Mycorrhizal status of herb-layer plants in a fertilized oak-pine forest

In the years 1986–1988 investigations were carried out on the influence of fertilizers on the mycorrhizal status of herb-layer plants of a mixed oak-pine forest in the Niepolomice Forest (Southern Poland). The site enrichment with N, P, K altered the frequency of mycorrhizal infection in most species investigated and decreased the percentage of colonized root cells. Some species disappear after fertilization (e.g. Vaccinium myrtillus L.). Among the species vigorously expanding after the treatment, mainly nonmycorrhizal plants (e.g. Festuca gigantea (L.) Vill.) were found. Some species (e.g. Milium effusum L.) favourably reacting to mineral fertilization, lost their mycorrhizae.