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Sirvi Autor "Polishchuk, S." järgi

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  • Pisipilt
    Kirje
    Research into properties of blue melilot and fenugreek cultivated using different sowing times
    (Estonian University of Life Sciences, 2022) Fedosiy, I.; Bobos, І.; Zavadska, O.; Komar, O.; Tonkha, O.; Furdyha, M.; Polishchuk, S.; Arak, Margus; Olt, Jüri; Estonian University of Life Sciences. Institute of Forestry and Engineering
    The paper presents the results of the research into the properties of blue melilot (Melilotus caeruleus (L.) Desr.) and fenugreek (Trigonella foenum graecum L.) with regard to the set of their economy-and-biology and biochemical indices in relation to the dates of their sowing. It has been established that the two species under consideration feature wide ranges of index variability depending on the sowing term and the weather conditions. The earliest ripening terms have been recorded for species in case of summer sowing dates (decade I of June), when short growing season lengths of 36–37 days were observed. At the same time, in terms of heavy plant herbage yield obtained from species in the green conveyor system, the early spring (decades II–III of April) and late spring (decade I of May) sowing terms are more suitable providing a herbage yield of 5.7–6.9 t ha–1 in case of blue melilot and 7.3–9.3 t ha–1 for fenugreek, with a solids content of 12.4–28.4%, total sugars of 2.5–5.0% and vitamin C - 38.0–51.8 mg (100 g)-1 . For the purpose of obtaining the spice named ‘Greek hay’ (foenum Graecum), a better choice is to cultivate fenugreek with early spring (decades II–III of April) and late spring (decade I of May) sowing times, as in this case a greater vegetation mass develops, resulting in a plant dry weight yield of 1.3–1.4 t ha–1. An increase in the total precipitation by 1 mm has contributed to the variation of the herbage yield within the range of 15.0 to 77.3 kg ha–1, dry matter yield - 0.693 to 25.9 kg ha–1. High seed yield has been noted in case of sowing the species in early spring (decades II–III of April), where the seed yield of blue melilot was equal to 0.4 t ha-1, fenugreek - 2.0 t ha-1 , their 1,000 seeds having a weight of 0.71 and 9.7 g, respectively.
  • Pisipilt
    Kirje
    Resistance of the soft winter wheat varieties to pests and their productivity in the northern forest-steppe zone
    (Estonian University of Life Sciences, 2024) Polishchuk, S.; Holyk, L.; Havryliuk, N.; Kuzmenko, L.; Shtakal, M.; Tkachenko, N.; Bulgakov, V.; Ivanovs, S.; Rucins, A.
    There are highlighted the results of research in order to determine the field and laboratory resistance of the winter wheat varieties in a competitive variety testing at the National Scientific Centre Institute of Agriculture of NAAS (2016–2020) against pests, and the level of their productivity is assessed. Among the studied varieties of winter wheat, varieties with complex resistance were found: to cereal aphids, wheat thrips powdery mildew and brown leaf rust - variety Efektna; to cereal aphids, wheat thrips and leaf rust - varieties Polisianka, Pyriatynka, Krasunia Poliska, Vodohrai, Kesariia Poliska, Myroliubna, Romanivna, Pamiati Hirka, and standard Lisova Pisnia St. When varieties were grown without the use of fungicides, insecticides and growth regulators, their yield varied over the years from 2.99 t ha–1 to 10.71 t ha–1. The best varieties of soft winter wheat in terms of their productivity were identified in the northern Forest - Steppe zone, which are included in the State Register of the plant varieties, suitable for distribution in Ukraine - Kesariia Poliska (7.67 t ha–1), Pyriatynka (7.10 t ha–1), Myroliubna (7.08 t ha–1), Merezhka (6.77 t ha–1), Kraeivyd (6.71 t ha–1), Pamiati Hirka (6.61 t ha–1), Polisianka (6.51 t ha–1) and Efektna (6.36 t ha–1). Consequently, with proper selection of the winter wheat varieties, it is possible to significantly limit the harmfulness of pests and diseases, to reduce the amount of the used pesticides, to increase the grain productivity, and to improve its commercial and seed quality.
  • Pisipilt
    Kirje
    Theoretical research into directional stability of trailed tandem- type disk harrow
    (Estonian University of Life Sciences, 2021) Bulgakov, V.; Olt, Jüri; Nadykto, V.; Volskiy, V.; Polishchuk, S.; Aboltins, A.; Beloev, H.; Estonian University of Life Sciences. Institute of Technology
    Disking is one of the methods of soil cultivation, provides its effective crumbling, loosening, partial mixing and soil inversion. This ensures that crop residues on the soil surface are shredded and intermixing with loosened soil particles. Since, in addition to crop stubble, weeds are also counted as crop residues, soil disking, along with the use of herbicides, is often regarded as the most effective method of controlling the weediness of the agricultural background. Despite the fact that numerous studies on the disk harrow working process are available, insufficient attention has been paid to the study of the stability of harrow machine-tractor units, especially trailed ones. The purpose of this study is to establish the theoretical patterns that would provide for selecting the trailed disk harrow parameters that ensure the desired directional stability of the implement, which, in its turn, helps to achieve the desired qualitative performance of the disk harrowing machine-tractor unit. The principles of the theory agricultural machine, analytical mechanics, higher mathematics, as well as methods of PC-assisted numerical calculations have been used. According to the results of the study, it has been established that sufficient directional stability of the trailed disk harrow can be ensured if its working width B, the distance from the hitch point to the centre of resistance (parameter d) and the operating speed 𝑉𝑜 are properly selected. Determining the above-mentioned parameters of the disk harrow with the use of the obtained new analytical relations ensures achieving just their optimal combination, which provides for the maximum field productivity of the harrow machine-tractor unit with the satisfactory stability of disk harrow movement in the horizontal plane.