Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Microclimate evaluation of a new design of insect-proof screens in a Mediterranean greenhouse
Get PDFThis work studies natural ventilation in a Mediterranean greenhouse, comparing a new experimental screen of 13×30 threads cm-2 (porosity 39.0%) with a commercial control screen of 10×20 threads cm-2 (porosity 33.5%). In addition, both screens were tested in a wind tunnel to determine the discharge coefficients Cd of the greenhouse side and roof vents, which proved to be 0.16 for the commercial control screen and 0.18 for the experimental screen at both vents. These values represent a theoretical increase of 11% (Cd,φ-10×20 /Cd,φ-13×30 = 0.89) in the natural ventilation capacity of the greenhouse when the experimental screen is used. The greenhouse was divided into two separate sections allowing us to analyze natural ventilation in both sectors simultaneously. Air velocity was measured in the lateral and roof vents with two 3D and six 2D sonic anemometers. Using the commercial control screen there was an average reduction of 16% in ventilation rate, and an average increase of 0.5ºC in the average indoor air temperature, compared to the experimental screen. In addition, the ventilation efficiency ηT was higher with the experimental screen (mean value of 0.9) than with the control (mean value 0.6). We have designed an experimental insect-proof screen (13×30 threads cm-2) with smaller thread diameter, higher thread density, smaller pore size and higher porosity than are used in most commercial meshes. All of these factors promote natural ventilation and improve the greenhouse microclimate
An analysis of the composition of gain and growth of primal cuts of Iberian pigs of 10 to 150 kg body weight as affected by the level of feeding and dietary protein concentration
Get PDFA meta-analysis was made of data from a total of 211 growing-finishing Iberian (IB) pigs from four separate and independent sets of trials. Within each set of trials, a factorial arrangement of treatments was used, involving several concentrations of ideal protein in the diets and two or three levels of feed intake. Pigs were slaughtered at several stages of growth from 10 to 150 kg body weight (BW). The partition of dietary protein in the body of the pigs, the empty-body gain (EBG), the chemical composition of EBG, growth of primal cuts in the cold eviscerated carcass (without head, feet, and tail), and mass of dissected tissues in trimmed shoulder and ham were determined. Linear regression equations allowed estimating N requirements for maintenance as 175 mg/(kg BW0.75 · kg dry-matter intake) · d-1 and an average value for the net efficiency of utilization of the dietary protein apparently absorbed of 0.386. In pigs offered adequate protein to energy diets, EBG was predicted as a function of average BW and feeding level (p<0.001). Multiple regression equations were constructed, which derived nutrient (g kg-1) or energy (MJ kg-1) composition of EBG as a function of empty-body weight (EBW), dietary protein to energy ratio, and level of feeding (p<0.001). These predictive equations, not applicable to pigs of lean and conventional genotypes, can contribute to the design of optimal feeding strategies to improve the efficiency of IB pig production systems and to achieve high quality standards in end products for the market
Fat, meat quality and sensory attributes of Large White × Landrace barrows fed with crude glycerine
Get PDFThe use of alternative raw materials like crude glycerine in animal feed to reduce final costs could be of interest as the sector seeks to increase its competitiveness. The aims of the present work were to evaluate the effect of crude glycerine on back-fat thickness and the proximate composition of pork and to examine the effect on pork quality of using growing-finishing feeds with different percentages of crude glycerine added. For this purpose 60 crossbreed (Large White × Landrace) barrows were subdivided into three groups according to the crude glycerine concentration administered in feed: C, control diet, no crude glycerine; and G2.5 and G5 with 2.5% and 5% added crude glycerine, respectively. This study evaluated proximate composition, pH, cooking losses, texture, colour coordinates, fatty acid profile, and sensorial analysis. No differences were found in any of the three groups studied (C, G2.5, G5) for measurements performed both before (with ultrasound equipment) and after slaughter (millimetre ruler). The proximate composition and the physical-chemical parameters of longissimus dorsi were similar between groups. There were no differences detected (p>0.05) between the three groups as regards the CIELab coordinates, textural profile and sensory attributes. Therefore, 5% crude glycerine to replace corn could be used as an ingredient in pig feed without appreciably affecting the back-fat and meat quality characteristics
Male sterility of triticale lines generated through recombination of triticale and rye maintainers
Get PDFThe Triticum timopheevi cytoplasmic male sterility (cms) system in triticale (xTriticosecale Wittmack) suffers from a low frequency of maintainers and environmental instability of the male sterility. On the other hand, the Pampa cms system in rye (Secale cereale) exhibits strong male sterility and a low frequency of restorers. Here, we report generating hybrids between maintainers of the T. timopheevi cms system in triticale and maintainers of the rye Pampa cms system. Ten hybrids were obtained. Their hybridity was verified by PCR (polymerase chain reaction) using ISSR (inter simple sequence repeats) primers. The cms maintaining ability of F2 individuals and their progeny was tested. The F2 plants were crossed to male sterile lines of triticale carrying the T. timopheevi cytoplasm. Among 180 G1 offspring of these crosses, 71 (39.4%) were completely male sterile. Fourteen F2 individuals (7.8%), as well as their F2S1 and progeny, generated stable male sterility in G1, G1BC1 and G1BC2 generations after the crosses. Our results suggest that it is possible to produce a more stable cms system in triticale based on the T. timopheevi cytoplasm as compared to the existing one
