1,720,973 research outputs found
Calibrazione del metodo fisico di separazione della SOM nelle frazioni libera, occlusa negli aggregati e stabilizzata dai minerali in Andosuoli campani
No full textProblematiche metodologiche nell’applicazione delle tecniche di diffrazione laser nello studio della granulometria dei suoli
No full textA modelling approach to discriminate contributions of soil hydrological properties and slope gradient to water stress in Mediterranean vineyards
No full textGrapevine is a widespread crop for grape and wine production, often cultivated on hilly areas. Moderate vine water stress plays an important role in determining high-quality viticulture. However, a precise quantification of the effect of hydraulic properties and slope gradient on hilly soil water balance and consequently on vine stress has not yet been addressed in the literature. The slope-gradient effect is generally taken for granted, without providing experiments validating such a qualitative assumption. We tested the hypothesis that soil hydraulic properties play a greater role than slope gradient in driving soil water status and vine stress. In two consecutive years, we studied an “Aglianico” vineyard grown along a 90 m slope, with up-slope soil having lower water holding capacity than down-slope. Up-slope vines were more stressed, as shown by lower leaf water potential, stomatal conductance, leaf CO2 assimilation and leaf area index, than down-slope vines.
Water flow was simulated by using the Hydrus (2D/3D) model, calibrated and validated towards a two-year set of soil water content measurements. Significantly lower soil pressure head and higher transpiration occurred in the up- than the down-slope site.
A viable procedure was developed to separate the effects of soil hydraulic properties and slope gradient by modelling soil water balance and therefore vine transpiration with and without the slope gradient. The simulations indicated that the difference in seasonal relative transpiration of 8% in 2011 and 5% in 2012 between the two sites was due to their differing soil hydraulic properties, and that the slope gradient had no contribution to this variation
Soil pollution in a decommissioned shooting range: a preliminary survey of the spatial variability of legacy pollutants
No full textOutdoor shooting ranges provide recreational facilities for millions of people in the world. However, there are many negative effects on the environment and public health arising from this activity.
In particular, potential risks are mostly associated with the residential or agricultural use of decommissioned outdoor ranges, where bullets and targets have been deposited during the shooting activity.
This is the case of an outdoor shooting range in Campania region (Southern Italy), located in an area of historical and naturalistic value, close to the ancient Etruscan village of Suessola (VII century b.C.). Specifically, the study site is located within an agricultural land declared unsuitable for agricultural and forest-pastoral production by the Italian Ministry of Agricultural, Food and Forestry Resources, due to an extensive long term soil contamination associated with Pb, Sb, PAHs, dioxins, PCBs and C> 12 hydrocarbons.
With the purpose of planning a detailed site characterization of the shooting range area, a preliminary environmental survey was carried out by means of field investigations (ultrasonic penetrometry, electromagnetic induction - EMI - and gamma spectroscopy) and geochemical prospecting.
Cone index data, obtained by ultrasonic penetrometer measurements, indicated the presence of a very dense, hard and impenetrable to hand hauger layer, recognised as travertine rock, from 25 to more than 55 cm of depth, and dipping northward.
Continuous EMI data and gamma spectroscopy (K %, eU ppm, eTh ppm) parameters were acquired in the field in order to identify homogeneous zones in which further geochemical investigations should have been focused. In fact, apparent electrical conductivity (ECa) map, consistently with the gamma ray dose rate distribution map, allowed to highlight three separated singularity areas N-S oriented.
XRF analyses, carried out through a portable analyzer on soil samples collected along soil profiles digged from topsoil until the travertine layer, showed a high contamination by Pb (greater than 1000 mg/kg) and Sb (greater than 30 mg/kg) in the first 15 cm of depth, at a distance of approximately 90 m from the shooting lanes.
Chemical analyses were also performed on 32 topsoil samples collected on the basis of a regular grid across the study area. Concentrations of 13 PAHs compounds were determined and the highest values were found close to the firing lanes where in soil a huge amount of shooting target fragments are present.
