Miscanthus × giganteus (M. × giganteus) is a perspective plant produced on marginal and contaminated lands with biomass used for energy or bioproducts. In the current study, M. × giganteus development was tested in the diesel-contaminated soils (ranged from 250 mg kg⁻¹ to 5000 mg kg⁻¹) and the growth dynamic, leaves quantity, plants total area, number of harvested stems and leaves, SPAD and NPQt parameters were evaluated. Results showed a remarkable M. × giganteus growth in a selected interval of diesel-contaminated soil with sufficient harvested biomass. The amendment of soil by biochar 1 (produced from wastewater sludge) and biochar 2 (produced from a mixture of wood waste and biohumus) improved the crop’s morphological and physiological parameters. Biochar 1 stimulated the increase of the stems’ biomass, while biochar 2 increased the leaves biomass. The plants growing in the uncontaminated soil decreased the content of NO₃, pH (KCl), P₂O₅ and increased the content of NH₄. Photosynthesis parameters showed that incorporating biochar 1 and biochar 2 to the diesel-contaminated soil prolonged the plants’ vegetation, which was more potent for biochar 1. M. × giganteus utilization united with biochar amendment can be recommended to remediate diesel-contaminated land in concentration range 250–5000 mg kg⁻¹.

To get additional tools for the assessment of carbon sequestration, along with the visual assessment of soil coloration with the applying of A. H. Munsell’s atlas, the analysis of color and spectral characteristics of soil using portable colorimeter NixPro and reflectometer Our Sci Reflectometer was carried out in this study. Elemental analysis of soil samples using X-ray fluorescence analysis was performed and the content of organic carbon was estimated. The spectral range of reflected light, which correlates most with the content of organic soil substance, was singled out. Based on the data, received by methods of reflectometry and colorimetry, prognostic regression models were constructed. A multiple linear regression equation with a statistically authentic luminosity predictor (L*) (R2=0.61) was obtained. It allows describing the link between the content of the organic substance in the studied soils and the parameters of the color setting system CIELab, as well as the equation describing 69 % of the data link dispersion between the integrated reflection coefficient and the organic carbon content of the soil. The link between the integral reflection coefficient and the total organic substance content was found. The most correlated spectral range with the content of organic substance – 500–632 nm was singled out. Regression models, which were based exclusively on the spectral data of pre-treated H2O2 soils, increased their predictability by 8–10 %. Approaches that can complement the tools for rapid determination of the organic carbon content in the soil were presented in the work. Researchers are expanding their arsenal of technical support for estimation of color or spectral coefficients of light reflection, based on which it is possible to conduct geospatial analysis and determine the content of the organic substance in low-humus soils with a probability of 69 %.

The use of biological preparations based on nodule bacteria and complexes containing, except rhizobia, biologically active substances is a cost-effective and environmentally sound element of legumminous cultivation technologies. The study aimed to establish the influence of pre-sowing treatment of seeds with microbiological preparations Ryzoboft and Ryzohumin according to the indicators of growth processes (Faba bona Medic) of Khorostkivskyi variety beans in the conditions of Western Forest-Steppe of Ukraine. The research was conducted during 2018–2020 in the felds of agrobiolaboratory of Ternopil National University named after Volodymyr Hnatiuk. During the vegetation period, the height of the stem was measured, the number of leaves on the plant was counted, and the raw and dry weight of the aboveground organs and the root system were determined. It was established that microbiological preparations Ryzoboft and Ryzohumin affect the growth processes of beans against the background of spontaneous inoculation by local populations of nodule bacteria. The increase in stem height of the experimental plants in comparison with the control of pre-sowing treatment of seeds with Ryzohumin at the beginning of flowering was 13,9 %, during flowering –14,1 %, and in the green bean phase – 9,0 %. Pre-sowing inoculation with Ryzoboft signifcantly increased the height of the bean stalk only in the green bean phase – 11,8 %. During flowering of beans with the use of the Ryzohumin signifcantly increased the number of leaves on the plant – by 25,7 % compared to the control. In the green bean phase, both studied preparations signifcantly influenced the process of leaf formation. There was a signifcant effect on the foliage of plants of the Ryzohumin, compared with Ryzoboft during the study period. Statistically signifcant increase in the indicators of raw and dry mass of aboveground organs of beans in the green bean phase under the influence of Ryzoboft and Ryzohumin was revealed. During flowering in the conditions of pre-sowing treatment of seeds with Ryzohumin, a signifcant increase in the raw mass of the root system was found. The obtained results indicate the prospects of further studies of production processes of bean plants under the influence of microbiological preparations Ryzoboft and Ryzohumin. Key words: beans, inoculation, Ryzoboft, Ryzohumin, vegetation period, biometric indicators.

The dynamics of changes in the chemical composition of soils contaminated with oil products during the vegetation of Miscanthus giganteus, as well as under the conditions of adding biochar (biochar) were studied. The possibility of using the culture of Miscanthus giant and biochar for soil remediation under conditions of oil pollution was analyzed. It was shown that the introduction of biochar into the soil enriched it with nitrate nitrogen, which was actively assimilated by giant miscanthus plants during the growing season. The absorption of nitrate anions by plants was especially active in the second series of the experiment, when the soil + biochar was contaminated with diesel fuel. It was established that the content of NH4+ ions in both series of the experiment increased until the end of the growing season. Obviously, ammonium nitrogen is absorbed to a lesser extent by M. giganteus plants, compared to nitrate. The increase in ammonium content can be additionally caused by the activity of soil microbes in the rhizosphere of plants, which contributes to the accumulation of ammonium nitrogen in the soil. It has been shown that miscanthus plants actively absorbed water-soluble forms of phosphorus, especially in the period from June to September. The application of biochar was a significant source of phosphorus, although its release into the soil is a rather slow process. It was determined that additional amounts of potassium were added to the soil with biochar, which was actively used by the M. giganteus culture. The minimum amounts of potassium in both series of studies were absorbed by plants of E groups, where the content of diesel fuel in the soil was the highest. The introduction of petroleum products had a minor effect on the value of exchangeable acidity. The addition of biochar contributed to the shift of the acid-base balance in the direction of alkalinity, but after the end of the miscanthus vegetation (September), a decrease in the pH of the saline extract of the soil was noted. It is shown that the most noticeable decrease in the concentration of diesel fuel in the soil was noted under the conditions of adding biochar and after growing miscanthus, which can be effectively used for the remediation of lands contaminated by oil products.