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Mobile phosphorus presence of typical Chernozems on fertiliser system
2024
Voytovyk, Мihaylo | Butenko, Andrii | Prymak, Іvan | Tkachenko, Mykola | Mishchenko, Yurii | Tsyuk, Оleksiy | Panchenko, Оleksandr | Kondratiuk, Irina | Havryliuk, Oleksandr | Sleptsov, Yurii | Polyvanyi, Anton
Due to the systematic utilisation of substantial amounts of phosphorus fertilisers on agricultural crops in crop rotation, the amount of available phosphate compounds increases in the soil. It ensures the maximum increase in crop yields. The study of the phosphate level in Chernozem soils in various agrocenoses is really up-to-date. The gist of our research was to determine the specifics of providing mobile phosphorus in typical Chernozem in field crop rotation, especially in sunflower, varying according to fertilisation systems in the forest-steppe zone of Ukraine. The assessment of mobile phosphorus content was conducted using the Chirikov method, which involves extracting mobile phosphorus compounds from the soil using a solution containing acetic acid (CH3COOH) at a concentration of 0.5 mol dmE−3, with a soil–to–solution ratio of 1:25. Phosphorus was determined with the spectrophotocolorimetric method, which is based on the colour intensity of the phosphorus-molybdenum complex. Our investigations showed that the typical low-humus Chernozems have considerable reservoirs of potentially exploitable phosphorus for plant nourishment. We established that the mineral and organic-mineral fertilisation system leads to a greater use of mobile phosphorus with agricultural crops of crop rotation resulting in the formation of elevated phosphate content in the Chernozem soil. By the end of the second rotation, the organic-mineral fertilisation system variant displayed the greatest concentration of mobile phosphorus within the 0–25 cm soil depth, marking a surge of 15.6 mg kgE−1 compared to the unfertilised variant. In the period of sunflower germination, the content of mobile phosphates increased in the soil layers at depths of 0–25 cm and 25–50 cm in the variant of the mineral fertilisation system on 17.6 and 22.2 mg kgE−1 of soil compared to the alternative without the fertiliser. In the sunflower’s ripening period, the mobile phosphorus concentration in the soil at 0–25 cm depth increased significantly in the variant of organic-mineral fertilisation system by 12.0 mg kgE−1 and mineral fertilisation by 14.7 mg kgE−1 of soil if compared with the variant lacking the fertiliser. In the variant of the mineral fertilisation system, the amount of mobile phosphorus increased in the 0–30 cm soil depth by 18.7 mg kgE−1 of soil in two crop rotations compared to the beginning of the first crop rotation.
Показать больше [+] Меньше [-]Environmental sustainability aspects in short food supply chains: The views of organic farmers and consumers
2023
Ušča, Maija | Aļeksējeva, Lāsma
Globally, food systems are the most significant cause of environmental change; therefore, efforts to create more environmentally sustainable food systems are presented. One of the directions is strengthening the local actors and short food supply chains. Simultaneously, changes in farming systems are needed, and organic agriculture is one of the ways to make food systems more environmentally sustainable. Despite the abundance of research on the environmental consciousness of consumers in short food supply chains, the question is raised whether local food chain farmers are also committed to environmental sustainability. Therefore, this paper aims to explore the importance of environmental sustainability to organic short food supply chain actors. More specifically, the research depicts the views of organic farmers and consumers and their relation to the actual environmental sustainability of short food supply chains. During the research, a specific short food supply chain – a direct purchasing network – was explored. A qualitative approach was applied to reach the aim. Thus, in-depth interviews and observations were used as a research method. The research results demonstrated the views of farmers and consumers of the specific network regarding environmental sustainability aspects in the network. In the research, such environmental aspects as the circularity of resources, biodiversity, chemicals in the environment, seasonality and locality of diets, and the distance (food miles) were admitted as crucial ones by the specific short food supply chain actors. The differences in opinions of consumers and farmers emerged when thinking about the scale of their views.
