2021, Vol. 19, No. 3

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/7130

Sirvi

Nüüd näidatakse 1 - 20 27

Development of the mathematical model of the electric resistance baking process
(2021) Kulishov, B.; Minkin, D.; Fedorov, A.; Novoselov, A.
The work is dedicated to the development of the mathematical model of the electric resistance baking process for the purpose of predicting temperature changes during baking of dough pieces of arbitrary sizes. The equation for the non-stationary thermal regime of a body with an internal heat source was used with a number of assumptions. The dynamics of the dough temperature changes was determined by numerical solution of the equation in Comsol Multiphysics. Due to the complexity of the dough baking process and the impossibility of solving the equation by analytical method only, a number of values included in the energy balance of ER baking were determined experimentally. A dough piece with dimensions of 100×50×80 mm was baked during the experiment. After the adjustment, the adequacy of the model was checked by comparing the data on the dough temperature changes during baking dough pieces of the same recipe, but of different sizes (150×49×80, 80×62×80, and 65×75×80). Statistical analysis using Fisher's criterion confirmed the adequacy of the model.
Laboratory analyses for assessing the potential for biogas production of various agricultural residues in Greece
(2021) Aravani, V.P.; Tsigkou, K.; Kornaros, M.; Papadakis, V.G.
Greece produces significant amounts of agricultural and livestock waste. For the needs of this study, Greece was divided into a Northern and a Southern part and relevant proposals were made for residues that can be used for energy production, through anaerobic digestion. For Northern Greece, this study concluded that the most abundant residues and potential substrates for anaerobic digestion valorisation are those of maize, inedible vegetables (including greenhouse vegetables), cattle manure, as well as the residues of beer and wine industry. For Southern Greece, the corresponding substrates are those of maize, inedible vegetables, sheep/goat manure and residues of wine, tomato, orange and olive processing, respectively. Based on the physicochemical characterization of individual feedstocks, corn silage, tomato husks, watermelon, malt, cattle manure, orange, and olive processing residues (olive pomace) were considered as the most suitable feedstocks for anaerobic digestion. Biochemical Methane Potential (BMP) assays for Northern Greece were also performed, testing the most abundant and appropriate residues for anaerobic digestion (of this area), namely corn silage, cattle manure and malt, in order to define their BMP yield as well as their prospective optimum mixtures. It was concluded that the BMP of the mono-substrates is in accordance with literature, while there were no statistically significant differences in the methane yield of all tested mixtures. The residual biomass originating from the three main categories of the agricultural sector (crop residues, agro-industrial residues, and animal manure) in Northern Greece can be efficiently valorised via anaerobic co-digestion, without observing, though, any synergistic effects on methane production.
Acoustic analysis of cement composites with lignocellulosic residues
(Estonian University of Life Sciences, 2021) Ferraz, P.F.P.; Abreu, D.H.S.; Huallpa, B.N.; Santana, L.S.; Cecchin, D.; Rabelo, G.F.; Rossi, G.; Barbari, M.
The concept of environmental sustainability has been seeking a way to develop projects that reduce the impacts provided by agricultural development and the excessive consumption of natural resources. However, there is still little knowledge about the acoustic insulation/absorption behaviour of lignocellulosic materials. Hence, this study aimed to evaluate the acoustic properties of five cement panels reinforced with the following lignocellulosic materials: eucalyptus, sugarcane bagasse, coconut shell, coffee husk, and banana pseudostem, which ones have as a reference a commercial plaster used as sealing in civil constructions. The proposed panels were produced with each lignocellulosic material residue. It was produced three replicates for each type including plaster (being 18 panels in total). The sound insertion loss (SIL) measurement of the above-mentioned panels have been performed using an acoustical treated inexpensive facility developed based on the literature. The characterization of the acoustic behaviour of the studied materials were analysed according to the IEC (61260-1). The acoustic measurements have been done in the range of 20 Hz to 20 kHz and the analysis in octave bands have been performed. To make the analysis easier, the overall range of frequencies mentioned above was divided as ‘low’, ‘middle’ and ‘high’ ranges. Additionally, the measurement of thickness, density and porosity structure parameters of the lignocellulosic samples have been performed. According to the results and doing a trade-off analysis, the eucalyptus presented the overall best performance considering the overall range of analysis, being the banana pseudostem and sugarcane bagasse materials as good competitors.
