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Estimation of forest parameters using the non-parametric techniques and satellite images at compartment level Texte intégral
2010
Jonikavicius, D., Lithuanian Univ. of Agriculture, Akademija, Kauno reg. (Lithuania) | Mozgeris, G., Lithuanian Univ. of Agriculture, Akademija, Kauno reg. (Lithuania)
This paper discusses the use of medium resolution Landsat TM satellite images to support conventional approaches of Lithuanian forest inventory practices. Estimation accuracies achieved using just field measured sample plots, Landsat TM satellite images and two non-parametric k-nearest neighbour and most similar neighbour estimators were studied at a level of compartments. 19 mature forest areas, prepared for final felling with GPS measured borders and all trees callipered, were used for validation. Notably higher estimation accuracies were achieved using field sample plots distributed through the whole forest area studied than just ones located on mature forest stands. The root mean square deviations in estimating compartment-wise volume of growing stock per 1 ha was around 27-28% if the best variant of estimation approach was used. Possible influence of the accuracy in locating the borders of validation areas on the estimations is discussed in the paper, too.
Afficher plus [+] Moins [-]Impact of amelioration system renovation on the growth of mature forest stands Texte intégral
2010
Zalitis, T., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Libiete-Zalite, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Both forestry theory and practice have proved that amelioration favours the growth of forest stands significantly. The growing stock increases even 10 times, if the amelioration system is well-functioning. Joint Stock Company Latvia State Forests that is managing half of forests in Latvia has started renovation of old amelioration systems aiming to improve the productivity of state owned forests in Latvia. In order to evaluate the impact of the renovation of the old amelioration systems, a tree ring width in 7 pine stands, 5 spruce stands and 3 birch stands was analysed. This study shows that the renovation itself has not affected the productivity of mature pine, spruce and birch significantly 3-4 years after the renovation. Authors have come to a conclusion that the reason for that could be too short observation period or particularities of a stand structure and age.
Afficher plus [+] Moins [-]Territorial organisation of game management in Latvia Texte intégral
2010
Baumanis, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ozolins, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The number of the most important game animals of artiodactyla species (moose, red deer, roe deer, wild boar) has been increasing in Latvia during the last 10 years. At the same time, the number of hunting districts where the census of these game animals is taken is also increasing, whereas the average area of the districts is diminishing. The studies show that at present the area of many hunting districts is notably smaller than the individual territory inhabited by these species. This particular study aims at establishing whether there is a relationship between the area of a hunting district on which a census is taken and the number of animals counted, as well as whether the number of animals is really increasing or the increase in the number is attributed to an increase in the census unit number. It was established that in respect of the four species there is a significant correlation between the area of the hunting district and the density of animals in the district. The number of moose and red deer may be assessed more objectively in the districts with an area exceeding 5,000 hectares. The census of roe deer and wild boars is notably influenced by the area of the territory where the census is taken, but the analysis does not explicitly show whether the number of roe deer and wild boars is under-assessed in large districts or over-assessed in the small ones.
Afficher plus [+] Moins [-]Effects of growing location and variety on free tryptophan and mineral nutrient content in wheat Texte intégral
2009
Lundegaardh, B., Swedish Univ. of Agricultural Sciences, Upsala (Sweden). Centre for Sustainable Agriculture | Jastrebova, J., Swedish Univ. of Agricultural Sciences, Upsala (Sweden). Dept. of Food Science | Zhokhov, S., Swedish University of Agricultural Sciences, Upsala (Sweden). Dept. of Chemistry | Maartensson, A., Swedish Univ. of Agricultural Sciences, Upsala (Sweden). Dept. of Soil and Environment | Oeborn, I., Swedish Univ. of Agricultural Sciences, Upsala (Sweden). Dept. of Plant Production Ecology
Tryptophan (Trp) is an essential amino acid for mammals since they cannot synthesise it. Wheat (Triticum aestivum L.) is a major source of dietary Trp, and wheat high in Trp would thus be very beneficial. This study investigated the impact of location and wheat variety on the content of free Trp and mineral nutrients in wheat grain. Four wheat cultivars from national variety tests on wheat with varying protein contents were selected from seven different locations of Sweden representing different climatic zones and soil contents of trace elements. Grain was analysed for Trp content using reversed phase HPLC. Mineral nutrients were analysed using inductively coupled plasma emission spectrometry. Wheat yield and grain content of nutrients and Trp differed significantly between sites. High N content in grain was correlated with a high content of Cu, Fe and S, and also Ca and Mg. However, it was correlated with a low content of K and Na. Trp content was positively correlated with Na and Zn content and negatively correlated with K/Na and K/(Na+Zn) ratio. The varieties differed in Trp content and the two ratios, but there were no significant differences in yields between the varieties at any location. The results indicated salt stress induction of Trp synthesis, which may protect wheat against salt stress and yield losses.