Показать больше [+] Меньше [-]A Case-study: Temperature Distribution and Heat Penetration in Steam-air Retort, Using Glass Jars and Retort Pouches
2021
Raits, Evalds | Pinte, Lasma | Kirse-Ozolina, Asnate | Muizniece-Brasava, Sandra
Retort thermal sterilization of canned food is a technology, which allows preserving food products by applying heat on packaged food in retorts (autoclaves) at temperatures up to 121 °C. The thermodynamics of the processes in the retort are influenced by the product stacking method in the basket and packaging material. The aims of this study were: 1) to analyse and compare temperature distribution (TD) and the slowest to heat location in the steam-air retort stacked with glass jars and with retort pouches; 2) to analyse and compare commercial product heat penetration (HP) characteristics in glass jars and retort pouches. Temperature measurements were performed with wireless thermocouples. The come-up time (heating phase) required to achieve in the retort temperature uniformity criteria of ±0.5 °C, is 28 min when the retort is stacked with glass jars, and 24 min when the retort is stacked with retort pouches. Total calculated process time (holding phase), necessary to achieve the sterilization value (F₀ of 3 min), for sample in glass jars was 67 min, but in retort pouches – 62 min. The overall sterilization process time difference between two considered packaging types was 9 min, which is significant amount of time in the context of commercial processing. The study clearly shows the necessity to perform the Temperature Distribution and Heat Penetration study, as each packaging material, stacking method and product will affect sterilization process thermodynamics and, therefore, the overall process time and consequently - the safety of food product.
Показать больше [+] Меньше [-]Theoretical and Experimental Investigation of the Thermal Inactivation of Thermoanaerobacterium Thermosaccharolyticum and Geobacillus Stearothermophilus in Different Canned Food Matrices
2021
Raits, Evalds | Raita, Svetlana | Kirse-Ozolina, Asnate | Muizniece-Brasava, Sandra
In the canning industry, thermal preservation processes typically are designed based on Clostridium botulinum thermal destruction kinetics. However, some bacteria can still survive, necessitating implementation of stricter timetemperature regimen for sterilization process. The aim of this study was to compare processing effectiveness at F₀ (sterilization value) 8 ±1 min from the perspective of the vegetable-based product canning facility, while analyzing the inactivation, viability, and recovery of thermophilic bacteria. Four commercial products [tomato soup and rassolnik soup - acidified food (AF), and mushroom soup and pea porridge - low-acid food (LACF)] with different heat transfer characteristics (convection and conduction) were inoculated with 6.6 log₁₀ spores/ml Geobacillus stearothermophilus LMKK 244 (reported as DSM 6790 and ATCC 10149 in other collections) and 4.8₁₀ log spores/ml Thermoanaerobacterium thermosaccharolyticum DSM 571 spore suspensions. Food samples contaminated with bacterial spores were processed in a steam-air retort at 118 °C for 75 min. G. stearothermophilus and T. thermosaccharolyticum growth was not detected in AF samples (pH = 4.4 and 4.5), but was observed in LACF samples (pH = 5.1 and 5.8). Practical evaluation showed that T. thermosaccharolyticum did not survive thermal processing, which was verified using a presence/absence test after incubation at 55 °C. G. stearothermophilus did not survive thermal processing, but recovered in pea porridge (pH = 5.8) during incubation. Our observations showed that food pH is a crucial factor determining microorganism survival during heat treatment and may be used by the vegetable-based product canning facilities to improve the food sterilization conditions.
