2023, Vol. 21, No. 2

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/8781

Sirvi

Nüüd näidatakse 1 - 20 28

Agrobiological assessment of productivity and nitrogen fixation of vegetable soybean (edamame) in the conditions of Forest-Steppe of Ukraine
(Estonian University of Life Sciences, 2023) Yatsenko, V.; Yatsenko, N.; Karpenko, V.; Poltoretskyi, S.; Lazariev, O.; Kravchenko, V.; Chynchyk, O.; Vyshnevska, L.; Tretiakova, S.; Kozyrsky, D.
Agrobiological evaluation of vegetable soybean cultivars (Glycine max var. Shirofumi) according to a complex of economically valuable traits for introduction in the conditions of the Forest-Steppe of Ukraine it was carried out with the aim of selecting the source material and selecting promising breeding forms according to morpho-biological and physiologicalbiochemical characteristics. The research was conducted in the conditions of the educational and production department of Uman National University of Horticulture during 2020–2022, collection cultivars of different ecological and geographical origins were used. The cultivars ‘Sac’ (166.00 g plant-1 ), ‘Vesta’ (139.33 g plant-1 ), ‘Fiskeby V’ (133.33 g plant-1 ), and ‘Fiskeby V-E5’ (146.67 g plant-1 ) possessed a large mass of edamame beans. The maximum yield of edamame beans was formed by plants of the ‘L 380-2-13’ (12.67 t ha-1 ), ‘Vesta’ (12.33 t ha-1 ), ‘Sac’ (13.20 t ha-1 ), ‘Fiskeby V’ (13.97 t ha-1 ), and ‘Fiskeby V-E5’ (14.53 t ha-1 ). Weather conditions during the period of research significantly influenced the yield and biochemical composition of edamame varieties. The yield of edamame beans ranged from 5.40 t ha-1 in 2020 (min) to 22.40 t ha-1 in 2021 (max), and the coefficient of variation by varieties was at the level of 19–41%. This phenomenon is explained by the minimum amount of precipitation in 2020 and the high amount in 2021, which is confirmed by the hydrothermal coefficient during the period of intensive pod growth (VII–VIII) - 2020 - 0.3; 2021 - 1.3 and 1.1 respectively for the month. The protein concentration in Edamame beans was in the range of 27.94–36.29%. A higher protein content relative to the standard was noted in one sample - ‘Karikachi’ - 36.29%. Minimal accumulation of oligosaccharides was noted in ‘Sac’ and ‘Astra’ cultivars, which indicates their suitability for consumption. Promising cultivars were identified by the amount of fixed nitrogen - ‘Sac’ (168.00 ± 4.32 kg ha-1 ), ‘Astra’ (161.67 ± 2.36 kg ha-1 ) and SybNYYSOH 6 (158.19 ± 4.56 kg ha-1 ). The conducted regression analysis showed close relationships (from moderate to functional) between various indicators of the development and productivity of the nodulation apparatus of edamame cultivars. The evaluation of the collection cultivars of vegetable soybeans, their use according to the variability of morphological features and productivity made it possible to single out the ‘Sac’ among the introduced collection cultivars based on a set of valuable traits for use in the selection process to create new cultivars of vegetable soybeans.
Amino acid composition of milk from Finnish Ayrshire cows and their crossbreeds with the Norwegian Red breed
(Estonian University of Life Sciences, 2023) Ruban, S.; Merzlov, S.; Matvieiev, М.; Borshch, O.V.; Borshch, O.O.; Bilkevich, V.; Lykhach, V.; Fedorchenko, M.; Bondarenko, L.
