Water consumption of corn under different methods of primary tillage after row-crop predecessors on an energy-storage soil maintenance system

The object of research was the light chestnut soil of the Chokh Agrofirm of the Gunibsky district in the Kizilyurt transhumance zone of the Republic of Dagestan. The humus content in the arable layer is 2.77%, P₂O₅ – 2.21, K₂O – 32.8 mg/100 g, the density of the arable soil layer is 1.24 g/cm³, the lowest moisture capacity (MC) is 29.2% (layer 0–0.6 m). The effectiveness of two row-crop predecessors was studied: sunflower for seeds and corn for grain, and the use of skimmers in the main tillage for corn. Soil moisture, watering and irrigation standards, incoming and outgoing items of the water balance and the coefficient of water consumption for corn were determined. In the second ten days of May, the plant remains of predecessors were crushed using double disking with heavy disc harrows BDT-3, plowing was carried out to a depth of 0.28–0.30 m with a PLN-4-35 plow with and without skimmers, the field was leveled with a small leveler MV – 6 and watered at the rate of moistening the soil layer of 0–0.6 m in strips with lateral release of water manually, vegetation irrigation was carried out in furrows. Sunflower sowing was carried out with seeds of the VNIIMK-8883 variety, corn – hybrid ROSS-299, the seeding rate for both crops was 72 thousand seeds/ha. Fertilizers for sunflower were applied at the rate of N₉₀Р₄₀К₉₀, including N₄₀Р₂₄К₇₄ for plowing, N₁₆Р₁₆К₁₆ – when sowing with seeds, N₃₄ for fertilizing in the phase of 5–6 leaves when cutting furrows, for corn – N₉₀Р₄₀, of which N₄₀Р₂₄ for plowing, N₁₆Р₁₆К₁₆ when sowing with seeds, N₃₀ in fertilizing in the phase of 3–5 leaves. It has been established that in the areas of irrigated agriculture of the Western Caspian region, when selecting row-crop predecessors for corn for grain, preference should be given to early-ripening varieties of sunflower for seeds, which are harvested in the third decade of July, and after harvesting it remains in the soil more than 15 t/ha of plant mass. At the same time, the maximum corn yield is achieved – 9.16 t/ha of grain, exceeding the control by 33.1%, due to which, with the same total water consumption as the control option, the water consumption coefficient is reduced by 23.7%.