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The effects of chestnut apical bud positions on vegetative and reproductive annual growth
No full textThe growth and fruiting pattern of chestnut annual branches was investigated in a traditional sweet chestnut (Castanea sativa Mill. ‘Marrone di Castel del Rio’) orchard. The development of the annual apical shoot, from the top four apical buds, was described in one-year-old branches, randomly selected in the orchard. A total of 60 shoots were weekly measured in length and diameter from bud break (07 BBCH stage) to a week before burr fall (83 BBCH stage). On the same annual shoot, once female inflorescences were well differentiated and fully receptive (65 BBCH stage), the burr diametral growth was also weekly measured and the number of burrs, in each shoot, counted. At harvest, nut quality (fresh weight and diameter) was also assessed. For each annual shoot, length and burr diameter absolute growth rate (AGR) were calculated. The shoot vegetative growth showed a rapid increase in the first part of the season, reaching a peak, in absolute growth rate, in the middle of May. Later, their growth reduced and being constant throughout the rest of the season. Shoot showed a reduced vegetative vigour, form the apical to the bottom part of each branch, although a limited presence of burrs in the lower ones. Once shoot stop completely their growth (middle of June), burr started to increase their growth rate, likely acting as the major sink. The apical bud, although carrying the highest number of burrs per shoot, showed generally the highest growth rate along the season with also improved nut quality traits recorded at harvest. These preliminary results highlight the importance of the apical bud in sustaining chestnut yield and quality
Growth analysis of sweet chestnut burr in two seasons with differing weather conditions
Full text linkIn Italy, most of the traditional sweet chestnut (Castanea sativa Mill.) orchards are still non-irrigated since they are located in mountain-hill areas with climate conditions that used to be optimal to sustain the vegetative and reproductive growth of this nut tree species. Nowadays, the increase of summer temperatures and the decrease of rainfall (due to climate change) are affecting negatively chestnut physiological performances. The aim of this experiment was to study sweet chestnut burr growth in two seasons, one warm/dry and one mild/rainy (2017 and 2018, respectively). The study was carried out in a traditional rainfed chestnut orchard. The seasonal burr growth was measured weekly from 30 days after full bloom (DAFB) to the beginning of burr valves opening. Air temperature and daily precipitation were measured at a nearby weather station. The results of this study highlighted that chestnut burr growth seems to be affected by seasonal weather conditions. Indeed, in 2017, the high summer temperatures and the moderate rainfall in summer (227 mm) and winter-spring (385 mm) appeared to affect negatively burr absolute growth rate (AGR; 0.31 mm day-1) and consequently final burr size (46.2 mm). The mild and rainy weather conditions that occurred in 2018 (663 and 340 mm of winter-spring and summer precipitation, respectively) positively influenced burr AGR (0.54 mm day-1) and therefore its final size (60.8 mm). These preliminary results suggest that the introduction of irrigation as a common management practice for chestnut orchards may promote their resilience to climate change with a positive effect on their productivity and fruit quality
Castanea sativa burr growth in its final stages
No full textThe daily growth pattern and vascular flows of Castanea sativa Mill. (‘Marrone di Castel del Rio’) burrs, were monitored during a sensitive burr growing phenological stage (nut filling), through plant-based sensors (fruit gauges) connected to a wireless data-logger system. Environmental parameters were also recorded by a weather station placed in the middle of the orchard. The daily burr growth pattern was generally characterized by a rapid shrinkage in the early afternoon, corresponding to the highest vapour pressure deficit (VPD), followed by nocturnal swelling until the early morning. Daily burr net growth was positively influenced by high air relative humidity (RH) values and precipitation events while negatively affected by VPD. Vascular flows confirm that the daily shrinkage was due to high burr water losses by transpiration. The xylem was fully active and able to replenish the amount of water lost during the day by the transpiration process. Phloem inflow was the major component for the net daily burr growth. These observations, coupled to the increase in nut dry mass content typical of this stage, suggest a passive model of burr phloem unloading, able to persist at high levels of RH, likely energized by the high burr epidermal transpiration. This study aimed both to establish the influence of environmental conditions on daily burr growth and to identify the vascular flow model supporting burr growth during a period of strong demand by the nut. Knowing and monitoring, in real-time, the burr daily growth, could be promising for the adoption of smart and sustainable practices for chestnut orchard management, especially in areas characterized by water shortages
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
Produrre energia in frutteto con coperture fotovoltaiche
No full textIl settore frutticolo è considerato, rispetto alla totalità dei settori agricoli, il meno impattante, ma il suo livello di emissioni è comunque considerevole, con valori che oscillano tra 4,5-10 t/ha di gas serra. Applicando film plastici fotovoltaici è possibile produrre energia e, al contempo, ridurre eccesso luminoso, traspirazione e consumo idrico
L’inerbimento del pereto può aumentare la sostenibilità aziendale
No full textI risultati del progetto Ifasa evidenziano benefici agronomici significativi tra cui il miglioramento della struttura del suolo, una maggiore fertilità e una minore compattazione. Limitata la proliferazione di malerbe che favoriscono la maculatura brun
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