Despite the high nutritional value of cowpea and its potential for sustainable farming, its cultivation is limited by the lack of vegetable varieties adapted to different soil and climatic conditions, which complicates the fight against food insecurity in many countries. Therefore, this study aims to conduct a comprehensive evaluation of cowpea (Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc.) varieties with the aim of identifying genotypes with high productivity potential and resistance to the main adverse environmental factors of the Right-Bank Forest-Steppe of Ukraine. The experimental study was carried out in a three-year period (2014–2016). Depending on the variant of the experiment, cowpea germination was observed from 25 May to 30 May. The shortest sowing–shoot period (10 days) was observed in the variety ‘U-Tya-Kontou’ (China), with the longest (13 days) in the varieties ‘Kafedralna’ (Ukraine) and ‘American Improved’ (USA). In the control variant, shoots were obtained on 28 May. Flowering started from 9 July to 16 July; technical maturity (unripe (green) beans) started from 27 July to 2 July; and biological maturity of the seeds started from 30 August to 5 September. For the variety ‘American Improved’, the shortest period of seedling–technical maturity (unripe (green) beans) (58 days) and seedling–biological maturity (92 days) was recorded. By cultivar, the maximum plant height was achieved with varieties ‘Groik’ (Israel) at 100.5 cm and ‘Gasson’ (Vietnam) at 61.8 cm, which are 52 cm and 13.3 cm more than the control height. They differ by the quick growth of the main and side shoots, which allows them to be grown on supports. The highest yield of green beans was recorded in the cowpea variety ‘Gasson’ at 14.4 t∙ha−1, which is 38.5% higher than the control. In the variety ‘Groik’, the yield of green beans (11.4 t∙ha−1) did not differ significantly from the control (‘Kafedralna’—10.4 t∙ha−1). The varieties ‘U-Tya-Kontou’ and ‘American Improved’ were characterized by the lowest yield of green beans, which reached 5.8 and 4.2 t∙ha−1, respectively, which is 44.2 and 59.6% less than the control. As a result of statistical analysis of cowpea yields, the limits of its fluctuation were established as follows: fluctuations in the sum of effective temperatures by 10 °C (>10 °C) contributed to a deviation in green bean yields from 20.0 to 24.7 kg (ha)−1, and fluctuations in precipitation by 10 mm contributed to a deviation in green bean yields in the range from 34.3 to 208.2 kg (ha)−1. The results of the study presented in this article have practical application for the development of effective methods of growing local varieties of long-stemmed cowpea, which will increase yields and meet the needs of both farmers and consumers in regions with similar climatic conditions.

There is a need to summarise information using phenological models to develop a sustainable saffron production technology with further regulation of flowering at a certain phenological stage and determination of the appropriate flowering period to improve yield and quality under different environmental conditions. The purpose of the study is to establish the course of phenological phases of saffron growth and development in the conditions of the Right-Bank Forest-Steppe of Ukraine. Phenological observations and biometric measurements were performed in the study. According to field observations, there are a total of 6 phenological stages of saffron development. The rest period lasts from the third ten days of May to October and is divided into primary and secondary dormancy. During the primary dormant period, corms do not show external morphological changes and growth, but internal physiological and morphogenetic changes occur. In the secondary dormant period, the initial emergence of leaves and flowers and their differentiation take place. During the dormant period, saffron plants were left without aboveground organs. The flowering period falls in October. The passage of this phenological stage may be affected by changes in environmental conditions or agricultural technology. The growth of the root system began with the appearance of flowers and leaves. During the growing season, the growth of the leaf apparatus and the development of the root system continue. During this period, daughter corms are also formed from the buds of the mother corm. During the winter, the replacement corms continue to grow using the nutrient reserves of the mother corm. In early March, the development of the root system slows down and the daughter corms reach almost the final size. At the end of the growing season, the root system of the mother corm stops growing. The leaves begin to age from the top to the base. By the end of May, the daughter corms are fully developed and are preparing for the transition to a dormant state. The number of corms produced per unit area depends on the age of the plot, nutrient supply, and the level of agricultural technology. Older fields produce more corms. Due to the higher density, a larger yield of stamens is formed. Therefore, understanding the phenological reactions and influence of climatic factors on the stages of saffron growth and development in certain soil and climatic conditions is useful for future forecasting of harvest time

