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2020, Vol. 18, No. 3

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/6244

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  • Kirje
    Theoretical study on forced transverse oscillations of root in soil with provision for soil’s elastic and damping properties
    (2020) Bulgakov, V.; Holovach, I.; Ruzhylo, Z.; Melnik, V.; Ihnatiev, Ye.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
    The topic of the paper is the theory of the forced transverse oscillations performed by the root fixed in the soil under the action of the harmonic perturbing force vectored at right angle to the root’s centreline and along the line of the translational motion performed by the lifter. On the basis of applying the Ostrogradsky-Hamilton variational principle and using the equivalent schematic model developed by the authors, the expressions have been obtained that allow to determine the amplitude of the forced transverse root body oscillations as function of the perturbing force amplitude value as well as the soil’s elastic deformation and damping coefficients. The ranges of the elastic soil deformation coefficient values, at which the resonant behaviour is observed, that is, at which the forced elastic root body oscillation amplitude value exceeds the tolerance limits, have been determined for the 10, 15 and 20 Hz frequencies of the perturbing force produced by the vibrational lifting tool. That said, the mentioned oscillation amplitude values can vary from 0.58 to 0.45 m, which is sufficient to result in the root breaking. Moreover, it has been proved that, with the increase of the perturbing force frequency, the resonant behaviour ranges shift towards the increased values of the elastic soil deformation coefficient. Therefore, such elastic soil deformation coefficient ranges should be avoided in case of the lifting tool design proposed in the paper. As regards the damping properties of the soil, it has been proved that they do not cause any resonance phenomena.
  • Kirje
    Relation between first lactation milk yield and functional traits in dairy cows
    (2020) Marinov, Iv.; Valchev, V.; Dimov, D.; Penev, T.
    The aim of the study was to analyze the relationship between first lactation milk yield (FLMY) and age at first calving (AFC), longevity and productive life in dairy cows. The study covered 944 Holstein cows housed in 5 dairy cattle farms in Bulgaria. All cows from the five farms culled in the period 2012–2018 with FLMY data were included. The average AFC for all culled cows included in the study was relatively high for the Holstein-Friesian breed - 29.75 months. The average FLMY of the herds included in the study was 7,660.94 kg with significant herd variation from 5,899.09 kg to 8,646.0 kg. Significant effect of the herd (P < 0.001), AFC and the associated effect of the herd and AFC (P < 0.05) on the average FLMY were found. The highest FLMY was reported in primiparous with AFC of 28–30 months – 7,860.8 kg, and the lowest in those with AFC ≤ 24 months – 7322.8 kg. In the herd with the lowest average FLMY - 5,899.09 kg 27.5% of the heifers had calved at age over 34 months. A statistically significant effect of AFC (P < 0.001) was found on longevity, whereas the productive life was significantly influenced by FLMY (P < 0.05). A tendency for higher longevity for cows with higher AFC of 34–37 months and over 37 months – 5.9 and 5.8 years, respectively was observed. The lowest were the longevity values for cows calved at age up to 24 months – 4.9 years. The cows with the lowest average FLMY (up to 4,000 kg) had the shortest productive. Both very low and high AFC were associated with lower first lactation cow productivity and shorter productive life. The losses for farmers were greater when keeping a high AFC in heifers, which increases the cost for housing them, and the lower productivity and longer productive life reduce the probability.
  • Kirje
    Formation and determination of the individual area of oilseed radish leaves in agrophytocenosises of different technological construction
    (2020) Tsytsiura, Y.
    For the successful control of the production process, determining the leaf area is a basic requirement. In this context, it is important to determine the regularities of leaf formation within the plant, considering technological parameters of agrophytocenosis construction. These are the important issues covered in this paper based on the years of research conducted between 2013 and 2018 on three cultivars of oilseed radish: one of the poorly explored members of the cruciferous family of multipurpose use. The conducted researches allowed to distinguish features of longline leaf formation of oilseed radish cultivars and mathematically describe features of formation of their area, length and width at the early flowering phase according to the Richards growth curve. The peculiarities of formation of individual leaf area depending on the combination of the variations of the stand density and fertilization in the context of the recommended process regulation of oilseed radish cultivation are also determined. It has been proved possible to use a non–destructive method of determining the individual leaf area of oilseed radish, basing on the evaluation of 29 models, using the following formula S = 7.9316– 2.3613L + 0.6897 (LW)+0.0458L2–0.0005 (LW)2 (under the following test parameters of the model: R2 0.9106; RMSE 9.75; d 0.956; BIAS –0.1523).