Evaluation of artificial agricultural landscapes biodiversity in Stavropol Botanical Garden
(2021) Grechushkina-Sukhorukova, L.A.; Peshchanskaya, E.V.
The meadow steppes recreated in the Stavropol Botanical Garden, Russia, by planting sod blocks after more than 40-year period of cultivation have preserved species composition similar to zonal steppes. The aim of our research is to evaluate the restored artificial cultivated land biodiversity. A parallel measurement of species saturation per 100 m², yield, botanical analysis by crops was conducted on model experimental sites and in nature. Systematic and biomorphological flora study, analysis of variance were carried out. Useful plant species were identified. The restored steppes represent a multispecies community including 236 species, 149 genera, and 36 families. It consists of 5 biomorphs which comprise 2.9% of phanerophytes, 3.0% of chamephytes, 74.6% of hemicryptophytes, 14.4% therophytes that have a high degree of similarity in quantity to the steppes of Central Fore-Caucasus. The cenoses are dominated by plants having life cycles of perennial ones which accounts for 81.0%, annuals, and biennials make up 19.0%, cereals and sedges amount to 32 species (13.5%), legumes represent 28 speies (11.9%), mixed herbs are 176 (74.6%). The projective cover of grass stand is 80.0–100.0%, that corresponds 73–109 species per 100 m². An average yield of the restored steppes grass stand is 2.8–3.8 t ha-1 . It exceeds the productivity of natural cenoses by 2.1–3.3 t ha-1 . The botanical analysis by crops demonstrated that in the grass stands samples of cereals (19.6–43.9%) and mixed herbs (18.3–31.2%) dominated. 18 rare plants are preserved in the cenoses. 171 species have useful properties. The site of the restored meadow steppe is an exposition and serves for sightseeing and educational purposes. Lately, sod blocks planting was widely used in experimental phytocenology and landscape design. Its implementation for natural vegetation restoration on the large areas is time-consuming and expensive compared to the method of cultivated lands, therefore it can be used in small sites as a component of combined options.
Theoretical research into directional stability of trailed tandem- type disk harrow
(Estonian University of Life Sciences, 2021) Bulgakov, V.; Olt, Jüri; Nadykto, V.; Volskiy, V.; Polishchuk, S.; Aboltins, A.; Beloev, H.; Estonian University of Life Sciences. Institute of Technology
Disking is one of the methods of soil cultivation, provides its effective crumbling, loosening, partial mixing and soil inversion. This ensures that crop residues on the soil surface are shredded and intermixing with loosened soil particles. Since, in addition to crop stubble, weeds are also counted as crop residues, soil disking, along with the use of herbicides, is often regarded as the most effective method of controlling the weediness of the agricultural background. Despite the fact that numerous studies on the disk harrow working process are available, insufficient attention has been paid to the study of the stability of harrow machine-tractor units, especially trailed ones. The purpose of this study is to establish the theoretical patterns that would provide for selecting the trailed disk harrow parameters that ensure the desired directional stability of the implement, which, in its turn, helps to achieve the desired qualitative performance of the disk harrowing machine-tractor unit. The principles of the theory agricultural machine, analytical mechanics, higher mathematics, as well as methods of PC-assisted numerical calculations have been used. According to the results of the study, it has been established that sufficient directional stability of the trailed disk harrow can be ensured if its working width B, the distance from the hitch point to the centre of resistance (parameter d) and the operating speed 𝑉𝑜 are properly selected. Determining the above-mentioned parameters of the disk harrow with the use of the obtained new analytical relations ensures achieving just their optimal combination, which provides for the maximum field productivity of the harrow machine-tractor unit with the satisfactory stability of disk harrow movement in the horizontal plane.
