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Abiotic risks of managing young forest stands of Norway spruce (Picea abies (L.) Karst.) Texte intégral
2013
Ruba, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Miezite, O., Latvia Univ. of Agriculture, Jelgava (Latvia) | Baltmanis, R., Latvia Univ. of Agriculture, Jelgava (Latvia) | Luguza, S., Latvia Univ. of Agriculture, Jelgava (Latvia)
According to the forecast, in future the number of storms in Latvia is going to increase. The wind and the snow are risk factors influencing damages of forests; the least tolerant species against wind damages is Picea abies (L.) Karst. It is impossible to avoid the damages caused by weather conditions – windbreaks, windthrows, snowbreaks, snow crushes and snowthrows in forests, since they reoccur in certain periods of time. The aim of the research was to analyze the impact of abiotic risk factors on the management of young Picea abies (L.) Karst. stands. Young stands of Norway spruce were researched in all regions of Latvia in 2011 and 2012. These stands were up to 40 years old. In total, 75 stands were measured and surveyed, and 257 sample plots were arranged, where the following damages were identified: frost damages, snow crushes, snowbreaks, snowthrows, windfall and windthrows. The sample plot method was used. The intensity of damages is higher on drained soils. The linear correlation between occurrence and intensity of impact damages caused by abiotic factors was significant (r = 0.988 is greater than r0.05 = 0.253). There is no significant (p = 0.686 is greater than α = 0.05) difference between the intensity of impact damages caused by abiotic risk factors in the stands with regular and irregular shapes of forest compartments. Irregular form forest plots have formed naturally, occurrence of abiotic factors there is 7.5% but the factor intensity – 6.7% and that is higher than in regular forest plots where abovementioned parameters reach 4.7% and 2.9%.
Afficher plus [+] Moins [-]Comparison of different electronic devices for detecting heterobasidion root rot Texte intégral
2013
Gruduls, K., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Donis, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Gaitnieks, T., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Root rot caused by Heterobasidion spp. is one of the most important pathogens in Norway spruce (Picea abies (L.) Karst.) stands in Latvia. It is estimated that in Latvia on average 22.9% of Norway spruce stumps are infected with Heterobasidion spp. The aim of this study was to compare four different electronic devices for Heterobasidion root rot detection in Norway spruce. In the autumn of 2009, in a sample plot located in the forests of Kalsnava district 27 trees were used to compare the possibility of instruments to detect root rot. The results show that IML-RESI F400 accuracy for detecting root rot in Norway spruce is high and the instrument is usable for detecting root rot, but additional accumulators are needed for large sample plots. Rotfinder’s accuracy for detecting root rot varies from probe to probe taken from one tree. Conditiometer AS-1 and Arbo-Sonic decay detector show slightly higher average values for infected trees, but the difference for both instruments between healthy and decayed trees is not significant, thus leaving the usage of instruments questionable.
Afficher plus [+] Moins [-]Linear regression analysis of indices describing Latvian wood processing industry Texte intégral
2013
Krumins, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Smits, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dagis, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Dubrovskis, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Arhipova, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
To forecast how different indices describing Latvian forest industry will develop in the future, the decision support program which is based on the research of supply chains and production processes as well as on systematic analysis of the whole industry should be developed. One of the most common types of analysis is modelling of processes. In this paper processes of forestry and wood processing in Latvia are modelled by using general approach for system modelling, and each process is described as an abstract system where only its input and output values were identified. Correlations of input and output value time series with a simple and multiple regression analysis method were analyzed. Regression analysis was created for 77 pairs of indices which theoretically could have significant correlations. Input and output factor linear regression analysis for set of processes Forestry and Wood processing shows that not always there is significant correlation between time series of chosen model factors. Some of correlations between time series of input and output data in the model of forest sector even showed controversial results. The amount of information about processes and their quantitative indicators in Latvian wood processing industry is not sufficient for development of precise simulation models. There is need to develop a list of criteria for missing information and carry out its collection process.
Afficher plus [+] Moins [-]The design guideline for therapeutic sensory gardens Texte intégral
2013
Balode, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
The research topic is sensory, healing, rehabilitation and horticultural gardens, and the related discourses. The first part of the paper describes the historic development of the rehabilitation and health gardens in Latvia. Then he research paper takes a look at the main aspects which dominate in the rehabilitation and sensory visual and functional garden sites in the world. The quest to create contemporary landscape sites for health reasons is still one of the main subjects to explore and find definitions for. The methodology used in this paper is descriptive, from the perspective of historical relaxation gardens and health sites. The aim of this research is to define the main development lines of health sites in Latvia, trying to answer such questions as: How we can start developing sensory gardens and what is needed for their development in the future? To achieve the goal, it is necessary to absorb the world experience and exchange best practices, find innovative solutions, and adapt advanced rehabilitation center area landscapes to individual needs. When creating the healing gardens, the aesthetic and functional criteria have to be applied. Depending on the availability of the natural environment, health and satisfaction will be enhanced.