  • Kirje
    The combined impact of energy efficiency and embodied energy of external wall over 30 years of life cycle
    (2020) Miljan, Matis; Miljan, Martti-Jaan; Keskküla (Leiten), Kadri; Miljan, Jaan; Estonian University of Life Sciences. Institute of Forestry and Rural Engineering. Chair of Rural Building and Water Management
    Decreasing the energy consumption in production and building activity is the main aim nowadays as well as in the future. Taking into account that almost 50% of European Union’s final energy consumption is used for heating and cooling, of which 80% is used in buildings it is essential to minimize this amount beforehand. Looking at the energy losses we see that the main heat losses are caused due to the transmission through the envelope and ventilation system. EU energy efficiency target for buildings to 2030 is at least 32.5%. According to this, national energy efficiency action plans were done, which mean that existing building stock need renovation and new buildings will be constructed according to the energy efficiency requirements. One important factor to improve energy efficiency is to modify thermal transmittance of the envelope. In 2017 minimum energy efficiency requirements were validated in Estonia and determined that the thermal conductance of outer wall must be less than 0.22 W m-2 K-1 (recommended range of U = 0.12–0.22 W m-2 K-1 ). According to this the energy loss through the envelope was calculated over the year taking degree-days as bases. In our area this number is 4,933 degree days per year, what gives us the calculated heat loss through the envelope 10.22 kWh m-2 if the thermal conductance of the wall is 0.092 W m-2 K-1 . This required value of thermal conductance we can achieve using good insulation materials. Still there are possibilities to choose between insulations. Done tests and calculations allow to conclude that energy consumption during building life cycle together with embodied energy of building materials gives us more realistic overview of the energy efficiency of the building. Our results confirm that the use of local natural insulation materials is 1.67 times more sustainable and energy saving than using industrial materials.
  • Kirje
    UAV photogrammetry for volume calculations
    (2020) Kokamägi, Kaupo; Türk, Kristina; Liba, Natalja; Estonian University of Life Sciences. Institute of Agricultural and Environmental Sciences. Chair of Environmental Protection and Landscape Management; Estonian University of Life Sciences. Institute of Forestry and Rural Engineering. Chair of Geomatics
    This research assesses the suitability of UAV (Unmanned Aerial Vehicle) photogrammetry for calculating stockpile volumes and analyses the compliance of the accuracy of results to current laws. In addition two different UAV’s and two different objects are compared and the necessity of using GCP’s (Ground Control Points) is investigated. The time spent on each work stage is also evaluated. Data used in this study was collected in two sites, where the objects differed in shape, colour and texture. The investigated objects were a regularly shaped peat stockpile and an irregularly shaped gravel stockpile. Data was collected with a terrestrial laser scanner, a GNSS (Global Navigation Satellite System) device and two different UAVs. Volume of the models calculated from different data was compared to the volume of the models based on laser scanning data for accuracy assessment. Relative errors of all of the photogrammetric models compared to the laser scanning based model were under 4%. It was concluded that the advantages of UAV based photogrammetry become apparent as the complexity and size of the measured objects grow. Results of the study show that using UAV photogrammetry to determine stockpile volumes is sufficiently accurate with both of the tested UAVs. The results show that without using GCPs (Ground Control Points), sufficient accuracy was still achieved. Nevertheless accuracy was increased by using GCP’s. It was concluded that using UAV’s can significantly reduce the time spent on collecting data for volume calculations, especially when GCP’s are not necessary.
  • Kirje
    Municipal organic solid waste composting: development of a tele-monitoring and automation control system
    (2020) Ahmadi, T.; Casas, C.A.; Escobar, N.; García, Y.E.