To achieve the optimal compromise between yield and soil fertility that will help balance two important aspects of agricultural production – high crop yields and long-term soil fertility – it is necessary to understand the impact of changing row spacing on vegetable crop growth and the soil environment. The research aims to determine the adaptive properties of the Pharaoh variety by studying the feeding area and plant density to obtain high-quality chufa nodules in the Kyiv region. The main research methods were field studies and analysis of the variance of morphological traits and economically valuable indicators of chufa. It was found that different plant densities had an impact on the development of vegetative organs of chufa due to competition for resources during the growing season. The variety “Pharaoh” showed a high intensity of aboveground mass formation in sparse crops with a plant density in the range of 28-33 thousand plants per hectare, with the number of leaf bundles reaching 145.2-147.4 pieces, and their average height is 50.4-52.3 centimetres. At the same time, the size of the nodules increased with a lower plant density, since with a larger feeding area, plants formed more powerful ones with thicker leaf bundles. Plants arranged in a 60 × 60 cm spacing (28 thousand plants/ha) formed larger nodules with the largest dimensions: 3.1 cm in length, 1.0 cm in width, and 1.2 cm in thickness. It has been substantiated that chufa of the “Pharaoh” variety was characterised by higher economic and valuable indicators under the schemes of planting 60×50 and 60×60 cm nodules. The high marketable yield of freshly harvested nodules was formed at a plant density of 28-33 thousand units/ha and amounted to 4.2-4.6 t/ha. The highest average yield of nodules after drying was obtained under the plant spacing of 60 x 60 and 60 x 50 cm, which was 3.35 and 2.99 t/ha, which was 20.9 and 7.8% higher than the control, respectively. Chufa is a promising crop in terms of food security and income generation, and precise management of plant placement will help to balance yield and soil fertility

The search and selection of cowpea varieties with optimal economic characteristics is a key factor in the development of cultivation technologies to increase yields. The purpose of the study was to determine the phenological and morphological characteristics of cowpea varieties and establish the relationship between economically valuable indicators and weather conditions. The leading approaches to studying this problem are field method – to assess the growth and development of cowpea varieties; statistical – to conduct variance and correlation analysis of the assessment of morphological features and economically valuable indicators of cowpea. Five cowpea varieties were studied: Groik (Israel), Kafedralna (Ukraine), Gasson (Vietnam), American improved (USA), and U-Cha-Kontou (China). It was found that the duration of phenological phases of cowpea varieties depended on weather conditions. Varieties of cowpea were characterised by early maturation periods for the sum of effective temperatures of 192.0-207.5°C and precipitation of 30.54-31.65 mm. Earlier maturation periods were the varieties American improved, Kafedralna, Gasson with the duration of the period from germination to the beginning of harvesting ripeness of the pod – 58-62 days and the duration of the period from germination to biological ripeness of seeds – 92-94 days. For the vegetable industry, bush varieties Kafedralna and U-Cha-Kontou with a plant height of 48.5-54.9 cm were promising, which formed tender long beans with a weak parchment layer (22.8-23.6 cm). Groik and Gasson varieties proved valuable for growing seedlings due to the small light-coloured seeds with a plant height of 61.8-100.5 cm and the formation of a large number of short beans on the plant (12.8-15.6 cm). A strong relationship between morphological features and economically valuable indicators of cowpea has been established. The average bean yield had a direct strong relationship with the total number of beans per plant (r=0.93) and a strong inverse relationship with the length of the bean (r=-0.88). As the length of the beans increased, the average yield of beans and the number of beans on the plant decreased, as evidenced by a strong inverse relationship between these indicators (r=-0.93). The materials of the paper are of practical value for increasing the species diversity of vegetable crops and improving the provision of valuable food products to the population

