Ecological and agrochemical bases of the nitrogen regime of typical chernozem depending on agrotechnical methods

In the environment of the southwestern part of the Central Black Earth Region (Central Chernozem) of the Russian Federation, an increase in the content of alkali-hydrolyzable and nitrate nitrogen, as well as an increase in the soil nitrification capacity in typical chernozem, is mainly due to increasing doses of mineral fertilizers, manure aftereffects, the use of perennial grasses in crop rotation as precursors of winter wheat, and for the most part, plowing in the main tillage system. The most noticeable variation in the content of alkali-hydrolysable nitrogen in the soil is 20-50 cm in soil, and soil nitrification capacity in the 0-20 cm layer. Nitrate nitrogen is characterized by the most significant increase in its content in the soil layer 0-20 cm with a combination of mineral fertilizers and manure, especially by plowing. The tendency to increase the nitrate content in the underlying layers is due to the use of an overdose of mineral fertilizer for winter wheat - N₁₂₀P₁₂₀K₁₂₀ + N₆₀ (saturation of 1 ha of the crop rotational area in the grass-growing crop rotation N₈₄P₁₂₄K₁₂₄ and in the grain-growing crop rotation N₁₂₀P₁₂₄K₁₂₄) and due to the aftereffects for the fourth year 40 and 80 t/ha of manure (saturation 8 and 16 t/ha). In the grain grass crop rotation, this is common in all studied soil layers — 0–20, 20–50 and 50–100 cm, and in grain cultivation crop rotation, only the 0–20 and 20–50 cm layers.