    The Organic Solid Waste (OSW) generation have experienced high growth in the last decades. Moreover, the treatment and management of them have become a priority in the environmental policy of many cities, due to the sanitary and environmental problems related to the OSW elimination. Between 2 and 3 metric tons per day of organic residues are generated in the local market square of Fusagasugá-Colombia, without having any transformation program or technological alternatives for their decomposition. This paper presents the design and implementation of an experimental reactor for composting that includes a measurement stage, signal conditioning, data acquisition (DAQ), and data storage, together with a control and telemetric supervision system through a Human-Machine Interface (HMI), which allows manipulation of some key variables of the composting process remotely via the Internet.
  • Kirje
    Genetic variation of traits affecting meal quality in black × yellow seeded doubled haploid population of winter oilseed rape
    (2020) Wolko, J.; Dobrzycka, A.; Bocianowski, J.; Szala, L.; Cegielska-Taras, T.; Bartkowiak-Broda, I.; Gacek, K.
    The by-product of oil production from oilseed rape (Brassica napus L.) is protein rich rapeseed meal. It is of great interest to improve the quality of rapeseed meal for poultry feed by reducing the level of anti-nutritional factors, mainly fibre and glucosinolates. The aim of the study was to assess genetic variation of traits affecting rapeseed meal quality in seeds from the M305 (black-seeded) × Z114 (yellow seeded) population of winter oilseed rape doubled haploid (DH) plants. The influence of weather conditions on these traits was tested under two-year field growing conditions in Poland. Significant effect of genotypes and the year of experiment was found for all of the studied traits, apart from neutral detergent fibre (NDF). The significant phenotypic variation in all of these traits makes future selection to improve quality of rapeseed meal possible. It was also found that all of the traits, apart from neutral detergent fibre, are regulated in a complex genetic manner involving additive and epistatic gene action. NDF is regulated by the additive gene action indicating that this trait might be easier for selection. Low heritability found for seed colour, fibre and glucobrassicin indicates great environmental effect on these traits. Large phenotypic variation for protein, oil, acid detergent fibre, neutral detergent fibre and glucosinolates found in this study will allow future genetic mapping analysis to identify key genes regulating these traits. The application of such genetic markers could enhance breeding programs aiming to improve oilseed rape which could be successfully introduced as poultry feed.
  • Kirje
    Experimental research into the effect of harrowing unit’s operating speed on uniformity of cultivation depth during tillage in fallow field
    (2020) Bulgakov, V.; Nadykto, V.; Kaminskiy, V.; Ruzhylo, Z.; Volskyi, V.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
    Retention of soil moisture is an urgent topic of the day in the cultivation of agricultural crops. Using fallow fields is one of the ways to solve the named problem, but the tilling of such fields requires observing some special conditions, in particular, the capillary effects in their upper soil layers must be cut down. For that purpose, the authors have proposed a special harrow equipped with the tools capable of fulfilling the above-mentioned task. The authors have carried out extensive field experiment research into the tillage of fallow soils with the use of the said implement. In order to apply the implement, a new harrow unit has been developed. The results obtained during the experiment research have been processed with the use of statistical methods and it has been established that the depth of harrowing in the tilled field decreases, when the operating speed of the combined unit under consideration increases to 3.3 m s –1 . At the same time, the variances of oscillations of the parameter under research in accordance with the Cochran's C test remain uniform. Also, the frequency of the harrowing depth oscillations changes insignificantly. That is supported by the correlation lengths of the normalized correlation functions of the process under consideration, which, at the above-mentioned operating speed, stay within the sufficiently narrow range of values: 0.16–0.20 m. According to the results of the experimental investigations, the maximum value of the normalized cross-correlation function for the relation between the oscillations of the field harrowing depth and the oscillations of the field’s longitudinal profile does not exceed 0.12. This testifies to the absence of any substantial interrelation between the said two stochastic processes, which is quite reasonable in view of the small values of the variance and period of the oscillations of the field’s longitudinal profile. The probability of the new combined tractor and harrow unit maintaining the tolerance of the fallow field cultivation depth oscillations within the range of ± 1 cm is equal to 82%. Within each 1.85 m of the distance travelled by the combined soil cultivation unit under consideration, only one instance of the field cultivation depth deviating from the ± 1 cm tolerance can be expected.
  • Kirje
    Studying the storage and processing quality of the carrot taproots (Daucus carota) of various hybrids
    (2020) Zavadska, O.; Bobos, I.; Fedosiy, I.; Podpryatov, G.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
    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–1 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)–1 of β-carotene.
