The Effect of Long-Term Use of Certain Elements of Agrotechnology on the State of Fertility of Gray Forest Soil in the Subtaiga Zone of the Omsk (Cis-)Irtysh Region

In a stationary experiment, an assessment of the state of fertility of gray forest soil was performed, depending on a type of crop rotations and application of mineral fertilizers. The study focuses on gray forest soil. The factorial experiment is of a 2 × 2 factorial design. Factor A consists in a four-field cereal–fallow rotations nos. 1 and 2 that different in the share (degree of incorporation) of cereal crops and the type of fallow. Factor B is mineral fertilizers: (1) without fertilizers (F0) and (2) N30P45K45 (F1). The observation period lasted for 20 years (2003–2022). It was found that substitution of seeded fallow for naked fallow and introduction of legume crops (peas) stabilized humus content in the soil due to a greater input of mortmass, with its high nitrogen enrichment (C : N = 9.9). The systematic use of phosphorus-containing fertilizers in crop rotations at a dose of P45 ensured a positive balance of this nutrient in the soil. It was found that in the conditions of the subtaiga zone, due to the scientifically based selection of crops in the crop rotation system, their productivity increased by 0.21 t/ha; with the use of fertilizers (N30P45K45), by 0.30 t/ha grain units.