خيارات البحث
النتائج 581 - 590 من 2,106
Research on formation of composed wood based biofuel النص الكامل
2011
Kurdjukovs, V., Latvia Univ. of Agriculture, Jelgava (Latvia)
Due to currently aggravating problems of global warming, more and more alternatives are being developed using a mixture of different fuels. The rapid development of science and engineering solutions can be the most efficient burning of the local biofuels to a minimum harmful substances from combustion process - including the CO2 emitted into the atmosphere. The research concerns fuel problem of choice between cost-effective, but environmentally harmful fuels. Research data will help further studies on the fuel in order to increase energy efficiency and rational use. The research was done in 2010, in Riga Technical University laboratories. An aspen wood and hard coal was used to create this fuel mixture. During the research, sampling, grinding, sifting and blending of different proportions, moisture and calorific value determination were carried out. It was determined that the calorific value of the mixture would increase linearly, exactly in the proportion of coal quantities added.
اظهر المزيد [+] اقل [-]Integration effect on Baltic States' dairy sector export performance النص الكامل
2011
Ozolins, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
Baltic States’ dairy sectors are important to their economies. All Baltic States have had substantial current account deficits that exceeded acceptable thresholds until the year 2009. The States are dairy product exporters. Export capability largely depends on international competitive position of dairy processing companies. Several factors, inter alia, company size determine the position. Largest companies have been formed by horizontal integration. At Baltic scale dairy processing is still fragmented. The aim of this paper is to evaluate economic effect aspects of integration related to exports in the Baltic States’ dairy sector secondary level. As the subject has not been explored earlier at company level, the author researched data of 188 annual reports of 53 Baltic dairy processing companies over the period 2003 to 2009. Descriptive statistics, time series analysis and regression analysis methods were primarily used. The author establishes that among dairy companies which generate significant exports turnover two-thirds are horizontally integrated and include all largest dairy processing firms in the Baltic States. A few smaller firms have succeeded in exporting due to suitable channel management. Among a large group of companies that generate less than 1% turnover from exports, 77% are non-integrated and all are small. Using regression analysis the author estimates that 1% increase in net turnover in the exporting dairy company group is expected to create 0.93 – 0.94% increase in net turnover from exports. Policies promoting mergers of some companies may thus lead to increased dairy exports, higher milk production and fuller realisation of economic potential of the sector.
اظهر المزيد [+] اقل [-]The method of landscape identity assessment النص الكامل
2011
Nitavska, N., Latvia Univ. of Agriculture, Jelgava (Latvia)
The theme of landscape identity becomes actualized beside with the impact of globalization. Landscape identity is closely linked to the Latvian national identity. The concept of identity is multifaceted and touches on a number of scientific areas that currently in Latvia are actively investigating this phenomenon. Landscape investigators admit the multidisciplinary structure of the concept of identity, including in their researches the investigations of historical, visual and associative aspects. Landscape identity is related to detection, identification and definition of landscape elements, because landscape elements are the key to the perception of identity. The method of landscape identity assessment is based on three stages: the assessment of the historic, visual and cognitive elements in formation of landscape identity. The assessment of historic elements in formation of landscape identity is associated with the investigation of historic materials and description of structural elements according to the stages of development. The assessment of visual structural elements of landscape identity is based on the material collected during the field work by filling in the landscape assessment matrix. The assessment of cognitive structural elements of landscape identity is based on the opinion survey, which makes it possible to find out the concealed associative identity. The information obtained in all stages of landscape identity assessment forms the landscape identity model. The aim of the research is to develop the method of landscape identity assessment. The research was carried out at Latvia University of Agriculture in 2010.
اظهر المزيد [+] اقل [-]The meaning of historical parks in the settlement landscape ecology النص الكامل
2011
Dreija, K., Latvia Univ. of Agriculture, Jelgava (Latvia)
The research was accomplished within the framework of the doctoral thesis, with the aim to clarify the role of Latvian Manor Park in the settlement landscape ecology. Significance of the Latvian Historical Park in the settlement landscape ecological processes in Kuldiga district was discussed and analyzed. To achieve set objective of the research, there was developed the landscape ecology assessment methodology of the settlements in the influence of the historical parks based on generalized scientific cognitions and researches in the landscape ecology, and scientific researches of the population loads and historical park value. The developed method was applied by surveying the selected historical parks in the settlement, and by assessing biodiversity factors, urbanization load, and landscape ecological networking compatibility degree. As a result, the selected settlements of historical parks were marked in the district of Kuldiga in the landscape ecological map, highlighting the importance of both national and European level. The results indicate significance of the historical parks in the settlement landscape ecology and that the role of historical parks in the settlement landscape ecology is essential, which ensures the natural basic resources air, water and soil quality. In the settlements, the historical parks existence is high value and quality environmental guarantee, which would have been managed according to the proposed principles of landscape ecology science.
