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Growth performance of Woyto-Guji and Central Highland goat breeds under traditional management system in Ethiopia
2016
Zergaw, N. | Dessie, Tadelle | Kebede, K.
The study was conducted to evaluate the productive and reproductive performance of Central Highland and Woyto-Guji goat breeds in Meta-Robi and Konso districts, respectively. A total of 240 farmers were interviewed using semi-structured questionnaires to describe kidding pattern, kidding interval, weaning age and milk production. On-farm performance traits were recorded on 730 goats of 157 households. In Konso, majority of kidding occurred in May, whereas in Meta-Robi it was in September. There was a difference in the average kidding interval and age at weaning between the breeds. Kids birth weight (2.03 Vs. 2.68kg) and does postpartum weight (26.6 Vs. 28.2kg) were lower in Woyto-Guji goats than in Central Highland goats. Average 90 day kids' weight and average daily weight gain between birth and 90 days were not different among the breeds. Average 180 day weight (15.7 Vs. 11.5kg) and average daily weight gain between 91 and 180 days (65.4 Vs. 31.9 g/day) were better in Central Highland goats than in Woyto-Guji goats.
显示更多 [+] 显示较少 [-]Genetic diversity of some Ghanaian pigs based on microsatellite markers
2016
Ayizanga, R.A. | Kayang, B.B. | Adomako, K. | Adenyo, C. | Inoue-Murayama, M. | Asamoah, L.
A knowledge of the level of genetic diversity is very important in ensuring the sustainable utilisation of animal genetic resources. To this end, the genetic diversity of some local pigswas assessed by genotyping 86 unrelated pigs in four regions of Ghana namely Northern (Tingoli = 9), Upper West (Papu = 31 and Babile = 32) and Upper East (Gia = 14) using 12 microsatellite markers.The number of alleles (Na), number of effective alleles (Ne), observed heterozygosity (Ho), expected heterozygosity (He) and inbreeding coefficient (FIS) were used to assess the level of genetic differentiation among the five populations in this study. All loci studied were polymorphic and the mean number of alleles ranged from 4.58 (Yorkshire) to 10.58 (Papu) with an overall average of 7.65 alleles. At all the 12 loci studied, inbreeding coefficient (FIS) deviated significantly from zero with a mean of 0.32. When the Nei’s standard genetic distance based on the proportions of shared alleles was used to construct a neighbour joining tree, pigs from the different communities sampled in the Upper West region emerged with the highest bootstrap value of 90%. Generally, the sampled pigs represent distinct populations with a moderate amount (12%) of genetic differentiation but considerable amount of inbreeding (29%) has taken place within these populations over the years. This is the first report of the genetic diversity of Ghanaian local pigs using microsatellite markers.
显示更多 [+] 显示较少 [-]Tree damages by icing in Scots pine (Pinus sylvestris L.) stands and factors affecting them
2016
Baders, E., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Adamovics, Andis, Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Purins, M., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Dzerina, B., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Icing notably increases the mass of a tree crown, causing damage to the tree. So far, a very limited number of studies have assessed the icing influence on coniferous trees, none of them in Latvia. The aim of the study was to assess the influence of tree parameters and recent thinning on the proportion of damaged trees and the type of damage in Scots pine stands. The study sites were located in the eastern part of Latvia, damaged in December 2012. In total, 98 pine dominated stands of different age were selected randomly. Eight (mean) plots per stand were established; in each plot, all trees larger than 2.1 cm were measured and the type of damage assessed. The above-ground biomass from 12 randomly selected stands (57 dominant trees) of different age was weighted with and without icing. The biomass of pine with icing exceeded that without 1.5 ± 0.27 times. The mean proportion of damaged trees in pine dominated stands was 26%; the proportion of broken trees peaked in the middle-aged stands (41 – 70 years old), but the largest proportion of pooled bent and uprooted trees was found in the young (11 – 20 years old) stands. The proportion of damaged dominant trees was affected by the slenderness coefficient – a higher proportion of such trees was found among more slender trees. The results suggest that the risk of icing damage could be reduced by silvicultural measures boosting individual tree stability.
显示更多 [+] 显示较少 [-]Growth of Fagus sylvatica in young mixed stand: case study in central Latvia
2016
Purina, L., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Adamovics, Andis, Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Katrevics, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Katrevica, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Dzerina, B., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Climatic changes are shifting the potential tree distribution limits of many tree species northwards. One of such species is Fagus sylvatica, currently represented in Latvia only by a few stands. In order to increase knowledge on its potential use in the forest management, the aim of our study was to characterize the growth of beech in a young stand in the central part of Latvia. The stand of beech and spruce, mixed in rows with an initial spacing of 2.5 x 2.5 m in Oxalidosa forest type was assessed. Survival of European beech in clear cutting was similar to that observed for the native Norway spruce (73% and 79%, respectively), but both height and diameter were notably and significantly superior for wildlings at the mean age of 15 ± 2 years, reaching on average 7.4 ± 0.30 m and 8.9 ± 0.69 cm, respectively. Increasing ring width with increasing tree age for both tree species was observed until the last four years, when large and increasing superiority of beech over spruce, coinciding with reduction of ring width of spruce, was noted. It was most likely caused by intensified competition due to very wide crowns formed by young beech trees in the plantation with wide spacing: average crown radius reached 2.4 ± 0.16 m, for few trees exceeding even 4 m.
