Determining the humus formation index of forest soils of the Vologda RegionYliya Duryagina, Ludmila Voropay, Svetlana Hamitova, Ilfir Galiullin and Olga KuztetsovaBIO Web Conf., 37 (2021) 00062DOI: https://doi.org/10.1051/bioconf/20213700062