Increase in Productivity of Chestnut Soils on Irrigated Lands of Northern and Central Kazakhstan

Natural conditions in North and Central Kazakhstan and the energy potential of chestnut soil testify to the efficiency of agriculture, especially on irrigated lands. The humus horizon of chestnut soils is 35–50 cm, and the humus content is 3.0–3.5%. The majority of the humus (75%) is contained in a half-meter layer, which emphasizes the short humus level. The phosphorus content, both gross and mobile, is very low at 0.98–0.031%. Potassium is in elevated amounts. Soils are most susceptible to the application of nitrogen–phosphorus fertilizers. According to the mechanical composition, chestnut soils are predominantly lightly loamy, light clays with substrates of souses. Salinization is low, with a salt content in the 0–100 cm soil layer of 0.10–0.20%. The mass of the arable soil layer is 1.3–1.4 g/cm 3 . Deep plowing and loosening of soils improve the water and nutrition regime, creating good conditions for arid agriculture. With deep autumn plowing up to 30 cm, the accumulation of sediment and spring meltwater reaches 1200–1500 m 3 /ha more than in spring disposal. Deep plowing ensures absorption of irrigation water, eliminates run-off during irrigation, and reduces the number of crops requiring extra irrigation. In an average dry year, at 50% water availability and 70% soil moisture content (MC), the number of irrigations is 4, and the irrigation rate is 300–470 m 3 /ha; at 60% MC, 2 irrigations are performed, and the irrigation rate is 600–650 m 3 /ha. On irrigated land, the yield of cereals is 2.8–2.6 t/ha; perennial grasses, 3.0–4.5 t/ha; potatoes, 23.2–24.1 t/ha; carrots, 35.0–40.0 t/ha; and cabbage, 50.0–75.0 t/ha.