Joint Business-to-Business recovery management: the moderating role of locus of failure
(2021) Nik Bakhsh, Naghmeh; Riivits-Arkonsuo, Iivi
Agricultural machinery manufacturers and services providers increasingly experience failure in core products and service deliveries. Despite the importance of recovery management in context, scant research exists on studying recovery management, collaborative recovery activities, and the impact of joint recovery management on post-recovery relationship quality. More pressing is the lack of research on the impact of relationship quality on the customer's intention of future co-recovery activities. Using an experimental design with data from 30 agronomy machinery and equipment manufacturers and service providers in Iran, we investigate how customers’ perception of relationship quality is influenced by the interplay of locus of failure and supplier recovery tactics (non-co-creation of recovery vs co-creation of recovery). The results reveal the locus of failure, interacts with the supplier recovery tactics to impact the customers' perceptions of relationship quality. Finally, all three dimensions of relationship quality (satisfaction, trust, and commitment) positively impact the customers’ intention for future co-recovery activities.
Technical and economic pre-feasibility study for the construction of septic tank-filter-sinkhole with alternative material
(2021) Martins, P.H.N.; Cecchin, D.; Azevedo, A.R.G.; Carmo, D.F.; Danagemma, R.A.; Waite, R.M.M.; Rodrigues, N.F.; Sousa, F.A.; Amaral, P.I.S.; Hüther, C.M.; Pereira, C.R.; Cruz, V.M.F.
The study of the different materials used in the construction of septic tanks aims to facilitate and spread the use of this sewage treatment system in places that are not assisted by municipal sewage systems and in the rural area, which despite having a smaller number of inhabitants compared to the urban area This study aims to carry out a technical and economic evaluation of the concrete and tires using in the construction of septic tanks-filter-sinkhole. The wastewater treatment systems were built according to the recommendations in NBR 7229/93 and 13969/97. To evaluate the efficiency of each system built, the following parameters were analyzed: chemical oxygen demand (COD), the potential of hydrogen (pH), alkalinity, acidity, and temperature. In the economic evaluation, the materials and labor required to install the systems were considered using the Brazilian cost database (SINAPI), and an economic and financial feasibility study was carried out. According to the technical and economic analysis of construction, both systems showed the same technical performance, however, the concrete design proved to be more advantageous than the tire design, considering the difficulty in acquiring the tires and the high cost if it is necessary to buy them, in addition to the greater difficulty in handling and installing the tire system compared to the concrete one.
Morphology of Camellia Sinensis L. leaves as marker of white tea authenticity
(Estonian University of Life Sciences, 2021) Durnova, N.; Simakova, M.; Isaev, D.; Simakova, I.; Simakov, A.
Tea is one of the most common drinks in the world. Classic tea is obtained by brewing the leaves of the Camellia sinensis L plant in hot water. However, even the leaves collected from the same branch of the same tea bush can have completely different anatomical, biochemical and taste characteristics. White tea is the youngest, immature apical leaves of the tea bush (fleshes) together with leaf buds (tips) which are is considered the most valuable parts of teaplant. The chemical composition of tea is studied in sufficient detail, however, there are still no uniform criteria for determining the authenticity of white tea leaves, which creates great preconditions for falsifying this most valuable type of raw material. The aim of this study was to study the macroand microstructure of white tea leaves from different manufacturers and to determine the morphological markers of the authenticity of white tea leaves. The objects of research were white tea from the Nandana Tea Factory (Sri Lanka) and white tea from an unknown manufacturer, purchased from a local tea shop. The study of raw materials was carried out in accordance with the requirements of GF XIV OFS 1.5.1.0003.15 ‘Leaves’ and OFS 1.5.3.0003.15 ‘Technique of microscopic and microchemical examination of medicinal plants and herbal medicinal products.’ The work was carried out on the basis of the laboratories of the Department of Food Technologies of FGBOU VO Saratov GAU named after N.I. Vavilov, and the Department of General Biology, Pharmacognosy and Botany, Saratov State Medical University named after V.I. Razumovsky Ministry of Health of Russia. Studies of the structure of white tea leaves from various manufacturers have shown that the structure and presence of morphological elements of leaves, such as hairs, stomata, leaf edge, druses, sclereids, differ markedly and can serve as reliable markers for identifying the variety of tea.