Abstract The article presents the results of studies of two samples of fenugreek: blue (Trigonella coerulea (Desr.) Ser.) and hay (Trigonella foenum graecum L.) on the set of economic, biological and biochemical parameters. The researched samples of fenugreek have a wide range of variability of indicators depending on the terms of sowing and weather conditions. More rapid development was shown by fenugreek species on the summer sowing dates (III decade of June) with a vegetation period of 36–37 days. To obtain a high yield of green mass of fenugreek plants, the early spring (II–III decade of April) and late spring (I decade of May) sowing terms were more suitable. The obtained green mass yield was: 5.7–6.9 t∙ha–1 – blue fenugreek, and 7.3–9.3 t∙ha–1 – hay fenugreek, with the content of the dry matter being 12.4–28.4%, the sum of sugars 2.5–5.0% and vitamin C – 38.0–51.8 mg∙(100 g)−1. To obtain spices called “mushroom grass”, it is promising to use hay fenugreek with early spring (II–III decade of April) and late spring (I decade of May) terms of sowing, as a more developed vegetative mass is formed with the dry weight yield of plants 1.3–1.4 t∙ha–1. An increase in the amount of precipitation by 1 mm resulted in fluctuations of green mass yield from 15.0 to 77.3 kg∙ha–1 and dry mass yield from 0.693 to 25.9 kg∙ha–1.

Among the unexplored technological elements of growing fenugreek in the conditions of Ukraine is the creation of conveyor cultivation of the culture. Therefore, the problem of the influence of sowing dates on the growth and development of plants, the parameters of the harvest and the qualitative composition of marketable products is acute. The purpose of this study was to substantiate the optimal sowing dates of fenugreek species to increase the yield of dried products in the conditions of Polissia on sod-podzolic soils. The leading methods employed to investigate this issue were the field method – to find the interaction of the object of research with biotic and abiotic factors, statistical method – to evaluate the research results to find the parameters of fenugreek’s adaptive capacity. During 2012-2014, for different sowing periods, the average yield of dry mass in blue fenugreek varied from 0.5 to 1.3 t/ha, and in hay fenugreek – from 0.6 to 1.5 t/ha. The early spring period and the late spring period of the 1st sowing period were characterized by the highest overall adaptive capacity. The highest value of the specific adaptive capacity was established during the late spring 2nd sowing period. The relative stability index ranged from 2.6 to 11.4. Blue fenugreek during the late spring 1st and 2nd sowing periods responds well to improved growing conditions (bi >1), and fenugreek hay during the late spring 2nd and summer sowing periods. Early spring and late spring 1st sowing period samples are characterized by high breeding value. An increase in the sum of effective temperatures by 1°C contributed to the fluctuation of green mass yield from 4.82 to 128 kg/ha, and dry mass yield from 0.401 to 6.63 kg/ha. At the same time, an increase in precipitation by 1 mm affected the fluctuation of the yield of green mass from 15.0 to 146 kg/ha, and of dry mass from 0.145 to 25.9 kg/ha. Commercial production of fenugreek species was formed within the range of the sum of air temperatures (>10°C) 383.9-487.1°C, the amount of precipitation 70.7-144.3 mm, and the growing season ranged from 35 to 55 days. The highest productivity of fenugreek species was found during sowing from the second decade of April to the first decade of May. The materials of this paper are of practical value for expanding the species diversity of vegetables and increasing the supply of the population with valuable food products and during the application of new and improved elements of technologies for growing valuable rare crops to achieve the maximum effect of fulfilling the genetic potential of plants

