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Changes in forest floor and tree vegetation in the level II monitoring plot in Valgunde parish, [Jelgava Municipality, Latvia] 全文
2017
Petaja, G., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lupikis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The objective of the research was to characterize the qualitative and quantitative changes in ground and tree vegetation within 10 years since the beginning of observations at Level II forest monitoring plot in Valgunde. Tree height, diameter, stem volume, radial increment, crown condition and cone yield were determined, as well as crown projective cover of each plant species was estimated. To study bioindication, the average Ellenberg’s and Düll’s indicator values for the monitoring plot were estimated. Species composition in the Level II monitoring plot in Valgunde is typical for Myrtillosa forest type – there is a distinct moss layer, in which Hylocomium splendens and Pleurozium schreberi predominate, and Vaccinium myrtillus is the most common in the herb layer. Shrub layer mainly consists of spruce seedlings, and the tree layer – of Scots pine. Changes in vegetation over 10 years are insignificant. It can be explained with no forest management activities occurring within the observation plot, such as logging or fertilization, and it may take a longer time to observe significant changes. Tree stand indicators correspond to the average in Latvia in Myrtillosa type forests, but the tree volume is higher in Valgunde monitoring plot.
显示更多 [+] 显示较少 [-]Evaluation of productivity and impact on soil of tracked ProSilva F2/2 forwarder in forest thinning 全文
2017
Rozitis, G., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Zimelis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Tracked forwarders is one of the solutions for the forest soils with poor bearing capacity providing ability to use well-known technology for reasonable cost to improve accessibility of forest resources. Tracked forwarders are not common in forest nowadays and only a few models are produced serially. The ProSilva F2/2 is a new middle-class forwarder, whose frontal tracks are replaced with big tires, ensuring large contact surface, increased mobility of the machine and significantly reduced mass without loosing the load capacity (15 tonnes). The aim of the study was to evaluate productivity, soil impact and cost of the roundwood forwarding using the ProSilva F2/2. The study was conducted in Finland. Productivity (time per crane cycle, split into operations and loads), load size, depth of ruts and soil compaction were estimated during the study. According to the study results, the average productivity is 16 m**3 per hour (driving distance to a landing site 200 m, driving speed 2.8 km hE-1, average load 9.7 m**3). The productivity can be significantly increased by more efficient utilization of the load capacity and by using gripper with the tilt function. The length of ruts on peat soil (56 m haE-1) does not exceed the permitted threshold values in Latvia. The compaction of soil took place mainly in topsoil, no changes in soil density were observed in deeper soil layers. The prime cost of forwarding according to the preliminary estimates is 2.5 € mE-3 if the annual production is at least 62000 m**3. Utilization rate is important to keep forwarding cost low.
显示更多 [+] 显示较少 [-]The impact of feed rollers on the quality of timber in the manufacturing of posts 全文
2017
Zimelis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Abele, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of the study was to determine the impact of the harvester cutting head feed roller type on the mechanical damages of processed roundwood timber in post manufacturing. The study presents the comparison of the gentle Moipu plate wheel rollers and conventional feed rollers having bigger spikes (hereinafter named - conventional feed rollers). The total amount of segments processed with the gentle Moipu plate wheel rollers was 2199, whereas the amount of segments processed using the conventional feed rollers was 5308. When processing roundwood with the gentle feed rollers, in the 1st flow 8.2% of timber was rejected as substandard due to defects. The corresponding figure in the 2nd flow was 5.2% of the material in which the damage in the form studs was caused by the feed rollers. When processing the timber with conventional feed rollers, the percentage of the damage – dents caused by these rollers in the 1st flow was 26.7%, in the 2nd flow – 43.7% and in the 3rd flow only 2.7%. Using the method of characteristics proportion comparison, significant differences have been observed between feed rollers (t = 17.8 is greater than t sub(0.05;∞) = 1.96).
显示更多 [+] 显示较少 [-]Quality changes during summer – autumn long term storage of birch (Betula pendula) roundwood 全文
2017
Magaznieks, J., Latvia Univ. of Agriculture, Jelgava (Latvia) | Millers, M., Latvia Univ. of Agriculture, Jelgava (Latvia) | Gžibovska, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
The homogeneous and light wood of birch is suitable for different types of treatment processes and is highly valued for products where visual aspect is important, however, birch assortments are highly susceptible to damages caused by fungi during the storage. Such fungal damages cause discoloration of birch roundwood intended for further woodworking. Sapwood discoloration development and its influencing factors for birch roundwood were analyzed in the summer - autumn period of the year 2016 (August, September and October). Control cut for assessment of sapwood discoloration development was made in four birch roundwood stacks in the districts of Auce and Daugavpils. In order to evaluate the influence of harvesting type, side surface damages, placement in pile, storage duration, diameter, distance from the end plane, daily average temperatures, precipitation amount and relative humidity on development of sapwood discoloration, 616 discs from birch log end planes were prepared. After conducting multiple factor linear regression, it was concluded that a significant development of discoloration and its changes for birch roundwood are promoted by harvesting type, placement in pile, distance from the end plane, daily average temperatures and relative humidity (R2 = 0.450). For birch logs that are prepared by harvester with the daily average air temperature + 6 °C, the first signs of discoloration appear after 17 – 18 days, but on all logs stacked in pile they appear after 68 – 69 days. Whereas, with the daily average temperature of + 18 °C, the first signs of discoloration can occur after only six days, but on all logs stacked in pile they appear after 23 days.