Dose-dependent effect of a single GnRHa injection on the spawning of meagre (Argyrosomus regius) broodstock reared in captivity
Get PDFThe present study aimed to determine the spawning efficacy, egg quality and quantity of captive breed meagre induced with a single gonadotrophin‐releasing hormone agonist (GnRHa) injection of 0, 1, 5, 10, 15, 20, 25, 30, 40 or 50 µg kg-1 to determine a recommended optimum dose to induce spawning. The doses 10, 15 and 20 μg kg-1 gave eggs with the highest quality (measured as: percentage of viability, floating, fertilisation and hatch) and quantity (measured as: total number of eggs, number of viable eggs, number of floating eggs, number of hatched larvae and number of larvae that reabsorbed the yolk sac). All egg quantity parameters were described by Gaussian regression analysis with R2=0.89 or R2=0.88. The Gaussian regression analysis identified that the optimal dose used was 15 μg kg-1. The regression analysis highlighted that this comprehensive study examined doses that ranged from low doses insufficient to stimulate a high spawning response (significantly lower egg quantities, p<0.05) compared to 15 μg kg-1 through to high doses that stimulated the spawning of significantly lower egg quantities and eggs with significantly lower quality (egg viability). In addition, the latency period (time from hormone application to spawning) decreased with increasing doses to give a regression (R2=0.93) which suggests that higher doses accelerated oocyte development that in turn reduced egg quality and quantity. The identification of an optimal dose for the spawning of meagre, which has high aquaculture potential, represents an important advance for the Mediterranean aquaculture industry
Radial variations of wood different properties in Diospyros lotus
Get PDFAim of study: The aim of this study was to determine some of the physical, biometry and mechanical strength properties of Diospyros lotus L. wood along radial direction from the pith to the bark and the relationship between wood various properties. Area of study: The study area is located in north Iran in the province of Mazandarn. Material and methods: Testing samples were taken at breast height of tree stem and three radial position of stem radius to determine physical (basic density), fiber biometry (fiber length, fiber diameter, cell-wall thickness) and mechanical properties (modulus of rupture and modulus of elasticity).Main results: The results of ANOVA indicated that there are significant differences along radial direction in above mentioned properties for persimmon wood. Basic density, fiber length, fiber diameter, cell-wall thickness, modulus of elasticity and modulus of rupture increased along radial direction from pith toward the bark. Research highlights: The persimmon wood isn’t suitable for pulp and paper production due to the unfavorable flexibility and Runkel coefficients.Keywords: Diospyros lotus; basic density; fiber features; modulus of rupture; modulus of elasticity
Effects of tree-length timber skidding on soil compaction in the skid trail in Hyrcanian forests
Get PDFAim of study: The study was conducted to examine impact of skidding traffic, trail slope, traffic frequency, and soil depth on the soil bulk density.Area of study: This study was carried out in the Kheyrud Forest in Hyrcanian forest, Iran.Material and methods: The level of soil compaction at eight levels of traffic (1, 4, 8, 10, 15, 20, 25, and 30 passes), four levels of skid trail slopes (0, 10, -10, and -20%) and three soil depth (5, 15, 25 cm) were applied in three replicates consequently. Bulk densities were measured on the undisturbed surface (control) and within the tracks. Timbers were extracted in the tree-length logging method using rubber-tired skidder (Timberjack 450 C).Main results: About 5.2% of total area of harvesting unit were disturbed and compacted. Uphill skidding increases compaction more than downhill skidding. In the four different slopes, the highest increasing of the bulk density was occurred during the first few passes of skidder, although the bulk density continued to increase in amount and depth with the number of passes. The increases in bulk density were still important at the maximum sampling depth of 20-30 cm.Research highlights: The results indicated that slope steepness had a strong effect on the soil physical properties and soil disturbance. Designated skid trails should be used to minimize the influence on the forest soil.Key words: soil compaction; tree-length logging method; rubber-tired skidder; Hyrcanian forest
Evaluating the quality of riparian forest vegetation: the Riparian Forest Evaluation (RFV) index