The main drivers influencing plant growth, yield increase and its quality characteristics are biotic and abiotic factors. Combinations of abiotic stresses, such as drought and heat, have a much greater impact on yields and product quality. Plants' response to these stresses can vary depending on the species and different stages of development. Understanding the mechanisms and how they protect plants from stress has become vital for improving the yield and quality of parsnip products in changing climates. The purpose of the study was to determine the influence of abiotic factors (temperature and precipitation) on the yield, duration of phenological phases of growth and development of plants, the dynamics of leaf and root mass growth of parsnip in the conditions of the Right-Bank Forest-Steppe of Ukraine. The research was carried out in the field experiment of the Department of Vegetable Growing and Closed Ground in the National Research Institute “Fruit and Vegetable Garden” of NUBiP of Ukraine within the conditions of the Right-Bank Forest-Steppe of Ukraine during 2015-2017. The area of the registered plot was 11.3 m2, and the repetition rate of the experiment is four times. The placement of variants is systematic. The research found that the shortest sowing-emergence period lasted 16 days in the variants sown in the 3rd ten-day period of May and the 1st ten-day period of June. A significant delay of 21 days in this period was noted for sowings from 1st to 3rd ten-day periods of April. The duration of the period from the beginning of root crop formation to bunch ripeness was the shortest when sown in the 1st ten-day period of April – 28 days, and the longest when sown in the 1st ten-day period of June – 51 days. The growing season ranged from 110 to 165 days and was characterised by GDD (> 10 °C) of 1102.4-1439.0 °C and precipitation of 128.1-225.2 mm. After sowing in April, intensive growth of root crops from 2.9 to 3.5 g / day was observed in the second half of August. After sowing in May, the greatest increase in root crops from 2.1 to 2.7 g/day was noted in the first half of September. Thus, for sowings in the 1st ten-day period of June, this figure was the highest in the second half of September (1.9 g/day). The variant sown in the 1st ten-day period of April provided a high yield of root crops of 50.3 t/ha, which is 5.3 t/ha or 11.8% significantly more than the control variant. When sowing in the following terms, a significant decrease in yields was observed compared to the control, namely: for 3rd ten-day period of April – by 3.5 t/ha, or 7.7%, for 1st ten-day period of May – by 8.8 t/ha, or 19.6%, for 2nd ten-day periods of May – by 17.4 t/ha, or 38.6%, for 3rd ten-day periods of May – by 23.0 t/ha, or 51.1%, for 1st ten-day period of June – by 31.7 t/ha, 70.6% compared to the control. A strong direct correlation (r = 0.74-0.99) was found between the growing season and yield, root mass, marketability, and biochemical parameters, namely: dry matter, dry soluble matter, sugars, vitamin C. An inverse correlation (r = -0.98) was observed between the duration of the growing season and nitrates. Increasing the growing season by 10 days increases the yield up to 6.9 t/ha, marketability up to 2.7%, root weight up to 31 g, dry matter content up to 0.7%, dry soluble matter up to 0.3%, sugars up to 0.5%, vitamin C up to 0.8 mg/100 g and reduces the nitrate content to 8.4 mg/kg. Leaf area, photosynthetic potential, and net photosynthetic productivity are strongly directly related (r = 0.92-0.98) to yield. For increasing the leaf surface area to 1.0 thousand m2 the yield is also growing up to 0.7 t/ha. Increasing the photosynthetic potential to 0.05 million m2 days/ha increases the yield to 0.2-1.2 t/ha. Also, the yield increases to 0.3-0.7 t/ha with an increase in net photosynthetic productivity to 0.05 g/m2 per day. The molecular knowledge on plant responses to abiotic stress is promising for further study and is likely to advance crop resilience to climate change and increase the economic efficiency of production

The main factors that have a great influence on plant growth, as well as on increasing the yield and its quality characteristics, are biotic and abiotic. Combinations of abiotic stresses, such as drought and heat, have a much greater impact on yields and product quality. The response of plants to these stresses can vary depending on the species, as well as at different stages of development. Understanding the mechanisms and how they protect plants from stress has become vital to improving the yield and quality of parsnip products in changing climatic conditions. The research aimed to study the influence of abiotic factors (temperature and precipitation) on yield, duration of phenological phases of plant growth and development, dynamics of growth of leaves and roots of parsnip in the Right Bank Forest-Steppe of Ukraine. The research was conducted in the field experiment of the Department of Vegetable Growing and Closed Soil in NL "Fruit and Vegetable Garden" NUBIP of Ukraine in the Right Bank Forest-Steppe of Ukraine during 2015-2017. The area of the accounting plot was 11.3 m2, the repetition of the experiment was 4 times. The arrangement of the research plots was systematic. As a result of research, it is established that the shortest period of sowing-seedlings lasted 16 days in the options for sowing in the 3rd decade of May and the 1st decade of June. Significant delay for 21 days of this period was observed for sowing from the 1st to the 3rd decade of April. The duration of the period from the beginning of root formation to beam ripeness was the smallest for sowing in the 1st decade of April – 28 days, and the largest for sowing in the 1st decade of June – 51 days. The vegetation period ranged from 110 to 165 days and passed for the sum of temperatures (> 10 °С) 1102.4-1439.0 °C and the sum of precipitation 128.1-225.2 mm. During sowing in April, an intensive increase in root crops from 2.9 to 3.5 g/day was observed in the second half of August. During sowing in May, the largest increase in root crops from 2.1 to 2.7 g/day was observed in the first half of September. Thus, for sowing in the 1st decade of June, this figure was highest in the second half of September (1.9 g/day). The option for sowing in the 1st decade of April provided a high yield of root crops of 50.3 t/ha, which is 5.3 t/ha or 11.8% significantly more than the control. When sowing in the following periods, a significant decrease in yield was observed compared to the control, namely: for the 3rd decade of April – by 3.5 t/ha, or 7.7%, for the 1st decade of May – by 8.8 t/ha, or 19.6%, for the 2nd decade of May – by 17.4 t/ha, or 38.6%, for the 3rd decade of May – by 23.0 t/ha, or 51.1%, for the 1st decade of June – by 31.7 t/ha, 70.6% compared to the control. There was a direct strong relationship (r = 0.74-0.99) between the growing season and yield, root weight, marketability, and biochemical parameters, namely: dry matter, dry soluble matter, sugars, vitamin C. The inverse of the strong (r = -0.98) was observed between the duration of the growing season and nitrates. Increasing the growing season by 10 days increases the yield to 6.9 t/ha, marketability up to 2.7%, root weight up to 31 g, dry matter content up to 0.7%, dry soluble matter up to 0.3%, sugars up to 0,5%, vitamin C to 0.8 mg/100 g and reduces the nitrate content to 8.4 mg/kg. Leaf area, photosynthetic potential, net photosynthesis productivity are in strong direct connection (r = 0.92-0.98) with yield. As the leaf surface area increases to 1.0 thousand m2/ha, the yield increases to 0.7 t/ha. Increasing the photosynthetic potential to 0.05 million m2 per day/ha increases the yield to 0.2-1.2 t/ha. Also, the yield increases to 0.3-0.7 t/ha by increasing the net productivity of photosynthesis to 0.05 g/m2 per day. Promising for further study is molecular knowledge of plant responses to abiotic stress, likely to pave the way for making crops resistant to climate change and increase the economic efficiency of production.

