Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Water-use efficiency of irrigated biomass sorghum in a Mediterranean environment
Get PDFA large interest is currently addressed to the no-food crops as an alternative source of energy. One of these crops is the biomass sorghum (Sorghum bicolor L. Moench) thanks to its high biomass productivity and high use efficiency of solar radiation and water. Aim of the research is assess the biomass sorghum response to the water in the Mediterranean environment. Biomass sorghum was subjected to four irrigation regimes, at 50, 75, 100 and 125% of ETc for three years (2008, 2009 and 2010). Water use efficiency (WUE), irrigation water use efficiency (IWUE) and water stress index (WSI) were calculated. Plant dry matter and green area index resulted different among the three years and the differences among irrigation treatments were more evident in 2009. The different soil water content at sowing among the three experimental years, affected the growth path during the growing crop cycle, explaining differences in term of biomass accumulation, leaf expansion and water consumption. WUE was higher in 2009 than in 2008 and 2010 with no differences among irrigation treatments for the first and third experimental year. WU ranged between 891 and 566 mm, the aboveground dry matter biomass between 4097 and 1825 g m-2 and WUE between 8.49 and 4.00 kg m-3. IWUE, similarly to WUE, was higher in the second year than in the first and third year, but with differences among irrigation treatments in the 2008 and 2010. WUE calculated from WU normalized with VPD gave a more stable parameter in the three years. This research showed the suitability of biomass sorghum as energy crop in Mediterranean environment and its ability to use water efficiently
Strategies to control odours in livestock facilities: a critical review
Get PDFOdours generated in livestock buildings constitute one of the most relevant air quality issues of intensive livestock production. Reducing nuisance episodes related to odour exposure is therefore essential for a sustainable livestock production. In this study, the state-of-the-art on odour mitigation techniques in livestock housing is critically reviewed. Scientific advances in the last decade are revised and research needs are also identified. The complex nature of livestock odours is firstly reviewed and examined. Then, the most relevant odour control strategies are analyzed in terms of present knowledge and future needs. The strategies considered are: nutritional strategies, manure additives, building design, air filtration, manure covers, manure treatment systems and windbreaks. Finally, future research needs and priorities when establishing mitigation techniques are identified. Despite important recent advances, there are still some challenges for scientists, producers and regulators, particularly related to field evaluation of odours. Therefore, to control livestock odours effectively, using standardized field assessment techniques will be required. Also, investigating measurement and model errors may be useful to better understand the limitations of the current methods, as well as to identify research priorities
Technical efficiency of Greek olive growing farms: a robust approach with panel data
Get PDFThe assessment of technical efficiency in the agricultural sector and the influence of exogenous (environmental) variables on the production process has been a major topic of economic research especially for managers and policy makers. The methological innovation of the present study involves the impact of environmental variables on efficiency and the utilization of panel data for the empirical analysis. This has been pursued using full nonparametric robust frontier techniques (the alpha-quantile estimator) and a panel data set of olive growing farms in Greece from the Farm Accountancy Data Network of the EU. According to the empirical results, the ratio of owned to total land, the ratio of family to total labor, the degree of specialization, and a farm’s location have a statistically significant impact on performance, which is not constant but varies over the 2006 to 2009 period considered
A comparison of three different cooling systems in parral type greenhouses in Almería
