The aim of this study was to determine the influence of various biological fertilizers on the growth and development of plants of the large-fruited cranberry and the degree of mycorrhizal association in their roots under controlled conditions. Plants of the 'Pilgrim', 'Stevens' and 'Ben Lear' cranberry cultivars were planted in rhizoboxes filled with soils collected from the areas of Krojczyn and Motoga. The following experimental treatments with fertilizers were applied: control plants, plants

more »

... fertilized with NPK, a bacterial-mycorrhizal consortium, Vinassa, lignite + Vinassa, Florovit Natura and the fertilizer Crop-UP. The study has shown that there was a tendency to stimulate the vegetative growth and development of cranberry plants through the use of bio-fertilizers and beneficial fungi obtained from the rhizosphere of these plants. There was a tendency for the fresh and dry weight of cranberry shoots to increase, especially in 'Ben Lear', under the influence of the bio-fertilizer Florovit Natura when compared with the control plants fertilized with NPK. Compared with the NPK control, all of the bio-fertilizers significantly increased mycorrhizal frequency in the roots of the tested plants of the large-fruited cranberry, with the exception of Crop-UP and lignite compost used in conjunction with Vinassa in 'Stevens'. No statistically significant differences were obtained for plant size and root colonisation by ericoid fungi in the plants grown in the soil from the areas of Motoga and Krojczyn.