Evaluation of carbon, nitrogen, and oxygen isotope ratio measurement data for characterization of organically and conventionally cultivated spring barley (Hordeum vulgare L.) grain
(2021) Buša, L.; Bērtiņš, M.; Vīksna, A.; Legzdiņa, L.; Kobzarevs, D.
With the growing interest of public in the quality of their consumed food, organic produce has been steadily gaining an important place in everyday menus of our society. The growing demand has boosted organic farming and we have also seen the price difference between organic products and their conventional counterparts. It is important to the public to have security, that the food labelled ‘organic’ has really been grown according to the good practices of organic farming and that it has not received any chemical pesticides, herbicides, and synthetic fertilizers. Stable isotope ratios of crops from different crop management systems can help to answer these questions, as these values depend on the growing conditions, fertilizers used etc. In this study, 10 barley grain samples from conventional and organic crop management systems have been studied. Carbon, nitrogen and oxygen isotope ratios have been determined and the element content in the samples has been calculated. Student’s t-test has been performed to evaluate whether the differences between various parameters are significant. For potential clustering and discrimination of organic and conventional grains principal component analysis has been carried out. The PCA showed that no significant clustering can be observed, however the Student’s t-test for δ15N values confirmed that barley grown with green-manure fertilizers are significantly (p < 0.01) enriched with the heavier nitrogen isotope. Furthermore, it has been concluded that the total element content of carbon and nitrogen in barley grains does not correlate with the stable isotope ratios and cannot help with discriminating of these samples.
Theoretical research into operation of rotary potato harvester
(2021) Olt, Jüri; Bulgakov, V.; Bonchik, V.; Ruzhylo, Z.; Volskiy, V.; Melnik, V.; Ihnatiev, Ye.; Kaletnik, H.; Estonian University of Life Sciences. Institute of Technology
The topic of the paper is the determination and justification of the rational design and kinematic parameters of clod breaking tools in rotary potato harvesters with the aim of improving their separating efficiency. A new mathematical model has been developed for the motion of a soil particle on the working surfaces of the cone-shaped and cylindrical vanes in the rotary tool of the new design developed by the authors. Differential equations have been generated for the motion of a soil clod as a material particle from the moment of its arrival to the surface of the vane until the moment of its departure from the said surface. As a result of the completed investigations, relations have been established between the time of contact and absolute displacement of the soil particle and the velocity of its departure from the rotor vane surface, on the one hand, and the kinematic and design parameters of the rotor, on the other hand. For example, when the machine translation velocity increases, the absolute displacement of the soil particle within the interval from the time zero to the moment of its departure from the vane surface increases from 0.59 m to 0.65 m, the velocity of soil particle departure from the vane surface - from 1.61 m s–1 to 1.81 m s–1. The highest values of the absolute displacement of the soil particle and the velocity of its departure from the vane surface are achieved at a machine translation velocity of 2.0 m s–1. The time of the contact between the material particle and the vane surface decreases with the rise of the translation velocity. When the rotor rotation frequency varies within the range from 20 min–1 to 100 min–1, the absolute velocity, with which the soil particle leaves the vane surface, rises to 4 m s–1. The duration of the contact between the material particle and the vane reaches its maximum value of 0.33 s, when the rotor rotation frequency varies within the range of 30–40 min–1.
Concentrations of CO₂ from composting under different treatments
(2021) Karandušovská, I.; Hlinka, P.; Páleš, D.; Szabóová, T.