显示更多 [+] 显示较少 [-]Analysis of damaged land changes in Klaipeda County of Lithuania 全文
2017
Ivaviciute, G., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania);Kaunas Forestry and Environmental Engineering Univ. of Applied Sciences (Lithuania);Klaipeda State Univ. of Applied Sciences (Lithuania)
The article presents the analysis of the current situation of the damaged land in Klaipeda County. The study found that the number of affected areas in the county – 266. Because the damaged areas consist of mineral quarries and territories occupied by dumps, the article contains the description and condition of these areas. It was found that mostly sand deposits (60) predominate in Klaipeda County, of which only 8 are used. The smallest number of the deposits – the salt deposits (2). The mainly used deposits in the county are sand and gravel deposits – 29, unused – sand deposits (52). The Klaipeda municipal waste management region comprises 7 municipalities, 39 old landfills and dumps were shut down. At present, 1 regional non-hazardous waste landfill has been arranged. In Klaipeda County, in 2015, damaged land occupied 2,391.06 hectares and amounted to 0.46 percent of the county’s area. During the period between the years 2005 and 2015 the damaged land area in Klaipeda County increased by 130.25 hectares. The analysis of the damaged land by type of ownership showed that the damaged land areas in private land increased by 75.54 hectares or 58.52 percent. In the state land, the damaged land area decreased by 442.35 hectares or 20.04 percent.
显示更多 [+] 显示较少 [-]The effect of vacuum cooking on enteral food made from fresh and semi-finished ingredients 全文
2017
Ozola, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kampuse, S., Latvia Univ. of Agriculture, Jelgava (Latvia)
Enteral feeding also known as enteral nutrition is nutrient delivery into the stomach. Products for enteral nutrition are a specific group of products designed to provide nutrients to the human body in case of various diseases and after surgery, when the daily intake of the product is affected. Today market offers special dietetic products, which are supplemented with synthetic vitamins and minerals, which bioavailability in the body is lower than that of natural organic complexes. Therefore it is important to develop special dietetic products from natural raw materials. The aim of this study was to evaluate the effect of vacuum cooking on the content of bioactive compounds, soluble solids, pH and shelf life of enteral food made from fresh and semi-finished (heated) fruit and vegetable juices. For this research enteral food was made using fresh or semi-finished fruit and vegetable juices. Products were vacuum cooked in 0.02 MPa pressure, with boiling point 67 °C, and 0.06 MPa pressure at 79 °C, withstander for 15 min. All samples were stored at room temperature and tested for their content of vitamin C, total carotenoids, anthocyanins, total phenols and antioxidant activity and microbiological safety, as control untreated enteral food samples were used. The obtained data showed that samples made from semi-finished juices have higher contents of vitamin C and total carotenoids and anthocyanins than samples prepared from fresh juices, but this wasn’t observed with content of total phenols and antiradical scavenging activity (DPPH), where the type of ingredients used for sample preparation had no significant effect.
显示更多 [+] 显示较少 [-]Effect of probiotics and herbals on health and shedding of resistant Escherichia coli in piglets 全文
2017
Galina, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Valdovska, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The purpose of this study was to evaluate the effect of probiotics, herbals and buckwheat bran (Fagopyrum esculentum L.) on growth, profile of blood, gut microbiota, profile of fatty acid in meat and shedding of resistant Escherichia coli (E. coli) in piglets. A total of 44 piglets (Sus scrofa domesticus) from age of day 14 to 56 were divided into 4 groups. Control received basal diet (group C), basal diet + probiotics (group P), basal diet + 3% buckwheat bran (group PB) and basal diet + 1.5% herbals (group H). No effect was observed in growth in all groups. The count of Lactobacillus spp. increased (p is less than 0.05) in jejunum in group P. In the faeces, Enterobacteriaceae decreased in the group P (p is less than 0.05) of 35 days old piglets, but Enterobacteriaceae and E. coli decreased in the group H (p is less than 0.05) of 56 days old piglets. The prevalence of resistance to at least one antibiotic class was 66.7% before and 50% after the experiment in all groups. Multidrug resistance of E. coli was not observed in 14 days old piglets, but was observed in 50% and more in all of study groups of 56 days old piglets. The fatty acid composition of Longissimus thoracis muscle had higher levels of α-linolenic acid and palmitoleic acid (p is less than 0.05), but lower level of stearic acid (p is less than 0.05) in group P. In conclusion, probiotics and herbals improved gut microbiota, fatty acid profile and affected shedding of resistant E. coli, but not growth performance.
