The aim of this research is to optimize growth and development of maize for biomass by selecting maize hybrids to fulfill their productivity potential.The following maize hybrids were the subject of research: Forteza, DM Native, DM Skarb.The greatest height of plants was formed in the interphase period of milk-wax maturity of grain in hybrid Forteza -286.4 cm.In hybrid DM Native the height of plants was -271.2 cm, hybrid DM Skarb -263.6 cm.Weight of one plant of hybrids studied during the maize growing season ranged from 442 g to 760 g.Thus, the largest mass of maize plants was recorded in the milk-wax maturity stage.It was the largest at the hybrid Forteza and amounted to 760 g, that is more than at the hybrid DM Native for 3.4% (26 g) and at the hybrid DM Skarb for 6.6% (50 g).The average crop yield of the hybrid Forteza for the period of research was 55.1 t ha -1 .Hybrids DM Native and DM Skarb provided this indicator at the level of 50.6 and 45.7 t ha -1 respectively.Hybrid Forteza provided a maximum crop yield 55.1 t ha -1 with plant height 286.4 cm, assimilation surface of one plant and a crop 0.59 m 2 ; 42.8 thousand m 2 ha -1 and plant weight 760 g.
Received: January 31st, 2021 ; Accepted: March 28th, 2021 ; Published: May 19th, 2021 ; Correspondence: jelena.pubule@rtu.lv
Received: February 1st, 2021 ; Accepted: May 2nd, 2021 ; Published: May 18th, 2021 ; Correspondence: Zane.Kusnere@rtu.lv
Indoor air disinfection has become particularly relevant recently because of the Covid-19 pandemics. A shielded device for air and surface disinfection with UV radiation and ozone has been developed. It contains 28 low intensity (11 W) UV lamps (254 nm) in a specially designed three-dimensional grid to provide a large flow cross-sectional area and long path for the air particles to be irradiated. The device can be used in medical institutions, veterinary clinics, manufacturing plants, public premises, poultry, and livestock farms. It does not generate air-ions and ozone concentrations do not exceed the allowed 8-hour average values. The large number of UV lamps and powerful fans ensure air disinfection in large rooms in a relatively short time (400 m3 h-1). Simultaneously, the floor surface under the appliance is disinfected. Disinfection efficiency tests demonstrated 99.9999% reduction for Escherichia coli, Staphylococcus aureus and Pseudomonas phage 6 aerosols within a single transfer through the system (10 seconds of treatment). The housing of the device protects from direct UV radiation;therefore, people can be in the room during the operation of the device. © 2021, Eesti Pollumajandusulikool. All rights reserved.
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
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.
The objective of this study was to examine the effect on the dry biomass yield of two dfferent sorghum hybrids (H1 and H2) under five different N-fertilization levels (0, 70, 140, 210 and 280 kg ha) in a soil which was formed by lacustrine deposits of Karla Lake and is characterized from the downward movement of calcium carbonate from the surface horizons due to leaching (Fluventic Xerochrept) during 2017. The results demonstrated a significant effect (P < 0.05) of fertilization only for one hybrid. Biomass yield ranged from 22.2 to 37.5 t ha. For both hybrids, sorghum accumulated a high amount of biomass in stems. Dry stem/total biomass ratio was rather constant throughout the different fertilization treatments achieving 81.6 and 77.5% for the first (H1) and the second hybrid (H2), respectively. The second hybrid (H2) had a higher percentage of leaf biomass (20.1 vs. 13.8%) than the first (H1), but lagged behind in seed production (2.4 vs. 4.6%). Biomass dry matter partitioning and total dry weight are important selection criteria for energy crops, due to different gross calorific value and ash content but also because of the different economic importance they may have e.g. the seed is also used as animal feed. The above high biomass yields of sorghum, confirming the high potential of this crop, should be taken into serious consideration regarding land use planning, but further investigation for the gross calorific value and the ash content is needed as well as biomass characteristics that are quite important in case to improve the combustion process.
