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Genotype-environment interaction in Latvian Scots pine growth and quality traits and its impact on progeny testing
2008
Jansons, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Progeny testing of Scots pine in Latvia is carried out in only few locations, however, material from selections via seed orchards is deployed in various climatic and soil conditions, therefore concerns arise for influence of genotype environment interaction on levels of genetic gain. Problem is addressed based on 3 open pollinated progeny tests, consisting of 80 open pollinated families, located in 3 distant climatic regions in Latvia. Test age is 27 years, therefore not only growth, but also branch quality traits can be reliably analyzed. Strong genetic correlation (rb=0.80-0.94) among sites for tree height and diameter was found, but considerably weaker for branch traits like diameter of thickest branch (rb=0.52-0.67), average branch diameter, and sum of branch diameters (rb=0.41-0.49). Coefficients of additive genetic variation and coefficients of phenotypic variation among family means, determining potential of improvement via breeding, can be inflated by up to half, based on single site estimates for growth traits and double for quality traits. Backward selection based on results of several trials, in contrast to forward selection or utilization of single experiment results, could lead to improvement of branch traits close to the same as for growth traits (height and diameter). Single site narrow-sense heritability estimates for analyzed growth and quality traits are up to twice as large as across site estimates, indicating possibilities of serious bias in genetic gain estimates based on results from one test site. Testing at 4-5 sites for further breeding work is recommended.
Show more [+] Less [-]Organic fertilizers and wood ash impact on growth of energy crops in peat - a laboratory study
2008
Lazdina, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Lazdins, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
Willows (Salix sp.) and reed canary grass (Phalaris arundinecea L.) (RCG) are fast growing perennial energy crop and potential cultures for recovering of cutaway peat lands. Cut away peat land soils are characterized by high acidity (pHKCl 2-3), high NH4**+1, and lack of P and K. Wood ash could be good liming agent and resource of potassium. Waste water sewage sludge (WWSS) compost is effective fertilizer and source of phosphorus. The objective of the study was to investigate the effect of application of WWSS compost and wood ash fertilizers of different doses on ingrown of willow cuttings and RCG in potted cultures. The wood ash addition of 10 g lE-1 and 20 g lE-1 to WWSS compost mix with peat from used query in proportions 1:1 and 4:1 were tested. The length of shoots and dry mass of shoots and roots were assessed to determine the effect of fertilization on growth of crops. Chemical analyses of growing media were performed to determine the content of main nutrient elements and pHKCl changes during season. The positive effect of fertilization on growth of crops was observed - an optimum dose for willows is (10 g lE-1) equivalent to 10 tDM haE-1 wood ash with mix of WWSS compost with peat. RCG produces more biomass in growing media containing largest doses of wood ash and WWSS compost premix. The willows produced bigger amount of biomass and accumulated more nutrients from growing media than RCG.
Show more [+] Less [-]Structure and ecology of ash forest communities pruno-fraxinetum in Latvia
2008
Reihmane, D., University of Latvia, Riga (Latvia). Faculty of Geography and Earth Sciences
The vegetation of Pruno-Fraxinetum plant communities was described in 2004 – 2005 according to the Braun-Blanquet method throughout Latvia, in forests where common ash (Fraxinus excelsior L.) are dominant species in tree layer on moist soils. Classification of relevés (in total 52) by two way indicator species analysis (TWINSPAN) resulted in two variants of this association: typical variant (typicum) and variant with Filipendula ulmaria. Ellenberg indicator values were used to find out the relationship of flora with climatic (light, temperature, continentality) and edaphic (soil reaction, nitrogen, moisture) factors. Canonical correspondent analysis (CCA) was used to find out differences between two variants of Pruno-Fraxinetum. Results of this research have shown that these forests have complicated structure (form four vegetation layers, high species richness), which mainly depends on moist, rich eutrophic soils, usually with presence of limes. Main differential soil factors in ecological analysis are gradients of soil richness: moisture and nitrogen regimes. The influence of other factors was less expressed. Due to the human influence, especially drainage, the moist ash forests are decreasing and the species composition is changed. As Pruno-Fraxinetum forests in Latvia lie on the northern border of its distribution, the species composition differs from forests in the rest Europe; species characteristic determined by floodplain forests in Central Europe are absent.
Show more [+] Less [-]Participatory characterization of the Short-eared Somali goat and its production environment around Dire Dawa, Ethiopia Full text
2012
Gebreyesus, G. | Haile, Aynalem | Dessie, Tadelle
Characterization of the Short-eared Somali goat population around Dire Dawa, Ethiopia, was undertaken in a community-based and participatory approach. Range of participatory tools, including Focal Group Discussions, participatory mappings and transect walks, were employed to study the local community's Indigenous knowledge and practices in animal breeding. The breeding objective was defined in a participatory manner through own-flock ranking experiments. Physical description of the goat population was made based on the "key characteristics" concept used by the community to distinguish their goat type among other breeds within their migratory reach. The Issa community maintains a perception of special association towards the Short-eared Somali goat type, claiming a historic role in its development and adaptation. Local myths persistent in the community associate the origin of the Short-eared Somali goat breed with the communal ethno-history. The community generally practices selective pure breeding employing rather complex indigenous knowledge and traditional practices aimed at polishing the gene pool towards the dictates of the environment. Patchy color patterns were generally dominant (59.8%) in the goat population, while 34% of the patched goats had a unique pattern of black spots on the center core of the face and a black stripe across the spine. Goats were kept for multifaceted purposes ranging from products like milk and meat to functions in socio-cultural and financial state of affairs. The production system was characterized with lack of feed supplementation and rangelands provide the only source of feed throughout the year. Although the production environment was characterized with recurrent droughts and high prevalence of goat diseases, goats were found to have significant contributions to the livelihood of the Issa pastoralists in the study area.