The purpose of this work was to study the effect of crossing of Finnish Ayrshire cows with Norwegian Red breed under the conditions of the temperate climate of Ukraine on indicators of the qualitative composition of milk, the content of essential amino acids (EAA) and their biological value. The research was conducted at a commercial farm in the Poltava region (50°02′39″ n.l., 33°51′09″ e.l.) using Finnish Ayrshire cows and their crosses with the Norwegian Red breed. According to the indicators of fat, protein and lactose content in the group of crossbred firstborns, purebred counterparts prevailed by: 0.22; 0.09 and 0.07%, respectively, and the energy value of 1 kg of milk by 0.053 Mcal kg-1 . For milk protein of Finnish Ayrshires, the first limiting EAA (lower than the recommended content in the reference protein) was methionine + cystine (affects the rate of clot formation during cheese making), the content of which was 96.3%. In the protein of crossbred cows EAA in which amino acid score (AAS) was less than 100%, were not detected. Phenylalanine + tyrosine - 143.7% and leucine - 122.1%, which are aromatic amino acids and affect the taste properties of milk, were the most excessive. The protein of crossbreds was characterized by a slightly higher value of the total utilitarian coefficient, compared to purebred counterparts (by 12.77%). Also, the aminogram of the crossbred group was closer to ‘ideal’.
Analysis of the power balance of a solar catamaran
(Estonian University of Life Sciences, 2023) Berjoza, D.; Jurgena, I.; Einstals, A.
Significant changes are expected in the percentage distribution of vehicles in the world over the next decade. It is planned to gradually replace conventional internal combustion vehicles with electric drive ones, thereby reducing environment impacts and the production of gases contributing to the greenhouse effect. It is necessary to foster similar trends regarding watercraft, replacing the internal combustion engines with electric motors. An experiment used a solar-powered catamaran equipped with a standard electric motor Minn Kota Endura 34, a 450 W monocrystalline solar cell and a 40 Ah lithium iron 12 V battery. A pyranometer was used to measure solar energy. The experiment used a data logger GL 220 that measured the energy flow to the battery and the electric motor. The experiment was conducted in Jelgava on 5 July 2022, with the maximum altitude of the sun reaching 56.7°. The experiment identified that at an average solar intensity of 500 W m-2 on a sunny day, the solar catamaran could be moved by means of solar energy without discharging the batteries at all power settings.
Application of UAV multispectral imaging for determining the characteristics of maize vegetation
(Estonian University of Life Sciences, 2023) Änäkkälä, M.; Lehtilä, A.; Mäkelä, P.S.A.; Lajunen, A.
Interest in forage maize (Zea mays L.) cultivation for livestock feed has grown in northern conditions. In addition, it is important to develop methods and tools to monitor crop development and other characteristics of the crop. For these purposes UAVs are very efficient and versatile tools. UAVs can be equipped with a variety of sensors like lidar or different types of cameras. Several studies have been conducted where data collected by UAVs are used to estimate different crop properties like yield and biomass. In this research, a forage maize field experiment was studied to examine how well the aerial multispectral data correlated with the different properties of the vegetation. The field test site is located in Helsinki, Finland. A multispectral camera (MicaSense Rededge 3) was used to take images from five spectral bands (Red, Green, Blue, Rededge and NIR). All the images were processed with Pix4D software to generate orthomosaic images. Several vegetation indices were calculated from the five spectral bands. During the growing season, crop height, chlorophyll content, leaf area index (LAI), fresh and dry matter biomass were measured from the vegetation. From the five spectral bands, Rededge had the highest correlation with fresh biomass (R2 = 0.273). The highest correlation for a vegetation index was found between NDRE and chlorophyll content (R2 = 0.809). A multiple linear regression (MLR) model using selected spectral bands and vegetation indices as inputs showed high correlations with the field measurements.
