Soil fertility management in apple orchard with microbial biofertilizers Andrei Kuzin, Alexei Solovchenko, Ludmila Stepantsova and Grigory Pugachev E3S Web of Conf., 222 (2020) 03020 Published online: 22 December 2020 DOI: 10.1051/e3sconf/202022203020