EN
The quantitative and qualitative composition of the soil microorganisms depends, amongst others, on whether monoculture or crop rotation is applied. The main phytopathogen infecting flax (Linum usitatissimum L.) is the Fusarium genus as well as fungi of the Alternaria, Phoma, Botrytis, Verticillium, Rhizoctonia genera, however soil hyperparasites of the Trichoderma genus can control them successfully. Both types of microorganisms were isolated from the roots sampled both from monocuture and crop rotation and from plants in emergence and flowering stage. The enzymatic activity was researched for a variety of nutrient substrates (cellulose, pectin, starch, protein) as well as the capacity for dissolving triphosphates. There was also investigated the extent of Trichoderma fungal antagonistic activity towards pathogens.