321 research outputs found

    Yield determination in olive hedgerow orchards. I. Yield and profiles of yield components in north–south and east–west oriented hedgerows

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    A study of the vertical distribution of flowering and fruit set and of components of yield (fruit numbers, fruit size, and fruit oil content) was maintained for 2 years in N–S- and E–W-oriented olive hedgerows of comparable structure (row spacing 4m, hedgerow height to 2.5 m, width c. 1m) near Toledo, Spain (39.98N). Mean yield of the N–S orchard was 1854 kg oil/ha without difference between sides or years. Yield of the E–W orchard was greater in 2006, producing 2290 kg/ha, but only 1840 kg/ha in 2007, the same as the N–S orchard. The S side of the E–Worchard yielded more (59%) than the N side in 2007. In both orchards and years, most fruit was produced at 1.0–2.0m height and fruit density was the most influential component in these differences, reflecting more intense bud initiation in these upper layers. Other components that determined fruit number, fertile inflorescences, fruits per fertile inflorescence, and fruit drop were not significantly different between layers. Fruit characteristics depended on hedgerow position. In both N–S and E–W hedgerows, fruit high in the hedgerow was the largest, most mature, and with highest oil content. These differences were more marked in N–S than in E–W hedgerows. Fruit growth and development were concentrated from the middle of September until the end November. Oil content per fruit increased linearly during that period when 65% of final oil content was accumulated. Similar patterns were observed between sides. The results of yield and yield profiles are discussed in the general context of light interception. The results suggest the importance of hedgerow porosity, and distinct penetration patterns of direct-beam radiation through N–S and E–W hedgerows, as the basis for explanation of the high yield of the N side of E–W hedgerows

    Yield determination in olive hedgerow orchards. II. Analysis of radiation and fruiting profiles

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    Profiles of fruit density, fruit size, and oil content were measured on 12 occasions in 7 olive orchards in Spain and 2 in Australia. Orchard structure varied widely. Height ranged from 2.0 to 5.5 m, row spacing from 3 to 6 m, and canopy width from 0.7 to 3m. Most orchards were oriented north–south (N–S) but one in Spain was oriented close to east–west (E–W)(208NE–SW). All orchards in Spain were cv. Arbequina, and in Australia they were cvv. Barnea and Picual. Analyses with a model of interception and transmission that estimated interception by individual sides of hedgerows revealed that fruit size and oil content were strongly related to intercepted radiation during the month before harvest across all orchards. Relationships were also evident between fruit density and interception but varied among orchards and years, indicating the importance of other environmental and probably physiological effects. In N–S orchards of cv. Arbequina, average fruit size and oil content increased linearly from 0.40 g (dry weight) to 0.72 g, and from 36 to 49% (of dry weight), as daily intercepted PAR increased from 6 to 25 mol/m2 (15–60% of horizontally incident radiation). The general principles of response extended to E–W orchards. There, it was shown that generally large fruit with high oil content on S sides was consistent with the plateau responses to radiation evident in the more extensive N–S data. On the N side, however, and accounting for transmission through the hedgerow, both fruit size and oil content were greater than in positions intercepting equivalent radiation inN–S orchards. Examples are provided of the utility of responses of fruit density, size, and oil content in establishing combinations of row height, row width, and row distance to improve or maintain productivity in some of the orchards included in the study

    Los cultivos mediterráneos en China : el caso del olivar

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    El mercado del aceite de oliva en China tiene un gran potencial, por ello, hay un interés creciente en incrementar la superficie de olivo en el país. En este artículo se describe la historia reciente del cultivo del olivo en China, las características del clima y suelo de la zona donde actualmente se cultiva el olivo y la adaptación del olivo a estas condiciones

    Simulation of oil productivity and quality of N-S oriented olive hedgerow orchards in response to structure and interception of radiation

