Using Beerkan experiments to estimate hydraulic conductivity of a crusted loamy soil in a Mediterranean vineyard

In bare soils of semi-arid areas, surface crusting is a rather common phenomenon due to the impact of raindrops. Water infiltration measurements under ponding conditions are becoming largely applied techniques for an approximate characterization of crusted soils. In this study, the impact of crusting on soil hydraulic conductivity was assessed in a Mediterranean vineyard (western Sicily, Italy) under conventional tillage. The BEST (Beerkan Estimation of Soil Transfer parameters) algorithm was applied to the infiltration data to obtain the hydraulic conductivity of crusted and uncrusted soils. Soil hydraulic conductivity was found to vary during the year and also spatially (i.e., rows vs. inter-rows) due to crusting, tillage and vegetation cover. A 55 mm rainfall event resulted in a decrease of the saturated soil hydraulic conductivity, Ks, by a factor of 1.6 in the inter-row areas, due to the formation of a crusted layer at the surface. The same rainfall event did not determine a Ks reduction in the row areas (i.e., Ks decreased by a non-significant factor of 1.05) because the vegetation cover intercepted the raindrops and therefore prevented alteration of the soil surface. The developed ring insertion methodology on crusted soil, implying pre-moistening through the periphery of the sampled surface, together with the very small insertion depth of the ring (0.01 m), prevented visible fractures. Consequently, Beerkan tests carried out along and between the vine-rows and data analysis by the BEST algorithm allowed to assess crusting-dependent reductions in hydraulic conductivity with extemporaneous measurements alone. The reliability of the tested technique was also confirmed by the results of the numerical simulation of the infiltration process in a crusted soil. Testing the Beerkan infiltration run in other crusted soils and establishing comparisons with other experimental methodologies appear advisable to increase confidence on the reliability of the method that seems suitable for simple characterization of crusted soils

The Impact of the Age of Vines on Soil Hydraulic Conductivity in Vineyards in Eastern Spain

Soil infiltration processes manage runoff generation, which in turn affects soil erosion. There is limited information on infiltration rates. In this study, the impact of vine age on soil bulk density (BD) and hydraulic conductivity (Ks) was assessed on a loam soil tilled by chisel plough. Soil sampling was conducted in the inter row area of six vineyards, which differed by the age from planting: 0 (Age 0; just planted), 1, 3, 6, 13, and 25 years (Age 1, Age 3, Age 6, Age 13, and Age 25, respectively). The One Ponding Depth (OPD) approach was applied to ring infiltration data to estimate soil Ks with an * parameter equal to 0.012 mm\u1000001. Soil bulk density for Age 0 was about 1.5 times greater than for Age 25, i.e., the long-term managed vineyards. Saturated hydraulic conductivity at Age 0 was 86% less than at Age 25. The planting works were considered a major factor for soil compaction and the reduction of hydraulic conductivity. Compared to the long-term managed vineyards, soil compaction was a very short-term effect given that BD was restored in one year due to ploughing. Reestablishment of Ks to the long-term value required more time

Analysis of Geometrical Relationships and Friction Losses in Small-Diameter Lay-Flat Polyethylene Pipes

