Microorganisms are still not widely used in forage grass production although higher and better quality yield is one of the goals of animal husbandry. The aim of this research was to investigate the effect of plant growth promoting microorganisms ( Azotobacter chroococcum and Streptomyces sp.) on the growth of English ryegrass and microbiological activity in its rhizosphere. Two types of English ryegrass ( Lolium perenne) were used - broad -leaved and narrow-leaved . The experiment was conducted in 10 l volume vegetation pots. Before sowing, 10 ml of inocula was introduced into the pots. Three Streptomyces sp. strains and three Azotobacter chroococcum strains were used for inoculation. The control variants were not inoculated. The number of microorganisms ( the total number, azotobacter, actinomycetes and fungi), dehydrogenase activity, height and dry mass of the plant were determined thirty days after sowing. The results showed that microorganisms can have a positive effect in the production of English ryegrass. In broad-leaved ryegrass, the application of all six strains resulted in greater height and dry mass of the plant, whereas the effect was weaker in narrow-leaved ryegrass. In the rhizosphere of broad-leaved ryegrass, the total number of bacteria increased only with the application of one strain of azotobacter. In the rhizosphere of narrow-leaved ryegrass, the total number of bacteria increased with the application of all three strains of Streptomyces sp. and one strain of azotobacter. The greatest number of azotobacter in the rhizosphere of both types of English ryegrass was recorded in the variants inoculated with azotobacter. The number of fungi in the rhizosphere of broad-leaved ryegrass increased with the use of one strain of azotobacter and one strain of actinomycetes, whereas in narrow-leaved ryegrass, it increased with the use of two strains of actinomycetes and one strain of azotobacter. The number of actinomycetes and dehydrogenase activity in the inoculated variants did not significantly change in comparison with the control.

azotobacter, actinomycetes, English ryegrass, yield, microbiological activity

Presentation: oral