Globally on an annual scale, considerable amounts of fruit and vegetables wastes (FVW) are generated in the agri-food industrial sector. Costs insured for safe disposal of FVW remains uneconomical and they can pose a serious environmental hazard if left untreated. However, FVW have high potential for reuse, recycle and recovery, which is an indication that there are productive, sustainable and affordable ways of reducing and tackling them at the industrial levels. Recent years have seen progressive innovative research on FVW management strategies, which has been developed with an idea of reducing wastes and fully exploiting its potential. Further, FVW represents a potential source of valuable compounds and bioactive ingredients. Today, there are many proposed innovative approaches for handling the FVW. These include reintroducing sub-standard fruit and vegetables (small sized or misshaped fruit and vegetable) in the market, reusing FVW for soil amendments, composting, or as an animal feed, and much more. In addition, the extracted bioactive compounds from FVW and by-products can find wide applications as a natural additive in food, cosmetics and/or in pharmaceutical applications. Currently, novel cost effective strategies have been developed for effective valorisation of agri-food wastes and by-products. The field of FVW management is still limited, thus leaving a wide gap for new ideas, novelty and applications of more efficient green techniques for complete utilization of agri-food wastes and by-products. Some of the interesting aspects on wastes and by-products management are discussed in relevance to Europe and in Estonia.
Nowadays fossil fuels are decreasing, causing the world's interest in renewable energy sources to rapidly grow. One of the most interesting renewable and ecologically pure fuels is biomass, which is considered to be carbon neutral. Biomass is a promising source of energy, as it can be used directly as an energy resource. Its quality characteristics such as gross calorific value and ash content are of paramount importance so as to improve the combustion process. Furthermore, during the last three decades, there has been an increasing interest in the production of biomass pellets for domestic and industrial use. Alternative feed stocks will need to be sourced to meet the demand for biomass pellets. Investigation for new energy crops that produce high amounts of biomass under low inputs and of high energy efficiency are the main tasks of this field. Therefore, the aim of this study is to assess the biomass yield and the quality characteristics (gross calorific value and ash content) of two perennial energy crops (Cynara cardunculus L. and Panicum virgatum L.) growing in a typical soil (Fluventic Xerochrept) of the main agricultural land of central Greece. The comparison for both cultivated crops was made in order to show the results during their 8 growing year. The examined factors were the irrigation (two levels: irrigated and rainfed) and the nitrogen fertilization (two levels: 0 and 80 kg N ha) as well as their effect on the dry biomass yield and the gross calorific value. It was found that higher dry biomass yield was produced from cardoon (21.3 vs. 14.23 t ha), while the higher average gross calorific value was observed for switchgrass biomass (17.31 vs. 15.65 Mj kg). Finally, multiplying the dry biomass yield (t ha) with the gross calorific value (Mj kg) it was found that 334 and 245 Gj ha from a cardoon and a switchgrass cultivation could be produced, respectively. Cardoon has better results than switchgrass probably due to the fact that switchgrass is growing from March till October; while cardoon’s growing period is from October to June and in such areas precipitation is in shortage during summer months. Both crops could achieve high amounts of energy per hectare and thus their introduction in future land use systems, for an environmentally friendly energy production should be seriously taken into consideration.
One of the promising ways of efficiently applying high power intensity tractors is their design and utilisation in the form of modular traction vehicles comprising two modules: the power module and the process module. In order to provide for the sufficient manoeuvrability of the modular traction vehicle, when its process module passes a turn, the latter is equipped with vertical and horizontal hinge joints. The freedom of the process module’s rotation with respect to the power module in the horizontal plane through the agency of the above-mentioned vertical hinge joint is restrained by a hydraulic cylinder, in which the chambers above and below the piston are connected via a throttle valve with a hydraulic resistance coefficient of about 1.03×10 N m s rad. This paper is concerned with the theoretical and experimental research into the stability of motion (on turn spaces as well as in the transport mode) of a modular combined unit, when its velocity changes and/or the slip resistance coefficient of the tyres on the wheels of the process module, in which the hydraulic cylinder is equipped with a throttle valve with the above-mentioned hydraulic resistance coefficient, changes.
