Growth parameters, nutrient status and colonization density of beneficial microbes in winter rye grown organically and conventionally.

The study focuses on the impact of a beneficial microbial consortium on the plant performance of winter rye under different farming practices during the vegetation period, including the winter growing season. Winter rye plants grown in a long-time field trial (Thy_ABS; 52°15’ N, 13°14’ E, 44 m a.s.l.) under conventional or organic farming practices were inoculated after plant emergence in autumn 2020 with a beneficial microbial consortium containing Pseudomonas sp. (RU47, drench inoculation with 2 L per m² of 7.5 x 107 CFU mL-1), Bacillus atrophaeus (ABi03, drench inoculation with 2 L per m² of 7.5 x 107 CFU mL-1) and Trichoderma harzianum (OMG16, soil inoculation with 100 mg inoculum per m²). The density of the microbial inoculants in the rhizosphere and root-associated soil as well as the plant performance and nutrient status was quantified in autumn and the following spring. Selective plating demonstrated that the beneficial microbes successfully colonized the rhizosphere and root-associated soil of winter rye throughout its early growth cycle. The inoculation with a beneficial microbial consortium enhanced the biomass of winter rye, especially under organic farming practices at the second sampling in spring. The consortium significantly improved the nutrient status of the winter rye plants, providing an effective way to overcome nutrient limitations often found in organic farming. Research domain: Plant Cultivation and Agricultural Technology Research question: We hypothesized that (i) early inoculation of winter rye enables sufficient colonization of each BMc member at early plant developmental stage, supporting its persistence in the rhizosphere throughout the vegetation period; (ii) the application of BMc shapes the composition of the rhizosphere bacterial community depending on the farming practice and thus differentially affects the plant performance.