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Analysis of influencing factors of use of agricultural land
2018
Cintina, V., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Pukite, V., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Land use efficiency is based on agricultural production. Correct and effective land use could solve several problems – food production, improving the welfare and provision of social stability. The use of land and natural resources is an important issue in the development of the country; therefore, many researchers and scientists have analysed and studied the use of agricultural land and land use efficiency. Efficient land use has an impact on different types of factors, which are mutually contradictory. In the paper several authors researches are analysed, studying influencing factors of the use of agricultural land. Influenced by several factors the main problems associated with the use of agricultural land are the increase of unused agricultural land, the continued degradation of land, but the major problem of land use is the existence of a fragmented property structure. For the efficient use of agricultural land, there are several conditions that need to be met or improved to achieve effective land use. The main conclusion is that analysing the problems that are associated with the use of agricultural land is seen as interactive interaction, as the fragmented property structure is one of the reasons influencing the use of agricultural land, which leads to an increase in unused areas of agricultural land, while unused areas of agricultural land are often overgrown with shrubs while promoting degradation of land.
Afficher plus [+] Moins [-]Phytoremediation as tool for prevention of contaminant flow to hydrological systems
2018
Valujeva, K., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Burlakovs, J., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Grinfelde, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Pilecka, J., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Jani, Y., Linnaeus Univ. (Sweden) | Hogland, W., Linnaeus Univ. (Sweden)
This paper aims to deal with the phytoremediation approach for protection of environment and preventing the streaming of contaminant flows to hydrological systems. Phytoremediation is a cost-effective environmentally friendly clean-up technology, which uses plants and microorganisms in rhizosphere for soil and groundwater treatment. Phytoremediation is enhancing degradation of organic pollutants and improving stabilization of inorganic contaminants where plants can be used to treat soil and water polluted with hydrocarbons, chlorinated substances, pesticides, metals, explosives, radionuclides as well as to reduce the excess of nutrients. Selection of species for this type of treatment processes is based on evapotranspiration potential and ability to bioaccumulate contaminants. The project entitled “Phytoremediation Park for treatment and recreation at glassworks contaminated sites” (PHYTECO) aimed at cross-sector international partnership. The challenge of project was to develop remediation strategy where negative consequences from centuries long anthropogenic influence are turned to be something positive – development of the recreation park from the glass dump. New “Knowledge in Inter Baltic Partnership Exchange for Future Regional Circular Economy Cooperation” (PECEC) project is sequential continuation.
Afficher plus [+] Moins [-]Computational fluid dynamics pressure wave and flow rate analysis of intake runner design in internal combustion engine
2018
Banis, K., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
This paper investigates the effect of intake runner design on pressure wave propagation and reflection in sparkignited internal combustion (IC) engine. These events are known to leave a noticeable influence on the overall engine performance therefore the aim of this study is to evaluate how changes in intake runner geometry affect pressure oscillations and volume flow rate. Time-dependent computational fluid dynamics (CFD) analysis was carried out to determine how these changes affect the pressure oscillations during a full engine cycle at constant crankshaft speed. Steady state CFD analysis at constant pressure differential was carried out to evaluate the effect on volume flow rate. The simulations were carried out in SolidWorks Flow Simulation environment. Honda CRF450R motorcycle engine was used to define the initial conditions and basic intake runner design. Intake air speed at port entrance cross-section was calculated based on engine parameters and operating speed. The average pressure values with respect to physical time were measured and graphed across the intake port opening cross-section. Six different intake runner designs were compared. It was concluded that the runner taper angle has influence on pressure wave-length but internal geometry (steps, curvature and taper angle) has influence on volume flow rate. It was observed that cylindrical intake runner design produced an increase in pressure wave-length but a cylindrical section of the intake runner with a stepped transition to tapered extension produced a slight increase in pressure wave amplitude.
Afficher plus [+] Moins [-]Increasing cyclone efficiency by using a separator plate
2018
Galins, J., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Laizans, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Galins, A., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
The aim of the work is to increase the efficiency of cyclone technology by using a separator plate. Cyclone technology is used not only in the processing of various agricultural products, but also in air purification from dust. Air flow trajectories and the movement of dust particles inside the cyclone unit were simulated and analysed using Computational Fluid Dynamics (CFD) and particle study analyses. The separator plate was designed in certain sizes and placed inside the cyclone, thus increasing the efficiency of the cyclone. The angle of position of the separator plate significantly affected the obtained results. The experimental equipment was assembled together to test the simulation results. Wood ash was used to determine the efficiency of the cyclone. Studies have shown that the effect of the separator plate on increasing the efficiency of the experimental equipment is less than that shown in the simulations. Most of the experiments used ash particles that were greater than 20 μm, thus cyclone efficiency was 98.9 ± 0.05%. This confirms the compliance of CFD simulations with the physical model. More detailed research should be carried out in order to use the separator plate effectively for the filtration of very small dust particles.
