TY CONF TI DYNAMICS OF HUMUS CONTENT DURING LONG-TERM APPLICATION OF FERTILIZERS ON GRAY FOREST SOILS OF THE VLADIMIR OPOLYE KW gray forest soil Vladimir Opolye KW content and reserves of humus KW organic and mineral fertilizers KW regression equations JO Scientific research of the SCO countries: synergy and integration AU Okorkov, V.V. PY 2024 PB AUS PUBLISHERS