Показать больше [+] Меньше [-]The Efficiency of Different Wood Coatings against Water Surface Absorption
2021
Iejavs, Jānis | Ruļuks, Oskars | Laiveniece, Laura | Jakovļevs, Vilnis | Pugovičs, Kārlis | Liše, Sigita | Spulle, Uldis
In the market of the Latvia different wood surface coating materials suitable for use in outdoor conditions are offered, but available information on the efficiency of these against direct water exposure is insufficient. For structural timber building elements, such as glued laminated timber (GLT), the surface coating should be applied taking into account technological, visual or colour changes (ISO 7724:1984) and – last, but not least – economic aspects are considered. Wood surfaces coated with coating materials, such as varnishes, paints, etc. can stabilize some properties such as movement of moisture content, dimensional changes and attack by microorganisms and fungi. The changes in the moisture content of timber may influence such important parameters as mechanical properties and the total life time of the structural timber elements. A study has been conducted with the aim of assessing the efficiency of coating materials used for wood protection against water absorption. In this study, six different commercial coating products used for the treatment of spruce (Picea Abies L. Karst.) and pine (Pinus Sylvestris L.) samples were tested. The efficiency of different coating substances was assessed using two modified test methods according to the standards EN 382-2 (1994) and EN 927-5 (2006), determining the surface water absorption after immersion in water for 24 h and the dynamics of water absorption of the glued laminated timber for 696 h kept in water. As a result of the study, it has been ascertained that organic solvent-based commercial coating products are more efficient against short-term and long-term wood water absorption compared to oil-based coating materials.
Показать больше [+] Меньше [-]Evaluation of patatin content in proteins of potato genotypes grown in Latvia
2021
Berga, Dace | Sterna, Vita | Sokolova, Elina | Taskova, Inese | Seile, Sanita | Dimante, Ilze | Skrabule, Ilze
Potato proteins contains essential amino acids in considerably high concentration, therefore potatoes are considered to be one of the most valuable plant origin food for human consumption. Patatin forms one of the largest group of potato proteins with high potential to be used in food industry as a novel food. This study has been performed to approbate patatin determination method for evaluation of protein quality of potato genotypes, as well as evaluate patatin relative abundance (PRA) for breeding programmes to create in the future potato cultivars with higher value and potential to develop new products. The evaluation of patatin was performed in following steps– extraction proteins from potato, determination of patatin concentration and calculation of its relative abundance in proteins. Separation of patatin from potato tubers was made using extraction by SDS extraction buffer and determination of patatin in organically and conventionally (with differnt N suply) grown samples of 20 potato genotypes. The results of one-year study showed that patatin relative abundance of different cultivars varied from 1.65% to 50.2% and it was significantly different among genotypes. The nitrogen content of soil and maturity type of potato did not affect PRA significantly. Results provide impetus for further research.
Показать больше [+] Меньше [-]Influence of Veneer Density on Plywood Thickness and Some Mechanical Properties
2021
Kūliņš, Laimonis | Meija, Anete | Roziņš, Rihards | Liepa, Kārlis Hermanis | Spulle, Uldis
It has been common knowledge that as the density of wood increases, the mechanical properties also improve. In turn, the density of wood depends on many factors, including the wood moisture content, location and cross-section in the trunk, the type of treatment and the parameters of technological processes. There is a great deal of research reported in the scientific literature on the effect of solid wood density on mechanical properties for different wood species as well as for structural timber. However, no research data can be found related investigation of the influence of veneer density on the properties of the birch plywood. In the present study, researching the properties of 7-ply birch plywood (thickness 9 mm), it was concluded that as the density of veneers increases, the bending properties of plywood in the direction of wood fibers (covered veneers) increases. When determining the plywood gluing quality, similar tendencies have been observed. For plywood with a lower density in all veneer plies the gluing quality (tensile-shear test) for perpendicular wood fiber veneers increases in the direction from the symmetry axis or middle veneer to the plywood outer plies, which can be explained by the fact that the outer plies become denser at the time of the hot pressing process. The results of the study will allow birch plywood manufacturers in direct production, sort veneers by density, to produce plywood with very predictable gluing quality, plywood thickness and mechanical properties in bending.