The key catabolic enzymes of D-xylose, an important structural component of different agricultural wastes, were studied in cells of mutant strains of the xylose-assimilating yeast Pachysolen tannophilus. The evaluation of catalytic activity and cofactor specificity of xylose reductase (ЕС 1.1.1.307) and xylitol dehydrogenase (ЕС 1.1.1.9) confirmed the dependence of intracellular catabolic pathway for D-xy lose on the NAD×H/NADP×H ratio, formed under microaerobic conditions. The study of total activity of some NAD/NAP×H-dependent dehydrogenases revealed the metabolic characteristics of the yeast cells, which could ensure selective ethanol or xylitol production. Thus, the efficient involvement of D-xylose into the Embden–Meyerhof–Parnas pathway provided not only the high activities of xylose reductase and xylitol dehydrogenase, but also of 1-glycerophosphate dehydrogenase (EC 1.1.1.8) and lactate dehydrogenase (ЕС 1.1.1.27), respectively. The inhibition of activity of these enzymes led to selective production of xylitol from D-xylose. On the base of the experimental results, the principles of metabolic engineering of xylose-assimilating yeasts were formulated. The possibility of bioethanol and xylitol production from different agricultural wastes using xyloseassimilating yeasts are discussed.
Float system is a less-intensive and low-cost technology that enables efficient control of the nutrition of the growing plants. The findings of experiments carried out under float system in various crops with or without organic fertilization need to be reviewed. The importance of float system for growing plants without inorganic fertilization and chemical pesticide use needs also to be pointed out. Float system can enhance root development of growing plants and control the height of produced transplants. This can result in increased yields and improved transplant quality, not only in tobacco transplant production systems but also in the case of vegetable crops such as tomato or lettuce. In the case of crops like tobacco and for the success of float system alkalinity and oxygen content of the water in the nutrient solution and selection of the growing media are crucial. Regarding vegetable crops, the combination of float system and organic fertilization can enhance root development in tomato as compared to the combination and lettuce resulting in high-quality products. Several aromatic and medicinal plants, including basil and spearmint, provide high yields and good product quality in floating systems especially along with organic fertilization. Conclusively, float system is a major method for producing high quality products or transplants. Further investigation is needed regarding the combined effects of organic fertilization and float system on more crops and under different climatic conditions.
Hunting farms can serve as a source of primary data on the state of natural resources. Taking into account the increasing anthropogenic impact on the environment, it is necessary to constantly monitor the situation with food for ungulates and predators in order to be able to take timely measures to improve the quality of habitat for wild fauna. Populations of wild large animals live in the host landscapes of so reduced that animals population become extremely vulnerable and unstable, signs of crisis can be seen in the data on the number of animals. Lack of natural food is a serious deterrent, especially in difficult times of the year, such as winter and spring. An analysis of the situation with food for a particular species will allow hunting farms to properly plan their feeding and other activities throughout the year in order to maintain a population of certain species on their territory and minimize the migration of species outside the protected areas. The aim of our work was to create a baseline for tracking data on the characteristics of wildlife animals. The research results allow hunting farms to use the data of animal feeding preferences during different seasons of the year for better organization of their biotechnical measures and improvement of feeding conditions for such species as red deer (Cervus elaphus), elk (Cervus canadensis), roe deer (Capreolus pygargus) and bear(Ursus arctos).
