Productivity of perennial herbage with the participation of Trifolium pratense L. on sod-podzolic soils of the Republic of KareliaLiubov Evstratova, Elena Nikolaeva, Olga Bakhmet, Larisa Kuznetsova and Elena KondratiukBIO Web Conf., 66 (2023) 05001DOI: https://doi.org/10.1051/bioconf/20236605001