Get PDFIn warm climates, high temperature can limit growth and development of greenhouse crops and their product quality. Therefore greenhouse cooling has a high-priority to reduce these adverse effects. Together with natural ventilation, shade produced by whitewashing the greenhouse roof is the most usual cooling method in the whole of the Mediterranean area. However, this technique is not homogeneous; it is not selective and not adjustable. This inconvenience can be overcome by the use of other techniques such as shading with folding or rolling screens and/or evaporative cooling. This work evaluates three cooling techniques in parral greenhouses using a sweet pepper crop: whitening, shading with a mobile internal screen and cooling with a low pressure fog system. The latter gave the highest reduction in air temperature in the greenhouse in warm periods. However, final water consumption in the fog system was 319 mm, whereas irrigation water consumption was 520 mm. The evaporative cooling system, with 6.5 kg m-2 of marketable production and the use of interior shade screens (with 6.7 kg m-2), did not increase the yield obtained by means of traditional whitening (7.1 kg m-2) used by growers in the are
Estimation of vector propensity for Lettuce mosaic virus based on viral detection in single aphids
Get PDFLettuce mosaic virus (LMV) is transmitted by aphids nonpersistently causing severe disease outbreaks in commercial lettuce crops. New strategies to control plant viruses have arisen based on molecular techniques, which analyze plantvirus- vector interactions. In this work, two PCR-based methods with a previous immunocapture phase, have been developed to detect LMV in single aphids. Detection rates using a RT-nested-PCR method in single aphids and transmission efficiency of Myzus persicae (vector species) and Nasonovia ribisnigri (nonvector species) were compared. Although the percentage of viruliferous aphids for N. ribisnigri (45.8 ± 2.3) was higher than for M. persicae (39.2 ± 3.5) after the same acquisition access period, N. ribisnigri was unable to transmit the virus while M. persicae proved to be an efficient vector (with a transmission rate per single aphid of 10.4 ± 0.8). A method was proposed to estimate vector propensity for nonpersistent viruses based on the relationship between the percentage of viruliferous aphids and their transmission ability. This methodology could be applied to decision-making and implementing control strategies to prevent virus spreadin
Empirical guidelines for forest management decision support systems based on the past experiences of the expert's community
Get PDFAim of the study: Decision support systems for forest management (FMDSS) have been developed world wide to account for a broad range of forest ecosystems, management goals and organizational frameworks (e.g. the wiki page of the FORSYS project reports 62 existing FMDSSs from 23 countries). The need to enhance the collaboration among this diverse community of developers and users fostered the rise of new group communication processes that could capture useful knowledge from past experiences in order to efficiently provide it to new FMDSS development efforts.Material and methods: This paper presents and tests an exploratory process aiming to identify the empirical guidelines assisting developers and users of FMDSS. This process encompasses aDelphi survey built upon the consolidation of the lessons-learned statements that summarize the past experiences of the experts involved in the FORSYS project. The experts come from 34 countries and have diverse interests, ranging from forest planners, IT developers, social scientists studying participatory planning, and researchers with interests in knowledge management and in quantitative models for forest planning.Main results: The proposed 37 empirical guidelines that group 102 lessons-learned cover a broad range of issues including the DSS development cycle, involvement of the stakeholders, methods, models and knowledge-based techniques in use.Research highlights: These results may be used for improving new FMDSS development processes, teaching and training and further suggest new features of FMDSS and future research topics. Furthermore, the guidelines may constitute a knowledge repository that may be continuously improved by a community of practice.Keywords: Forest management; guidelines; guidelines definition process; lessons learned; decision support systems; system architecture; knowledge management; participatory planning; Delphi
Silviculture conditions and wood properties of Samanea saman and Enterolobium cyclocarpum
