Kabanets V. Agrotechnological substantiation for realizing the hemp potential in the conditions of North-Eastern Forest-Steppe of Ukraine

The dissertation presents the results of experimental research aimed at forming the theoretical basis and practical solution to the problem of improving the efficiency of hemp crop through its technological differentiation. The problem was solved by using the features of plant growth and crop formation in hemp, development of basic parameters for technologies of bilateral crop use, technologies aimed at obtaining marketable seeds, formation of phytomeliorative crops and monoculture of hemp. The dynamics of input, absorption and reflection of energy flow of photosynthetic active radiation by crops with different pre-harvest density was estimated. The conditions and dynamics of re-weeding depending on the density of crops were determined. The identification of hemp varieties according to the indicators of chlorophyll content and structure by the complex of photophysical parameters of the plant leaves was carried out. Indicators and range of basic elements content in straw and hemp seeds were determined. The coefficient value of biological accumulation of radioactive elements and heavy metals in the aboveground part of plants was calculated. Significant differences in the total indicators of toxic elements removal per unit area depending on the variety, growth conditions and harvesting phase were revealed. The growth parameters of fibrous hemp in monoculture were established. Positive or stable balance of humus and basic macronutrients in monoculture plots was ensured by annual application of organic fertilizers at rate above 40 t/ha or complex application of organic fertilizers at the rate of 20 t/ha + and mineral fertilizers at the rate of N 60P45K45 per hectare. The optimal rates of sowing and mineral fertilizers application for obtaining marketable seeds were established. On the basis formation model of final plant density in wide-row crops the correction coefficients for sowing rate depending on the rate of mineral fertilizers were calculated. The dynamics of crop structure parameters in wide-row crops at the level of individual plants and crops was analyzed. It was substantiated that the main limiting factor for the increase of seed yield in wide-row crops was the insufficient level of plant reaction (in terms of seed productivity) to the growth of the nutrition area.