Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Reliability of agriculture universal joint shafts based on temperature measuring in universal joint bearing assemblies
Get PDFThis paper presents a research into reliability calculations of agriculture double universal joint shafts based on temperature measuring in cardan-type universal joint bearing assemblies. Special laboratory equipment was developed for this research which is presented in the paper. The objective of this research was to test the real life span of universal joint shafts in the laboratory and in field, to obtain the results which can be used to improve the reliability of universal joint shafts. If the presented research were used along with maintenance measures recommended in the paper and with proper use, the level of reliability of the shafts would be 2.1 times higher. The presented results of the research showed that needle bearings, i.e. bearing assemblies of the joints, are the most critical elements on universal joint shafts and are possible causes of their lower reliability. The second universal joint is the part with the lowest reliability in the observed technical system
Case studies of the expansion of Acacia dealbata in the valley of the river Miño (Galicia, Spain)
Get PDFAim of study: Acacia dealbata is a naturalized tree of invasive behaviour that has expanded from small plots associated with vineyards into forest ecosystems. Our main objective is to find evidence to support the notion that disturbances, particularly forest fires, are important driving factors in the current expansion of A. dealbata.Area of study: We mapped it current distribution using three study areas and assesses the temporal changes registered in forest cover in these areas of the valley of the river Miño. Material and Methods: The analyses were based on visual interpretation of aerial photographs taken in 1985 and 2003 of three 1x1 km study areas and field works.Main result: A 62.4%, 48.6% and 22.2% of the surface area was covered by A. dealbata in 2003 in pure or mixed stands. Furthermore, areas composed exclusively of A. dealbata make up 33.8%, 15.2% and 5.7% of the stands. The transition matrix analyses between the two dates support our hypothesis that the areas currently covered by A. dealbata make up a greater proportion of the forest area previously classified as unwooded or open forest than those without A. dealbata cover. Both of these surface types are the result of an important impact of fire in the region. Within each area, A. dealbata is mainly located on steeper terrain, which is more affected by fires. Research highlights: A. dealbata is becoming the dominant tree species over large areas and the invasion of this species gives rise to monospecific stands, which may have important implications for future fire regimes.Keywords: Fire regime; Mimosa; plant invasion; silver wattle
Physico-mechanical properties of Spanish juniper wood considering the effect of heartwood formation and the presence of defects and imperfections
Get PDFAim of study: Determining the main physical and mechanical properties of Spanish juniper wood from Soria (Spain) considering the effects of heartwood formation and the presence of defects and imperfections; and comparing the resulting characteristics with similar existing data for other regional softwood species of commercial interest. Area of study: Berlanga de Duero (Soria, Castilla y León), Spain.Material and Methods: Wood physico-mechanical performance was determined by Spanish UNE standards in order to provide proper comparisons to other regional softwood species. An individual tree representing average plot characteristics was selected in all eight 10 m radius circular plots that were established well-representing the heterogeneity of this woodland. The age of every tree was determined reading the number of growth rings at the base of each sampled tree. Every physico-mechanical property was assessed at least 4 times for every wood sample type (sapwood and heartwood, whether clear or with the presence of defects) of each tree. Two-way ANOVA was run to assess significant differences in the results. Post hoc all pairwise comparisons were performed using Tukey's test (p < 0.05).Research highlights: Spanish juniper wood resulted harder than other regional commercial conifers, and showed semi-heavyweight heartwood and lightweight sapwood; whereas shrinkage figures remarked its great dimensional stability. The high presence of knots within heartwood made it even heavier, harder, and more resistant to compression parallel to grain. A commercial use of this rare precious wood may contribute to juniper forests preservation in the frame of forest sustainable management plans. Key words: heartwood effect; Juniperus thurifera L.; physico-mechanical wood properties; wood classification; wood defects
