Phytomeliorative properties of <i>Cannabis sativa</i> L. plants depending on varietal features of the culture

Purpose. To investigate the varietal characteristics of the hemp plants for improving the quality indices of the soil they grow in, determine the amount of inorganic elements in the soil, level of their accumulation in plant stalkі and seeds. Methods. Field and spectrometric methods were basic. The results were processed using conventional methods in agriculture, crop growing and statistics. Variants of the experiment were as follows: varieties ‘Hliana’, ‘Hlesiia’: 1) soils; 2) stalks; 3) seeds. Schemes of experiments included: a) technical maturity of plants, row spacing 45 cm; b) tech­nical maturity of plants, row spacing 15 cm; c) biological maturity of plants, row spacing 45 cm; d) biological maturity of plants, row spacing 15 cm. Results. The amount of the accumulation of alkaline earth metals and their compounds by seeds and stalks of hemp plants depending on their content in vegetation soils was determined. It was found that stalks of the ‘Hlesiia’ plant accumulated strontium (Sr) and its compounds far less than that of ‘Hliana’, whereas in the seeds of the ‘Hlesiia’ variety the content of this chemical element was higher comparing with the previous variety by 70 and 78%, respectively. The difference in the accumulation of barium (Ba) compounds in seeds of hemp plants was not significant, while the tissues of the plant stalks of the ‘Hlia­na’ variety accumulated its compounds significantly more as compared to the ‘Hlesiia’ variety. The degree of influence of the variety, feeding area and the maturity stage on the processes of magnesium compounds (Mg) accumulation by plants was not revealed. Plants of the ‘Hlesiia’ variety accumulated far less calcium (Ca) and its compounds in the stalk tissues as compared to the plants of the ‘Hliana’ variety: in variants of the technical maturity stage of plants with row spacing 45 cm (a) and d – plants of narrow-row sowing (15 cm) in the biological maturity stage 30,94 and 15,95 mg/kg more in the presence in soil and in variants of the technical maturity stage of plants of narrow-row sowing (15 cm) and in the biological maturity stage with broad-sowing (45 cm) 34.54 and 24.19 mg/kg less in the presence in soil. Conclusions. The indices of accumulation of alkaline earth metals by hemp plants were significantly affected by the concentration of compounds of a certain chemical element in the arable layer, the level of energy (light) obtained by plants during vegetation, the varietal features of hemp, the stages of organogenesis of hemp plants and the specificity of their aboveground parts – stalks to accumulate these chemical elements as well as cumulate them by seeds. The varietal dependence as for accumulation of heavy metals by hemp plants tissues and seeds was established. In order to obtain environmentally friendly products, it is necessary to take into account the varietal features of plants concerning the ability to absorb and accumulate the relevant chemical elements and their compounds in the process of hemp culti­vation.