Show more [+] Less [-]Comapison of carcass characteristics of Boran and Arsi-Bale goats under different durations of feedlot management Full text
2005
Hailu D. | Tatek W. | Tesfaye L.
The objective of this study was to assess the carcass characteristics of two goat breed types under different durations of feedlot management. Forty eight yearling intact male Borana (n=24) and Arsi-Bale (n=24) goats were used in a 2 x 3 factorial arrangement, the factors being breed-type (Borana and Arsi-bale) and feeding days (90, 120 and 150). The goats were slaughtered after 18 hours fasting to evaluate the various carcass traits. The carcasses were separated into leg, lion, rack, shoulder and neck and breast and shank primal cuts. The Borana goats possessed heavier live weight, empty body weight, carcass weight and length than the Arsi-Bale goats in the feedlot environment. Dressing percentage varied from 41.0 to 45.9% for both goat breed types. Borana had greater rib eye area than Arsi-Bale goats for 120 (42.9±3.99) and 150 (47.3±1.28) feeding days. Back fat thickness was higher for both breed-types for 150 days feedlot feeding. The highest bone proportion was 30.9% for Arsi-Bale goats while the lowest was 25.7% for Borana goats. The percentage of rack fat of Borana was higher than for the Arsi-Bale goats.
Show more [+] Less [-]Long-term influence of large forest fire on ground vegetation Full text
2016
Purina, L., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Straupe, I., Latvia Univ. of Agriculture, Jelgava (Latvia) | Liepa, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Libiete, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Zadina, M., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Jansons, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Fire is a major disturbance in hemiboreal forests; it affects not only trees, but also ground vegetation. Previous studies have analysed the succession of ground vegetation after the fire, but not addressed the impact of the size of the burned area on revegetation of it. Therefore, the aim of our study was to assess the differences in post-fire ground vegetation in relation to the distance from the edge of the affected area. Vegetation data were collected using Braun-Blanquet method in three sites (122 sample plots) affected by forest fire and five clearcuts (not affected by fire) (92 plots), all regenerated by Scots pine 6 – 7 years before the assessment. The number of ground vegetation species (in all sites predominantly birds or wind dispersed) as well as their projective cover was not affected by the distance from the nearest edge of burned or clearcut, except in burned sites on dry sand soil (Vaccinosa and Myrtillosa), where herbaceous plant and shrub cover was decreasing (from 23.5% to 11.6%) and bryophyte and lichen cover – increasing (from 3% to 13.9%) with an increasing distance from the edge of the area. The total number of plants in burned areas was twice smaller than in clearcut in the same soil conditions but such large difference in projective cover was not observed. There were no significant differences between burned and clearcut areas in respect to Ellenberg’s indicator values on both soil types, as well as no trend in Ellenberg’s values for soil moisture in relation to distance from the nearest stand edge.
Show more [+] Less [-]Genetic differences in needle cast damage of Scots pine (Pinus sylvestris L.) Full text
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).
Show more [+] Less [-]Impact of needle cast damage on sanitary condition in young Pinus sylvestris stands in central Latvia Full text
2016
Polmanis, K., Latvian State Forest Research Inst. Silava, Salaspils (Latvia);Latvia Univ. of Agriculture, Jelgava (Latvia) | Miezite, O., 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)
Recent studies have demonstrated the occurrence of different needle cast (Lophodermium spp.) species in young Scots pine Pinus sylvestris L. stands in different regions of Latvia. The impact of these fungi has been known also historically, but is predicted to increase in future due to climate changes that are forecasted to have a positive impact on presence and vigour of various species of fungi. The aim of the study was to characterize the needle cast damage in young Scots pine stands in central Latvia. Material was collected in 12 Scots pine stands at the age of 3 to 26 years in 28 plots with a total area of 8.1 ha in the middle of two consecutive growing seasons (years 2012 and 2013). The impact of disease was visually assessed using a 5 grade scale, depending on the proportion of damaged (brown) one-year old needles. Incidence of damaged trees (P, %) and damage intensity (R, %) was calculated and used to characterize the occurrence and severity of the infection in the stands as well as its link to other stand parameters. Damage incidence (ranging from 20 to 100%), as well as the intensity (from 4 to 35%) was slightly (incidence-also significantly) higher in 2013 in comparison to 2012; correlation between those two parameters was strong in both years (r = 0.94 and r = 0.84, respectively). The stand age, density (ranging from 1200 to 6900 trees haE-1) and tree height did not significantly correlate with the damage incidence or intensity. Forest type (Hylocomiosa or Myrtillosa mel.) was not a significant factor, too.
Show more [+] Less [-]Impact of wood ash and potassium sulphate fertilization on growth of Norway spruce stand on organic soil Full text
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).
Show more [+] Less [-]Sapropel as an adhesive: assessment of essential properties Full text
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.
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