Changes in the content of soil organic carbon and total nitrogen in the organic and conventional cropping systems
(Estonian University of Life Sciences, 2023) Kuht, Jaan; Eremeev, Viacheslav; Loit, Evelin; Alaru, Maarika; Mäeorg, Erkki; Talgre, Liina; Luik, Anne; Estonian University of Life Sciences. Institute of Agricultural and Environmental Sciences
Maintaining and increasing the stock of soil organic carbon is of vital importance in maintaining the soil fertility. In present research the changes in the content of organic carbon (SOC) and total nitrogen (Ntot) in the soil are investigated. The data is collected from the long-term field experiment, which compares organic and conventional farming systems in a crop rotation (barley undersown with red clover, red clover, winter wheat, pea, potato) during 2014–2018. Based on the 5-year experiment, it was concluded that the cropping systems have a significant effect on the SOC content and a smaller effect on the Ntot content of the soil. The diversification of organic cropping systems with cover crops and composted cattle manure significantly increases the content of organic carbon in the soil. The results of the experiment indicate that the content of organic carbon was significantly lower (by 7.6–12.6%) in conventional systems, where pesticides had been applied and cover crops and manure had not been used, compared to the organic cropping systems. The correlations between the SOC contents of main crops and precrops were statistically more significant in organic farming system, compared to the conventional system. Highest SOC and Ntot values were observed in organic systems with cover crops and composted manure fertilization. Hence, it can be stated that in order to improve the soil fertility and fix more carbon and nitrogen, high amounts of organic material should be applied into the soil and the activity of soil microbes should be a priority. The organic cropping systems have more advantages for sustainable crop production.
Comparison of different chemical-free pretreatment methods for the production of sugars, ethanol and methane from lignocellulosic biomass
(Estonian University of Life Sciences, 2023) Sjulander, Nikki; Rooni, Vahur; Rocha-Meneses, Lisandra; Kikas, Timo; Estonian University of Life Sciences. Institute of Forestry and Engineering. Chair of Biosystems Engineering
Most pretreatment methods for lignocellulosic biomass use strong chemicals, such as sulphuric acid and ammonia, to open up the cellular structure of plant biomass. However, those chemicals are not environmentally friendly and their use leads to safety risks. As a result, different chemical-free pretreatment methods have been developed, which focus on the usage of pressure, high or low temperatures and mild chemicals. Freezing pretreatment and explosive decompression pretreatments, using different operating gases, such as nitrogen and steam, are compared in the context of glucose, ethanol and methane yield in this review. For the methane production, the stillage from bioethanol production is used. The usage of this waste improves the overall valorisation of lignocellulosic biomass. The review also investigates, whether the nitrogen explosive decompression pretreatment is suitable for the treatment of softwoods, hardwoods and herbaceous materials. In the comparison of different chemical-free pretreatment methods, it is concluded that heat and water are the most influential parameters for opening up the lignocellulosic biomass structure. The operating gas and pressure in the pretreatment reactor are less relevant. Steam explosion, nitrogen explosive decompression pretreatment and autohydrolysis pretreatment are the most suitable chemical-free pretreatment methods for lignocellulosic biomass.
The content of mobile aluminium compounds depending on the long-term use of various fertilizing and liming systems of Albic Pantostagnic Luvisol
(Estonian University of Life Sciences, 2023) Olifir, Y.; Нabryel, A.; Partyka, T.; Havryshko, O.; Kozak, N.; Lykhochvor, V.
Today, climate change is exacerbating the problems of efficient and environmentally friendly use of acidic soils, which are widespread in Ukraine. At the same time, the role of mobile aluminium compounds in acidity formation is also becoming increasingly important. In this regard, chemical amelioration remains a primary and very important factor in the system of resource-saving and environmentally friendly agricultural measures for the efficient and balanced use of acidic soils. Therefore, the main objective of the research is to establish scientifically sound doses of chemical ameliorant that reduce the content of mobile aluminium compounds and ensure environmental safety and high productivity of agrocenoses on Albic Pantostagnic Luvisol. The research was carried out in a long-term stationary experiment established in 1965 with different doses of mineral fertilisers, manure and lime on an Albic Stagnic Luvisol. It was found that with a prolonged application of mineral fertilisers and the use of this soil without fertilisers, the content of mobile aluminium compounds at the end of the X rotation at pHKCl 4.20 and 4.42 was 68.4 and 58.5 mg kg-1 respectively. Under the organo-mineral and mineral fertilisation systems with liming with 6.0 t ha-1 of CaCO3 calculated by hydrolytic acidity, the content of mobile aluminium compounds decreased to 7.2 and 6.7 mg kg-1 of soil respectively. Under identical fertilisation systems with a lime application by pH-buffering capacity (2.5 t ha-1 CaCO3), the content of mobile aluminium compounds is 10.8–10.0 mg kg-1 soil.