Afficher plus [+] Moins [-]Influence of maize hybrid and harvest time on yield and substrate composition for biogas production Texte intégral
2009
Bartusevics, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Maize is increasingly used for energy production in agricultural biogas plants. The first biogas production project in agriculture is realized in the Research and Study Farm (RSF) Vecauce of the Latvia University of Agriculture in 2008 and animal manure together with plant biomass are planned to be used as substrate. The paper aimed to evaluate ten maize hybrids possibly suitable for biomass production at three different harvesting times. Field trial was carried out in Research and Study farm Vecauce of the Latvia University of Agriculture in 2008. Ten maize hybrids with different maturity rating according FAO numbers (FAO 180 - 270) were harvested at three different times beginning on 5 September at fourteen days intervals. Results showed that harvest time effect on maize yield was substantial (p is less than 0.05), but hybrid influence on the average yield per all harvest dates was not substantial (p is greater than 0.05). The highest organic dry matter yield was obtained harvesting maize on October 3. The Total N, crude ash, protein, fibre, cellulose, lignin, neutral detergent fibre (NDF) and acid detergent fibre (ADF) concentration decreased, but crude fat concentration increased during plant development. Relevance was not noticed between harvest dates and total carbon and hemi - cellulose content. The C : N ration rose from 34.76 at first, early harvest on 5 September to 37.97 at the last harvest on 3 October.
Afficher plus [+] Moins [-]Stability of morphological traits in Latgale's melon lines Texte intégral
2009
Balins, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Alsina, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Lepse, L., Pure Horticultural Research Centre, Tukuma reg. (Latvia)
The investigation was carried out from 2006 to 2008 with the aim of observing the stability of morphological traits in Latgale's melon (Cucumis melo L.) lines in the Tukums region of Latvia. Four lines of Latgale's melons ('8', '14', '5(2)', and '4(3)') were grown in high plastic tunnels: five plants from each line. The following parameters were measured to determine stability of morphological traits in melons: fruit petiole and flower scar diameters (cm), length and wide of melon fruit (cm), and thickness of flesh (cm). Results showed that there was a significant difference in fruit petiole scar diameter between the years 2006 and 2007 for all lines. The melon line '14' was stable in all parameters from 2006 till 2008 except fruit flower scar diameter. The melon line '4(3)' was less stable in all parameters between all melon lines in all years of investigation.
Afficher plus [+] Moins [-]Diversity of non-starter lactic acid bacteria in Latvian semi-hard cheeses Texte intégral
2009
Mikelsone, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ciprovica, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
The most non-starter lactic acid bacteria (NSLAB) isolated from semi-hard cheeses are heterofermentative and handled as one of the reasons of cheese off-flavours and yield defect but at the same time majority of researches argued positive effect of NSLAB on cheese flavour formation and diversification due to rendered compounds of chemical reactions. The amount of NSLAB in cheese varies from 10 at the beginning of ripening to 105 cfu mlE-1 within 6-8 weeks. The aims of this paper were to establish diversity of NSLAB in commercial samples of Krievijas and Holandes cheeses, and to evaluate the effect of ripening temperatures on NSLAB in the trials of Krievijas cheese. A total of 12 commercial cheese samples from seven different Latvian manufacturers and trials from one cheese manufacturer were examined. The trials were ripened for 60 days at different temperatures - 6 deg C and 12 deg C. Serial dilutions of each cheese sample (1:1000 and 1:10 000) in saline were made. NSLAB were cultivated using MRS media. Strain identification was performed by the API 50 CHL system (BioMerieux, Marey l'Etoile, France). In commercial samples of Krievijas cheese dominance of L. curvatus was observed, simultaneously L.plantarum and L.paracasei subsp. paracasei were isolated. Whereas in Holandes cheese samples dominance of L.paracasei subsp. paracasei was noted and L.plantarum, L.curvatus, L.rhamnosus and L.acidophilus were isolated. In the trials ripened at different temperatures prevalence of L.curvatus was noted. Concentration of Lactobacillus spp. varied from 104 cfu mlE-1 on the first day of ripening and reached the highest concentration (106 cfu mlE-1) after 6 weeks of ripening.