Afficher plus [+] Moins [-]Disturbance of the functionality in immunocompetent organs of chickens due to accumulation of cadmium
2018
Vasiljeva, S., University of Latvia, Riga (Latvia) | Basova, N., University of Latvia, Riga (Latvia) | Smirnova, G., University of Latvia, Riga (Latvia)
The high toxicity, bioaccumulative and increased distribution of cadmium (Cd) in the environment, makes it the most dangerous to any biological system, including immune system in human and animals. The effect of dietary intake of Cd (8.25 mg per kg) on accumulation and distribution of this heavy metal in various tissues, and functional changes in organs of immunity (thymus, bursa of Fabricius, spleen) in 35-day-old broiler cockerels were investigated, using biochemical and immunological methods. Significant increases in the Cd concentration both in central immunocompetent organs (thymus, bursa of Fabricius) and peripheral (spleen) were established. Excessive tissue level of Cd induced the prooxidative effect of this heavy metal in the organs. It was manifested in an increase of cell membrane lipid peroxidation (the enhanced malondialdehyde (MDA) concentration) in immune system organs. The oxidative stress resulted in immunocompetent cell damage. The fall of vital dye absorptive ability of immunocyte indicated the increase in the injured cell number. This harmful effect is in accordance with T- and B (C3) – population prominent depletion, organ relative mass reduction, and growth retardation in chicks, and was established as a result of dietary Cd loading for 5 weeks of the experiment.
Afficher plus [+] Moins [-]High pressure effect on the sensory and physical attributes of pork
2018
Sazonova, S., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Galoburda, R., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)) | Gramatina, I., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Straumite, E., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
High-pressure processing (HPP) is typically used for the microorganism inactivation, which provides safety and prolonged shelf life of meat and meat products. However, for consumers along with safety, it is important to have good sensory properties, which is a combination of tender and juicy meat with an intense meat flavour. These attributes may change because of the high pressure processing; therefore, the aim of the study was to evaluate the effect of HPP on sensory and physical attributes of pork upon processing at 300 and 600 MPa at room temperature for 1 and 15 min. After HPP the processed pork samples were cooked within the package in a water bath. Colour of cooked pork did not differ among samples. Moisture content of samples decreased with the increased processing time. Sensory evaluation revealed that HPP treatment did not influence the colour and flavour of cooked pork irrespective of treatment parameters applied in the current study. The panellists indicated that increased pressure made pork samples drier and tougher, thus changing such sensory attributes as juiciness and chewiness, which are important for meat palatability. The correlation found between chewiness determined by sensory analysis and toughness determined by Warner-Bratzler shear device suggested this instrumental method as a better tool when compared to the instrumental texture profile analysis (TPA).
Afficher plus [+] Moins [-]Rye and oat crispbread improvement with biologically active substances from plant by-products
2018
Konrade, D., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia) | Klava, D., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Vegetable processing in food industry results in significant number of by-products – peel, mark, bark, seeds still rich in bioactive compounds. The objective of this study was to investigate the stability of total phenolic content (TPC) and antioxidant activity after high temperature short time (HTST) extrusion cooking of a rye and oat- based matrix with addition of apple, carrot and pumpkin by-product flour (BPF) in various amounts (5%, 10%, 15% and 20%). Extrusion was performed with co-rotating twin-screw extruder (compression ratio 8:1) at Ltd MILZU. The main drive of extruder was provided with a 7.5 HP motor (400 V, 3 HP, 50 cycles). Temperatures for extrusion zones were 125 °C /135 °C /145 °C. TPC was determined using the Folin Ciocalteu method. Antioxidant activity was evaluated by free radical 2, 2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant scavenging activity. TPC in cereal-based crispbread was 62.03 ± 0.15 mg GAE gE-1 DW before extrusion and 37.73 ± 1.96 mg GAE gE-1 DW after extrusion. Addition 20% of apple BPF increased TPC in crispbread to 193.92 ± 1.37, carrot BPF 171.36 ± 6.97 and pumpkin BPF to 195.09 ± 4.68 mg GAE gE-1 DW after extrusion. Antioxidant activity of control (20% oats, 80% rye flour blends) sample was 0.516 ± 0.192 mg TE gE-1 DW but in samples with addition of 20% by-products, it was significantly higher reaching 0.926 ± 0.05 TE gE-1 DW in samples with pumpkin by-products after extrusion.
