1,720,985 research outputs found
Effects of nitrogen foliar fertilization on the vegetative and productive performance of the olive tree and on oil quality
No full textThe correct management (dose, time of distribution) of N fertilization in olive growing is still not completely clarified but is nowadays essential in order to guarantee sustainable production. In this regard, in central Italy over a 4-year-period a study was carried out to investigate the effect of high nitrogen availability during oil accumulation in the fruit (second phase of fruit growth) on vegetative and productive activities of olive trees and oil quality. In May of each year, secondary branches were selected and girdled in their proximal part. Afterwards, half of the girdled branches were sprayed three times with a solution containing urea (2% w/w), whereas the other half was sprayed only with water. The nitrogen treatments did not cause any damage to the foliage and fruits nor did it cause appreciable changes in leaf photosynthesis and specific weight, fruit-drop, ripening pattern and weight, water and oil contents, pulp/pit ratio of the fruits, fatty acid composition, polyphenols content, and sensorial characteristics of the oil. The N provided via foliar fertilization during the oil accumulation phase in trees in conditions of good supply of N does not induce significant effects on the vegetative-productive activity of the tree
Application of Encapsulation Technology: In Vitro Screening of Two Ficus carica L. Genotypes under Different NaCl Concentrations
Full text linkSalinity stress represents an increasing issue for agriculture and has a great negative impact on plant growth and crop production. The selection of genotypes able to tolerate salt stress could be a suitable solution to overcome the problem. In this context, in vitro cultures can represent a tool for identifying the NaCl tolerant genotypes and quickly producing large populations of them. The possibility of exerting selection for tolerance to NaCl by using encapsulation technology was investigated in two genotypes of fig: 'Houmairi' and 'Palazzo'. The effects of five concentrations of NaCl (0, 50, 100, 150 and 200 mM) added to the artificial endosperm were tested on the conversion of synthetic seeds and on the growth of derived shoots/plantlets. Moreover, proline (Pro) and malondialdehyde (MDA), the enzymatic activities of catalase (CAT), guaiacol peroxidase (POD), and EL (Electrolytic Leakage), as well as the chlorophyll content, flavanols, anthocyanins, and Nitrogen Balance Index (NBI) were determined on shoots/plantlet. The obtained results clearly showed that 'Houmairi' and 'Palazzo' could tolerate salt stress, although a strong difference was found depending on each specific physiological pathway. Indeed, 'Houmairi' was revealed to be more tolerant than 'Palazzo', with different response mechanisms to salt stress. The use of encapsulated vitro-derived explants proved to be a useful method to validate the selection of genotypes tolerant to salinity stress. Further investigation in the field must validate and confirm the legitimacy of the approach
Planting systems for modern olive growing: Strengths and weaknesses
No full textThe objective of fully mechanizing olive harvesting has been pursued since the 1970s to cope with labor shortages and increasing production costs. Only in the last twenty years, after adopting super-intensive planting systems and developing appropriate straddle machines, a solution seems to have been found. The spread of super-intensive plantings, however, raises serious environmental and social concerns, mainly because of the small number of cultivars that are currently used (basically 2), compared to over 100 cultivars today cultivated on a large scale across the world. Olive growing, indeed, insists on over 11 million hectares. Despite its being located mostly in the Mediterranean countries, the numerous olive growing districts are characterized by deep differences in climate and soil and in the frequency and nature of environmental stress. To date, the olive has coped with biotic and abiotic stress thanks to the great cultivar diversity. Pending that new technologies supporting plant breeding will provide a wider number of cultivars suitable for super-intensive systems, in the short term, new growing models must be developed. New olive orchards will need to exploit cultivars currently present in various olive-growing areas and favor increasing productions that are environmentally, socially, and economically sustainable. As in fruit growing, we should focus on "pedestrian olive orchards", based on trees with small canopies and whose top can be easily reached by people from the ground and by machines (from the side of the top) that can carry out, in a targeted way, pesticide treatments, pruning and harvesting
Allelopathic effects of Artemisia vulgaris L. (mugwort) on seed germination and growth of Sinapis alba L., Triticum aestivum L. and Lolium multiflorum Lam.
No full textThe aims of this study were to evaluate allelopathic potential of different plant tissues of A. vulgaris and their activity against wheat (T. aestivum) and L. multiflorum, respectively one of the main crop in Italy and its most problematic weed due to resistance to ACCase inhibiting herbicides
Long-term effects of amendment with olive millwastewater on soil chemical properties, microbial community, and olive tree vegetative and productive activities
No full textThe long-term effects of the olive mill wastewater (OMWW) spreading on soil chemical properties, microbial community, and olive tree parameters have been far poorly investigated. Therefore, this study aims to evaluate the effect of OMWW application on an olive orchard, and samples were collected at two different depths (0–20 cm and 20–40 cm) and 14 days, one year and two years from the end of the OMWW spreading on soil chemical characteristics and soil microbial structures. Variations of soil chemical parameters (pH, salinity, available P, and waterextractable organic C) were observed particularly at 14 days after spreading at both depths. All these parameters reached similar values to the soil after two years, except for available phosphorus. Firmicutes, Proteobacteria, and Actinobacteria are the most abundant phyla: Only Firmicutes were negatively affected by the OMWW spreading after 14 days, suggesting that Gram-positive bacteria were probably negatively influenced by the addition of OMWW. The abundance of bacterial taxa in the soil is restored along time, except for the decrease of Firmicutes. This evidence suggests that the OMWW spreading in the long term does not affect the endemic soil bacterial community of the olive grove, as well as leaf net photosynthesis, the olive tree vegetative activity, yield, and fruits characteristics
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
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