Development of a custom-built RTK-GNSS positioning system for agricultural operations
(Estonian University of Life Sciences, 2023) Lajunen, A.; Pietarinen, J.
The objective of this research is to assess positioning accuracy of a custom-built RTK (Real Time Kinematic) base station. Setting up a RTK base station with open-source tools is rather straightforward process requiring only few components and basic programming skills. The base station and receiver unit were developed by using a SparkFun GPS-RTK2 Board with U-Blox ZED-F9P module. The board was paired with U-blox Multi band GNSS (Global Navigation Satellite System) antenna. The board can use GNSS satellite signals from Galileo, BeiDou, Glonass and GPS systems. The positioning accuracy was evaluated in a fixed position and during operations in agricultural fields. The RTK correction signal was used in connection with soil scanning measurements in different crop fields of the Viikki Research Farm of the University of Helsinki. For accuracy assessment, comparative measurements were carried out with a commercial network RTK (NRTK) correction signal. The vertical and horizontal accuracy of the positioning signal were evaluated based on the accuracy variables calculated by the receiver. The vertical accuracy was also evaluated by mapping the scanned trajectories on the height map which was obtained from NSL (National Land Survey of Finland) open map data service. The custom-built RTK positioning system accuracy was considered generally precise enough for autonomous field work, but the reliability of the observed accuracy should be confirmed with more extensive measurements. The commercial NRTK signal accuracy was considered very good and reliable also for the vertical direction.
A digital transformation into occupational health and safety systems: a review of the best practices in Europe
(Estonian University of Life Sciences, 2023) Demikhov, O.; Opanasiuk, Y.; Demikhova, N.; Merisalu, Eda; Estonian University of Life Sciences. Institute of Forestry and Engineering. Chair of Biosystems Engineering
Digitization is actively spreading and widely implemented in the occupational health and safety (OHS) systems. Progressive technologies make it possible to effectively implement digitalised systems in all the elements of management cycle - from planning to monitoring, evaluation and solutions in the different economy sectors. Aim. The purpose of the article is to give a review on the current state of digital transformation in OHS policy of European countries and Ukraine and identify the positive and negative aspects of digitization in OHS management systems. Method. The review is based on full research articles, reports and conference proceedings in Scopus, Web of Science and Google Scholar database, where the keywords ‘digitization’, ‘occupational health’, ‘safety’, ‘robots’ and ‘management systems’ for literature search have used. Results. In total 51 sources were under analysis, including 23 full research articles and 28 publications from EU-OSHA, ILO and OECD. The database formation and use of big data systems and control tools for monitoring and assessing work environment, digital guidelines, legislation and e-teaching platforms are the main digital instruments in OHS management systems. Use of workplace navigator programs helps to collect necessary information and make right regulations by the law. Use of new digital technologies allows more effectively perform OHS inspection, service and risk prevention functions, and diminish work related injuries and illnesses. Conclusions. A new ideology of public policy in developing digitalised OHS management systems (DOHSS) will make the evidence-based solutions effective and achieve high safety standards and stimulate business growth of specific industries on the national and EU level. The best European experiences of digital transformation into OHS management systems can be implemented also in Ukraine.
The effect of plant growth regulators on productivity of lavender (Lavandula angustifolia Mill.) in the conditions of the Southern Steppe of Ukraine
(Estonian University of Life Sciences, 2023) Manushkina, T.; Kachanova, T.; Samoilenko, M.