Commercial products of parsnip were formed in the conditions of the Right-Bank Forest-Steppe of Ukraine within the sum of effective temperatures of 1356‑1495 °C, precipitation amounts of 171‑318 mm, and relative humidity of 57‑64%. The yield value had an inverse relationship with the sum of temperatures and a direct relationship with the amount of precipitation, relative humidity, and hydrothermal coefficient. The highest yield in the conditions of the Right-Bank Forest-Steppe of Ukraine is provided by Stymul and Pul's varieties with a total yield of 46.2 and 44.8 t/ha, and a marketability of root crops of 89 and 88%, respectively. Pul's and Stymul varieties had the highest breeding value of genotype in terms of yield (BVGi = 46.2 and 44.8, respectively), high ecological stability (Sgi = 3.43 and 1.96, respectively), and plasticity (bi = 1.47 and 0.89%, respectively). The highest indicator of general adaptive ability for plant productivity was observed in the Stymul (GAA= 3.12) and Pul's (GAA= 1.76) varieties. According to the indicator of specific adaptive ability, the Stymul variety (SAA = 2.52) and Pul's (SAA = 0.78) were highlighted. According to the biochemical composition of root crops, the varieties under study did not exceed the control. However, in the Borys variety, the content of dry matter – 25.1%, dry solute – 15.8%, and sugar content – 6.4% was at the control level. All varieties were identified to have a high content of vitamin C – 8.9‑10.1 mg/100 g. The varieties did not tend to accumulate nitrates and their content ranged from 67 to 80 mg/kg and was below the maximum allowable level (MAL 250 mg/kg). The highest tasting score of 5.6 points was given by the Pul's variety. It is recommended to grow highly productive varieties of parsnip – Stymul and Pul's to obtain a consistently high yield of root crops (44.8‑46.2 t/ha) and their marketability at the level of 88‑89% with a high content of basic biochemical components in the conditions of the Right-Bank Forest-Steppe of Ukraine on ‑medium-podzolic coarse-pollinated light loamy turf soil

This paper presents the results acquired from the study of eight carrot hybrids which are suitable for growing in the climatic zone of woodland steppes, while considering a set of economical and/or biological, biochemical, and organoleptic properties. The carrot hybrids that were studied have a wide range of variation in their economic value indicators, which makes it possible to grow them for storage and processing in various soils and climate conditions without irrigation. The most productive carrot hybrids are White Sabine F1 and Yellowstone F1 with a commercial yield of 55.8–58.7 t hа and an average taproot weight of 118.7–136.2 g. The levels of preservation of the taproot of the hybrids White Sabine F1 and Purple Haze F1 after seven months of storage in conditions that involved the use of a stationary pit storage facility was at 81.4% and 80.2% respectively. The use of the taproots of the hybrids Yellowstone F1 and Viking F1 for drying ensures a yield of a high-quality, biologically-valuable finished product with a yield of 11.4–11.7%. Dry hybrid Evolyutsiya F1 and Mars F1 carrots contain more than 40 mg (100 g) of β-carotene.