The preliminary results showed how the contamination due to the previous activity in the area produced a spatial distribution of contaminats differentiated on the basis of their source material and their role in the shooting process
Ischia landslides (Italy): a multidisciplinary approach aimed to the knowledge of soil properties
No full textAn integrated approach (chemical, hydrological, mineralogical and micro-tomographic) has been used to study the soils of the landslides occurred in the Ischia island (Italy) on April 2006. The study has been carried out on three soil profiles sampled on representative detachment crowns. The main outcome indicates: (i) presence of volcanic soils, very rich in primary glass, characterised by the presence of poorly ordered kaolinite in all horizons and expandable clay minerals only in the deepest horizons (CBb and Cb), (ii) high values of water content near saturation for all soil horizons, (iii) a relevant vertical discontinuity of soil physical properties. In particular, the deep silty horizon (Cb) retains high amounts of water at low matric potential and shows the lowest value of the saturated hydraulic conductivity than the other horizons. The micro-tomographic analysis of this deep horizon indicates a very complex intra-aggregate pore space, which seems an important factor influencing the specific rheological behaviour of this sliding horizon.
In terms of pedogenetic processes, the soils of M. Vezzi northern slope are very different from those described for other catastrophic landslides of the Campania region (Sarno, Quindici, etc.), but they have in common the presence, along the soil profile, of marked physical discontinuities surely contributing to the initiation mechanisms of the landslides
Assessing the dynamics of soil salinity with time-lapse inversion of electromagnetic data guided by hydrological modelling
Full text linkIrrigated agriculture is threatened by soil salinity in numerous arid and semi-arid areas of the world, chiefly caused by the use of highly salinity irrigation water, compounded by excessive evapotranspiration. Given this threat, efficient field assessment methods are needed to monitor the dynamics of soil salinity in salt-affected irrigated lands and evaluate the performance of management strategies. In this study, we report on the results of an irrigation experiment with the main objective of evaluating time-lapse inversion of electromagnetic induction (EMI) data and hydrological modelling in field assessment of soil salinity dynamics. Four experimental plots were established and irrigated 12 times during a 2-month period, with water at four different salinity levels (1, 4, 8 and 12dSm−1) using a drip irrigation system. Time-lapse apparent electrical conductivity (σa) data were collected four times during the experiment period using the CMDMini-Explorer. Prior to inversion of time-lapse σa data, a numerical experiment was performed by 2D simulations of the water and solute infiltration and redistribution process in synthetic transects, generated by using the statistical distribution of the hydraulic properties in the study area. These simulations gave known spatio-temporal distribution of water contents and solute concentrations and thus of bulk electrical conductivity (σb), which in turn were used to obtain known structures of apparent electrical conductivity, σa. These synthetic distributions were used for a preliminary understanding of howthephysical context may influence the EMI-based σa readings carried out in the monitored transects as well as being used to optimize the smoothing parameter to be used in the inversion of σa readings. With this prior information at hand, we inverted the time-lapse field σa data and interpreted the results in terms of concentration distributions over time. The proposed approach, using preliminary hydrological simulations to understand the potential role of the variability of the physical system to be monitored by EMI, may actually allow for a better choice of the inversion parameters and interpretation of EMI readings, thus increasing the potentiality of using the electromagnetic induction technique for rapid and non-invasive investigation of spatio-temporal variability in soil salinity over large areas
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
Le frane d’Ischia (Italia): un approccio integrato finalizzato alla protezione ambientale
No full textUn approccio integrato (chimico, idrologico, mineralogico e microtomografico) è stato usato per studiare i suoli delle frane (colate rapide di fango) avvenute ad Ischia nell’aprile del 2006. Lo studio è stato condotto su campioni di suolo prelevati da tre profili pedologici rappresentativi descritti nelle nicchie di distacco delle frane. Il principale risultato indica: (i) presenza di suoli vulcanici, molto ricchi di vetro primario, caratterizzati dalla presenza di caolinite a basso ordine cristallino in tutti gli orizzonti e minerali argillosi a reticolo espandibile negli orizzonti più profondi (2CB e 2C), (ii) elevata capacità di ritenzione idrica in tutti gli orizzonti del suolo, (iii) una discontinuità verticale delle proprietà fisiche del suolo. In termini di processi pedogenetici, i suoli del versante nord del M. Vezzi sono molto diversi da quelli descritti per le altre frane catastrofiche della regione Campania (Sarno, Quindici, ecc), ma hanno in comune la presenza, lungo il profilo del suolo, di una marcata discontinuità fisica che certamente contribuisce ai meccanismi di innesco delle frane
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
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