Search results for " conductivity"
showing 10 items of 794 documents
Evaluation of Green Roof Ageing Effects on Substrate Hydraulic Characteristics
2020
The vegetated substrate of green roofs may undergo various chemical and physical changes with time. Minidisk infiltrometer (MDI) tests were conducted to assess the short-term variations of the near-saturated hydraulic conductivity, K0, in the extensive green roof test plot established at the University of Palermo. Sampling was repeated four times: before planting (Age 0) and then after four months (Age 1), seven months (Age 2) and ten months (Age 3). A total of 144 infiltration tests were conducted at two pressure heads, h0 = −3 cm and h0 = −0.5 cm and infiltration data analysed by the Zhang (Soil Science Society of America Journal 61(4):1024–1030, 1997) model. Both K-3 and K-0.5 underwent …
An Italian survey of pitches for soccer
2004
On soccer grounds, grass cover is often reduced and the ground surface becomes uneven. Therefore, in order to assess the effects of climatic conditions, construction types and maintenance of the Italian soccer pitches, a detailed study was carried out. During 2000-2001, 61 soccer grounds were analysed, from continental to Mediterranean environments. First and second division Italian League grounds were about 30%, 40% were semi-professional and 30% were public grounds. Several parameters such as overseeding, fertilization, aeration, weed control, mowing and irrigation were collected in winter and at the end of the playing season, in order to evaluate soil profiles, grass mixtures and composi…
Using a transient infiltrometric technique for intensively sampling field-saturated hydraulic conductivity of a clay soil in two runoff plots
2012
The point measurement of soil properties allows to explain and simulate plot scale hydrological processes. An intensive sampling was carried out at the surface of an unsaturated clay soil to measure, on two adjacent plots of 4 × 11 m2 and two different dates (May 2007 and February–March 2008), dry soil bulk density, ρb, and antecedent soil water content, θi, at 88 points. Field-saturated soil hydraulic conductivity, Kfs, was also measured at 176 points by the transient Simplified Falling Head technique to determine the soil water permeability characteristics at the beginning of a possible rainfall event yielding measurable runoff. The ρb values did not differ significantly between the two d…
Soil structure and bypass flwo processes in a Vertsol under sprinkler and drip irrigation.
2007
In this paper morphological and physical characteristics, as well as flow behaviour of a Mediterranean Vertisol under the influence of two different irrigation systems currently used for irrigation, i.e. drip and sprinkler systems, were compared. No differences in soil texture, compaction and in potential cracking were found on cores from the two fields. However, field application of methylene blue showed the presence of continuous macropores, penetrating up to depths of 20-25 cm from the soil surface, in the field where the drip system was in use (field 1). This was considered to be the pre-existing soil structure. Instead, macropores terminating at a depth ranging between 5 and 10 cm from…
Using Static and Dynamic Indicators to Evaluate Soil Physical Quality in a Sicilian Area
2013
Both capacitive indicators derived from the water retention curve and dynamic measurements of the flow-weighted mean pore radius, R0, were used to assess the soil physical quality of two agricultural areas (cropland and olive orchard) and two natural areas (grassland and managed woodlot plantation) potentially subject to soil degradation. The overall idea of the study was to investigate whether a dynamic indicator quantitatively derived from hydraulic conductivity measurements could be used to supplement the traditionally applied capacitive indicators retrieved from water retention measurements. According to the available criteria, only the surface layer of the cropland site showed optimal …
A field assessment of the Simplified Falling Head technique to measure the saturated soil hydraulic conductivity
2012
Abstract The Simplified Falling Head (SFH) technique to measure field saturated soil hydraulic conductivity, Kfs, has received little testing or comparison with other techniques. Different experiments were carried out to i) determine the effect of ring size on the measured conductivity; ii) compare the SFH and Pressure Infiltrometer (PI) techniques in a clay loam soil; and iii) evaluate the approach used in the SFH methodology to estimate the α* parameter. Sampling a relatively large number of sites allowed to detect statistically significant relationships between the Kfs values obtained with rings differing in diameter (0.15 and 0.30 m, respectively). The ring size effect was substantial (…
Application and evaluation of the SWAP model for simulating water and solute transport in a cracking clay soil
2005
In Sicily, the increasing scarcity of quality water is leading to irriga- from salinization (Crescimanno et al., 2004). tion with saline water in soils having a considerable susceptibility to In Sicily, the increasing scarcity of good quality water cracking. Irrigation systems involving high application rates are used coupled with intensive use of soil under semiarid to arid in these irrigated areas, and bypass flow during irrigation is thus climatic conditions, is leading to irrigation with saline prevalent. Adoption of management practices accounting for cracking water on soils having a high shrink-swell potential and is therefore necessary to prevent salinization and land degradation. su…
Testing infiltration run effects on the estimated water transmission properties of a sandy-loam soil
2016
Abstract Testing factors influencing determination of soil water transmission properties by an infiltrometer method helps better interpretation of the collected data and allows the development of appropriate sampling strategies for the intended use of the data. These factors include the soil water content at the start of the experiment, the height from which water is poured onto the soil surface, and the duration of the infiltration run. A sandy-loam soil was sampled with the BEST (Beerkan Estimation of Soil Transfer parameters) procedure of soil hydraulic characterization and two heights of pouring of water (0.03 and 1.5 m) under three different initial soil water content, θ i (0.12 ≤ θ i …
Soil hydraulic properties determined by infiltration experiments and different heights of water pouring
2014
Abstract Establishing the dependence of the soil hydraulic characterization carried out by an infiltration experiment on the procedure used to apply water on the confined soil surface may help to better interpret the collected data and also to develop more accurate strategies for soil hydraulic characterization. Soil was sampled at four Sicilian sites with both the Simplified Falling Head (SFH) technique and the Beerkan Estimation of Soil Transfer parameters (BEST) procedure and two heights of water application (0.03 and 1.5 m). The most appropriate BEST algorithm to analyze the data was determined and the effect of the height of water pouring on the measured soil hydraulic properties was e…
Soil physical quality changes under different management systems after 10 years in the Argentine humid pampa
2015
Abstract. South American countries with the highest surface of land under no-tillage (NT) management are Brazil, Argentina and Chile. In Argentina, 78.5% of the agricultural land is cropped under NT management. Several experiments have confirmed the improvements in soil aggregation and infiltration achieved by NT management in dry-land farming areas associated with increases of bulk density (δb) under NT management. An increase in bulk density implies a reduction of the macro and mesoporosity that is in contradiction with the increased infiltration that occurs at macro and mesopores. We hypothesize that the increase of bulk density in NT management mainly affects the mesopores. We evaluated…