The current state of the essential oil industry in Ukraine requires the expansion of areas for essential oil crops. Nowadays, the demand for natural vegetable raw materials and lavender essential oil is growing. Therefore, the aim of the research was to study the morpho-biological features and productivity of lavender plants by treatment with plant growth regulators Radostim and Stimpo during the third-fifth years of the growing season in the Southern Steppe of Ukraine. The research was conducted during 2018–2020. The material for the research work was lavender plants such as Lavandula angustifolia Mill., the varieties of Sinieva and Vdala. The field experiment was done with the method of split randomized blocks. The research was accompanied by phenological, biometric, structural and laboratory observations in accordance with generally accepted methods. Treatment with the growth regulator Stimpo has the greatest stimulating effect on the processes of growth and productivity in lavender plants. Using this method, the highest yield was formed in all years of vegetation from 6.70 to 7.90 t ha-1 at standard humidity, which is by 14.8–21.1% more than in the control. The mass fraction of essential oil in vegetable raw materials is quite high (1.85–2.32%), it differs in lavender varieties and does not depend on treatment with plant growth regulators. The largest harvest of essential oil in all years of vegetation was obtained by treating plants with the growth regulator Stimpo from 137.30 up to 147.36 kg ha-1 , which is by 15.9–16.7% more than in the control.
Estimation of biomethane yield from silage fermented biomass of oilseed radish (Raphanus sativus l. var. oleiformis Pers.) for different sowing and harvesting dates
(Estonian University of Life Sciences, 2023) Tsytsiura, Y.
The potential possibility of using oilseed radish biomass of different sowing dates (technological interval from spring to summer (post-harvest) sowing) and phenological harvesting (budding-green pod) after the silage fermentation procedure for the production of biogas and biomethane using the methodology of anaerobic digestion with the addition of inoculum was investigated. Comprehensive methods for assessing the kinetics and dynamics of production of both total biogas volumes and biomethane production levels were applied, with an assessment of the levels of approximation of the curves of daily volume fixation. Based on a systematic analysis with an assessment of the individual characteristics of the kinetics of the process of anaerobic digestion of silage substrate for each variant of the experiment, the high potential of this crop at different terms of its sowing and harvesting with a level of bioproductivity at the level of 0.54–3.62 t ha-1 DM (depending on the phase and timing of sowing) at the level of biomethane productivity in the range of SMY 201.03–319.66 LN kg-1 ODM at the level of biomethane concentration in the range of 49.92–59.11%. The maximum level of biomethane production was achieved when using silage mass (inoculum subtracted) obtained by silage fermentation from fresh biomass harvested in the flowering phase during the first sowing period with a level of biochemical methane potential (BMPGomp) of 344.13 LN kg-1 ODM, specific methane yield (SMY) of 319.66 LN kg-1 ODM at a maximum specific methane production rate (Rm) of 33.74 LN kg-1 ODM d-1.
Genotype by yield × trait (GYT) biplot analysis for the identification of the superior winter and facultative barley breeding lines
(Estonian University of Life Sciences, 2023) Hudzenko, V.M.; Lysenko, A.A.; Tsentylo, L.V.; Demydov, O.A.; Polishchuk, T.P.; Khudolii, L.V.; Buniak, N.M.; Fedorenko, I.V.; Fedorenko, M.V.; Petrenko, V.V.; Yurchenko, T.V.; Suddenko, Y.M.; Ishchenko, V.A.; Kozelets, H.M.