Показать больше [+] Меньше [-]Slaughter Results, Meat Chemical Composition and pH of Aberdinangus, Hereford and Limousin bulls
2021
Muizniece, Inga | Kairisa, Daina
Beef production must combine the interests of both producers and consumers, taking into account the sustainable use of environmental resources. The aim of the study was to analyze and compare the slaughter results, meet chemical composition and pH value of three beef breeds – Aberdinangus (AA), Hereford (HF) and Limousin (LI) bulls. The bulls were fattened on Latvian and Lithuanian farms, mainly using grass forage. The breed and age of bulls before slaughter significantly affected all slaughter results, except for fat class. From the meat chemical composition traits, the bull breed and age before slaughter had a significant effect only on the protein content. LI bulls showed the highest carcass weight 301.1±6.8 kg (p<0.05), dressing percentage 58.2±1.1% (p<0.05) and conformation score 3.56±0.18 points. The best fattened carcasses were obtained from AA bulls - 2.43±0.20 points. Muscle samples of musculus longissimus (M. longissimus) bulls of LI breed showed higher content of moisture (72.0±1.0%), protein (23.0±0.2%), ash (1.1±0.0%) and cholesterol (56.7±6.6 mg 100 g⁻¹). AA breed bulls showed higher total fat (6.6±1.2%) and iron content (13.1±0.6 mg). The highest pH was observed in the meat obtained from AA bulls – 6.0±0.1, LI and HF breed bulls showed pH 5.8±0.0 and 5.8±0.1 respectively. Correlation analysis showed a significant, strong positive correlation between cold carcass weight and dressing percentage for AA and LI bulls, r=0.90 and r=0.88, respectively. For LI breed bulls, a strong positive correlation was also found between the cold carcass weight and the conformation score (r=0.98, p<0.01).
Показать больше [+] Меньше [-]Impact of Crop Rotation and Soil Tillage on the Severity of Winter Wheat Leaf Blotches
2021
Bankina, Biruta | Bimšteine, Gunita | Arhipova, Irina | Kaņeps, Jānis | Darguža, Madara
Reduced tillage is considered as one of the main tools to save biological diversity; however, it increases pressure of diseases, including wheat leaf blotches. The aim of present study was to clarify the impact of reduced soil tillage on the development of winter wheat leaf blotches in different schemes of crop rotation. The impact of different growing technologies on the severity of winter wheat disease was evaluated in a two-factorial experiment: A – soil tillage system, and B – different combinations of wheat pre-pre-crop and pre-crop (wheat, oilseed rape, barley and faba beans). Diseases were assessed every 10 days approximately and total impact of diseases was evaluated by calculating AUDPC (Area under Diseases Progress Curve). Tan spot, caused by Pyrenophora tritici-repentis was dominated disease over the long period, regardless of meteorological conditions. Development of Septoria leaf blotch was not influenced by neither crop rotation nor soil tillage. The level of tan spot was essentially higher after wheat, regardless of the pre-pre-crop. Reduced soil tillage promoted severity of tan spot. Ploughing mitigated effect of previous crops and differences in tan spot level were insignificant. Despite many positive effects of conservation tillage, increasing of fungicide treatment could be necessary, in conditions, when the tan spot is most devastating and widespread wheat disease.
Показать больше [+] Меньше [-]Impact of High-pressure Impregnation and Fire Protective Coatings on the Reaction to Fire Performance of Birch Plywood
2021
Rudzīte, Sanita | Bukšāns, Edgars
Birch plywood has a wide range of applications for interior and exterior use. The demand for plywood with improved fire protection properties and good visual appearance is increasing year by year. The impregnation at high pressure of the whole plywood panels is one of the options to achieve it. The aim of this study was to develop good visual looking birch plywood product for interior design purposes as well evaluate different influencing factors to reaction to fire properties of fire-retardant treated birch plywood. This study consists of three parts. At the first stage, high pressure industrially impregnated plywood properties were studied by two influencing factors – distribution of fire retardant in plywood panel plane and sanding process influence on reaction to fire performance of product. At the second stage, seven different industrial finishing systems were selected for covering high-pressure impregnated birch plywood and their effect on fire reaction performance was studied. In addition, two surface coating systems were studied on standard birch plywood substrate. At the third stage, intumescent coating consumption effect on reaction to fire performance was studied. The reaction to fire performance of birch plywood was evaluated by performing a flammability test using the Single Burning Item test according to EN 13823:2010. It was found that high pressure impregnation of plywood cannot ensure even saturation of fire retardant throughout the sheet, which significantly affects the fire performance of product. The impact of different finishing materials to reaction to fire performance has been described by the results of this research.
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