The aim of this study was to analyse the production of CO2 concentrations in relation to the composting technology used. Three loose piles of bio-waste (V1, V2, V3) were created with the same volume. V1 reference pile was without any treatment. The biological preparation containing probiotic bacteria was added to the pile V2. The pile V3 was treated once a week by turning and watering. The degassing shafts were installed in each pile and the Multigas Monitor 1312 gas analyser with the Multipoint Sampler 1309 were used to measure of gas concentrations during the degradation process. Continuous 24-hour measurements of carbon dioxide concentrations from each pile were performed in the first, fourth, and seventh week of the degradation process to compare the amount of concentrations between piles in those weeks. At the beginning of the process, there were no significant differences in the production of CO2 concentrations from the monitored piles V1, V2 and V3. In the fourth week, significantly higher values of CO2 concentrations were recorded from the pile V3 (P < 0.05), which was turned and irrigated, than from V1 and V2. At week 7, significant differences were found between all treatments at the significance level (P < 0.05), with the highest values from the V3 pile. It has been shown that turning and humidifying results in the highest release of CO2 into the air, but in a more rapid decomposition of the microorganisms, that reducing the time required to achieve a stable compost product and increasing the efficiency of the composting plant.
China food security assessment
(2021) Chernova, V.Yu.; Kheyfets, B.A.
Ensuring food security is a strategic goal of any state, especially in the face of population growth. A review of the academic literature showed the presence of problems in ensuring a high level of food security in China: the rigidity of demand for food, limited land resources, structural contradictions between supply and demand. This study proposes an approach to assessing the level of food security, based on the calculation of an integral index consisting of four units of indicators: the sub-index of provision of crop products, the sub-index of productivity, the sub-index of provision of livestock products, and the sub-index of food import dependence. The results show that, in general, the level of food security in China has increased over the period under review, but there are problems in self-sufficiency in crop and dairy products, as well as in an increase in food import dependence. A forecast of the dynamics of the integral index of the food security level and its sub-indices was constructed, which showed that a decrease in the integral index might occur due to a decrease in self-sufficiency in livestock products and import dependence, while the availability of crop products and yields will increase. The study showed that the measures taken by the Chinese government led to some positive changes, but it is necessary to take a comprehensive approach to this problem, to solve which it is necessary to use the potential of all sectors of the food industry.
Woodworking wastewater biomass effective separation and its recovery
(Estonian University of Life Sciences, 2021) Vitolina, S.; Shulga, G.; Neiberte, B.; Reihmane, S.
The aim of the study was to develop a new Al-based hybrid coagulant that was effective in removing wood biomass from the wastewater formed in water basins of plywood plants during hydrothermal treatment of birch wood. The organic-inorganic coagulant was prepared by interaction of high molecular polyethyleneimine (PEI) with the inorganic polyaluminium chloride-based composite coagulant (KHPAC) in aqueous medium. Owing to the hybrid nature, the developed coagulant could simultaneously perform both the coagulation and flocculation function. The influence of a hybrid coagulant composition, its dosage, pH and a temperature on the efficiency of wastewater biomass separation was investigated. The best coagulationflocculation efficiency was achieved with the hybrid coagulant having a mass ratio of PEI/KHPAC equal to 0.3–0.5 and at the optimal dosage of 70–80 mg L -1 , reaching 97% yield of the total wood biomass and 60% yield of the lignin recovery. The efficient dosage of PEI and KHPAC in hybrid coagulant was about 1.4–1.8 and 1.7–2.2 times lower than if these coagulants/flocculants were used alone. As a result of the coagulation-flocculation process, wood biomass sludge is formed, which is a sufficiently large source of renewable organic matter, with the potential to obtain value-added products. The components of the biomass sludge were found to have surface activity and binder properties, as well as cation exchange capacity. Based on these properties, its ability to structure dusty soil particles with the formation of mechanically resistant soil aggregates was studied.