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    Simulations of oil yield and quality are presented for N–S oriented, hedgerow olive orchards of a range of structures (viz. canopy depth, canopy width, canopy slope and row spacing) using responses of yield and quality parameters to solar irradiance on canopy walls measured in a range of orchards, cv. Arbequina, in Spain. Results reveal that orchard yield of hedgerows of rectangular shape reaches a maximum when canopy depth equals alley width (row spacing−canopy width) and decreases at wider spacing, and/or with wider canopies, as the length of productive row decreases per unit area. Maximum yields for 4-m deep canopies were 2885 kg ha−1 at 1-m width and 5-m row spacing, 2400 kg ha−1 at 2-m width and 6-m spacing, and 2050 kg ha−1 at 3-m width and 7-m spacing. Illumination of canopies can be increased by applying slopes to form rhomboidal hedgerows. Substantial yield advantage can be achieved, especially for wide hedgerows, partly by closer row spacing that increases row length per unit area. By comparison, responses to latitude in the range 30–40◦ are small and do not warrant different row spacing. Oil quality parameters also respond to orchard structure. Responses are presented for oleic and palmitic acid, stability, and maturity index. Oleic acid content declines as alley spacing increases and is smaller, shallow than in wide, deep canopies. Palmitic acid content, stability, and maturity index increase with row alley spacing and are greater in narrow, shallow than in wide, deep canopies

    Diseño y manejo del olivar en seto : avances y retos

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    La conducción del olivar en seto en plantaciones comerciales se inició en España a principios de los 90. En el manejo y diseño del olivar en seto intervienen varios aspectos. Las dimensiones del seto deben permitir la recoleccion con vendimidora y una adecuada iluminación. En este documento se recogen los principales avances realizados en el conocimiento de la respuesta de la producción de aceituna a diferentes niveles de radiacion y su aplicación al diseño de los setos de olivo

    Yield characteristics of N–S oriented olive hedgerow orchards, cv. Arbequina.

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    Las caracteristicas de la aceituna dependen de la radiacion interceptada. En este trabajo se estudia esta relación en estratos de 11 olivares en seto de la variedad Arbequina orientados NS

    Diseño y manejo del olivar en seto: efecto en la producción y calidad del aceite

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    El olivar en seto adaptado a la recolección con vendimiadora modificada, supone una alternativa viable a los olivares preparados para la recolección con vibrador de tronco. Presenta como principales ventajas: altas producciones en los primeros años, bajo coste de recolección, menor mano de obra y recolección rápida en el momento óptimo. Sin embargo, estas características sólo son posibles con estructuras óptimas, mantenidas en el tiempo. La intercepción de la radiación solar es el factor determinante de la producción de aceite, así la estructura óptima del seto deberá tender a maximizar la iluminación de la copa. Debido a que el olivar en seto es de reciente implantación, se desconoce la respuesta de la producción y calidad de aceite en setos de diferentes tamaños en distintas localidades. Las simulaciones de producción y calidad de aceite para distintos diseños serán útiles para el sector a la hora de decidir la estructura óptima. En este artículo describimos los avances realizados en este sentido y los retos que, agricultores e investigadores, deberemos ir resolviendo

    Recent developments in monitoring and modelling airborne pollen, a review

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    Public awareness of the rising importance of allergies and other respiratory diseases has led to increased scientific effort to accurately and rapidly monitor and predict pollen, fungal spores and other bioaerosols in our atmosphere. An important driving force for the increased social and scientific concern is the realisation that climate change will increasingly have an impact on worldwide bioaerosol distributions and subsequent human health. In this review we examine new developments in monitoring of atmospheric pollen as well as observation and source-orientated modelling techniques. The results of a Scopus® search for scientific publications conducted with the terms ‘Pollen allergy’ and ‘Pollen forecast’ included in the title, abstract or keywords show that the number of such articles published has increased year on year. The 12 most important allergenic pollen taxa in Europe as defined by COST Action ES0603 were ranked in terms of the most ‘popular’ for model-based forecasting and for forecasting method used. Betula, Poaceae and Ambrosia are the most forecast taxa. Traditional regression and phenological models (including temperature sum and chilling models) are the most used modelling methods, but it is notable that there are a large number of new modelling techniques being explored. In particular, it appears that Machine Learning techniques have become more popular and led to better results than more traditional observation-orientated models such as regression and time-series analyses

    Contribution of Color Information in Visual Saliency Model for Videos

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    International audienceMuch research has been concerned with the contribution of the low level features of a visual scene to the deployment of visual attention. Bottom-up saliency models have been developed to predict the location of gaze according to these features. So far, color besides to brightness, contrast and motion is considered as one of the primary features in computing bottom-up saliency. However, its contribution in guiding eye movements when viewing natural scenes has been debated. We investigated the contribution of color information in a bottom-up visual saliency model. The model efficiency was tested using the experimental data obtained on 45 observers who were eye tracked while freely exploring a large data set of color and grayscale videos. The two datasets of recorded eye positions, for grayscale and color videos, were compared with a luminance-based saliency model. We incorporated chrominance information to the model. Results show that color information improves the performance of the saliency model in predicting eye positions
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