Grain crops yield models depending on the organic substance content in the soil

The purpose of the study: to create models of grain yield depending on the content of organic substance in the soil. Research objectives: to develop information-logical models of the yield of spring wheat on gray forest and sod-podzolic soils, as well as to construct a model of the yield of grain crops on the chernozem of the Krasnoyarsk forest-steppe, depending on the content of organic substance in the soil. The studies were carried out on gray forest and sod-podzolic soils of the subtaiga zone adjacent to the northern part of the Achinsk-Bogotol forest-steppe, as well as on ordinary chernozems and leached chernozems of the Krasnoyarsk forest-steppe. The methods of field and microfield experience, analytical, mathematical modeling and information-logical analysis, the method of modeling the relationship between the main components of soil organic matter and yield were used. To assess the level of fertility of gray forest soils, the most acceptable model is Y = G × (M × (pH × P) with a predictive effect of 72 %. M × (pH × FG)) and Y = G × (pH × (M × P)). The predictive effect according to the models is 77–78 %, which can be used to increase soil fertility, and is also applicable for their appraisal. In all models with a significant degree of recognition, the leading place is occupied by humus. The thickness of the humus horizon has a high rank. Mathematical models of the yield of grain crops, depending on the content of organic substances in the soil, made it possible to calculate the minimum, average and maximum values of the carbon of humus, mobile humic substances and the corresponding levels of yield of grain crops. It turned out that the minimum humus content corresponds to 2.10–3.03 %, average – 3.02–4.02, high – 4.02–5.10 %. The lower value of the optimal content of total carbon can be taken as 2.33 % or 4.00 % of humus, which corresponds to the upper value of the average content and the lower value of the high humus content.