White poplar (Populus alba L.) - Litter impact on chemical and biochemical parameters related to nitrogen cycle in contaminated soils
Get PDFAim of study: The aim of this study was to determine the effect of litter from Populus alba on chemical and biochemical properties related to the N cycle in soils with different pH values and trace element contents. We hypothesized that this litter would influence several parameters related to the N cycle and consequently to soil health.Area of study: we collected two reforested contaminated soils of different pH values (AZ pH 7.23 and DO pH = 2.66) and a non-contaminated soil (RHU pH 7.19).Materials and methods: Soil samples were placed in 2,000 cm3 microcosms and were incubated for 40 weeks in controlled conditions. Each soil was mixed with its corresponding litter, and soils without litter were also tested for comparison. Ammonium (NH4+-N) and nitrate (NO3–-N) content, potential nitrification rate (PNR), microbial biomass nitrogen (MBN), protease activity, and several chemical properties such as pH, available trace element concentrations (extracted with 0.01 M CaCl2) were determined at different times of incubation.Main results: Values of available trace elements did not vary during the incubation and were always higher in acid soil. In neutral soils litter presence increased values of Kjeldahl-N, NO3–-N content, potential nitrification rate (PNR), microbial biomass nitrogen (MBN) and protease activity. Presence of trace elements in neutral soils did not alter the parameters studied. However, acidic pH and high content of available trace elements strongly affected NH4+-N andNO3–-N, microbial biomass N and protease activity.Research highlights: Our results showed the negative effect of the acidity and trace element availability in parameters related with the N-cycle.Key words: microbial biomass N; protease activity; soil pH; N mineralization; nitrification; phytoremediation
Ignition probability of fine dead surface fuels of native Patagonian forests or Argentina
No full textAim of study: The Canadian Forest Fire Weather Index (FWI) is being implemented all over the world. This index is being adapted to the Argentinean ecosystems since the year 2000. With the objective of calibrating the Fine Fuel Moisture Code (FFMC) of the FWI system to Patagonian forests, we studied the relationship between ignition probability and fine dead surface fuel moisture content (MC) as an indicator of potential fire ignition.Area of study: The study area is located in northwestern Patagonia, Argentina, and comprised two main forest types (cypress and ñire) grown under a Mediterranean climate, with a dry summer and precipitations during winter and autumn (~500-800 mm per year).Material and Methods: We conducted lab ignition tests fires to determine the threshold of fine dead fuel ignition at different MC levels. Moisture content of dead fine surface fuels in the field was measured every 10-15 days from November to March for three seasons. We calculated the FFMC during these seasons and correlated it with the measured MC by applying a logistic regression model. We combined the results of the ignition tests and of the regressions to suggest FFMC categories for estimating fire danger in Patagonian forests.Main results: The ignition threshold occurred at MC values of 21.5 and 25.0% for cypress and ñire sites, respectively. The MC measured varied from 7.3 to 129.6%, and the calculated FFMC varied between 13.4 and 92.6. Highly significant regressions resulted when FFMC was related to MC. The ignition threshold corresponded to a FFMC=85. We proposed to divide the FFMC scale in three fire danger categories: Low (FFMC≤85), High (85<FFMC≤89) and Extreme (FFMC>89).Research highlights: Our results provide a useful tool for predicting fire danger in these ecosystems, and are a contribution to the development of the Argentinean Fire Danger Rating and a reference for similar studies in other countries where the FWI is being implemented.Keywords: Austrocedrus chilensi; Nothofagus antarctica; wildfire; fire behavior; fuel moisture; fire weather index
