o:6870 EFFECT OF COMMERCIAL BIOFERTILIZER ON THE GROWTH PARAMETERS OF TWO-YEAR-OLD NORTHERN RED OAK (QUERCUS RUBRA L.) SEEDLINGS en Microbiological biofertilizers are gaining more and more attention in the global market as an environmentally healthier substitute for conventional chemical fertilizers. This paper investigated the effect of treatment of two-year-old northern red oak seedlings with commercial biofertilizer Slavol® during one growing season. The medium was prepared according to the producer’s instructions and applied foliar in late June. Seedling height and root collar diameter were measured as the prominent representatives of seedling quality growth parameters. The results confirmed the positive impact of the biofertilizer on seedling growth. Mann-Whitney U test showed a statistically significant difference in seedlings height (U = 42.000; p < 0.001) and root collar diameter (U = 56.000; p < 0.001) among the treated seedlings group at the beginning and the end of the experiment. In the control group, the statistically significant difference was noted for seedling root collar diameter (U = 55.000; p ˂ 0.001), but not for seedling height (U = 163.000; p = 0.624) at the experiment beginning and end. The results indicate that Slavol® biofertilizer influenced two-year-old northern red oak seedling height enhancement at the end of the experiment, but not on seedling root collar diameter, which had significant growth in both control and treated plants. northern red oak, biofertilizer, seedlings 1552100 978-99976-816-8-3 91552100 COBISS.RS-ID 141807105 2025-01-14T08:44:54.575Z 44 yes 46 Sanja Jovanović 0000-0001-9468-2628 46 Aleksandar Vemić 0000-0001-9195-8967 46 Aleksandar Lučić 0000-0002-4473-1791 46 Ljubinko Rakonjac 0000-0002-8736-6771 46 Vladan Popović 0000-0003-4326-3364 application/pdf 504799 https://unilib.phaidrabg.rs/o:6870 no yes 1 70 92000004 2024 71A07 Book of proceedings AgroSym2024 1501 1505 University of East Sarajevo, Faculty of Agriculture, Republic of Srpska, Bosnia 2024