Get PDFAim of study: This paper presents a novel index, the Riparian Forest Evaluation (RFV) index, for assessing the ecological condition of riparian forests. The status of riparian ecosystems has global importance due to the ecological and social benefits and services they provide. The initiation of the European Water Framework Directive (2000/60/CE) requires the assessment of the hydromorphological quality of natural channels. The Directive describes riparian forests as one of the fundamental components that determine the structure of riverine areas. The RFV index was developed to meet the aim of the Directive and to complement the existing methodologies for the evaluation of riparian forests.Area of study: The RFV index was applied to a wide range of streams and rivers (170 water bodies) inSpain.Materials and methods: The calculation of the RFV index is based on the assessment of both the spatial continuity of the forest (in its three core dimensions: longitudinal, transversal and vertical) and the regeneration capacity of the forest, in a sampling area related to the river hydromorphological pattern. This index enables an evaluation of the quality and degree of alteration of riparian forests. In addition, it helps to determine the scenarios that are necessary to improve the status of riparian forests and to develop processes for restoring their structure and composition.Main results: The results were compared with some previous tools for the assessment of riparian vegetation. The RFV index got the highest average scores in the basins of northernSpain, which suffer lower human influence. The forests in central and southern rivers got worse scores. The bigger differences with other tools were found in complex and partially altered streams and rivers.Research highlights: The study showed the index’s applicability under diverse hydromorphological and ecological conditions and the main advantages of its application. The utilization of the index allows a better understanding of the status of riparian forests, and enhances improvements in the conservation and management of riparian areas.Keywords: riparian quality; Water Framework Directive; connectivity; indicator; hydromorphology.
Evaluating management regimes for European beech forests using dynamic programming
Get PDFAim of study: This contribution describes a systematic search method for identifying optimum thinning regimes for beech forests (Fagus sylvatica L.) by using a combination of optimization heuristics and a simple whole stand growth prediction model. Area of study: Data to build the model come from standard and management forest inventories as well as yield tables from the Northern and Western part of Germany and from southern and central Denmark.Material and Methods: Growth projections are made from equations to project basal area and top height. The remaining stand variables are recovered from additional equations fitted from forest inventory data or acquired from other authors. Mortality is estimated through an algorithm based on the maximum density line. The optimization routine uses a two-state dynamic programming model. Thinning type is defined by the NG index, which describes the ratio of the proportion of removed trees and basal area with respect to the same proportion before thinning. Main results: Growth equations fitted from inventory data show high goodness of fit with R2 values larger than 0.85 and high significance levels for the parameter estimates. The mortality algorithm converges quickly providing mortality estimates within the expected range.Research Highlights: The combination of a simple growth and yield model within a Dynamic Programming framework in conjunction with NG values as indicators of thinning type yield good estimates of practical thinning schedules compared to thinning recommendations provided by diverse authors.Keywords: beech (Fagus sylvatica L.); NG ratio; thinning optimization; growth and yield simulation; mortality
Resource potential of bamboo, challenges and future directions towards sustainable management and utilization in Ethiopia
Get PDFAim of study: Bamboo, the fastest growing and high yielding perennial plant of the world has more than 1500 species and 1500 versatile socio-economic uses and ecological services. Ethiopia has two indigenous bamboo species namely Yushania alpina and Oxytenantheria abyssinica, covering about one million ha with a wide distribution. The objective of this paper is to highlight the potential of bamboo resources, challenges including biodeterioration damage, opportunities and future research directions towards its sustainable management and rational utilization.Area of study: Bamboo resources of EthiopiaMaterial and Methods: Reconnaissance survey was done to some parts of the bamboo growing potential areas in Ethiopia besides the literature review. Main results: The bamboo resource, despite its socio-economic and environmental benefits, currently, in most areas has been under high pressure due to land use changes, bamboo mass- flowering, poor processing with low value addition, and damage by biodeteriorating agents (termites, beetles and fungi). The preservative tests on Ethiopian bamboos revealed low natural durability and highlighted the paramount importance of appropriate protection measures such as Tanalith and vehicles used motor oil to increase durability, service life and rational utilization of bamboo-based products and structures as potential alternative construction and furniture material.Research highlights: Therefore, integrated research and development interventions involving different propagation and managements techniques, harvesting season, processing, value addition including proper seasoning and preservation technologies and marketing are recommended to fill the information and technological gaps on sustainable management and rational utilization of this fast growing and multipurpose bamboo resources in Ethiopia.Key words: Bamboo; challenges; management; socio-economic and environmental significance; utilization