Luzhanskyi I. Efficiency of irrigation, basic tillage and fertilization in the cultivation of grain sorghum in the South of Ukraine

Object of study – is the process of forming the productivity of grain sorghum crops by different methods and depth of the soil basic tillage, fertilizers and irrigation regimes on dark-chestnut soils of the south of Ukraine. Purpose – is to develop new and improve existing methods of basic tillage and fertilization systems of irrigated soils, which will provide favorable agrophysical properties, water and nutrient regime for realization of potential opportunities for grain sorghum productivity. Methods – field - conducting a two-factor experiment to determine the agrophysical properties of the soil, the state of soil moisture, phenological and bioenergetic observations, the dynamics of plant growth, yield accounting; laboratory - research of soil samples; calculation - determination of economic and energy efficiency; statistical - processing the reliability of research results. Results – an agro-technological assessment of five methods of basic tillage was carried out against the background of organic and two organic-mineral fertilizer systems with the introduction of fertilizer doses N90P60 and N120P60, which contributed to the optimization of soil fertility indicators, an increase in the yield and quality of grain sorghum grain while reducing the cost of cultivation. The density of composition, porosity, water permeability are experimentally studied; the features of the formation of reserves of available moisture in the soil and the parameters of water consumption of grain sorghum by various methods and depth of the main tillage are established; the volume of organic matter and mineral nutrition elements in the soil is determined due to plant residues of winter wheat, as a precursor of grain sorghum, and the balance of biogenic elements for its cultivation is established. Novelty – consists in the theoretical justification and establishment of regularities of the formation of economically and energetically justified, sorghum grain yield depending on the basic tillage and organic-mineral fertilizer systems using post-harvest crop residues of crop rotation on irrigated lands of the Southern Steppe of Ukraine. The scientific value – improved scientific approaches to the development of technology for growing grain sorghum on irrigated lands in the south of Ukraine, which ensures the creation of favorable agrophysical properties and a nutritional regime for the formation of grain yield of sorghum grain. Sector – agriculture.