Научный журнал

The article examines the uneven distribution of calcium in reserve (general, potential, close and labile) forms on irrigated and gray-earth-meadow soils of the experimental site of Research Institute of Breeding, Seed Production and Agricultural Technology of Cotton Growing in the Gulistan district of the Syrdarya region of the Republic of Uzbekistan in the farms "Sokhil" and "Okoltin". According to generally accepted methods, reserve forms of calcium were studied, their easily digestible forms for plants were determined with the aim of subsequent application of calcium-containing fertilizers. Studies have shown that, on irrigated serozem-meadow strongly saline medium loamy soils, the near reserve form of calcium in the arable layer is 310 mg / 100 g of soil, in the subsoil at a depth of 60-76 cm its decrease is observed and in subsequent horizons it increases again. The labile reserve of calcium in irrigated serozem-meadow, highly saline, medium loamy soils ranges from 175 to 260 mg / 100 g of soil. The potential reserve form of calcium both in irrigated meadow soils and in sierozem-meadow soils ranges from 98.04% to 91.65%. With a high concentration of gypsum and calcium carbonates in the soil profile, the potential reserve form of calcium in soils prevails over other types of reserve forms of calcium and its potential reserve ranges from 14001 to 4040 mg / 100 g of soil. Along the soil profile of the studied soils, the distribution of calcium forms is uneven. The alkaline soil environment, characteristic of the Central Asian region, contributes to the accumulation of a potential form of calcium that is not assimilated by plants. The studied irrigated meadow and sierozem-meadow soils require the application of calcium-containing fertilizers to replenish the shortage of labile and nearby reserve forms of calcium, which are most important for plants.