B2G and Azotobacter chroococcum AZ7) significantly (by 15.2-34.2 %) increased the biomass of the lettuce. The strains of B. subtilis Ch-13 and B. subtilis TR6 increased the yield of lettuce but insignificantly. Among the studied strains, B. subtilis НС8 should be noted, which significantly (by 15.2-42.1 %) increased harvest of radishes and lettuce in pot experiments. Application of microbial preparations based on endophytic and rhizobacteria can be effective promising element of modern technologies of barley ( Hordeum vulgare L.) cultivation, significantly reducing production costs and improving the efficiency of application of mineral fertilizers for its cultivation. Thus, the grain yield of barley variety Danuta (2-year field experiments) due to application of microbial preparations on the basis of endophytic and rhizobacteria has been increased by 23.8-43.9 % compared to the control and by 11-29 % compared to mineral fertilizers. Due to inoculation of barley seeds with promising strains of the endophytic and of rhizobacteria the efficiency of nitrogen, phosphorus and potassium use from mineral fertilizers increased by 11.7-22.1 %, 5.1-10.3 %, and 10.2-19.4 %, respectively.