Suitability of various onion (allium cepa) varieties for drying and long-term storage
(2021) Zavadska, O.; Bobos, І.; Fedosiy, I.; Podpriatov, H.; Komar, O.; Mazur, B.; Olt, Jüri; Estonian University of Life Sciences. Institute of Technology
In the paper, the results are presented obtained in the research into the fresh bulbs and the dried products of 9 onion varieties cultivated in the conditions of the Ukrainian Forest Steppe area with regard to their economical biology, biochemical, marketability and organoleptic indices. The varieties that are most suitable for convection drying and long-term storage have been identified. It has been established that the marketability of both the fresh bulbs and dried products depends on the masses of the bulbs. The Bronze d’Amposta and Harmony varieties deliver the greatest amount of marketable output (94.0 and 93.2%) featuring marketable bulbs with masses of 67.4 g and 70.4 g, respectively (r = 0.82). As the bulb mass increases, the amount of non-standard (r = -0.81) and small (r = -0.76) particles in the dried product decreases substantially. It has been found that the content of solid matter and sugars in fresh bulbs has effect on the yield and quality of the dried and reconstituted products. The Harmony and Skvirskaya varieties, the bulbs of which during the vegetation season build up 12.9% and 13.8% of solid matter, respectively, are distinguished by the highest dry product yield - 17.1 and 16.8%, respectively. Correlation has been established between the contents of solid matter and sugars in fresh bulbs (r = + 0.58). During the tasting of reconstituted onion products, the highest scores were awarded to the samples produced from the Skvirskaya and Harmony varieties - 7.0 points each on the 9-point scale, as their bulbs had accumulated over 7.0% of sugars (total). Judging by the aggregate of the researched indices, the Harmony and Skvirskaya varieties of onions are the most suitable for convection drying. It has been established that the preservation of onions in the conditions of stationary buried storage without artificial cooling depends on the duration of storage and the specific varietal features. Within the five months of the test storage, the preservation of bulbs of all the varieties was high and varied within the range of 80–93%. Longer storage is expedient only in case of the Harmony, Skvirskaya and Gospodinya, for which the bulb preservation rates for a seven month storage period has been shown to be equal to 90.2, 88.4 and 87.2%, respectively. It has been proved that the quantity of healthy bulbs depends to a significant extent on the solid matter content in the bulbs (r = 0.93).
The biological basis for the use of acrylic hydrogel and protein growth stimulant in the soft wheat and triticale cultivation
(Estonian University of Life Sciences, 2021) Kolesnikov, L.E.; Uspenskaya, M.V.; Kremenevskaya, M.I.; Orlova, A.G.; Razumova, I.E.; Kolesnikova, Yu.R.
The development of technologies for the environmentally friendly biopreparations production and use including biopreparations based on acrylic hydrogel and protein growth stimulant, which is obtained by chemical hydrolysis from by-products of slaughtered animals processing is carried out as part of the optimization of the phytosanitary condition of wheat crops and creation of favourable agro-ecological conditions for its cultivation. An important feature of acrylic hydrogel is the ability to retain and release water to plants when needed. At the same time, protein hydrolysate can provide plants with an additional source of nitrogen which is a component of plant proteins, chlorophyll and it is necessary for normal growth and development of plants during the vegetation. The addition of the protein growth stimulant to acrylic hydrogel expands the potential application of Super Moisture Absorbent (SMA) due to the long-term growthstimulating effect on plants. The acrylic hydrogel and protein growth stimulant were added to the soil when wheat sowing in the certain concentrations and proportions. Wheat productivity was studied by the indicators complex, characterized the plants morphological features and the yield structure. Assessment of the degree of plant affection caused by pathogens was carried out both according to the generally accepted phytopathological indicator - conditional intensity of development, and using additional parameters. In the research, it was found that acrylic hydrogel and protein growth stimulant provide an increase in wheat yield and reduce the pathogens harmfulness. In combined application, they can be used in agriculture for wheat cultivation as a low-cost and environmentally friendly soil conditioner.
