TY JOUR TI STUDY OF THE INFLUENCE OF COMPLEX HUMATISED MINERAL FERTILIZERS ON GRAY SOILS FERTILITY KW complex humatised mineral fertilizers KW field experiment KW soil humus KW labile phosphorus KW exchange potas-sium KW fertile soil qualities KW gray soils JO Bulletin of KSAU AU Arziev, Z.A. AU Zholdoshev, B.S. AU Arziev, N.Z. PY 2018 IS PB Krasnoyarsk State Agrarian University