Role of planting stock size and fertilizing in initial growth performance of rowan (Sorbus aucuparia L.) reforestation in a mountain frost hollow
Get PDFThe aim of study: (1) to compare the survival rate, growth performance and nutrition of large and common-sized planting stock of rowan (Sorbus aucuparia L.) on a frost-exposed site and (2) to assess whether fertilizing had any effect on the plantations.Area of study: The Jizera Mts., an area heavily disturbed by air pollution situated on the Czech-Polish border close to GermanyMaterials and methods: Two types of planting stock were tested in a mountain frost hollow on an acidic mountain humic podsol: (a) the bare-rooted saplings 131–140 cm tall and (b) common-sized containerized transplants 26–35 cm. One half of the saplings and common-sized transplants were left untreated and the other half were fertilized with a low dose (30 g per tree) of a slow release fertilizer based on methylene urea and potassium magnesium phosphate. Growth performance and nutrition of plantations were investigated.Main results: Due to serious deformations and stem breakages inflicted by snow and frost, the prospects of common-sized transplants seem much worse than those of saplings. The height growth of saplings was significantly more rapid than that of common-sized transplants. As for growth, neither the saplings nor common-sized transplants did significantly respond to fertilizing. The effects of fertilizing on nutrition of rowans were unconvincing. The extreme temperature events during growth seasons and snow deformations in winters might be the decisive factors influencing growth performance of rowans under referred conditions.Research highlights: On the frost-exposed sites, the height of taller saplings might partly compensate for a missing shelter of forest stand since the terminal leaders are above ground-frost zone.Key words: mountain ash; sapling; common-sized transplants; nutritional status; temperature.Abbreviations: CS – Control Saplings; CT – Control Transplants; FS – Fertilized Saplings; FT – Fertilized Transplant
Alkalinity and structure of soils determine the truffle production in the Pyrenean Regions
Get PDFAim of study: The program "Typology of truffle stations in the Pyrenean Regions" aimed to define the ecological conditions and culture practices that favor Tuber melanosporum growth and fruiting in this area.Area of study: Navarra, Catalonia, Midi-Pyrénées and Languedoc-Roussillon.Material and methods: The program was based on the survey of 212 wild and cultivated truffle beds of evergreen oaks (Quercus ilex). The data collected in the field consisted of photographs, samples of soil, roots and mycorrhizae, and information on cultural practices followed by truffle growers.Main results: (i) truffle soils are alkaline, from neutral, dolomitic, to moderately or very calcareous soils; (ii) truffle soils are light, well-structured and stable to water immersion; (iii) mycelium that colonizes roots survives in suboptimal conditions, but it does not necessarily bear ascocarps. Finally our results suggest that T. melanosporum is a relatively ubiquitous fungus able to grow, or at least to persist, in a wide range of physical and chemical soil conditions. We propose a probabilistic model of the environment favorable for fruiting, built around a two-dimensional graph with an axis for the chemical conditions, like soil alkalinity, and another axis for the physical conditions, like soil structure. Research highlights: Soil alkalinity and structure allow to built a convenient representation of the ecological capacity of a place to be good T. melanosporum habitat, and thus of the probability for truffle growers to harvest truffles according to the environmental properties of their truffle orchards.Keywords: dolomite; limestone; mycorrhizae; Quercus ilex; field survey; Tuber melanosporum
Influence of feeding system on growth performance, carcass characteristics and meat and fat quality of Avileña-Negra Ibérica calves’ breed
