Indicators of Soil Fertility of the Typical Chernozem after Long-Term Application of Various Fertilizer Systems

The objective of the research was to study the effect and aftereffect of various fertilizer- and soil-treatment systems on the main fertility indices of typical chernozem. The work was carried out in a long-term field experiment in a grain crop rotation under conditions of Belgorod oblast. The soil of the experimental plot is typical chernozem, medium-deep, low-humus, heavy loamy on loess-like loam. The experimental design included studying the effect of mineral fertilizers in doses of N₆₄P₆₄K₆₄ and N₁₂₈P₁₂₈K₁₂₈, organic fertilizers with a crop rotation saturation of 8 and 16 t/ha of the cattle’s manure crop rotation area, and combinations of organic and mineral fertilizers. Fertilizers were applied against the background of three methods of primary soil treatment: plowing, chisel plowing, and minimum tillage. For six rotations of a five-field crop rotation, without the use of fertilizers, humus losses amounted to 0.06–0.27%, with an actual content of 4.96–5.15%; the content of mobile phosphorus decreased by 2.8–9.2 mg/kg to 47.6–51.2 mg/kg, and mobile potassium remained almost at the original level of 108.4–116.2 mg/kg. The best content of basic nutrients in the soil is provided by the use of an organomineral system with the introduction of mineral fertilizers in doses of N₆₄P₆₄K₆₄ and N₁₂₈P₁₂₈K₁₂₈ against the background of 8 t/ha crop rotation area of manure. At the same time, the humus content reaches 5.30–5.64%, mobile phosphorus 222.6–255.1 mg/kg, and mobile potassium 156.6–173.5 mg/kg. With long-term use of manure with a crop rotation saturation of 16 t/ha, the humus content was 5.34% (on average for the method of primary soil cultivation) and phosphorus and potassium were 122.0 and 143.3 mg/kg, respectively.