  • Kirje
    Olive pomace compost use for fenugreek germination
    (2020) Ameziane, H.; Nounah, A.; Khamar, M.
    Morocco is among the major olive-growing countries around the Mediterranean, its productivity increases from one year to the next, especially after the introduction of the Green Morocco plan, which aims for an increase in the olive-growing area by the year 2020. The increase in productivity especially in olive oil is strictly accompanied by an increase in waste generated after crushing. The objective of this study is to value the olive pomace compost from traditional system as a soil amendment, and study its effect on the cultivation of herbaceous plants. The germination test is carried out in small pots, placed in a sunny place in a laboratory. 25 Fenugreek seeds were germinated in each pot which contains soil and a well-defined percentage of compost (5%, 10%, 15%, 20% and 25%). The seeds were irrigated regularly twice a week. All the tested seeds in different percentages of compost germinated at a rate of more than 90%. The final germination rate for the different concentrations was significantly important from the control (the pot that contains only soil). However, the 5% compost concentration allows an optimal germination rate. As well as the vigour of the seedlings that approves the positive effect of using olive pomace compost with a significantly high vigour index for all compost percentages (5%, 10%, 15%, 20% and 25%). The olive pomace compost use also improved the dry matter weight of the fenugreek seedlings for all percentages.
  • Kirje
    Effects of lake sediment on soil chemical composition, dehydrogenase activity and grain yield and quality in organic oats and spring barley succession
    (2020) Edesi, Liina; Kangor, Tiia; Loide, Valli; Vettik, Raivo; Tamm, Ilmar; Kennedy, Hannah Joy; Haljak, Merlin; Tamm, Ülle; Võsa, Taavi; Tamm, Kalvi; Talve, Tiina; Karron, Elina
    In organic farming, it is important to maintain soil fertility with organic fertilisers; often organic compost, manure, or slurry is used. However, the effects of lake sediment in maintaining and improving soil fertility are less studied. The direct and residual effects of a one-time application of 50 t ha-1 or 100 t ha-1 of lake sediment were compared to an unfertilised control for oats (Avena sativa) (2015) followed by spring barley (Hordeum vulgare) in 2016, under organic farming conditions. Soil chemical composition, microbial activity in the 0–20 cm soil layer, grain yield, and grain quality were tested. The application rate, 100 t ha-1 , increased (P < 0.05) the soil organic carbon (SOC), the amount of mobile calcium (Ca), total nitrogen (Ntot), and boron (B) content in soil. Both application rates increased (P < 0.05) the amount of magnesium (Mg), copper (Cu), and manganese (Mn) content in the soil. The application rate had no effect on soil pH. Soil dehydrogenase activity (DHA) was higher (P < 0.05) at 100 t ha-1 than the control and the lower application rate. Both rates of lake sediment application significantly (P < 0.05) increased the grain yield and test weight for oats in 2015. Positive residual effects on spring barely yield only occurred in the 100 t ha-1 treatments in 2016. No residual impact of lake sediment was found on spring barely quality.
  • Kirje
    Lighting source as cause of changes in cucumbers’ physiology and morphology
    (2020) Alsiņa, I.; Dubova, L.; Dūma, M.; Erdberga, I.; Augšpole, I.; Sergejeva, D.; Avotiņš, A.
    The demand of fresh fruits and vegetables is growing. Therefore cultivation of them is essential all year round. The growth in the dark period of a year is not imaginable without artificial lighting sources. Therefore the experiments were carried out to investigate the effects of three different lighting sources on the growth of cucumbers at the early stages of development. Plants were grown in the polycarbonate greenhouse under three different lighting sources: Led cob Helle top LED 280, induction lamp and high pressure sodium lamp Helle magna. Cucumbers were grown in 16h photoperiod with PAR at the tips of plants 200 ± 20 µmol m-2 s -1 . Plant growth parameters, specific leaf area, pigments, phenols and flavonoids content in leaves, leaf light reflection parameters were determined. Results showed that cucumber plants grown under Led cob Helle top LED 280 in average were smaller, with less chlorophyll, carotenoids and phenols, but leaves have higher chlorophyll a and b ratio and specific leaf area in comparison with traditionally used in greenhouses High Presure Sodium Lamps (HPSL). Cucumber plants grown under Induction lamp in average were shorter, but with larger leaf area, with higher chlorophyll and carotenoids content, but decreased phenols content in comparison with HPSL. Lichtenthaler index 1 (LIC1) and NDVI are useful for assessing the physiological state of cucumber plants. Despite the fact that the plants grow well and develop normally under all lamps, the results show that sodium lamps are the most suitable for cucumbers. Further research is needed to adjust LED lighting for cucumber cultivation.