Afficher plus [+] Moins [-]Changes in quality of parents stock hens meat during chilled storage Texte intégral
2009
Ramane, K., Latvia Univ. of Agriculture, Jelgava (Latvia) | Galoburda, R., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim was to study changes of chemical composition (fat content, protein content), pH and colour of poultry meat during chilled storage. Various criteria are used for evaluation of bird and carcass quality, while the combination of several indices determines the quality of poultry meat, which has an important role in the following meat processing and quality of end product. Chilled poultry meat is offered in retail and it is used in processing plants for various meat products production. Chemical composition (fat content, protein content), pH and colour are important quality determinants. Hens' meat is cheaper compared to broiler meat; therefore its use in processing is profitable. Parents stock hens of the cross Ross 308 were used for the study. Parent stock hens were fed compound feed. After chilling a hen fillet [musculus pectoralis], hen thighs [musculus biceps] and hen drumsticks [musculus gastrocnemius; musculus fibularis longus] were separated from carcasses. The obtained products were refrigerated at temperature +1+-0.5 deg C. The analyses were performed 1 day after slaughter and on the 5th day of storage. The following parameters were analysed: pH value (3510pH Meter - JENWAY); total protein content (LVS ISO 937:1978); fat content (LVS ISO 1443:1973); colour changes (Color Tec-PCM; software ColorSoft QCW for colour data analysis). The analysed parameters significantly differ in 'white' and 'red' poultry meat, and in various cuts of 'red' meat.
Afficher plus [+] Moins [-]Methodology of dietary fibre determination in grain products Texte intégral
2009
Ozolina, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gramatina, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kunkulberga, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
The dietary fibre is edible parts of plants' carbohydrates that are resistant to digestion in human small intestine. Diets naturally rich in dietary fibre support to prevent constipation, improve gastrointestinal health, glucose tolerance and the insulin response, and reduce the risk of colon cancer, hyperlipidemia, hypertension and other coronary heart disease risk factors. About 45% of the dietary fibre intake comes from grains and grain mixtures. In Latvia, there are neither data, nor investigations of the dietary fibre content in grain products during processing and in the end products in which manufacturers and consumers are interested. The aim of this paper was an approval of dietary fibre determination methodology by using analytical equipment the Full option science system (FOS) Analytical Fibertec E 1023. The dietary fibre determination experiments were carried out in the Research Laboratory of the Department of Food Technology at the Latvia University of Agriculture in 2009. The Total Dietary Fibre (TDF) content was analyzed in the samples of rye whole grain flour, rye whole grain bread, and wheat biscuit. Experiments showed that the fibre content in rye whole grain flour is 13.8 g 100 gE-1, in rye whole grain bread - 11.6 g 100 gE-1, and in the wheat biscuit - 1.9 g 100 gE-1. Reached data are comparable with results of other researchers' data.
Afficher plus [+] Moins [-]Theoretical and economic aspects of the reformed Common Agricultural Policy of European Union Texte intégral
2009
Upite, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Agricultural and food industries constitute a significant part in the economy of European Union (EU), thus providing 15 million jobs and creating 4.4% of the gross domestic product. EU Common Agricultural Policy (CAP) is adopted in all 27 member states and a significant part of budget is allocated to implement it - in 2008 it was 58.8 billion EUR or 44.5% of the total budget. This research performed the analysis of the theoretical, historical and economic aspects of the CAP. Eight main stages of the reform can be distinguished in the CAP development. They have their own characteristics, goals and main support tools. The process of the CAP reform has not been finished yet.
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