In the present study, in a panel of promising winter and facultative barley (Hordeum vulgare L.) breeding lines, the peculiarities of yield performance and its combination with resistance (tolerance) to the most common under conditions of the Ukrainian Forest-Steppe abiotic and biotic stresses have been determined. In 2016-17–2018-19 the breeding lines were differentiated based on grain yield, thousand kernel weight, frost resistance, leakage of electrolytes, relative drought tolerance, lodging resistance, and resistance to powdery mildew (caused by Blumeria graminis (DC.) E. O. Speer, f. sp. hordei emend. É. J. Marchal (anamorph Oidium monilioides Link)), spot blotch (caused by Cochliobolus sativus (anamorph Bipolaris sorokiniana [Sacc.] Shoem.)), and leaf rust (caused by Puccinia hordei Otth.). GYT (genotype by yield × trait) biplot model was used for comprehensive evaluation of the breeding lines by a combination of yield with a complex of traits. As a result, the winter breeding line ‘Pallidum 5096’ and facultative breeding line ‘Pallidum 5110’ superior to others in terms of yield × traits combinations have been identified. These breeding lines as new varieties ‘MIP Atlas’ and ‘MIP Yanus’ accordingly have been submitted to the Ukrainian Institute for Plant Variety Examination for further State Qualification Examination. The winter (‘Pallidum 5134’, ‘Pallidum 5097’, ‘Pallidum 5024’, ‘Pallidum 5090’, and ‘Pallidum 5130’) and facultative (‘Pallidum 5153’, ‘Pallidum 5102’, ‘Pallidum 5126’, and ‘Pallidum 5131’) breeding lines can be used as valuable genetic sources in breeding programs in Ukraine and some other Central a nd Eastern European countries.
Impact of changing weather on the crops yield stability in different cropping systems
(Estonian University of Life Sciences, 2023) Viikoja, Ragnar; Alaru, Maarika; Keres, Indrek; Lillak, Rein; Voor, Ivo; Loit, Evelin; Estonian University of Life Sciences. Institute of Agricultural and Environmental Sciences. Chair of Crop Science and Plant Biology
Changes in weather conditions make it possible to change the schedule of agricultural works and introduce new crops and crop rotations in Northern Europe. It is important that the yield of the crops in the rotation are stable under highly variable weather conditions, which would ensure a high total yield for the rotation. One of the goals of this long-term field experiment (2008–2022) was to study the effect of weather conditions on the total yield and stability in the crop rotation; crops of the given crop rotation were grown in organic and conventional cropping systems. Compared to the pre-experimental period 1964‒2007, the annual average air temperature of the test period 2008‒2022 was higher by 1.1 degrees, whereas the increase in the annual average temperature was primarily due to the increase in winter and June–July temperatures. In the 3rd cropping cycle (2018–2022) the total yield of crop rotation as an average of fertilizer variants and experimental years was 21% and 24% lower than in the 1st (2008–2012) and 2nd (2013–2017) cropping cycles, respectively, which was mainly caused by the decrease in field pea yield. The effect of weather on yield stability was greatest for field pea. Fertilization with mineral fertilizers improved the stability of the total yield in the conventional cropping system. Correlation, factorial analyses of variance (ANOVA) and two-factor ANOVA were used to test the effect of cropping systems and climatic conditions on total and average DM yield of crop rotation, also each crop’s DM yield. Despite the negative impact of the weather, most of the yield loss can be prevented or the damage can be eased by careful planning and detailed knowledge about the influence of different weather factors. Further investigation is required to determine the change in growing season length, sowing dates and harvesting to provide farmers more detailed tools to predict and plan their actions.
Impact of storage conditions on preparation of activated carbon from sheep wool fibres
(Estonian University of Life Sciences, 2023) Avotina, L.; Zarins, A.; Nesenbergs, J.; Vanags, E.; Lescinskis, A.; Ansone, A.; Selga, T.; Baryshev, M.; Kizane, G.