Wheat cultivars exposed to high temperature at onset of anthesis for yield and yield traits analysis
(2021) Goher, R.; Akmal, M.
Temperature fluxes at some critical growth stages adversely affect the crop yield. Heat stress (HS) of limited duration shows mild to marked effects on crop yield. The study focused on evaluating HS of limited durations on wheat crop effective from anthesis. Four wheat cultivars (Pirsabak-2005, Pakhtunkhwa-2015, Pakistan-2013, and DN-84) and three advanced lines (P-2, P-12, and P-18) were subjected to HS for 48, 72, and 96 h evaluating changes in the yield and yield contributing traits. The experiment was conducted in a randomized complete block design during 2017–18 and 2018–19 at Agronomy Research Farm, the University of Agriculture Peshawar Pakistan. At the onset of anthesis, plants were exposed to HS in the plastic tunnel for limited durations. The temperature inside and outside tents was recorded periodically. The mean across the years showed a significant effect on yield traits by HS imposition at anthesis stage. The mean data across the two years showed a significant effect of HS on yield and yield contributing traits. In comparison with control, spike weight (g) reduced by 29, 40, and 49% under limited HS of 48, 72, and 96 h, respectively. Grains per spike were decreased by 45, 61, and 69% and grain weight by 29, 36, and 45% from control to imposed HS of 48, 72, and 96 h, respectively. Overall grain yield decreased by 44, 61, and 70% upon exposed to 48, 72, and 96 h of HS, respectively. The differences among the cultivars for yield and yield contributing traits were different under various HS conditions. The study concluded that HS effective from anthesis has an adverse effect on grain weight and number and hence the grain yield. Among the cultivars, Pakistan-2013 showed better resistance to HS of limited duration when exposed at the anthesis stage of the crop growth.
Comparison of spatial-temporal analysis modelling with purely spatial analysis modelling using temperature data obtained by remote sensing
(Estonian University of Life Sciences, 2021) Dos Santos, L. M.; Ferraz, G.A.S.; Alves, H.J.P.; Rodrigues, J.D.P.; Camiciottoli, S.; Conti, L.; Rossi, G.
Variations in climatic elements directly affect the productivity of agricultural activities. Temperature is one of the climatic elements that varies in space and time.Therefore, understanding spatial variations in temperature is essential for many activities. Given the above, the objective of this work was to compare the performance of the proposed spatiotemporal analysis model with that of purely spatial analysis using temperature data obtained by remote sensing. The experimental data were arranged in a grid with 403 spatial locations, with 22 samples collected in a 24-hour period. The statistical software R Core Team (2020) was used to perform the analysis. The packages used in the analyses were ‘geoR’, ‘CompRandFld’, ‘scatterplot3d’, and ‘fields’. For making the maps, the software ArcGIS was used. The behavioural analysis of spatiotemporal dependence indicated, through the covariogram graph of the data, that there is a strong spatial dependence. For the cases of purely spatial analysis of phenomena, a separate spatial model for each time is justified because this type of model presents a smaller prediction error and requires simpler processing than the space-time model. It was possible to compare the space-time analysis with the purely spatial analysis using temperature data obtained by remote sensing images. The data modelled with the purely spatial analysis had, on average, lower error than those with the space-time model.
Application of pineapple fiber in the development of sustainable mortars
(Estonian University of Life Sciences, 2021) De Azevedo, A.R.G.; Rocha, H.A.; Marvila, M.T.; Cecchin, D.; Xavier, G.C.; Da Silva, R.C.; Ferraz, P.F.P.; Conti, L.; Rossi, G.