اظهر المزيد [+] اقل [-]Philosophic methodological bases for evaluation of educator's competitiveness النص الكامل
2011
Katane, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Since the change of the paradigms of competitiveness is taking place now, the concept ‘competitiveness’ also changes its semantic meaning. In the article the concept ‘educator’s competitiveness’ is analyzed and scientifically substantiated according to different views. The aim of the article is to present the results of theoretical research, performed by author for several years in the field of concurentology, actualizing the new meaning of the concept ‘educator’s competitiveness’ in the pedagogy science and education, and proposing an insight into the substantiation of the philosophic methodological basis for the evaluation of educator’s competitiveness. In the article, the author applies the concept ‘educator’ according to its broader meaning. The research shows that there exists: 1) diversity in relation to the definitions and explanations of the competitiveness of an educator as a specialist; 2) three methodological approaches in the research of competitiveness: a biometric, a functional and a structural approach. According to the author’s opinion, the structural approach would be the most appropriate for the development of the evaluation methodology, including the system of evaluation indicators, in relation to the components of an educator’s competitiveness structure.
اظهر المزيد [+] اقل [-]Winter oilseed rape (Brassica napus L.) autumn growth النص الكامل
2011
Balodis, O., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Lack of data about effect of meteorological conditions, sowing date, sowing rate, fungicide as growth regulator application and other agroecological factors on rape autumn growth is observed in Latvia. The aim of our research, started in autumn 2007 and continued up to autumn 2010 in Research and Study farm ''Vecauce'', was to investigate the influence of agroecological factors (sowing date, sowing rate and fungicide (as growth regulator in autumn)) application as well as meteorological conditions on autumn plant growth of two types of winter rape varieties. Winter rape biometrical parameters were estimated, and meteorological parameters (hydrothermal coefficient (HTC) and growing degree days (GDD)) were calculated. Four year results showed that winter oilseed rape seed germination was affected by precipitation and air temperature around the sowing time. Calculated GDD correlated with plant biometrical parameters during trial years. HTC showed moisture effect on rape emergence time. Sowing date was important factor which had strong and significant impact on biometrical parameters of rape plants in autumn. Earlier sowing date increased height of growth point, root neck diameter, plant and root mass, and main root length significantly for both cultivars in four trial years. Such agro-ecological factor as sowing rate (plant density) affected plant biometrical parameters only in some trial years. Plant weight was significantly influenced by sowing rate for both cultivars if sowing rates were equal. Other important parameter - height of growth point - was not significantly influenced by sowing rate for both cultivars when similar sowing rates were used in all years; exception was year 2009 for 'Californium'.
اظهر المزيد [+] اقل [-]Identification and control of rape stem weevil Ceutorhynchus spp. in winter oilseed rape in Latvia النص الكامل
2011
Grantina, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Apenite, I., Latvian Plant Protection Research Centre, Riga (Latvia) | Turka, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Research on identification of Ceutorhynchus spp. on winter oilseed rape in Latvia was done during the vegetation season of 2009 and 2010. Field trials were located in the Research and Study Farm ''Peterlauki'', Jelgava municipality, Latvia (56 deg 32 min 17.38N, 23 deg 43 min 17.65E). Four species of brassica stem weevils were identified: cabbage stem weevil Ceutorhynchuspallidactylus Marsh., syn. C. quadridens Pan., rape winter stem weevil C. picitarsis Gyll., blue stem weevil C. sulcicollis Pay., and C. typhae Herb. One of the most common species in winter oilseed rape was cabbage stem weevil C. pallidactylus. Use of a sweep net for identification of particular species cannot be applied, as in practice no specimens have been collected by this method. One of the most appropriate methods for identification of Ceutorhynchus spp. on winter oilseed rape has been yellow sticky traps and water traps that have been used to collect the greatest number of specimens (24) during the vegetation season. First pests appear during the 2nd decade of April, when the plant reaches 33 BBCH. Pest control using systemic insecticide Proteus 110 OD (tiakloprid 100 g LE-1, deltametrin 10 g LE-1) with a dose of 0.75 L haE-1 was applied when the plant reached 39-44 BBHC. Despite the high population density (2 to 10 insects on 40 plants), significant (p is less than 0.05) decrease in pest damage by 43-51%, when compared to untreated area, was recorded during vegetation seasons of 2009 and 2010. Pest control with a systemic insecticide when the plant is in the stem elongation phase provided a significant (p is less than 0.05) yield increase of 0.5 to 0.7 thaE-1.