Get PDFAim of study: The objective of this work is to examine wood properties of a mixed plantation of Samanea saman and Enterolobium cyclocarpum, combined with native species of Costa Rica.Area of study: Mixed plantation in dry tropical zone of Costa Rica.Material and Methods: It was measured by total diameter, heartwood, bark thickness, several physical wood properties (green density, specific gravity, volumetric, tangential and radial shrinkage and moisture content) and wood color.Main results: The largest of this diameter are reached when S. saman is planted with E. cyclocarpum, E. cyclocarpum and Swietenia macrophylla and Simarouba glauca. Meanwhile the largest total diameter and heartwood in E. cyclocarpum was found when this species is planted with Dalbergia retusa. Heartwood percentage, bark percentage, and some physical properties are not affected when S. saman or E. cyclocarpum are planted with other species. However, parameters of wood color were affected mixture plantation of S. saman or E. cyclocarpum with other species. The lowest difference between wood from mixed plantations and wood from trees growing in native forests is produced when S. saman is mixed with E. cyclocarpum, but this last species is mixed with Hymenaea courbaril and produced wood with the lowest difference in wood color compared to trees growing in the natural forest.Research highlights: S. saman and E. cyclocarpum tress planted in a mixed plantation produce variation in breast diameter, physical properties, heartwood percentage and wood color.Keywords: silvicultural condition; wood properties; tropical species; plantation species.Aim of study: The objective of this work is to examine wood properties of a mixed plantation of Samanea saman and Enterolobium cyclocarpum, combined with native species of Costa Rica.Area of study: Mixed plantation in dry tropical zone of Costa RicaMaterial and Methods: It was measured by total diameter, heartwood, bark thickness, several physical wood properties (green density, specific gravity, volumetric, tangential and radial shrinkage and moisture content) and wood color.Main results: The largest of this diameter are reached when S. saman is planted with E. cyclocarpum, E. cyclocarpum and Swietenia macrophylla and Simarouba glauca. Meanwhile the largest total diameter and heartwood in E. cyclocarpum was found when this species is planted with Dalbergia retusa. Heartwood percentage, bark percentage, and some physical properties are not affected when S. saman or E. cyclocarpum are planted with other species. However, parameters of wood color were affected mixture plantation of S. saman or E. cyclocarpum with other species. The lowest difference between wood from mixed plantations and wood from trees growing in native forests is produced when S. saman is mixed with E. cyclocarpum, but this last species is mixed with Hymenaea courbaril and produced wood with the lowest difference in wood color compared to trees growing in the natural forest.Research highlights: S. saman and E. cyclocarpum tress planted in a mixed plantation produce variation in breast diameter, physical properties, heartwood percentage and wood color.Keywords: silvicultural condition, wood properties, tropical species, plantation species
Short Communication. Effect of the health status and geographical origin on the cork production characteristics of Western Algeria cork oak stands
No full textAim of study: To analyze the effect of health status on cork production, analyzing if this influence is uniform or is affected by site conditions.Area of study: Two Western Algerian cork tree forests have been studied: M’Sila located in the coastal plains under semiarid climate, and Zarieffet, located in the mountainous interior under sub-humid climate.Material and Methods: 40 trees were selected in each forest and classified according to their health status as healthy, weakened, or decaying. A sample of cork from each tree has been obtained to measure the key variables related to cork production. A two-way ANOVA was performed considering two factors: site and health status.Main results: Quercus suber L. productivity is affected by the vitality of trees in the same way in both sources, showing values between 5.96 ± 7.1 kg • m-2 (coast, weakened trees) and 8.13 ± 0.45 kg • m-2 (mountain, healthy trees). The health status also affects the number and area of pores, especially in the cork oak groves of the coast, where the coefficient of porosity ranges from 3.79 ± 0.84% (healthy trees) to 8.11 ± 1.91% (decaying trees). The variables where the site has presented a stronger effect are those related to the amount of cork produced by the phellogen (density -kg·l-1, p<0.000- and productivity -kg·m-2, p=0.001-), and pore density (1·cm-2, p=0.001). Scrap thickness (mm) and porosity (%) show a smaller effect although still representative (p=0.041 and 0.038 respectively). Porosity and pore density show interaction site*health status. They all have higher values in the mountain (Zarieffet) than in the coast (M’Sila). The effect of tree vitality on the formation of pores in the cork oak phellogen is lower in the mountain than in the coast. No significant effects were found for any of the two factors neither on the annual growth rate nor on the thickness of the cork.Research highlights: Results lead to the conclusion that the effect of health status on traumatic phellogen formation and activity is clear but not uniform. Further studies are necessary for a deeper understanding of the effect of stress situations on pore formation and characteristics.Keywords: mean annual growth; density; productivity; porosity; deca
