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ANNOTATION. In the context of water scarcity, changes in the hydromodular zoning of irrigated lands in southern Karakalpakstan, the distribution of irrigated lands by hydromodular regions and the definition of scientifically based irrigation regimes for cotton in the main hydromodular regions.
INTRODUCTION. The water that enters the plant cell leads to an increase in the volume of sap in the cell and increases its pressure on the cell membrane, thereby maintaining the turgor state of the cell and plant tissue. Along with the water in the soil, several nutrients enter the plant and spread to the leaves and other organs. The process of photosynthesis, which ensures the formation of organic matter, cannot be carried out without water.
The mechanism of water movement in plants and the relationship between physiological processes and productivity of the plant water regime have been studied by many scientists: S.N. Ryjov (1937, 1953), H. Karrien, S. Stokking (1951), N.A. Petinova (1954) and others. The highest productivity of all agricultural crops is achieved by providing them with uninterrupted water supply at all phases of the period of growth and development.
The basics of control of cotton irrigation norms were recommended by S.N. Ryjov (1938). According to his recommendation, the main part of the cotton root is placed in a layer of 1 m, and the main part of the water is absorbed for transpiration from a depth of 30-90 cm. Therefore, it was found that irrigation is less effective than wetting the layer after 100 cm.
One of the main issues to be addressed during the study of irrigation procedures and the development of recommendations for its application is that the pre-irrigation moisture in the soil is at the lowest moisture capacity, which requires regular irrigation. Plants consume different amounts of water during the irrigation period, so a specific irrigation regime has been established for each transition phase of their development, taking into account soil conditions.
Based on the experiments conducted by M.Khamidov, it was found that the most favorable conditions for growing cotton in low-salinity meadow heavy sandy soils with a groundwater level of 1.2-1.6 m, when the soil moisture content before irrigation is limited to 70-80-60%; as it arises. Such a soil moisture regime is created by nutrient irrigation...