Saflufenacil has been used to control glyphosate resistant weeds, including hairy fleabane. There are several glyphosate formulations, which are related to different salts and adjuvants. Differences between these formulations may result in variations in efficacy, especially in the face of unfavorable environmental conditions, such as the occurrence of unexpected rainfall after application. The objective of this study was to evaluate the control of hairy fleabane with saflufenacil in tank mix with different formulations of glyphosate subjected to simulated rainfall after application. The treatments evaluated were salts of glyphosate (isopropylamine, potassium and ammonium salt), different periods of simulated rainfall after herbicide application (30, 120 and 240 min, and no rainfall), and the presence or absence of saflufenacil and a non-ionic adjuvant. Absorption of saflufenacil by hairy fleabane is rapid, since simulated rainfall after 30 min after application did not result in loss of efficiency when the herbicide is applied with adjuvant. The association of isopropylamine and ammonium salts of glyphosate with saflufenacil increases the control of hairy fleabane and prevents the occurrence of regrowth when rainfall occurs at 30 min after the application. The occurrence of simulated rainfall after 240 min reduces the glyphosate efficiency by 30%, 15% and 60% for the isopropylamine, potassium and ammonium salt formulations, respectively. The addition of adjuvant improves the efficiency of glyphosate salt of potassium by 40%. The response of the mixture of glyphosate and saflufenacil is variable, mainly in situations of rainfall after application.
This article describes using renewable energy for bioethanol production. Kostanay Region is a developed agricultural region. Most part of its area is under grain crops and corn, oil crops and vegetables. In the course of production, transportation, storage and processing of agricultural crops, a large part of them becomes unsuitable for use; in future they cannot be used for the intended purpose. Substandard product often stays in the fields to rot or is thrown away. Information considered in this article demonstrates that agricultural waste can be used to produce rather inexpensive bioethanol. Most part of the population in this region is rural. Settlements are far apart from each. It would be reasonable to use bioethanol as a source of electric and thermal energy to meet the needs of rural residents and infrastructure. Wastes from bioethanol production can be used for feeding animal stock what is also important for rural areas and reduces environmental burden. In the course of human life, solid waste is formed that is suitable for producing bioethanol, and consequently, for generating thermal and electric energy. Presented calculations show the feasibility of processing municipal solid waste into bioethanol. EU countries successfully use researches performed by their scientists for developing technologies for the production of bioethanol and synthetic fuels. Kazakhstan, with its experience in cultivation of oilseeds and required planted area, can successfully develop bioethanol industry. No researches in this respect have been conducted to this day in Kazakhstan. Using bioethanol provides consumers with their own energy sources that meet quality standards, thereby increasing energy security of region, reducing the amount of harmful emissions into the atmosphere, and creating small-scale energy enterprises where rural residents can work.
By-catch fish is caught unintentionally during the fishing and is currently thrown back in water bodies to cause the water pollution. Currently fishermen does not have a motivation to bring the by-catch fish to the shore, as it needs to be sorted by fish species, causing fishermen extra work without additional income. Estonian Ministry of Rural Affairs decided to give funding to present study with purpose to find solution to this matter. One possible solution for by-catch fish utilization is to produce high value nutrient rich fertilizer in order to close nutrient cycle and return valuable nutrients into soil. The adaptive study of outdoor windrow composting was conducted with consecutive treatments, rather than simultaneously, in order to make adaptive improvements to the set-up of each consecutive treatment. The consecutive treatments showed that fish waste composting is manageable from a technical perspective, feasible in a temperate climate, and that this type of compost holds high potential as an organic fertiliser or soil improver. Composting process started rapidly and, as required by the EU Commission regulation EU 142/2011, temperatures exceeded 70 h in all windrows. While initial treatments suffered from odours, as well as events inhibitive to the composting process, these disadvantages were successfully avoided in later treatments by adding a biofilter and inoculant from previous composting windrows, as well as lake sediments. Rather than disposing of low-value fish, these can be recycled into stable and nutrient-rich compost on-site, near fishing harbours.