[EN] The use of lay-flat polyethylene pipes to irrigate horticultural crops has been receiving widespread attention in the last decade, due to the significant improvements in their hydraulic performance, their potentially high application efficiency, and their limited installation costs. However, even if hydraulic design procedures for conventional microirrigation systems are fairly well established, there is still the need to know how different pipe-wall thicknesses of lay-flat pipes can affect the pipe geometry under different operating pressures as well as the related consequences on friction losses. This paper, after comparing two different procedures (caliper and photographic) to assess the geometry of lay-flat polyethylene pipes under different operating pressures, analyzes the friction losses per unit of pipe length, J, in order to identify and to assess a procedure for their evaluation. Hydrostatic tests, initially carried out on pipes with wall thicknesses of 6, 8, and 10 thousandth of an inch (mil), evidenced that the pipe dimensions measured with both methods are quite similar, despite the generally higher standard deviations characterizing caliper measurements when compared to photographic method. Tests allowed to verify that most of the changes in pipe dimensions occur within a range of pressure from 0 kPa to about 30 kPa, with pipe horizontal width and vertical height quite similar at higher pressures and pipes have a tendency to become circular. Additionally, due to the elasticity of the material, over a certain limit of water pressure, both the pipe dimensions tend to rise, with a trend depending on pipe thickness. According to the experimental data, the relationships between pipe effective diameter and water pressure were then determined for the three considered pipes. Moreover, based on measured friction losses and pipe effective diameters, it was confirmed that the relationship between the Darcy-Weisbach friction factor, f, and the Reynolds number, R, can be described by a power equation in which, by assuming a value of -0.25 for the exponent, it results a coefficient c = 0.285, lower than the theoretical. For the three investigated pipes the errors associated to estimated J were finally evaluated by considering (1) the experimental relationships between friction factor and Reynolds number as well as between pipe diameter and operating pressure (Case A); (2) the same value of c, but pipe effective diameters of 16.20, 16.10, and 15.85 mm corresponding to p = p(lim) (Case B); (3) the standard procedure, with a value of c = 0.302 and the pipe diameter equal to 16.10 mm, as suggested by the manufacturer. The results evidenced that suitable estimations of J need to account for the variations of the pipe effective diameter with water pressure. On the other hand, incorrect values of pipe diameter combined with inexact values of the friction factor generate inaccurate estimations of friction losses, with unavoidable consequences in pipe design. (C) 2015 American Society of Civil Engineers.The research was cofinanced by Universita di Palermo (FFR 2011) and Ministero dell'Istruzione, dell'Universita e della Ricerca (PRIN 2010). All the authors setup the research and discussed the results. V. Alagna and D. Autovino carried out the experimental measurements and G. Provenzano wrote the paper. A special thank to the Committee for International Relations Office (CORI) of University of Palermo to support the research cooperation with the University of Valencia.Provenzano, G.; Alagna, V.; Autovino, D.; Manzano Juarez, J.; Rallo, G. (2016). Analysis of Geometrical Relationships and Friction Losses in Small-Diameter Lay-Flat Polyethylene Pipes. Journal of Irrigation and Drainage Engineering. 142(2):1-9. https://doi.org/10.1061/(ASCE)IR.1943-4774.0000958S19142

Impact of climate, soil properties and grassland cover on soil water repellency

Numerous soil water repellency (SWR) studies have investigated the possible causes of this temporal phenomenon, yet there remains a lack of knowledge on the order of importance of the main driving forces of SWR in the context of changing environmental conditions under grassland ecosystems. To study the separate and combined effects of soil texture, climate, and grassland cover type on inducing or altering SWR, four sites from different climatic and soil regions were selected: Ciavolo (CI, IT), Cs´olyosp´alos (CSP, HU), Pwllpeiran (PW, UK), Sekule (SE, SK). The investigated parameters were the extent (determined by repellency indices RI, RIc and RIm) and persistence (determined by water drop penetration time (WDPT) and water repellency cessation time, WRCT) of SWR, as well as field water (Sw) and ethanol (Se) sorptivity, water sorptivity of hydrophobic soil state (Swh) water sorptivity of nearly wettable soil state (Sww) and field hydraulic conductivity (K). Our findings showed an area of land has a greater likelihood of being water repellent if it has a sandy soil texture and/or a high frequency of prolonged drought events. Water infiltration was positively correlated with all the sorptivities (r = 0.32–0.88), but was mostly negatively correlated with RI (r = – 0.54 at CI), WDPT (r = – 0.47 at CI) and WRCT (r = – 0.58 at CI). The importance of natural and synanthropized vegetation covers with regards to SWR was not coherent; moving to regions having coarser texture or moving to drier climatic zones led to higher risk of SWR conditions. Climate change has been predicted to lead to more frequent extreme weather events and prolonged dry periods across Europe, which will most likely increase the extent of SWR-affected areas and increase the role of SWR in water management of grassland ecosystems. Therefore, there is a need to determine SWR risk zones to prevent decreases in soil moisture content, soil fertility, carbon and nitrogen sink potentials, as well as biomass production of the related agro-ecosystems