In the European Union, up to 200 thousand tons (Zoccola et al., 2015) of sheep wool fibres, that are not used for textile fabrication, are a secondary by-product with wide field of application possibilities, including preparation of activated carbon. Taking into account, that wool fibres can be stored for long time, under impact of the local climate conditions (including low temperatures) before their application, for example, under variety of temperature, presence of air and light, different moisture conditions, it is necessary to estimate the impact of wool’s storage conditions on the preparation of activated carbon. In the present work, various parameters, such as, temperature, presence of air and daylight as well as humidity, were selected for comparison. After storage of wool fibres under selected various conditions, thermogravimetry/differential thermal analysis (TG/DTA) followed by with Fourier transform infrared (FTIR) spectrometry were used in order to estimate the impact of each parameter on the thermal decomposition processes: release of moisture, sulphur and nitrogen containing compounds and oxidative degradation followed by release of carbon dioxide. It was estimated, that one year of storage under varying conditions does not significantly affect the thermal decomposition properties of the wool fibres. However, minor impact of humidity absorbed from air on wool is observed. Wool samples that were stored at elevated humidity gave higher residual carbon yield (R) in comparison to the fibres stored in dry conditions. The obtained results are used to develop recommendations for preparation of activated carbon from wool fibres and for its application in air filtrating systems.
Importance of GIS solutions for beekeepers: a review
(Estonian University of Life Sciences, 2023) Kotovs, D.; Zacepins, A.
In today's realities, beekeeping encounters a number of different challenges, including the lack of suitable areas, urbanisation, intensive farming methods etc. In order to meet the current needs, modern beekeeping uses various information technology solutions that support beekeepers in their activities. Among such solutions, the use of geographic information systems and spatial data is relevant. At the time of writing this work, its authors are developing software solution for beekeepers based on Geographic Information System (GIS) and an interactive map within the scientific project named Hiveopolis. To further develop this solution, it is necessary to investigate the current situation related to issues in modern beekeeping and the solutions already available. In this study, a detailed review of solutions was carried out, which, according to the authors, are the most similar in subject matter to their developed solution. During the review, the authors studied the actual problems of beekeeping solved with the help of the considered solutions, and also provided possible ways to improve existing solutions, presenting their developed system. As a result, the study confirmed the relevance of this direction, and also made it possible to identify challenges for beekeeping and possible improvements to existing solutions.
The influence of nitrogen fertilization and legume species on the productivity of multi-species swards in four production years
(Estonian University of Life Sciences, 2023) Adamovics, A.; Gutmane, I.
The aim of current research was to investigate forage yield and crude protein content of legume-grass mixtures during four years of sward use, applying three nitrogen (N) fertilisation rates: N0, N60, and N120. Three perennial legume species - red clover Trifolium pratense (Tp), lucerne Medicago sativa (Ms) and fodder galega Galega orientalis (Go) were tested in mixtures with grasses (G). Mixtures were composed of 50% of legumes and 50% of grasses. Lucerne and fodder galega are introduced forage legume species in Latvia, and are raising an ever-growing interest in Latvia. The studies of persistency, quality and yielding ability of these legume species in Latvian agroclimatic condition in comparison with traditionally used red clover are actual. Significant differences in dry matter (DM) yields were found between successive production years, mixtures, and N fertilization rates. The highest average DM yield was found for the mixture with lucerne (Ms+G). The decline in productivity between the first and fourth production years was more expressed for red clover mixture, but a more stable productivity was demonstrated by swards with galega (Go+G). The N rate increase contributed to a significant DM yield increase for all mixtures. The positive effect of the increased N rates on DM yield increase was better expressed for red clover mixture (Tp+G). Red clover mixture (Tp+G) had the lowest average crude protein (CP) content. Mixture with galega had a higher CP content in the third and fourth production years. The CP content of red clover mixtures increased by nitrogen rate.
Knowledge of packaging waste among czech university students
(Estonian University of Life Sciences, 2023) Altmann, V.; Zhao, S.
The residential sector generates around 14% of the overall waste production in the Czech Republic. This essential share requires special attention to analyze with particular emphasis for citizen education, especially on young people. Thus, this research is dedicated to citizens' awareness about packaging waste to increase their knowledge. The experiment was conducted in the form of a survey, and students from a Czech university were asked to estimate the weight of the packaging waste presented to them in term to verify their knowledge about packaging waste. This experiment featured different groups of students over time. The result showed no difference in knowledge between these student groups over time. The long-term home study caused by COVID-19 did not appear to have affected students' knowledge of packaging waste. This study showed students' actual knowledge about packaging waste and highlighted the gap and importance of education in waste management.
