Search results for "soil"
showing 10 items of 3493 documents
The contrasted response of ash to wetting
2013
Abstract After a wildfire the soil is covered by ash. Ash properties depend on vegetation type, amount of fuel and fire intensity. The ash layer controls the post-fire soil hydrologic response, but little is known about the effect of ash thickness and ash type on infiltration, which is relevant for post-fire runoff and soil losses and for ecosystems rehabilitation and restoration. This paper analyses the role of i) ash type (black or white), ii) thickness (5, 15 and 30 mm-thick) and iii) temporal variation (0, 15 and 40 days) under three simulated rain events (55 mm for 1 h) on soil surface hydrology. The rainfall was simulated on 0.25 m2 plots, and time to ponding, runoff and runoff discha…
Soil water erosion on road embankments in eastern Spain.
2007
Abstract Road embankments erosion is a serious problem in Spain. By means of simulated rainfall experiments (45 mm h − 1 during one hour on 0.41 m 2 plots) soil and water losses were measured on five road embankments located on the SW of the Valencia province, Spain. The bare road embankments, still under construction, contributed with 30 times more soil erosion than the vegetated ones. The measurements here presented demonstrate that road embankments are an important source of sediments, especially during the construction works, and it is recommended that restoration works should be undertaken after the road construction to reduce sediment removal, protect the road and avoid traffic accide…
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…
Runoff generation, sediment movement and soil water behaviour on calcareous (limestone) slopes of some Mediterranean environments in southeast Spain
2003
Abstract An interpretation of soil hydrology and erosion data obtained from limestone areas in southeast Spain is presented in the framework of recent hypotheses on runoff generation mechanisms in Mediterranean environments. The main objective is to synthesise and harmonise the data in theoretical concepts or behavioural models of hydrological functioning of Mediterranean limestone slopes. For this purpose, data were collected in a typical limestone area, with climatic characteristics ranging from subhumid to semiarid. Several sites were chosen with comparable slopes, vegetation and soils along a transect of 20 km to carry out several research projects. The data discussed in this paper cons…
Modeling of Water Distribution under Center Pivot Irrigation Technique
2021
AbstractAiming to quantify the impacts of the center pivot irrigation technique on soil moisture dynamics and to improve irrigation crop water needs, a mathematical model was developed to estimate ...
Comparison of SWAP and FAO Agro-Hydrological Models to Schedule Irrigation of Wine Grapes
2012
This paper compares two agro-hydrological models that are used to schedule irrigation of a typical Mediterranean crop. In particular, a comparison between the Food and Agriculture Organization (FAO) model, which uses a black box approach, and the soil-water-atmosphere-plant (SWAP) model, which is based on the numerical analysis of Richards' equation, are shown for wine grape. The comparison was carried out for the 2005 and 2006 irrigation seasons and focused on hydrological balance components and on soil water contents. Next, the ordinary scheduling parameters were identified so that the performance of the two models, which aimed to evaluate the seasonal water requirements and the irrigatio…
On Saline Irrigation Problems in Sicily Remarks to Professor Cavazza’s Report
1968
I should like to clarify that part of Professor Cavazza’s report which deals with the activities of the Agronomy Institute in the University of Palermo. This Institute, under my direction, has interested itself — among other subjects — in the utilization, for irrigation purposes, of the waters of the River Salso which crosses Sicily from North to South. The water from this river becomes saline because of the hydric contribution of affluents originating from zones which belong, from the geological point of view, to gypsum-sulphuric formations also rich in rock-salt deposits.
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…
Bypass flow, salinization and sodication in a cracking clay soil
2004
Abstract In Sicily, the increasing scarcity of good-quality waters is spreading irrigation with saline–sodic waters, thus enhancing the risk of soil secondary salinization and sodication. Sustainable management strategies are urgently needed in Sicily to prevent extent of salinization and sodication, thus preserving soil quality. Since irrigation is performed in cracking soils using irrigation systems involving high application rates, bypass flow of water and solutes occurs during irrigation. The objectives of this paper were (i) to investigate the process of Na–Ca exchange and subsequent salinization/sodication during bypass flow and (ii) to explore possibilities of using cyclic strategies…
Application of the SWAP model to predict impact of climate change on soil water balance in a Sicilian vineyard
2012
In Sicily, the increasing scarcity of quality water is leading to irrigation with saline water in soils having a considerable susceptibility to salinization and degradation. In this paper, water flow and solute transport in a Sicilian irrigated soil was simulated by using the SWAP model, and the simulated results compared to measured values of soil moisture and salinity. The investigation was carried out in a vineyard located in Sicily (Mazara del Vallo, Trapani Province) within the framework of the Project: Evolution of cropping systems as affected by climate change (CLIMESCO). The soil hydraulic parameters were obtained by inverse method based on multi-step outflow experiments. The result…