Extent and persistence of soil water repellency induced by pines in different geographic regions

This work was supported by the Slovak Scientific Grant Agency VEGA Project Nos. 2/0054/14 and 2/0009/2015, the Slovak Research and Development Agency Project No. APVV-15-0160, and it results from the project implementation of the “Centre of excellence for integrated flood protection of land” (ITMS 26240120004).Peer reviewedPublisher PD

Laboratory evaluation of falling-head infiltration for saturated soil hydraulic conductivity determination

Falling-head one-dimensional infiltration procedures, such as the simplified falling-head (SFH) technique, yield estimates of saturated soil hydraulic conductivity, Ks, with parsimonious and rapid experiments. Factors that can influence determination of Ks by the SFH technique were tested in the laboratory on three repacked soils differing by particle diameter ranges (0-2000, 0-105 and 105-2000 m, respectively). Using the theoretically calculated depth of ponding on the infiltration surface, D, instead of the measured one had a small impact on the Ks calculations (means differing by a factor of 1.1-1.2, depending on the soil). For the finest soil, Ks decreased by 3.1 times as D increased from 40 to 135 mm but D did not affect Ks for the coarsest soil, yielding in general the highest Ks values. The abrupt increase of the infiltration rate close to the end of the run did not influence appreciably Ks calculations since it determined an increase in Ks by a mean factor never exceeding 1.1. The most frequent result of the developed procedure for estimating the * parameter was failure of the experiment although the valid * calculations were plausible, being higher for the coarse textured soil (17 m-1) than the finer soils (9.2-9.3 m-1). The depth of the wetting front at the end of the run was 1.1-1.2 times deeper than that calculated theoretically before the run, depending on the soil. In conclusion, the method used to determine D should not affect very much Ks determination but larger D values can yield smaller Ks values in fine-textured soils. Air escapes from the sampled soil volume when almost all water had infiltrated but this circumstance does not have a great impact on calculation of Ks. A falling-head one-dimensional ponded infiltration process is not recommended to estimate *. The theoretical depth of the wetting front can approximately be predicted before the run. The SFH technique appears a rather robust method to simply and rapidly determine Ks

Influence of soil surface sealing and hydrophobicity on water infiltration

Nella tesi viene affrontato lo studio dell’impatto dei fenomeni di sealing superficiale e di idrofobicità sui processi di infiltrazione dell’acqua nel suolo. A tal fine vengono utilizzati diversi tipi di esperimenti infiltrometrici che consentono di determinare le modificazioni delle proprietà idrauliche del suolo indotte da questi due fenomeni permettendo di valutare così le loro ripercussioni negative sui processi idrologici.The thesis aims at investigating the effects of soil sealing and hydrophobicity on the water infiltration process. Different field infiltrometric techniques are applied at this end due to their ability to characterize modifications of soil hydraulic properties that directly determine negative impacts on the hydrological processes

Combining pressure transducer and tipping bucket rain gauge to measure high variable runoff rate collected from a green roof