Afficher plus [+] Moins [-]A study on possibilities of electronic document circulation in public sector for rural development Texte intégral
2013
Leikums, T., Latvia Univ. of Agriculture, Jelgava (Latvia)
Electronic circulation of documents and electronic services have become the most significant IT development trend in the public sector. During the last few years public sector institutions in all Europe have significantly improved the quality of the provided services. With the evolving options offered by the internet and the digital signature getting more widely used, citizens expect a more up-to-date approach to communications from governmental institutions. Successful operation of electronic services would not be possible without a proper circulation of electronic documents on the national level. This article briefly inspects the history of the electronic service development and analyses the conditions of the development, deals with the experience of different countries with the implementation of e-services. Particular attention has been paid to Latvia, its current situation and historical analysis of e-services. A special part is dedicated to Agricultural Ministry of the Republic of Latvia which is most closely related to national rural development, projects of transition towards electronic document circulation and provision of electronic services.
Afficher plus [+] Moins [-]Career-related possible selves of rural adolescents Texte intégral
2013
Pavulens, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
The first independent career related decisions are made during the ninth grade of the elementary school when the further educational institution is selected. The concept of possible selves can be used in career education to help students increase self-awareness, explore and generate options, and formulate plans to achieve future goals. The aim of the article is to examine rural adolescents’ ability to generate career-related possible selves and plausible strategies to attain these possible selves. On the basis of the Possible Selves Theory, the open-ended measure was developed by the author. The pilot research was carried out in Latvia in January 2013. Forty six nine-graders from two rural elementary schools and two rural secondary schools participated in the research. Next year and adult possible selves generated by rural adolescents include such domains as education, employment, leisure activities, physical and personal development, as well as interpersonal relationships and lifestyle. The most important ones are domains of education and employment. Statistically significant differences of the results among the gender subgroups are not found in the research, statistically significant differences exist between the possible selves and their attaining strategies generated by rural secondary school students and rural elementary school students.
Afficher plus [+] Moins [-]Evaluation of yield and grain quality of oat cultivars Texte intégral
2013
Brunava, L., Latvia Univ. of Agriculture, Jelgava (Latvia);State Stende Cereals Breeding Inst., „Dižzemes”, Dižstende, Lībagi parish, Talsi municipality (Latvia) | Alsina, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
Oat breeders have improved yielding ability potential of oat (Avena sativa L.) cultivars, but set lower standards for biochemical composition of grain. Nowadays the quality of grain for consumers has become important especially in terms of lipids and β-glucan content. Experiments were carried out at State Stende Cereal Breading Institute in the year 2012 to evaluate the oats yield and grain quality. 15 different cultivars of Stende collection were compared by yield and parameters of productivity (test weight and 1000 kernel weight) as well as biochemical parameters (protein, starch, lipid, β-glucan, content). Biochemical parameters were tested by Infratec Analyser 1241. To obtain an equal research background all cultivars were grown in a plant breeding crop rotation field, with similar growing conditions (sowing-time, fertilizer, plant protection activities), which agree with generally accepted technology of oat cultivation in Latvia. Experiments were done in four replications. Plots were laid randomized. ANOVA procedures were used for data analysis. Yield of experimental cultivars varied between 4.28 ± 0.19 - 5.93 ± 0.22 t haE-1, test weight 46.85 ± 0.99 - 52.75 ± 0.44 kg hLE-1, 1000 kernel weight 33.70 ± 0.24 - 46.34 ± 0.80 g. Significant differences of tested yield parameters among oat cultivars were observed. The highest protein content was observed for local breed cultivars ‘Arta’ and ‘Mara’ 119.5 ± 02.6 and 110.5 ± 1.9 g kgE-1 accordingly. Low starch content, but high β-glucan content is characteristic for all Latvian cultivars.