Get PDFThe effect of feeding system (calves reared under free-range conditions supplemented with concentrate vs. calves fed on concentrate and cereal straw in confinement) during finishing period on growth performance, carcass traits and meat and fat quality was investigated. Fourteen entire males of Avileña-Negra Ibérica breed were used. The feeding system had no effect on growth performance, carcass characteristics, muscle colour, drip losses and intramuscular fat (IMF) percentage in Longissimus thoracis. Free-range calves had more content of vitamin E in omental fat and tended (p<0.1) to have more vitamin E in IMF than calves finished in confinement. C16:0 and C16:1 n-9 proportions in omental fat were higher in calves finished in confinement, while C18:1 n-7, C18:3 n-3, Σn-3 proportions were lower. The ratio Σpolyunsaturated fatty acids (PUFA) to Σsaturated fatty acids (SFA) was significantly greater in omental fat from free-range calves. The C14:0, C16:0, C16:1, C17:0, C17:1, C18:1 n-9 and Σmonounsaturated fatty acids (MUFA) were higher and C18:3 n-3 and Σn-3 proportions lower in IMF from calves finished in confinement. The ratio C18:1 n-9 to C18:0 was higher in IMF from calves fed on concentrate and straw and the ratio ΣPUFA to ΣSFA tended (p<0.1) to be greater in free-range calves. Intramuscular fat percentage affected to fatty acid composition of Longissimus thoracis. Feeding system based in finishing calves in confinement with straw and concentrate can be replaced by supplementation with concentrate in grazing without detrimental effect on quality
Effect of rosemary (Rosmarinus officinalis) extracts and glutathione antioxidants on bull semen quality after cryopreservation
Get PDFThe present study determined the effects of the addition of rosemary extract (ROM), glutathione (GSH), and their combination (ROM + GSH) to freezing extender on the quality of bull semen after cryopreservation. Before cryoperservation, the samples were diluted in a tris-egg yolk (TEY) extender containing 5 mM GSH (treatment I), 5 or 10 g L–1 ROM (treatments II and III), and ROM with GSH (5 mM GSH with 5 or 10 g L–1 of ROM) (treatments IV and V). An extender containing no antioxidants (non-ROM/GSH-treated) served as control group. Kinematic parameters were evaluated by means of a computer-assisted semen analysis (CASA). The viability and membrane integrity of the sperm were assessed using eosin-nigrosin stain and the hypo-osmotic swelling test (HOST) at 0 and 2 h after freezethawing. Lipooxidative parameters, superoxide dismutase, and glutathione peroxidase (GPx) activity were assessed after thawing. Treatment III showed positive effects for total motility (TM) (p < 0.01), average path velocity (VAP) (p < 0.001), viability (p < 0.01) and HOST (p < 0.01); however, lipid peroxidation (LPO) decreased (p < 0.05) and GPx activity increased (p < 0.05) immediately after thawing compared to the control. The TM (p < 0.01), VAP (p < 0.01), viability (p < 0.01), HOST (p < 0.01) decreased in LPO (p < 0.01) and GPx activity (p < 0.05) for treatment V and the viability and GPx activity (p < 0.05) for treatment I were significantly higher than for the control group at 2 h after thawing. It was concluded that the inclusion of ROM and its combination with GSH improves the post-thaw quality of bull semen
Use of endometrial cytology and metabolic profiles for selection of embryo donor cows
Get PDFThe aim of this study was to evaluate the use of endometrial cytology and metabolic profiles for selection of donor cows in embryo transfer programmes. For this purpose, 69 clinically healthy Holstein cows were enrolled in the study. At the start of the superovulation procedure (Day 0), blood and endometrial samples were obtained to determine metabolic and uterine status, respectively. The cows were then subjected to porcine follicle stimulating hormone (pFSH) superovulation treatment, and embryos were recovered after 7 days. The mean number of embryos obtained per flush was 9.89±8.21 (4.63±5.34 viable embryos, 0.82±2.01 degenerated embryos and 4.57±6.44 unfertilized ova). The following statistically significant variables were entered in a regression model: beta-hydroxybutyrate, serum cholesterol, body condition, number of calvings and percentage of neutrophils. In almost all cases, the model explained some percentage of the variance: total number of embryos, 4.8% (p<0.05); number of degenerate embryos, 4.2% (p=0.051); and number of unfertilized ova, 14.2% (p<0.01). Statistical models for the percentage of viable embryos and unfertilized ova accounted for 24.0% and 29.4% of the variance, respectively, and both were statistically significant (p<0.01). The model for the percentage of degenerated embryos was statistically significant (p<0.05) and explained 4.4% of the variance. In conclusion, we have demonstrated that positive energy balance and healthy uterus can improve ovarian response and the proportion of viable embryos in cows. Efficient tools for monitoring the metabolic and uterine status should therefore be used in bovine embryo transfer programmes