Urban areas are constantly expanding in terms of space and density. It is known that the effect of urbanization is an increase of the area of impermeable surfaces. The infiltration decreases, the surface runoff increases (Baiamonte, Singh, 2017) and the existing stormwater infrastructure may become no more appropriate to face flooding (Berndtsson, 2010). Berndtsson (2010) described the numerous benefits that can be achieved by turning the roofs green through covering them with soil and vegetation. Green roofs i) reduce and attenuate stormwater runoff, which in turn lowers risks of urban floods and improves the urban water balance thus approaching the natural one (Mentens et al., 2006), ii) allow thermal benefits consisting of reductions in cost of heating and air conditioning, iii) reduce urban heat island effect (Fang, 2008), iv) reduce noise and air pollution (Currie and Bass, 2008), and v) provide wildlife habitat and biodiversity enhancement (Dunnett et al., 2008). A challenging task when approaching full-scale investigation on green roofs is the accurate measurement of water runoff rate, which can be characterized by a wide range of variability as a consequence of many factors (as the precipitation regime, the soil thickness, the soil hydraulic characteristics, the vegetation cover, etc.). In fact, if low fluxes can be easily measured by the classical tipping bucket rain gauge (TBR), high fluxes can overcome the maximum peak flow, Q*, of these gauges, and alternative approaches are needed. This is the case of a small experimental green roof (20 square meters) that was designed and constructed at the Department of Agricultural, Food and Forest Sciences of the University of Palermo, with the aim to investigate some of the features previously mentioned, by also using and testing simplified models of runoff response for high permeable porous media, recently developed (Baiamonte, 2016; Baiamonte and Agnese, 2016). A tipping bucket rain gauge (TBR) located at the outlet of the green roof was combined with a tank discharge gauge (TDG), consisting of a PVC vertical pipe equipped with a stainless steel pressure transducer (PT), SISGEO P252R, 25 mm filter diameter, 191.5 mm length, with a measurement range of 4 - 20 mA, with an accuracy of 0.01% of the full scale, located at its bottom. A flush/square edged connector, also located at the bottom of the TDG, allows water outlet to flow into the TBR. The outflow from the green roof is measured by a combination of both TBR and TDG techniques, with a time resolution of 1 min starting at the onset of a storm event. This study present the results of the preliminary calibration of the TDG. First, the head-discharge equation for flush/square edged connector was theoretically derived. Then, the head-discharge equation was tested in the laboratory using a hydrostatic head. In addition, time for emptying of the hydrostatic water column was theoretically derived and experimentally checked. Results showed that the TDG can be used in combination with a classical TBR to accurately measure runoff rate in a wide range of variability

Approccio combinato laparoscopico e mini-laparotomico in un voluminoso linfangioma cistico pancreatico

Cystic lymphangioma is a rare disease of lymphatic system; in particular, pancreatic cystic lymphangioma is an unusual localization. A correct differential diagnosis with more common glandular lesions allows to plan a proper therapeutic approach. The Authors report the observed last case, a lesion in the head of the pancreas laparoscopically treated, and discuss about this infrequent disease

INDAGINE SULL\u2019 IDROREPELLENZA DEL SUOLO DI UNA PINETA ARTIFICIALE MEDITERRANEA

Nell\u2019indagine \ue8 stata caratterizzata l\u2019idrorepellenza del suolo di una pineta artificiale Mediterranea utilizzando sia il tradizionale Water Drop Penetration Time (WDPT) test che due indici desunti da esperimenti di infiltrazione condotti con il MiniDisk Infiltrometer (MDI). In particolare, il Repellency Index (RI) \ue8 stato calcolato come rapporto tra i valori di sorptivit\ue0 misurati con etanolo e acqua, mentre il Water Repellency Cessation Time (WRCT) \ue8 stato ricavato utilizzando l\u2019informazione acquisita nella fase idrofobica e in quella idrofila del processo di infiltrazione con acqua. Tutti gli indici hanno inequivocabilmente indicato che la lettiera di Pinus pinaster \ue8 altamente idrofobica come conseguenza dell\u2019elevato contenuto di sostanza organica. Tuttavia, il suolo minerale della pineta ha presentato livelli di idrorepellenza significativamente maggiori di quelli di un suolo non-boscato avente un contenuto di sostanza organica confrontabile, portando a concludere che la bagnabilit\ue0 del suolo \ue8 influenzata dalla composizione piuttosto che dalla disponibilit\ue0 complessiva della sostanza organica. Gli indici RI e WRCT hanno fornito risultati confrontabili con l\u2019indice WDPT, consentendo per\uf2 di segnalare condizioni di idrorepellenza subcritica non rilevate con il tradizionale test WDPT. Essendo ricavati da un esperimento infiltrometrico, gli indici RI e WRCT sono stati ritenuti particolarmente adatti a caratterizzare l\u2019idrorepellenza in termini di effetti sui processi idrologici del suolo