Zagrozenie zgorzela i mikotrofizm siewek swierka [Picea abies [L]H.Karst.] hodowanych na substratach trocinowo-torfowych o roznym okresie uzytkowania w szkolce lesnej

The paper presents the results of the study on sowing efficiency and the intensity of the post-emergence damping-off of spruce (Picea abies (L.)H.Karst.) seedlings grown on fresh sawdust-peat substratum and utilized for 5, 8 and 11 years ones under a foil tunnels. The frequency of occurrence of mycorrhizae and mycorrhizal spectrum of 4-month-old seedlings grown on those substrata were investigated as well. It was found that a long term utilization of sawdust-peat substrata do not create a threat to spruce seedlings by the damping-off fungi. Tested substrata do not favour a natural formation of mycorrhizae on spruce seedlings. The percentage of mycorrhizae was low and the spectrum of mycorrhizal types was poor.