Dependence of Soybean Productivity on Ecological and Agrochemical Factors

Resumo

The results of research into the efficiency of mineral and organic-and-mineral fertilization systems in a long-term, stationary five-field rotation, including soybean and grain crops, are analyzed as dependent on certain agro-ecological factors. The aim of this work was to study the effect of continuous application of mineral (annual N₄₂Р₄₈ per ha of the crop rotation area) and organic-and-mineral (annual N₂₄Р₃₀ + 4.8 t of manure per ha of the crop rotation area) fertilization systems on the productivity of soybean in the crop rotation. The subjects of research were the middle and early ripening varieties of this crop, sown after annual grasses (soybean and oats mixture) and spring wheat. The preceding crop, the variety, and the hydrothermal conditions in 1963–2017 were considered as agro-ecological factors. The highest yield was obtained when sowing soybean crops after wheat: throughout a number of years, the yield of 1.8–2.0 t ha^–1 was by 16% more frequent in this case than when soybean was cultivated after annual grasses. The maximum increase against the reference (0.17 t ha^–1) was obtained with long-term application of organic and mineral fertilizers to the soybean crop cultivated after wheat. In cold wet years, using such a system of fertilization ensured the plant’s resistance to adverse weather conditions as well as an increase in soybean yield by 0.18 t ha^–1 against the reference. The following midseason soybean varieties were the most responsive to fertilization: their grain yield was 0.03–0.20 t ha^–1 higher compared to the reference and the potential productivity was fulfilled 2–7% better.