Due to the great worldwide increase in pineapple production, countries like Brazil and India have problems regarding the correct disposal of residues from the production of this fruit. One of the possibilities is the reuse of these residues in the form of fibers in cementitious materials, as is the case with mortars. As a result, the objective of this work is to evaluate the application of pineapple fibers in mortars in the proportion of 1: 4 (cement: sand) with addition of fiber treated in NaOH in the proportion of 3 and 6%. The properties of mechanical resistance, water absorption, mass density and adhesion were evaluated, aiming to apply the mortar in coatings of rural environments. The results indicate that the fibers reduced the mortar density and increased the mechanical strength. However, there was a reduction in adherence, especially with the use of 6% fiber, in addition to an increase in water absorption. Based on the results, it is concluded that it is feasible to use 3% of pineapple fiber for the production of coating mortars in rural environments because the results obtained in the investigation are compatible with this application and with the established normative limits.
Identification of the effectiveness of associative rhizobacteria in spring wheat cultivation
(Estonian University of Life Sciences, 2021) Kolesnikov, L.E.; Belimov, A.A.; Kudryavtseva, E.Y.; Hassan, B.A.; Kolesnikova, Yu.R.
The maximum increase in wheat yield (by 67% to the control), associated with a decrease in the root rot development by 19%, an increase in the productive bushiness by 18%, the spike weight by 26%, in the grains number per spike by 8% was noted when using the Bacillus subtilis strain 124-11; the strain effect on leaf diseases was insignificant (2–5%). The plants differed in the maximum changes (to control) in the total bushiness by 59%, the plants vegetative part weight by 27%, the flag leaf area by 21%, the pre-flag leaf area by 28%, the roots numbers and weight by 20% and 62%. After plants treatments with the Pseudomonas fluorescens strain SPB2137, the wheat maturation period was reduced by 9% (to the control), wheat yield increased by 58% due to a decrease in the development of root rot and septoria by 18%, the yellow rust pustules area by 44%; the productive bushiness and plant height increased by 25% and 19%, the plant vegetative weight by 21%, the spike length by 4%. The most expressed protective and growth-stimulating effect was shown by the Sphingomonas sp. K1B, which caused a maximum decrease (to the control) in the root rot and yellow rust development by 22% and 7%, the strips length by 22%, the pustules number in the strip by 29%, brown rust by 10%, septoria by 11%. Wheat plants were characterized by a large number and length of roots by 17% and 13%, root weight by 49%, a maximum increase in the nodal roots number and length by 15% and 17%; total bushiness by 34.5%; a maximum increase in plant vegetative weight by 37%; the spike length by 3%.
Some mechanisms of winter resistance in apricot flower buds in the period of ecodormancy
(2021) Golubev, A.M.; Alyoshina, N.A.; Anfalov, V.E.; Kulikov, A.A.; Vdovenko, V.S.
The accelerated development of flower buds during the thaw in apricots and almonds during the ecodormancy period leads to significant damage to the flower elements during return frosts and loss of future crops. The aim of the research was to identify the mechanisms of delay in the rate of development of flower buds during the ecodormancy period, their relationship with the degree of frost resistance and the timing of flowering in apricots. The following indicators of flower buds were analyzed: the degree of exit from endodormancy, frost resistance at temperatures of -18 °C and -31 °C, the degree of morphological development of flower elements, the activity of α-amylases at temperatures of + 15 °C and + 60 °C, total content water, phenolcarboxylic acids, flavonoids and free proline. A significant positive correlation was revealed between the percentage of death of flower buds at a temperature of -18 °C and the percentage of buds emerging from endogenous dormancy (0.64*), the percentage of death of buds at a temperature of -31 °C and the degree of development of flower elements (0.70*), water content and the degree of development of flower elements (0.76**), amylase activity at +60 °C and amylase activity at +15 °C (0.76**), the content of phenolcarboxylic acids in the bark of shoots and flower buds (0.61*). For the first time, psychrophilic forms of α-amylases have been discovered in apricot flower buds.

Sirvi

Sirvi 2021, Vol. 19, No. 3 Kuupäev järgi

Tulemused lehekülje kohta

Sorteerimisvalikud