The influence of biostimulants on the rhizospheric microorganisms of scorzonera (Scorzonera hispanica L.)

Scorzonera (Scorzonera hispanica L.) is a particularly valuable species among little-known and rarely cultivated vegetables. It is a root vegetable of high dietary and nutritional values. The suitable microbiological activity of the soil favors the growth and development of scorzonera. Biostimulants can positively affect the communities of rhizospheric microorganisms of cultivated plants, including this important vegetable. The studies established the influence of biostimulants on the microbial communities in the scorzonera rhizosphere. Before setting up the field experiment, scorzonera seeds were dressed with fungicide Zaprawa Nasienna T 75 DS/WS or biostimulants Beta-Chikol, Bio-Algeen S-90, and Asahi SL. The laboratory microbiological analyses of scorzonera rhizosphere soil were conducted and determined the total population of bacteria and fungi. The obtained rhizosphere isolates of fungi Albifimbria, Clonostachys, Epicoccum, Penicillium, and Trichoderma sp. were tested to check the influence on fungi pathogenic to scorzonera (Fusarium culmorum, Fusarium oxysporum, Sclerotinia sclerotiorum, and Rhizoctonia solani). The experiments showed that biostimulants, especially Asahi SL and Beta-Chikol, favored the development of rhizobacteria populations (including Bacillus sp. and Pseudomonas sp.). All biostimulants (Beta-Chikol, in particular) and the fungicide decreased the population of rhizospheric fungi and limited the occurrence of polyphagous fungi in the rhizosphere of scorzonera. Biostimulant Beta-Chikol and fungicide Zaprawa Nasienna T 75 DS/WS were most effective in stimulating the development of antagonistic fungi. Clonostachys rosea, Trichoderma sp., and Albifimbria verrucaria predominated as antagonistic rhizospheric fungi.