显示更多 [+] 显示较少 [-]Clinical symptoms and sex steroid measurements in domestic ferrets (Mustela putorius furo) with Hyperadrenocorticism 全文
2017
Grinblate, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Ilgaza, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Hyperadrenocorticism (excessive adrenal production of sex steroids related to adrenocortical adenomas and carcinomas) is a common disease in neutered male and female pet ferrets (Mustela putorius furo) and causes significant morbidity. Incidence of ferret adrenal disease in Latvia is high because the majority of them are gonadectomized. The most common clinical symptoms include symmetrical alopecia and recurrence of sexual behavior. Sex steroids used to diagnose disease are estradiol, androstenedione and 17α-OH progesterone. It is mentioned that androstenedione is the most sensitive during development of the disease. The aim of this study was to sum up, evaluate and compare clinical findings and blood hormone measurements in ferrets diagnosed with hyperadrenocorticism. Forty two ferrets (n = 20 female, n = 22 male) with various clinical symptoms related to hyperadrenocorticism were included in this research. Clinical examination based on clinical symptom protocol was performed and blood samples were taken in all cases. There is a high correlation between the age of neutering and onset of clinical signs in female ferrets. In both sexes, there is no correlation between clinical signs and levels of sex steroids. In male and female group, symmetrical alopecia, pruritus, scaling and fragility of skin and lethargy are the most common findings. During this research, a ranking system (from 1 to 4) for the severity of alopecia was developed. All ferrets had one or two elevated sex steroid levels. In our research, androstenedione was elevated in 25 cases out of 42. Clinical signs and sex steroid measurements are important in diagnosing hyperadrenocorticism in ferrets.
显示更多 [+] 显示较少 [-]The environmental aspects of energy crops growing in the condition of the Czech Republic 全文
2017
Kopecky, M., University of South Bohemia, Ceske Budejovice (Czech Republic) | Moudry, J. jr., University of South Bohemia, Ceske Budejovice (Czech Republic) | Bernas, J., University of South Bohemia, Ceske Budejovice (Czech Republic) | Suchy, K., University of South Bohemia, Ceske Budejovice (Czech Republic)
Renewable energy resources have been developing very fast due to negative effects and finite reserves of the fossil fuels. Biomass is ranked among the most promising renewable energy resources within the Central Europe. Corn (Zea mays L.) is currently the most widely grown crop in the Czech Republic; nevertheless, the cultivation of corn provokes soil erosion by water. Perennial energy grass called tall wheatgrass (Elymus elongatus subsp. Ponticus cv. Szarvasi-1) is supposed to be a good and environment-friendly alternative to corn. Field trials including these two crops were established in the experimental locality of South Bohemia. Their yield potential was monitored during spring harvest periods (use for combustion). Dry phytomass was fundamentally analysed (N, C, H, S) and higher heating value was determined too. Universal Soil Loss Equation was calculated for both crop species. Corn provided much higher average yield in a three-year interval; corn phytomass reached higher heating value as well. The area of Elymus elongatus should enlarge considerably, if we wanted to get the identical amount of energy from corn and Elymus elongatus. However, we found that, compared to Zea mays L., water erosion theoretical land losses would be several times less serious for Elymus elongatus.
显示更多 [+] 显示较少 [-]The incidence of wheat crown rot depending on agronomic practices 全文
2017
Paulovska, L., Latvia Univ. of Agriculture, Jelgava (Latvia);Agroķīmija, Saldus SIA, Birzītes, Saldus parish, Saldus Municipality (Latvia) | Bankina, B., Latvia Univ. of Agriculture, Jelgava (Latvia) | Roga, A., Latvian Biomedical Research and Study Centre, Riga (Latvia) | Fridmanis, D., Latvian Biomedical Research and Study Centre, Riga (Latvia)
Wheat crown rot is a harmful disease that can be caused by different pathogens. The control of this disease is complicated because of the diversity of pathogens and an insufficient efficacy of fungicides; therefore, the agronomic practices of wheat production are an important tool for reducing the disease development. The aim of this study was to estimate the incidence of wheat crown rot depending on soil tillage system and on the pre-crop of wheat in the year 2016. The field experiment was carried out at the Research and Study farm ‘Peterlauki’ of the Latvia University of Agriculture in the autumn of 2008. The data obtained in 2016 are analysed in this study: A – soil tillage system: 1 – traditional soil tillage with ploughing at the depth of 22 – 24 cm, 2 – reduced soil tillage with disc harrowing up to the depth of 10 cm; B – pre-crop of winter wheat: 1 – wheat, 2 – oilseed rape, 3 – faba beans. The incidence of crown rot was not influenced by soil tillage system, but the impact of pre-crop was significant (p = 0.006). The level of disease was essentially higher in continuous wheat sowings. The experiments showed that the main causal agents of the disease were Fusarium spp. and Oculimacula spp. The spectrum of pathogens was not dependent on a particular agronomic practice.
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