Afficher plus [+] Moins [-]Influence of organic product extracts on the potato yield and quality in the conventional growing system Texte intégral
2013
Vojevoda, L., Latvia Univ. of Agriculture, Jelgava (Latvia);State Stende Cereals Breeding Inst., „Dižzemes”, Dižstende, Lībagi parish, Talsi municipality (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Agricultural farms in modern production system are specialized; therefore, animal-origin organic fertilizers are not available for many of them. Researches on the use of organic products in agriculture to restrict the use of pesticides and mineral fertilizers have been performed for a long time. Nowadays different organic preparations that are acquired as a result of complex processes are produced, ensuring ready-to-use biologically active substances in them and also activating their properties. One of the purposes of the research was to evaluate the impact of extracts from organic products on the potato (Solanum tuberosum) yield and tuber quality in the conventional cultivation system. A field experiment using cultivars ‘Borodyansky Rozovij’ (early maturity) and ‘Lenora’ (mid-early maturity) was arranged in the State Stende Cereals Breeding Institute in 2011 and 2012. Peat elixir and vermicompost extract obtained at different temperatures: + 45 °C and + 95 °C, as well as a mixture of these extracts were used for treatment of tubers and plants. The research included 24 treatments in total, including control (without treatment) and a standard potato cultivation technology. Tubers were treated immediately before planting, but plants were treated three times during the vegetation period. Average two-year research results showed that the use of organic product extracts significantly (p is less than 0.05) affected the tuber yield in different treatments for both cultivars ‘Borodyansky Rozovij’ and ‘Lenora’. The content of nitrates in tubers, using extracts, did not exceed the allowable level (160 mg kgE-1) in any of treatments.
Afficher plus [+] Moins [-]Influence of sowing type, time and seeding rates on the buckwheat (Fagopyrum esculentum) yield quality Texte intégral
2013
Vilcans, M., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian Plant Protection Research Centre, Riga (Latvia) | Gaile, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
In the last years total area of buckwheat (Fagopyrum esculentum) has increased notably in Latvia, including the Eastern part of the country but there is a lack of actual information about buckwheat growing, best terms of sowing and seeding rates. This study presents the influence of different sowing times, methods and rates on the seed quality of buckwheat yield – (TGW) thousand grain (nutlet) weight and (HLV) bulk density. A field experiment was conducted on the farm “Arāji”, Krāslava region in 2010 and 2012. Buckwheat was sown on six different dates - 15.05, 25.05, 30.05, 05.06, 10.06 and 15. 06. Two types of sowing were used – drill sowing, where 4 seed rates were used - 200, 300, 400, 500 fertile nutlets per m2 , and the column sowing with the three seed rates - 150, 250, 300 fertile nutlets per square m. It was found out that crop sowing time and type significantly affected buckwheat yield quality. Compensation mechanisms of yield in early terms of sowing when lower seeding rates were used were expressed less than that in later sowing terms. It could be concluded, that in early terms different seeding rates could be used with equal success. In later terms of sowing, smaller seeding rates are more appropriate. After two year investigation the most suitable sowing terms were around 4th and 9th June, where TGW and HLW was the highest. The most inappropriate terms were around 25th and 30th May, because meteorological conditions after sowing in both years were unfavorable that resulted in 0.5 to 1.0 t haE-1 lower yields.
Afficher plus [+] Moins [-]Impact of nitrogen fertilizer rates on industrial hemp growth and development Texte intégral
2013
Sausserde, R., Latvia Univ. of Agriculture, Jelgava (Latvia) | Adamovics, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
TThe aim of this study was to evaluate an impact of nitrogen fertilizer rates on industrial hemp’s (Cannabis sativa L.) growth and development in Latvia. The trial was carried out during 2012 on the Research and Study farm Peterlauki of the Latvia University of Agriculture in the sod calcareous soil. There were three industrial hemp cultivars ‘Futura 75’, ‘Tygra’ and ‘Felina 32’ tested under different fertilizer rates: N0P0K0 – control, N0P80K112 – background fertilizer (in text marked as F), F+N30, F+N60, F+N90, F+N120, F+N150, F+N180 kg haE-1. Weather conditions were proper for good hemp biomass production. Depending on the selected cultivars, the optimal fertilizer rate was in the range of 90 – 150 kg ha-1. Industrial hemp stalk length was significantly (p is less than 0.05) influenced by the applied nitrogen fertilizer rate and cultivars. The highest stalk length was observed in the cultivar ‘Futura 75’ under all nitrogen fertilizer rates. The highest stalk length (3.18 m) had reached under the nitrogen fertilizer rate 150 kg haE-1 at 138 growing day from sowing. At the beginning of growing season (June - July) the growth intensity of hemp stalk length is high. Within one month the stalk length grew up for 1.23 meters of cultivar ‘Futura 75’. The intensive growth of hemp stalk declines when the flowering stage is reached. Flowering stage occurred in early August, and it was dependent on nitrogen fertilizer rate. Under higher nitrogen fertilizer rate the flowering stage reached later.
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