Reserves for increasing the yield of field crops on chestnut soils of the dry steppe of western Siberia

The research was carried out in order to assess reserves for increasing the yield of spring soft wheat, oats and sunflower on chestnut soils of the dry steppe of the south of Western Siberia to increase the productivity of arable land. The work was performed in 2016–2023 in a long-term stationary field experiment in the West Kulunda subzone of the Altai Territory. The experimental scheme provided for a comparative study of the effectiveness of field crop rotations with different saturation of wheat and sunflower on non-fertilized and fertilized (N₃₀). On chestnut soils of the dry steppe, the effect of nitrogen fertilizers was decisive in changing the yield of wheat by pure steam (87.4 % influence), strong ‒ oats (68.2 %) and sunflower (57.5 %), significant ‒ wheat by non‒paired precursors (36.8 %), significant – arable land productivity (24.2 %), whereas The effect of crop rotation was decisive in changing the productivity of arable land (74.2 %), strong ‒ wheat by non-paired precursors (62.5 %), significant ‒ sunflower (41.4 %) and oats (31.5 %), weak ‒ wheat by steam (11.7 %). The most favorable conditions for wheat and sunflower were formed after steam, for wheat by non‒steam precursors – when placed after oats, and oats after wheat in grain-to-crop crop rotations with one sunflower field. The productivity of arable land was minimal in crop rotations without sunflower (0.46…0.57 thousand grain units/ ha), with its share of 16.7…25 % increased by 0.16…0.28 thousand grain units/ha (28.1…60.9 %), and at 50 % ‒ by 0.31…0.42 thousand grain units/ha (54.4…91.3 %), in relation to the grain-pair crop rotation and permanent wheat. The application of nitrogen fertilizers for the crops of these crop rotations provided an increase in arable land productivity by 0.15…0.25 thousand grain units/ ha (20.5…28.4 %), relative to the non-winded background, with a payback of 1 kg of nitrogen up to 8.33 grain units.