اظهر المزيد [+] اقل [-]Influence of warmth conditions characterizing parameters on yield and chemical composition of maize in Latvia النص الكامل
2011
Bartusevics, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Maize yield and quality are affected by many factors, including production practices, diseases, pests, and differences in the climate. Usually it is not possible to do much to change the effect of temperature, but it is important to grow better adapted or characterized with right maturity rating hybrids. The paper is aimed to determine the impact of accumulated growing degree days (GDD) on maize development, organic dry matter yield, ODM and chemical composition of maize hybrids. A field trial was carried out in the Research and Study farm ’’Vecauce’’ of the Latvia University of Agriculture (LLU) from 2008 till 2010. Ten (in 2008), eleven (in 2009) and fifteen (2010) maize hybrids with different maturity ratings according to FAO numbers (FAO 180-340) were harvested at three different times beginning on 5 September at fourteen-day intervals. GDD were calculated when maize reached a certain growth stage (full emergence, first tassels, full tassels, first ears, full ears, specific harvest date) to characterize conditions for maize growing in a specific year. Composition of fresh maize was analyzed for all hybrids using standard methods. Results were statistically processed using methods of correlation and regression analysis. Our results presented evidence that ODM yield in 2008 and 2009 on last harvest dates was lower than that on the first harvest date in 2010. Organic dry matter yield was higher in years when more GDD were accumulated. Results also showed that GDD negatively correlated with the total N, protein, fibre cellulose, hemi-cellulose, NDF, and ADF concentration.
اظهر المزيد [+] اقل [-]Influence of rootstock on wintering and health status of plum cultivar 'Victoria' النص الكامل
2011
Dekena, D., Pure Horticultural Research Centre, Tukuma reg. (Latvia);Latvia Univ. of Agriculture, Jelgava (Latvia) | Alsina, I., Pure Horticultural Research Centre, Tukuma reg. (Latvia);
The choice of rootstock is the main precondition for establishing of high yielding and sustainable plum orchards. Therefore influence of rootstock on the plum cultivars wintering in Latvia climatic conditions becomes more and more actual. Investigation was carried out with the aim to clarify influence of rootstock on the wintering and health status of plum cultivar 'Victoria'. Investigation was carried out at Pure Horticultural Research Centre during two different wintering seasons of 2008/2009 and 2009/2010, in the orchard planted in 2001. The winter of 2008/2009 was characteristic with sharp temperature fluctuations, but winter of 2009/2010 was snowy with stable low temperatures. Sixteen widely used rootstocks known in Europe were included. Plum general tree health status (scored by 1-5 points) and percentage of dead trees were evaluated. No statistically significant differences among rootstocks were established according to the evaluation of tree health status. Differences in wintering ability among rootstocks were stated between two years of investigation. Trees grafted on Brompton seedlings and St. Julien d' Orleans demonstrated the highest winter hardiness (4.3 points). No one dead tree was registered on these two rootstocks. Rootstock GF8/1 was the least suitable for Pure conditions - with general health status scored at 2.3 points after severe winter of 2009/2010, and only 25% of alive trees.
اظهر المزيد [+] اقل [-]Potassium removal with grass in an apple orchard under influence of mulch and irrigation النص الكامل
2011
Surikova, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklins, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Potassium (K) is one of the most important nutrients necessary for many life functions of plants, like shoot growth, fruit and flower bud set, and fruit size. The aim of this study was to determine the content of potassium in orchard lawn for reduction of potassium fertilizer application and to include the potassium from mown grass into K balance and turnover calculation. The investigation was done at the Latvia State Institute of Fruit-Growing in Dobele in 2009, on the basis of an established field experiment planted in 1997 with apple (Mains domestica Borh.) cultivar 'Melba' (rootstock B9), trees spaced at 1.5 x 4 m distances. Three different treatments of soil moisture management were compared: control, sawdust mulch, and fertigation. Soil of the experimental plot was Pisocalcic Cutanic Luvisol (Hypereutric, Hyposkeletic); loam. Organic matter - 25 g kgE-1, soil reaction pH - 6.5. Plant-available P was 130.9, K - 157.7, and Mg - 102.2 mg kgE-1. Inter-row strips were covered with grass vegetation (Lolium perenne L. and Poa pratensis L.). Grass samples were collected during cutting, 3 times per season of 2009: May 19, June 20, and August 11. The uptake and removal of potassium was calculated as kilograms per hectare area. The concentration of potassium in the lawn and the height of grass growth were significantly influenced by the mowing time and the soil moisture treatment. These results can be a base for further studies of potassium turnover in an orchard, as well as for fertilizer planning and management.
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