  • Kirje
    Feasibility study of the grinding process of grain materials
    (2020) Lebedev, A.; Iskenderov, R.; Zhevora, Y.; Lebedev, P.; Marin, N.; Pavlyuk, R.; Zaharin, A.
    For a comparative assessment of the effectiveness of various types of grinders of grain materials, various approaches are used. As the main criterion, the correspondence of the crushed material according to the particle size distribution can be taken as an indicator of the reliability of the grinding process. A comparative assessment of rotary crushers is carried out using the technical and economic indicator Eg, which is the ratio of total costs to the implementation of a given amount of work. Under the reliability of the grinding process, we have accepted the condition that the particle size distribution will comply with the requirements for agricultural feeding animals, which is possible while maintaining a rational gap between the stator and rotor riffles. The contradiction manufacturing techniques for the experiment are divided into: option No. 1 – steel 3 (HRC 10–12), option No. 2 – steel 45 (HRC 15–17), option No. 3 – hardened steel 45 (HRC 45–50), option No. 4 – steel 45 hardened and having a thin-film coating of FPH (finish plasma hardening), microhardness of 13 GPa. If reliability of the grinding process equal to 80%, wear on the fourth option, the cost was 1,171 rubles per ton, which is 16% lower than the cost of the first version of the production of a rotor crusher equal to 1,405 rubles per ton, respectively, this all speaks of the possible use of the proposed options for various forms of ownership of agricultural enterprises.
  • Kirje
    Electric infrared heating panels as an alternative source of heating for greenhouses
    (2020) Kic, P.
    The aim of this article is to show the possibilities of supplementary heating of greenhouses. There was used for this research an electric infrared heating panel ITA 700. The average total power was 630.8 W in laboratory measurements, of which 504.3 W has been transferred by the front part of the panel, of which 267.2 W has been transmitted by radiation. The total radiation efficiency of the front part was 42.4%. Similar measurements have been carried out in an experimental greenhouse (length 24 m, width 3.5 m). Approximately 448 W of average total power 603.7 W has been transferred by the front part of the panel, of which 159 W has been transferred by radiation. The total radiation efficiency of the front part was 26.3%. Differences between measured surface temperatures confirmed the influence of panel radiation on the flower bed. The average temperature in the soil (9 °C) shows that the influence of heating is mainly on the surface of the flower bed, where it could protect cultivated plants during the lowest temperature period. The obtained results can be useful for choosing suitable panel parameters for the placement in small horticultural or hobby greenhouse.
  • Kirje
    Effect of winter wheat variety, hydrothermal coefficient (HTC) and thousand kernel weight (TKW) on protein content, grain and protein yield
    (2020) Kulyk, М.І.; Rozhkov, А.О.; Kalinichenko, О.V.; Taranenko, А.О.; Onopriienko, О.V.
    The aim of the research is to clarify the physiological and biochemical processes in the plant organism that occur in the optimal and stressful conditions, as well as to search for anthropogenic methods of their manifestation in connection with the protein content in grain of wheat varieties of different origin in the conditions of the Forest-Steppe Ukraine. The impact of temperature factor and the moistening mode of the period of winter wheat seed formation and ripening (Ttiticum aestivum L.) has been studied. The impact of varieties of Ukrainian and foreign plant breeding on the protein content in grain of the obtained offspring (reproduction yield) has been studied too. The ways to eliminate the influence of weather conditions on the protein content in grain and on the bases of sowing of different seed fractions have been searched. Research methods: field (studying the influence of growing conditions on grain quality), laboratory (determination of protein content), correlation-regression (establishing connection between factors), statistical method (to confirm the difference between variants). According to the results of the first stage of research, the dependence has been established: sowing with seed, grown in the arid conditions, allows obtaining offspring with high protein content, and vice versa. This is confirmed by the strong correlation both for winter wheat variety. At the second stage of research it has been determined that sowing with fine seed raises the yield protein content in grain, and protein yield without additional costs, but using seed, formed in the arid conditions.