显示更多 [+] 显示较少 [-]Genetic differences in needle cast damage of Scots pine (Pinus sylvestris L.)
2016
Polmanis, K., Latvian State Forest Research Inst. Silava, Salaspils (Latvia);Latvia Univ. of Agriculture, Jelgava (Latvia) | Klavina, D., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Gaitnieks, T., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Baumanis, I., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The impact of climatic and genetic factors on needle cast damage, as well as relationship between the degree of damage and survival and growth of trees was evaluated in the study. The analysis was done in two series of experiments, both established in two locations in Latvia (central and eastern part). Needle cast damage (in 5 grade scale) as well as the height and height increment, diameter of root collar and survival of trees were assessed. Results suggest that the degree of needle cast damage was influenced by the genetic, as well as climatic factors, and also their interaction. The average degree of needle cast damage in experiment of open-pollinated families was 4.7 ± 0.01 in central and 4.6 ± 0.03 in eastern Latvia; in the experiment of control-crossed families it was 4.6 ± 0.02 in central and 3.4 ± 0.04 in eastern Latvia. The impact of genetics on the needle cast damage degree was statistically significant (p is less than 0.05), and this effect was observed when any of growth traits (diameter, height or height increment) was used as a covariate in analysis. Results suggest the potential to select more resistant families, since the genetic correlation of grade of the damage between locations was significant (r = 0.40 - 0.72) and therefore improve also the growth of trees, since the grade of the damage had a negative correlation with growth traits both at provenance and family mean level (r = -0.69 and r = -0.42; p is less than 0.01).
显示更多 [+] 显示较少 [-]Productivity and quality of hybrid aspen at the age of 18 years
2016
Zeps, M., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Adamovics, Andis, Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Smilga, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Sisenis, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
Fast-growing hybrid aspen clones are recommended for establishment of plantation on abandoned agriculture land in Northern Europe. In this study we assessed the productivity, quality and assortment structure of hybrid aspen clones at final felling. Data were collected during the hybrid aspen clonal experiment conducted in the central part of Latvia. Large variation in the productivity level between different clones was affected by growth and survival. From the compared 5 most and least productive clones, based on the yield m**3 haE-1, the faster growing clones have about 17% better survival rate at age 10. Also, the mean annual increment (MAI) differed notably and significantly (p is less than 0.05, α = 0.05) between hybrid aspen clones at the age of 18 years ranging from 7 to 34 m**3 haE-1 yearE-1. Theoretical assortment structure of hybrid aspen at the age of 18 years was the following: 43 ± 4.86% of small dimension saw logs (SDS logs), 21 ± 4.86% high quality saw logs (HQS logs), 18 ± 4.33% pulpwood, 4 ± 0.77% firewood and 13 ± 0.08% of logging residues (tops). The outcome of HQS logs on average is more than 30% from the 5 best clones and further increase can be predicted with age. Stem volume (H2 = 0.32), height (H2 = 0.47) and quality parameters (stem straightness - H2 = 0.73, branch angle - H2 = 0.60) had a high heritability and large differences between clones, indicating notable possibilities to improve the productivity of plantations via selection of the best-growing genetic material.
显示更多 [+] 显示较少 [-]Impact of wood ash and potassium sulphate fertilization on growth of Norway spruce stand on organic soil
2016
Okmanis, M., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Skranda, I., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdina, D., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Wood based ash can be used as a liming material and fertilizer in forest, thus providing a solution for utilization of wood ash and formation of additional increment of trees, especially on organic soils, where lack of potassium and phosphorus is a well-known factor limiting the growth of trees. Yet, many studies have been made with adverse results mostly because of different soil types and species investigated. However, by now the best results on fertilization with wood ash have been found on drained peatlands, where some nutrient deficiencies have emerged. The aim of this study was to find out the growth response of Norway spruce on drained organic soils after spreading of potassium sulphate (K2SO4) and wood ash (WA). The experiment was carried out in three middle aged Norway spruce (Picea abies) stands on drained mineral and peat soil. Experiment consisted of three replications of each treatment in each stand including WA, K2SO4 and the control on 400 square meter sub-sample plots each. The diameter and height of trees were measured. The samples of increment cores were collected 4 years after fertilization to determine the additional volume increment, which varied from 8.5 m**3 haE-1 in WA plots and from 9.7 m**3 ha-1 to 17.2 m**3 haE-1 on K2SO4 plots. Both - the wood ash and potassium application - significantly increased the increment of Norway spruce on drained mineral and peat soil, although no significant differences were found between the treatments (p = 0.82, α = 0.05).