Growing crops under artificial conditions need a very favourable environment, especially the spectral composition of radiation influencing the plant biometry greatly. The study objective was to find how to assess the closeness of real growing conditions to the optimal ones using a single coefficient, which would reflect several time dependencies of individual growth indicators. The plant growth friendliness factor (KG)was proposed for this purpose. Tomato transplants (Lycopersicon Esculentum Mill., ‘Polonaise F1’) were grown in a peat substrate under two lighting systems with different light quality.One system consisted of eight fluorescent lamps OSRAM L58W / 840 LUMILUX Cool White and eight lamps L58W / 77 FLUORA mounted on the standardframe, alternating the lamp types (Type I spectrum).In theother lighting system, the PCB Star LEDs with wavelengths of red 630 nm and far-red 735 nm were added(Type II spectrum). The irradiance level was maintained at 140 μmol m s, the photoperiod was 16 h. The ratio of long-wave flux to the total flux KL was calculated for these lighting systems (0.37 rel.units for Type I spectrum and 0.50 rel.units for Type II spectrum) and KG factor was determined by the proposed formula. The value ofKG was found to be twice as small for Type I spectrumthan for Type II spectrum. The significant difference in biometric parameters of tomato transplants grown under Type I and Type II spectrawas revealed. The plants grown in the environment characterized by higher KG, were higher; they had more significantwet mass and stem neck diameter.
The introduction presents the primary reasons for the decrease in the working efficiency of plain bearing assemblies and suggests key areas for the formation of a stable working capacity of these assemblies. In addition, the introduction discusses preexisting methods for improving the working efficiency of plain bearings. These methods are based on the use of antifriction coatings and have the drawbacks which are considered in the text. The authors proposed a technology for producing an antifriction coating based on a metal composition. This antifriction coating is produces by highspeed laser processing of powder materials. The technology allows to create antifriction coatings, which have significant wear resistance and the effect of self-lubrication while also provide a minimum run-in time of the bearing assembly. The methodology validates the choice of materials for the formation of an antifriction coating. An alloy with significant tribotechnical properties based on babbitt B83 was chosen as the basis (matrix). To improve the bearing capacity of the coating, the babbitt base was transformed with MoS2 molybdenum disulfide. The laser radiation usage in the formation of an antifriction coating based on babbitt B83 synthesizes finely dispersed intermetallide phases and forms a porous coating structure due to incomplete melting of the powder material. Molybdenum disulfide is released mainly through the porous structure, which leads to self-lubrication of the bearing assembly during oil starvation. The results of microstructural and X-ray diffraction analysis are presented to display the structure of the obtained coatings based on antifriction materials. Research value is characterized by the presence of the following intermetallide phases in the structure of the formed coating: Fe2Sn, SnSb, Cu3Sn. The dispersivity of the formed phases is much greater than that of standard babbitt coatings, which is determined by higher crystallization rates under conditions of laser radiation processing. The analysis of diffractograms makes it possible to conclude that the distribution of intermetallide phases along the coating depth is uneven. The underlying layers close to the basis (matrix) are more soft and supple due to the presence of α solid solution. The surface layers are solid and saturated with the finely crystalline Cu3Sn phase. The research undertaken on formed
Nutrition value of legumes has been traditionally attributed to its high protein content. Protein content of legumes is variable dependent on different species and varieties, and highly affected by environmental factors. Usually protein quality is characterized by its owns amino acid profile in nutritional point of view. Therefore, the present study was conducted to determine the protein contents and amino acid profiles of pea (Pisum sativum L), faba beans (Vicia faba L) and soya (Glycine max L) grown in Latvia and evaluate their potential for food production. Overall results of a five-year analysis (2013 2017) showed that the protein content of peas, faba beans and soybean ranged from 20.0 to 26.1%, 26.6 to 30.5% and 35.9 to 40.9%, respectively. The corresponding values of total crude fat ranged from 0.8 to 1.2%, 0.7 1.3% and 16.6 to 19.3%, respectively. Results of study showed that the protein content of peas, faba beans and soybean was not differed by growing system (p < 0.05). The percentage of essential amino acids for pea, faba bean and soya were 34 to 38%, 57 to 59% and 62 to 64% respectively. The composition of pea flakes was preserved protein content of raw material. The pea flakes has high content of lysine of 10.1 g kg-1, phenylalanine+thyrosine of 11.6 g kg-1 and the sum of essential amino acids of 66.4 g kg-1. In nutritional point of view, pea flakes could be product with high-quality protein composition.