  • Kirje
    Investigation of the long-term toxic effect of nanoparticles of different physical-chemical characteristics
    (2020) Churilov, D.G.; Polischuk, S.D.; Churilov, G.I.; Churilova, V.V.; Byshova, D.N.
    The purpose of this work is to study the effect of metal and oxide nanoparticles on some ecological and functional groups in the soil-plant-animal system to form the stability limits of organisms. Nanoparticles of cobalt, iron, zinc, copper, copper oxide, zinc oxide and titanium dioxide sized 20–80 nm were studied. The concentration range was 0.01–1,000 g of nanoparticles per ton of seeds or soil. Objects suitable for biotesting and environmental monitoring were selected: earthworms (Lumbricina), rats (white outbred) and Wistar rats. It was previously found that nanoparticles of the studied metals up to a concentration of 100 g t -1 of seeds, unlike oxides, practically do not affect bacterial populations. The use of indicators of biochemical and cytomorphologic reactions of invertebrates seems promising because worms are able to bind pollutants and reduce their penetration into plants. They are also an indicator of soil biotesting for metal contamination. Reactivity and toxic effects of nanoparticles (NPs) in natural conditions depend both on the type of soil and on the size and concentration of nanoparticles. With sizes (NPs) of up to 20 nm (depending on the type of soil and physicochemical characteristics), NPs are much more reactive and reduce the survival of microorganisms. Small nanoparticles (less than 20 nm) are characterized by a large interface. Such nano-objects exhibit high physical-chemical activity and are safe only at very low concentrations. The specifics of the environmental impact of oxide NPs compared to metal NPs was revealed. It was associated with accumulation of oxides in living systems and the peculiarities of changes in the morph physiological, histological and reproductive parameters of organisms and morphological and biochemical parameters of animals. Oxide nanoparticles accumulate in a living organism, exhibit toxic properties, lower the activity of enzymes and hormones and are transferred along trophic chains, which is not typical for metal nanoparticles.
  • Kirje
    A comparative study of the properties of industrially produced humic substances
    (2020) Klavins, M.; Upska, K.; Viksna, A.; Bertins, M.; Ansone-Bertina, L.; Krumins, J.
    Humic substances (HSs) are produced industrially in large quantities from low rank coal, weathered coal, peat, also from soils, composts and other sources. Considering that the applications of industrially produced HSs also include food, pharmaceutical applications and environmental technologies, it is important to evaluate their composition and quality and to identify their sources. The aim of the present study is to compare the properties of industrially produced HS samples. HSs were characterised using spectroscopic and other methods. For the identification of origin of HSs, different methods can be used, such as elemental analysis and ratios of light stable isotopes. The results of the study indicate that many industrially produced HSs are of poor quality (low concentration of basic substance, admixture of undesirable substances, pollutants, no quality indications). In this situation, rigorous quality control should be implemented, providing detailed characteristics of the product. The composition of materials suggested for agricultural applications has not been analysed much. Most of the studied materials were designated as HAs, followed by fulvic acids (FAs) and HSs. However, an analysis of the humic matter types indicates that the majority of substances offered on the market are in fact mixtures of HAs and FAs; so, it would be more appropriate to designate them as HSs or their salts. This study identifies the main quality problems of industrially produced humic substances: 1) lack of strict quality indicators, 2) absence of indication of source materials/origins of HSs.
  • Kirje
    A linear assignment based conceptual lifecycle assessment method for selecting optimal agri-industrial materials production pathway: A case study on Nigerian yam value chain
    (2020) Dunmade, I.S.