Large building facilities towards energy transition
(Estonian University of Life Sciences, 2023) Karapidakis, E.; Markaki, M.; Yfanti, S.
Large buildings complexes present significant amounts of energy consumption. Sport centers compose a more special case of large volume buildings, compared to other facilities. This is related not only to the specific requirements of the thermal environment regarding the type of activities taking place as well as the considerable loads enforced by the presence of people. The aim of this paper is to evaluate the energy consumption of a Sports center, through energy audits, extract energy baselines and propose energy-saving interventions and RES utilization. More precisely, a cost-benefit analysis will be carried out to assess the energy production and the relevant contribution of the potential energy interventions. As a result, the priority list of proposed measures will be extracted, with all the data regarding energy gains, capital costs, and cash flows. Particularly, a capital budgeting analysis of each measure will support the final decision of a holistic energy approach at the specific building facilities.
Methanol-HVO blends for efficient low-temperature combustion: analytical research on fuel properties
(Estonian University of Life Sciences, 2023) Wang-Alho, H.; Sirviö, K.; Hissa, M.; Mikulski, M.; Niemi, S.
Next-generation low-temperature combustion (LTC) engines can accommodate ultra-high efficiency with near-zero NOx and PM emissions. Reaction kinetics is the governing mechanism in LTC. Onboard fuel reactivity control is, thus, becoming an interesting concept that ultimately provides pathways toward a fully fuel-flexible engine. No matter the technical realisation - in-cylinder blending or pre-blending/emulsification - the reactivity control requires fuels with complementary properties. Methanol and hydrotreated vegetable oil (HVO) seem to be one of the most promising, yet under-studied combination for LTC engines. They are both renewable and can be mixed together. Methanol’s high knock resistance and large latent heat of evaporation enable a wide engine load range, with a propensity to reduce NOx emissions and mitigate thermal or mechanical stress. The same properties on the other hand require highly reactive fuel to enable the mixture to self-ignite controllably in LTC conditions. HVO is amongst the most reactive renewable alternatives and its clean paraffinic structure further mitigates particle matter formation. - Importantly, in pre-blending HVO emulsification can resolve the lubricity issues of methanol. In this paper, the aim was to study the engine-relevant properties of HVO-methanol fuel blends. The analysed properties were the distillation properties, density, kinematic viscosity, cetane index, and flash point. Based on the results, the suitability of the chosen blend shares for LTC concepts was evaluated.
Microstructure analysis and Hardness of Al C355.0 with step varying weight of Hematite particulate reinforcement
(Estonian University of Life Sciences, 2023) Rajesh, T.R.; Venkatanarayan, B.; Vutukuru, S.K.; Prabhakar Kammar, B.
A detail study on the microstructure of engineered Al C355.0 metal matrix with step varying weight of hematite particulate reinforcement from 0–12% in the step of 3% by using stir casting method in the copper chills with and without water circulation is carried out in the present work. It was earlier realized that copper chills increase the hardness of metal matrix compared to its base alloy. The novelty lies in the circulation of water during solidification process so that a stronger matrix reinforcement bonding, low cluster regions, grain reinfinement with minimum porosity could be achieved. The maximum hematite particulate size was 150 μm. From the Scanning Electron microscope, it is clear that there was good distribution of reinforcement in the matrix but not exactly clear whether it is uniform or non-uniformly distributed. SEM and XRD analysis results show the presence of hematite in the matrix. With increase in reinforcement the hardness increased up to 9% of the reinforcement and then decreased. It is concluded that water circulation on casted composites have good effect in improving the hardness of the Al C355.0 at 9% of hematite resulting to BHN 128 and without water circulation it was found to be BHN 124. It is realized that water circulation improves the hardness of the composite for all the cases with hematite as particulate reinforcement for Al C355.0.

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