Afficher plus [+] Moins [-]Characterization of yellow rust (Puccinia striiformis Westend.): review
2018
Feodorova-Fedotova, L., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia);Latvian Plant Protection Research Centre, Riga (Latvia) | Bankina, B., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia)
Yellow rust caused by Puccinia striiformis is a significant wheat disease in cereal growing areas worldwide. On average, yellow rust can cause 50% big yield damages resulting in economic losses. Yellow rust damages wheat leaves, leaf sheaths, awns, and glumes. Puccinia striiformis is divided into four lineages – P. striiformis sensu stricto, P. pseudostriiformis, P. striiformoides, P. gansensis. Different races of yellow rust have been determined. After 2000 three new aggressive races – ‘Warrior’, ‘Kranich’ and ‘Triticale aggressive’ have been identified. New races are characterized by shorter latent period, extended spore germination and tolerance to a high temperature in comparison with the races determined before 2000. These characteristics allowed the new races to replace races dominant before 2000. Yellow rust is a biotrophic heteroecious fungus with a complicated life cycle. For successful development, Puccinia striiformis requires cereals as primary hosts and Berberis spp. as alternate hosts. The history of studies regarding yellow rust is more than two hundred years old but only in 2010 the ecidiospores of yellow rust were found on the alternate host Berberis spp. Two types of resistance – seedling (or all-stage) resistance and adult plant resistance (APR) were discovered. Since 2000 multiple severe epidemics of yellow rust have been observed in cereal growing areas with warmer climate. In recent years, the incidence of yellow rust in Latvia has increased. Particular studies about the biology, distribution, and races of Puccinia striiformis in Latvia are necessary. This article summarizes the information about the classification, biology and harmfulness of the yellow rust.
Afficher plus [+] Moins [-]Leaf optical properties reflect changes of photosynthetic indices in apple trees
2018
Lauzike, K., Lithuanian Research Centre for Agriculture and Forestry, Akademija, Kedainiai distr. (Lithuania) | Samuoliene, G., Lithuanian Research Centre for Agriculture and Forestry, Akademija, Kedainiai distr. (Lithuania);Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
The impact of light penetration into crown and the effect of rootstocks and distance between trees on photosynthetic behaviour were analysed. Apple cultivar ‘Auksis’ was grafted onto dwarfing rootstock P60 and super-dwarfing rootstock P22 and planted at different distances (3 × 1 m, 3 × 0.75 m and 3 × 0.5 m). Nitrogen balance index and photochemical reflectance index were measured at two heights: 0.8 m above ground inside the canopy and 1.5 m above ground outside the canopy; specific leaf area, fresh and dry weight were evaluated from all canopy. The significantly positive effect of dwarfing rootstock P60 on all tested indices was observed comparing to P22 rootstock. Increasing density between trees lead to a decreased specific leaf area and increased nitrogen balance index. The dry and fresh weight ratio and photochemical reflectance index were also significantly affected, but no general tendency was identified. Photochemical reflectance index was not affected by light penetration into canopy, but the nitrogen balance index significantly decreased in the upper part of the canopy. Summarizing, it can be stated that decreasing light penetration into the crown results in an increase in the specific leaf area and photochemical reflectance index, and leads to a decrease in dry and fresh weight ratio and nitrogen balance index.
Afficher plus [+] Moins [-]Effects of different fertilizer treatments on grain yield and yield components of spring wheat
2018
Mikos-Szymanska, M., New Chemical Syntheses Inst., Pulawy (Poland) | Borowik, M., New Chemical Syntheses Inst., Pulawy (Poland) | Wyzinska, M., Institute of Soil Science and Plant Cultivation – State Research Inst., Pulawy (Poland) | Rusek, P., Institute of Soil Science and Plant Cultivation – State Research Inst., Pulawy (Poland)
The present research was carried out to investigate the effects of different fertilizer treatments on grain yield and yield components of spring wheat (Triticum aestivum L.) ‘Harenda’ cultivar. The five treatments were as follows: control (standard NPK fertilization), standard NPK fertilization plus liquid NPK (10-11-11) fertilizer, standard NPK fertilization plus liquid NPK (10-11-11) fertilizer with microelements, standard NPK fertilization plus calcium micronized suspension fertilizer, and standard NPK fertilization plus Cu, Mn, Zn, Ca micronized suspension fertilizers. The field trials were conducted in 2017 at the Experimental Site of Institute of Soil Science and Plant Cultivation – State Research Institute in Puławy, Poland. Applications of calcium micronized suspension foliar fertilizer and a mixture of Cu, Mn, Zn, Ca micronized suspension fertilizers significantly increased grain yield of spring wheat, respectively by 44.5% and 38.6% in comparison with control (standard NPK fertilization). These fertilizer treatments also enhanced yield components of spring wheat. Moreover, micronized suspension fertilizers (Ca and the mixture of Cu, Mn, Zn, Ca) had a significant effect on ear number and thousand grain weight of spring wheat compared to control and NPK fertilizers. Liquid NPK and micronutrient-enriched NPK fertilizers had a significant effect on thousand grain weight compared to control.
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