The aim of this study is to provide for the intensification of the process of removing impurities from the potato heap by oscillating devices, which takes place, when potato tubers are cleaned in the spiral separator during their lifting. The authors have devised a new design of the spiral separator, which can be used in the process of lifting potatoes from the soil. It comprises cantilever cleaning spiral springs, which in their simultaneously rotary and oscillatory motion clean and transport the potato tubers with good quality. However, the removal of impurities from the cleaning area and the cleaning of the side surfaces of potato tuber bodies from the stuck soil can be significantly more effective, if the spiral springs perform their oscillatory motions in the longitudinal and vertical plane during their operation more intensively. In order to achieve that, the authors have worked out a new theory of the oscillatory motion of the cleaning spiral working under the action of the potato heap. That promotes the intensification of the process of cleaning potato bodies from the stuck soil. The authors have generated a new partial differential equation, which describes the oscillations of the cantilever cleaning spiral. The PC-assisted numerical solving of the said differential equation and further numerical modelling have made it possible to obtain the analytic expressions of the relations between the change in the helix pitch distance of the cleaning spiral and its deformation, in particular, the simultaneous longitudinal extension and transverse bending. That result, in its turn, provided for finding the maximum limit amount of the above-mentioned deformation under the condition that the potato tubers may not fall through the spaces between the spiral turns, taking into account the design and kinematic parameters of the cleaning spiral itself, the material it is made of and the process-dependent mode of operation of the separator. As a result of the PC-assisted numerical modelling, it has been found that the total deflection of the spiral on its length varies within the range of 0 to 0.05 m under the following parameters: angular velocity of rotation of the spiral ω = 30 rad s, density of the material of the spiral ρ = 7,700 kg m, elastic modulus Е = 2∙10 Pa, cleaning spiral bar stock radius r = 8.5 mm and a uniform load intensity of 1,000 N m. Such variation ensures the good quality of cleaning and transportation of potato tubers. According to the results of the PC-assisted numerical calculations, the helix pitch distance of a cleaning spiral with the above parameters and the original helix pitch distance S = 48 mm, due to the spiral’s deformation under the proposed transverse oscillations, can change up to 54 mm, which makes impossible for potato tubers to fall

Silicon plays the significant role in the growth and development of plants, their resistance to stress conditions. However, there is limited research on the content of various forms of silicon in soils, the relationship with soil cations, which is particularly relevant in the context of intensive agriculture and climate aridization in Ukraine. The purpose of the present study was to determine the content of silicon compounds of different mobility in the arable soils of the Khmelnytsky region, the spatial variation of these parameters, and to detect the dependence between the content of silicon compounds and soil particle size. The study was performed at the area of LLC "Lotivka Elit" of Shepetivka district of Khmelnitsky region in field crop rotation. We determined for soil samples: particle size distribution and content of fractions of granulometric elements of different sizes, pH of salt extraction (1,0 M KCl solution), humus content, calcium and magnesium exchangeable compounds by extraction with 1,0 M KCl solution. The results showed that the content of silicon compounds in soils depends on the particle size distribution of soil, the value of exchangeable acidity, humus content, and the composition of exchangeable cations.