Contractual arrangements and food quality certifications in the Mexican avocado industry
Get PDFThe adoption of private quality certifications in agrifood supply chains often requires specific investments by producers which can be safeguarded by choosing specific contractual arrangements. Based on a survey data from avocado producers in Mexico, this paper aims to analyze the impact of transaction costs and relationship characteristics of the joint choice of contractual arrangements and quality certifications. Using a bivariate probit model, it shows that a producer’s decision to adopt private quality certifications is directly linked to high levels of asset specificity and price. In order to ensure the high level of specificity under the presence of low levels of price uncertainty, producers have relied on relational governance supported by the expectation of continuity in their bilateral relationships with buyers.The adoption of private quality certifications in agrifood supply chains often requires specific investments by producers which can be safeguarded by choosing specific contractual arrangements. Based on a survey data from avocado producers in Mexico, this paper aims to analyze the impact of transaction costs and relationship characteristics of the joint choice of contractual arrangements and quality certifications. Using a bivariate probit model, it shows that a producer’s decision to adopt private quality certifications is directly linked to high levels of asset specificity and price. In order to ensure the high level of specificity under the presence of low levels of price uncertainty, producers have relied on relational governance supported by the expectation of continuity in their bilateral relationships with buyers
Comunicación corta. Análisis molecular de los RNAs genómicos 1 y 2 del primer aislado del Arabis mosaic virus detectado en España infectando vid
No full textThe Arabis mosaic virus (ArMV) is one of the causative agent of the grapevine fanleaf disease, one of the most widespread and damaging viral diseases of grapevine. Recently, the ArMV has been detected in Spanish vineyards, and its determination and molecular characterization was undertaken. To this aim, the nucleotide sequence of the genomic RNAs 1 and 2 of the first isolate of ArMV infecting grapevine detected in Spain (ArMV-DU13) has been determined. The ArMV-DU13 genomic sequences were compared to the corresponding sequences of other isolates of ArMV, or nepoviruses. The most divergent genes among ArMV isolates were the X1 and VPg genes on the RNA 1, and the 2A gene on the RNA 2, with identity levels at the amino acid level of 78% (X1 and VPg) or 69% (2A) between the most distant isolates. Interestingly, the VPg genes were identical between the two grapevine isolates ArMV-Du13 and –NW, suggesting a possible implication of the host. The phylogenetic analysis of the RNA 2 showed that the Spanish isolate was close to Grapevine fanleaf virus isolates. The analysis of the full length RNA 2 suggests a recombination event between ArMV-DU13 and GFLV-GHu isolates between nucleotides 54 and 586 in the ArMV-DU13 isolate. Altogether, these results confirm the high variability between isolates of ArMV, and will be helpful to design more appropriate and reliable molecular diagnostic techniques for the control of this emerging virus in Spain.Arabis mosaic virus (ArMV) es uno de los agentes causales de degeneración infecciosa, una de las enfermedades más extendidas y problemáticas en vid. Recientemente, ArMV ha sido detectado en viñedos de España y en este estudio se ha caracterizado molecularmente. Se ha determinado la secuencia nucleotídica de los RNAs genómicos 1 y 2 del primer aislado de ArMV infectando vid (ArMV-DU13). Las secuencias genómicas se compararon con otras secuencias de ArMV y nepovirus. Los genes más divergentes entre los aislados de ArMV fueron X1 y VPg en el RNA 1, y el gen 2A en el RNA 2, con niveles de identidad a nivel aminoacídico del 78% (X1 y VPg) y 69% (2A) entre los aislados más distantes. Los genes VPg fueron idénticos entre los aislados de vid ArMV-Du13 and -NW, sugiriendo una posible implicación del huésped El análisis filogenético de RNA 2 mostró que el aislado español estaba próximo a los aislados de Grapevine fanleaf virus. El análisis de la secuencia completa de RNA 2 sugiere un evento de recombinación entre ArMV-DU13 y GFLV-GHu entre los nucleótidos 54 y 586 en el aislado ArMV-DU13. Estos resultados confirman la gran variabilidad entre aislados de ArMV y permitirán diseñar técnicas de diagnóstico molecular más apropiadas para el control de este virus emergente en España