Search results for "Sistemazioni idraulico-forestali"
showing 10 items of 760 documents
Detecting crop water requirement indicators in irrigated agroecosystems from soil water content profiles: An application for a citrus orchard.
2022
Abstract Most perennial crops sensitive to water scarcity, such as citrus, can benefit from efficient water management, which allows for reduced water consumption while increasing crop production on a long-term basis. However, when implementing water-saving strategies, it is necessary to monitor soil and/or plant water status in order to determine crop water demand. A plethora of devices providing indirect measurements of volumetric soil water content, such as the “drill and drop” multi-sensors probes (Sentek, Inc., Stepney, Australia), have been developed over the last decade. The objective of the paper was to analyse time-series of soil water content profiles and meteorological data colle…
Effect of laboratory procedures on the integrity of a sandy-loam soil sample for bi-directional measurement of saturated hydraulic conductivity
2011
Practical and validated methods to measure anisotropy of saturated, Ks, or field-saturated, Kfs, soil hydraulic conductivity on a single soil sample are still lacking. The objective of this investigation was to test factors affecting anisotropy measured in a sandy-loam soil by the constant-head laboratory permeameter and the modified cube method. The ratio, RK, between the conductivity results obtained with a long (6 h) and a short (0.5 h) duration run varied from a minimum of 0.29 to a maximum of 0.88 with the considered experimental procedure, differing by both the employed constant-head device (Mariotte bottle, siphon) and the initial soil water content (unsaturated, saturated). Maximum …
Predicting maximum annual values of event soil loss by USLE-type models
2017
Abstract Previous experimental investigations showed that a large proportion of total plot soil erosion over a long time period is generally due to relatively few, large storms. Consequently, erosion models able to accurately predict the highest plot soil loss values have practical importance since they could allow to improve the design of soil conservation practices in an area of interest. At present USLE-based models are attractive from a practical point of view, since the input data are generally easy to obtain. The USLE was developed with specific reference to the mean annual temporal scale but it was also applied at the event scale. Other models, such as the USLE-M and the USLE-MM, app…
L'approvvigionamento idrico per l'agricoltura
2008
La monografia contiene la descrizione delle fonti di approvvigionamento idrico da acque superficiali e sotterranee, con particolare riferimento alla impostazione del dimensionmento idraulico ed alle problematiche tecniche riguardanti i laghetti collinari costruiti in alveo e fuori alveo.
Testing the shape-similarity hypothesis between partide-size distribution and water retention for sicilian soils
2012
Application of the Arya and Paris (AP) model to estimate the soil water retention curve requires a detailed description of the particlesize distribution (PSD) but limited experimental PSD data are generally determined by the conventional sieve-hydrometer (SH) method. Detailed PSDs can be obtained by fitting a continuous model to SH data or performing measurements by the laser diffraction (LD) method. The AP model was applied to 40 Sicilian soils for which the PSD was measured by both the SH and LD methods. The scale factor was set equal to 1.38 (procedure AP1) or estimated by a logistical model with parameters gathered from literature (procedure AP2). For both SH and LD data, procedure AP2 …
Assessing the suitability of American National Aeronautics and Space Administration (NASA) agro-climatology archive to predict daily meteorological v…
2017
Abstract For decades, the importance of evapotranspiration processes has been recognized in many disciplines, including hydrologic and drainage studies, irrigation systems design and management. In this research, the suitability of the Prediction Of Worldwide Energy Resource database published by the American National Aeronautics and Space Administration (POWER-NASA), to estimate daily meteorological variables and ET 0 was assessed in Sicily, Italy, for the period 2006–2014, based on ground data measured by a network of climate stations belonging to the regional Agro-meteorological Information Service (SIAS). After comparing the climate data (minimum, T min , maximum, T max , and average, T…
Using HYDRUS-2D model to assess the optimal drip lateral depth for eggplant crop in a sandy loam soil of central Tunisia
2016
The main objective of the work is to assess the optimal drip lateral depth for Eggplant crop (Solanum melongena L.) irrigated with a drip system in a sandy loam soil by means of field measurements and simulation models. Initially, the performance of Hydrus-2D was assessed based on the comparison between simulated soil water contents (SWC) and the corresponding measured in two plots, in which laterals with co-extruded emitters were laid on the soil surface (drip irrigation, DI-0) and at 20 cm depth (subsurface drip irrigation, SDI-20), respectively. In order to identify the optimal position of the lateral, the results of different scenarios, obtained by changing the installation depth of the…
Testing a Simplified Approach to Determine Field Saturated Soil Hydraulic Conductivity
2013
Abstract Interpreting and simulating hydrological processes need a large number of field saturated soil hydraulic conductivity, Kfs , data that should be collected with simple and rapid field experiments. A Simplified method based on a Beerkan Infiltration run (SBI method) was recently developed and tested successfully on Burundian soils. With the SBI method, a cylinder is inserted to a short depth into the soil and the infiltration time of a few small volumes of water repeatedly applied at the surface of the confined soil is measured. Calculating Kfs needs the slope of the linearized cumulative infiltration vs. time relationship and an estimate of the so called α* parameter. In this invest…
Predicting soil loss in central and south Italy with a single USLE-MM model
2018
Purpose: The USLE-MM estimates event normalized plot soil loss, Ae,N, by an erosivity term given by the runoff coefficient, QR, times the single-storm erosion index, EI30, raised to an exponent b1> 1. This modeling scheme is based on an expected power relationship, with an exponent greater than one, between event sediment concentration, Ce, and the EI30/Pe(Pe= rainfall depth) term. In this investigation, carried out at the three experimental sites of Bagnara, Masse, and Sparacia, in Italy; the soundness of the USLE-MM scheme was tested. Materials and methods: A total of 1192 (Ae,N, QREI30) data pairs were used to parameterize the model both locally and considering all sites simultaneously. …
Overland flow hydrodynamic characteristics in rough beds at low Reynolds numbers
2022
This paper considers overland flow resistance at low Reynolds numbers through analysis of experimental runs carried out using water only and water/glycerol mixtures. We first examined the power relationship between the Darcy–Weisbach friction factor f and the Reynolds number Re to obtain the values of the K coefficient and b exponent. These results confirmed the applicability of the values of b suggested in literature, while K required a specific calibration for laminar open-channel flows. The analysis revealed that transition from a laminar to turbulent flow regime for water only flows occurred at a threshold value of Re equal to 500 as described historically. The estimate of f by the powe…