When digging potato tubers from the soil, one of the main problems is separation of a large amount of the soil and plant admixtures from the heap, which is fed into the potato harvester.We have developed a new design for a potato heap cleaner that consists of five cantilever-fixed cleaning driving spirals, arranged in a wave-like manner, significantly expanding the working zone of separation of the incoming potato heaps, and this, in turn, will contribute to its better dispersal over the working surface of the cleaner, more intense destruction of the soil lumps, and, consequently, improved screening of the soil and plant admixtures, and reduced clogging of the cleaning spirals.The experimental studies conducted under the field conditions showed that the process of cleaning tubers from the soil and plant admixtures, using this cleaner, occurs due to intense movement of the potato heaps by means of the coils of the cantilever-fixed cleaning spiral springs.The springs are rotating at a pre-set angular velocity, making oscillatory movements because of the deflection of their longitudinal axes under the impact of the weight of the heap arriving into the working zone of the cleaner.There was built a mathematical model of the movement of the body of a potato across the surface of the spiral separator.In addition, there was analytically considered the relative motion of a single body of the potato tuber across the surface of the spiral coil with a pre-set radius and angle of the pitch of the helix.As a result of mathematical simulation, a system of differential equations of the movement was compiled, the solution of which made it possible to determine, at the pre-set design parameters, the optimal kinematic characteristics that ensure the guaranteed movement of the potato tuber across the surface of the cleaning spiral spring.

Sustainability in the agricultural field suggests the conservation and maintenance of a natural environment of soil. Nevertheless, in the potato production chain, the mechanized harvest is carried out with the concurring removal of impurities and fertile soil. The authors have developed a new spiral potato cleaner which is able to capture and efficiently remove soil lumps of various sizes and shapes, as well as various plant residues. Theoretical and experimental studies have been performed on this soil clod cleaner to determine the structural and kinematic parameters that provide efficient capturing, motion and sifting down of the soil, through the gaps between the helices of its cleaning spirals. An analytical description of the motion of the clod of soil has been made and a system of differential equations has been compiled, whose numerical solution made it possible to determine the indicated reasonable operative parameters of the developed spiral potato cleaner. The results of the experimental research confirmed those ones obtained through the numerical solution of the mathematical model, i.e., rational angular speed ω of the rotation of the spirals from 20.0 to 30.0 rad s−1 and the radius R of spirals between 0.12 and 0.15 m.

Summary The special attention require the soil studies in Ukraine according to the introduction of the agricultural land market in Ukraine. That is why our aim was to study the content of silicon compounds of different mobility in soils and its correlation with indicators of soil physicochemical properties. Magnetic methods demonstrated high efficiency and low cost when applying to detect soil erosion, indicate the physicochemical properties, and perform fast soil mapping. Soils of the Mokiyivtsi area have an average pH of 4.9–5.4, the acidity of these soils decreases with increasing content of physical clay, the investigated soils of the Khmelnytsky region have mainly low-deficient silicon balance, both of readily-available and hard-soluble forms. However, individual samples of the Mokiyivtsi area have an average deficiency of silicon, in particular if the evaluation is carried out on the content of readily available (actual) silicon compounds in the arable layer of the studied soils. The results of the magnetic studies confirmed the high degree of relationship between MS and salt extract pH (p = −0.80) for the area Hotkivka.

The aim of the study was to determine the optimal design and kinematic parameters of the separator that cleans potatoes from impurities and has a design of the spiral type. The authors have devised a highly efficient design of the spiral type potato heap separator, in which the motion of the potato tubers takes place in the channel formed by two spiral members made in the form of cylindrical spiral springs. In order to substantiate the optimal kinematic and design parameters of the new spiral type potato heap separator, the authors have generated a mathematical model of the motion of a single potato tuber on the cleaning surface formed by two spirals. As a result of solving the obtained analytical expressions, the graphical relations between the parameters of the investigated process of the motion of a single potato tuber body situated between two adjacent spirals have been plotted, which has enabled selecting the optimal design and kinematic parameters of the spiral separator. It has been established in the completed investigation that the angular velocity of rotation of the cleaning rolls has to be within the range of 27 40 rad s-1 in order to ensure the efficient transportation and cleaning of the potato tuber with a diameter of 50 mm that moves on the surface of the spiral with a radius of 75 mm wound from the round bar with a diameter of 15 mm, in case the spirals are mounted with an eccentricity of 10 mm. By analysing the kinematics of motion of the potato tuber on the surface of the spiral type cleaning machine, in case the tuber contacts the spirals at two points, it has been established that the increase of the angular velocity of rotation of the spirals results in the respective growth of the transportation capacity of the cleaning tool, while the separating efficiency at the same time becomes reduced to some extent.

Received: March 6th, 2021 ; Accepted: May 12th, 2021 ; Published: May 14th, 2021 ; Correspondence: jyri.olt@emu.ee