1,720,957 research outputs found
Effect of foliar boron application on olive (Olea europaea L.) fruit set and yield
No full textBoron is an essential element for higher plants and its fundamental role in plant vegetative growth and reproductive process is clearly recognised. Several studies report its crucial function in improving flower fertility and fruit setting percentage in olive. Deficiencies phenomena, responsible also for suboptimal yield, are observed in olive groves and are sometimes not identified. As recent studies have shown that B is mobile in the phloem of all species that utilize polyols as a primary photosynthetic metabolite, such as olive, then B deficiencies may be treated with foliar applications. The aim of the present research was to evaluate the efficacy of a foliar fertiliser containing B in increasing fruit set and yield in olive. The study was carried out in 2004 on an olive orchard, cv. Leccino, located in Southern Italy (BR), during a bearing year. A control was compared to a B fertilised treatment that received two foliar applications with a product containing 9 g B 100 g-1, at 270 mg B L-1, in pre and post anthesis. During the crop cycle, the fruit setting percentage, on 2 plants per plot and 2 shoots per cardinal direction and, at harvesting, the main quantitative yield parameters were determined. Total number of flowers and fruits per shoot varied significantly with shoot length and canopy exposition. Neither fruit set nor yield were influenced by B foliar application. Average values of 4.29 and 4.65%, for fruit set percentage, and 32.2 and 30.6 kg olives per plot, for yield, were recorded, respectively for treated and not treated plants. Further research is needed to evaluate the efficacy of different application timing and amounts and to assess plant response in low fruit load years
Leaching effect of rainfall on soil under four-year saline water irrigation
Full text linkIn the context of the overall competition for water resources it is important to understand the complex dynamics of crop water management including evapotranspiration, water quality, and leaching requirement, each of them depending on the site-specific conditions. The research started with grain maize and continued with sunflower, grain maize, and wheat, at the experimental field. On both grain maize and sunflower, 10 irrigation treatments were compared that resulted from the factorial combination of two types of water (fresh and brackish water) with five irrigation regimes; the scheduled treatments were applied by furrow irrigation. The amount of salts brought into the soil with the irrigation water during the three irrigation seasons of our trial increased shifting from the lowest to the highest irrigation regime and with the increase of salinity in the irrigation water. From the study of salt distribution in the soil it follows that at the end of the irrigation season the salt concentration increased by passing from the middle of the furrow, a zone more subject to leaching during irrigation, to the intermediate zone between the furrow and the ridge, and in the middle of the ridge between two contiguous furrows, an area of confluence of the wetting and salt accumulation fronts. The leaching water supplied during the irrigation season was poorly efficient in leaching the salts brought in through irrigation, whereas the rainfall water of the autumn-winter period after the irrigation season ensured a good control of soil salinit
Effect of water salinity and irrigation regime on maize (Zea mays L.) cultivated on clay loam soil and irrigated by furrow in Southern Italy
No full textMaize is a crop with high irrigation needs in Italy. In many cultivated areas of the world, the water used for irrigation has a high salinity. To limit the damage caused by the salts provided by irrigation, suitable irrigation strategies can be adopted in relation to the crop, soil characteristics and rainfall regime. Therefore, in order to evaluate the most appropriate irrigation strategy to be used in the cultivation of maize on a clay loam red soil, subject to salinity, a research on a four-year crop rotation was carried out in southern Italy. Maize grain yield and yield characteristics irrigated by furrow with two water salinity levels and five different irrigation regimes, were compared. Grain yield was reduced by 34% in the third crop rotation year when the soil salinity, on average, raised from 3.8 to 7.4 dS m−1. Higher yield occurred restoring 100% of maximum crop evapotranspiration, instead of leaching requirement application which did not affect yield. Soil salinity improved grain protein content and reduced grain moisture content. Rainfall was not sufficient to leach all salts supplied by irrigation. The leaching requirements did not reduce the soil salinity and the harmful effect of salinity on maize yield, because of more salts supplied by higher irrigation volumes
Maize Yield Response, Root Distribution and Soil Desiccation Crack Features as Affected by Row Spacing
Full text linkPlant density is among the most critical factors affecting plant yields and resource use efficiency since it drives the exploitation of the available resources per unit area, root distribution and soil water losses by direct evaporation from the soil. Consequently, in fine-textured soils, it can also affect the formation and development of desiccation cracks. The aim of this study, carried out on a sandy clay loam soil in a typical Mediterranean environment, was to investigate the effects of different row spacings of maize (Zea mais L.) on yield response, root distribution and the main features of desiccation cracks. The field experiment compared bare soil and soil cropped with maize using three plant densities (6, 4 and 3 plants m−2), obtained by keeping the number of plants in a row constant and varying the distance between the rows (0.5–0.75–1.0 m). The highest kernel yield (16.57 Mg ha−1) was obtained with the greatest planting density (6 plants m−2) with a row spacing of 0.5 m; significantly lower yields were recorded with spacings of 0.75 and 1 m, with a decrease of 8.09% and 18.24%, respectively. At the end of the growing season, soil moisture in the bare soil was on average 4% greater in comparison to the cropped soil and was also affected by row spacing, decreasing with the decrease in the inter-row distance. An inverse behaviour was observed between soil moisture and both root density and desiccation crack size. Root density decreased to the increase in soil depth and to the increase in distance from the row. The pluviometric regime occurred during the growing season (total rainfall of 343 mm)-resulted in the formation of cracks of reduced size and with an isotropic behaviour in the bare soil, whereas in the cultivated soil, the cracks were parallel to the maize rows and increased in size with decreasing inter-row distance. The total volume of the soil cracks reached a value of 135.65 m3 ha−1 in the soil cropped with a row distance of 0.5 m, and was about ten times greater in comparison to the bare soil and three times greater in comparison to a row spacing of 1 m. Such a volume would allow a recharge of 14 mm in the case of intense rainy events on soil characterised by low permeability
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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