    Lifecycle assessment is a robust tool for comprehensive environmental impact assessment of products and processes. It provides users opportunities to identify the hotspots along the lifecycle of a system and thereby enable them to implement improvement opportunities as deemed appropriate. Production of agri-based industrial raw materials could be energy and water intensive. Such endeavour could take a heavy toll on the environment in terms of resource consumption and environmental pollution. The goal of this study was to develop an easy to use and less data intensive conceptual LCA methodology for selecting optimal pathway along a value-chain under two decision scenarios: the optimal techno-environmentally friendly pathway, and optimal sustainability pathway. This proposed Linear Assignment Method integrated LCA is a less data intensive conceptual LCA method that facilitates the selection of an optimal production and processing pathway for agri-industrial materials, minimizes resource consumption and reduction of potential climate change impact of agri-industrial materials value chain. The LCA ISO 14040s aligned conceptual LCA method will be found useful in identifying potential hotspots in a agri-industrial production process lifecycle, in selecting activity options that would result in minimum ecological footprint, and help in removing obstacles in implementing a scoping lifecycle analysis where cost, time and data availability are the impediments.
  • Kirje
    Different proportion of root cutting and shoot pruning influence the growth of citronella plants
    (2020) Daflon, T.M.; Hüther, C.M.; Cecchin, D.; Santos, C.M.P.P.; Borella, J.; Carvalho, L.F.; Correa, N.P.C.; Oliveira, J.R.; Correia, D.M.; Pereira, C.R.; Machado, T.B.
    Environment concern, sustainable products demand, and natural components conscious are currently global movement factors. Related to the global movement factors, citronella grass (Cymbopogon nardus L.) is being widely used in folk medicine, and has insect repellent activity, fungal and bactericidal action. Its essential oil has high content of citronellal, citronellol, geraniol. The essential oil is mostly extracted from leaves which turns this plant with high commercial demand. However, to obtain the best therapeutic quality and productivity of medicinal plants, which culminates in greater quantity and quality of the active compounds, the proper management of the crop is fundamental, as several factors can interfere during its growth and development. Thus, we analyzed the growth of citronella plants submitted to different levels of shoot and root cuts. Five different proportions of root pruning (0, 25, 50, 75, 100%), after 145 days of seedling planting and four cuttings in the shoots: blunt; a cut at 145 DAP (days after planting) along with the root cut; a cut at 228 DAP; and cuts at 145 and 228 DAP (two cuts). Four harvesting for dry matter accumulation and photoassimilate partition data were performed. The treatment with 100% root cut, but without leaf cut, increased the total dry mass accumulation of the plant in relation to the other treatments, for the last analysis period, demonstrating a recovery. Thus, the application of two leaf cuts or no leaf cutting within the 100% root cut treatment for leaf dry mass accumulation is more effective when compared to the blunt root treatment.
  • Kirje
    Properties of Populus genus veneers thermally modified by two modification methods: wood treatment technology and vacuumthermal treatment
    (2020) Meija, A.; Irbe, I.; Morozovs, A.; Spulle, U.
    Due to environmental concerns the use of wood materials is becoming more extensive and is causing wood supply shortage, therefore the use of Populus genus wood species with a short rotation period is vital. Populus genus species wood has several shortcomings - it is not durable, has low density and is hygroscopic. Thermal modification is a technology that can be used to improve the situation. In this study aspen (Populus tremula L.) was thermally treated using the Wood Treatment Technology (WTT) device for 50 min at 160 °C (50–160 WTT) and poplar (Populus x canadensis Moench) was vacuum-treated (VT) 120 min at 204 °C (120–204 VT), 120 min/ 214 °C (120–214 VT), 180 min 217 °C (180–217 VT) and 30 min 218 °C (30–218 VT). Mass loss (ML), colour change, density, tensile strength along the fibres, moisture exclusion efficiency and weight loss (WL) after brown rot fungus Coniophora puteana were determined and also light microscopy images were taken. Aspen veneers showed a ML of 5.3% between 120–214 VT (6.2%) and 30–218 VT (4.6%) treatment that coincided with the same mass loss in aspen boards cited in the literature. The highest ML was 8.7% calculated from 180–217 VT, while the lowest ML was 2.9% computed from 120–204 VT. The total colour change ΔE was 44, where lightness parameter L provided the greatest impact that was reduced twice after modification. Tensile strength reduced by 47% in the WTT process and had ~29% reduction in the VT process. The WL after fungus C. puteana was 33% at 50–160 WTT. After VT treatment, WL was 0–2.4%. 120–214 VT and 180–217 VT poplar veneers were the most suitable for plywood production.