显示更多 [+] 显示较少 [-]Soil compaction in young stands during mechanized logging of biofuel and roundwood assortments
2016
Prindulis, U., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Kaleja, S., Forest Sector Competence Centre, Ltd., Riga (Latvia) - MNKC | Lazdins, A., Forest Sector Competence Centre, Ltd., Riga (Latvia) - MNKC
Impact of a variety of forestry machine types on soil compaction is evaluated in this study according to the measurement of soil penetration resistance at 0 to 80 cm depth. It is concluded in the study that soils with poor bearing capacity (PBC), comparably small penetration resistance and organic layer thicker than 5 cm are less vulnerable to soil compaction. The use of small-size forwarder Vimek 610 allows to reduce soil compaction to an insignificant level in comparison to the control sites, and most or ruts disappear within a few days in PBC conditions. Whereas John Deere 810E, which belongs to the middle-size class of forwarders, significantly compacts soil through the whole measured depth in similar conditions. Rottne F10B and John Deere 810E forwarders represent the same weight category, and soil compaction due to the use of these machines on soils with moderate bearing capacity (MBC) is similar too; however, on soils with weak (WBC) and good (GBC) conditions results are different, mostly due to a different amount of extracted roundwood in both trials. Tracked forwarder was used only in GBC conditions and the results demonstrated significant compaction only down to 22 cm depth. The trials confirm that the depth of the intensity of impact depends on the weight of the machine and amount of material extracted; however, additional measurement data are necessary to characterize the impact quantitatively in different conditions.
显示更多 [+] 显示较少 [-]Sapropel as an adhesive: assessment of essential properties
2016
Obuka, V., University of Latvia, Riga (Latvia) | Veitmans, K., Latvia Univ. of Agriculture, Jelgava (Latvia) | Vincevica-Gaile, Z., University of Latvia, Riga (Latvia) | Stankevica, K., University of Latvia, Riga (Latvia) | Klavins, M., University of Latvia, Riga (Latvia)
Recently, a renewed interest in non-harmful, environmentally friendly adhesives has ensued among the industry professionals, both environmental and healthcare scientists. In this study, organic rich lake sediments (sapropel) from two lakes located in Latgale Region of Latvia were used as a glue to investigate the potential use of such adhesive for manufacture of composite materials from wood. Sapropel is a valuable resource with multiple areas of application, e.g., agriculture, balneology. Available amount of sapropel in Latvia is estimated at up to 2 billion m**3. Prior the tests, characterization of sapropel samples was done. Properties of the obtained composite material samples from wood and sapropel, as well as the mechanical properties were investigated. Tests involved the assessment of static bending strength and shear strength tests, durability according to their operating performance (D1-D4), as well as dried natural peat tensile strength perpendicular to the grain direction were determined and compared to the literature data; and the opportunities to use new composite materials in accordance with to the standards were discussed. The results of the study revealed an insight into possibilities to develop products of higher added value from sapropel as adhesive in combination with various resources. Results indicated that the samples made from Lake Pilvelis sapropel gain to better results of bending strength determination (parallel bending - 88.7 MPa). The aim of this study was to explore options to produce veneer using two kinds of sapropel as a glue and to determine the optimal properties according to the standards, as well as to characterize properties of the obtained composite material.
显示更多 [+] 显示较少 [-]Productivity of Latvian and Lithuanian rural farms and main factors influencing it
2016
Veveris, A., Latvia Univ. of Agriculture, Priekuli, Priekuli parish, Priekuli Municipality (Latvia). Inst. of Agricultural Resources and Economics | Sapolaite, V., Lithuanian Inst. of Agrarian Economics, Vilnius (Lithuania) | Dambina, L., Latvia Univ. of Agriculture, Priekuli, Priekuli parish, Priekuli Municipality (Latvia). Inst. of Agricultural Resources and Economics
The aim of the paper is the assessment of the changes in productivity expressed as the share of production costs in total output and its breakdown by major cost types of Latvian and Lithuanian farms over the period of the implementation of Rural Development Programme (RDP 2007 – 2013). The country’s agricultural productivity is determined by comparison of the total agricultural output value (in producer prices) and total inputs which include intermediate consumption expenditure, depreciation, labour costs and other external costs. The information for the analysis was sourced from the standardized Farm Accountancy Data Network (FADN) data. The results show that productivity level is higher in Lithuanian farms, although the tendency is that the share of costs in production value is increasing in Lithuania, so the difference between two countries is reducing. The changes of productivity in both countries infer the relative growth in the productivity in crop farming both in Latvia and Lithuania respective to dairy farming, as well as the productivity of large farms respective to small and medium farms. The comparisons of major cost items reveal an especially high level of energy costs in Latvia, as well as a high and soaring level of depreciation in Lithuania, especially in dairy farms. In the future policy making, it is worthwhile to design the measures targeting the confinement of risks and negative trends identified in the study.
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