Search results for "soil"
showing 10 items of 3493 documents
Relationships between climate and soil hydrological and erosional characteristics along climatic gradients in Mediterranean limestone areas
1998
An investigation was undertaken to determine the relationships between climate and soil hydrological and erosional characteristics. Rainfall simulation experiments were carried out along three climatological gradients on similar limestone lithologies in the Mediterranean region. Standard experiments were used to characterize each site so that an objective comparison could be made. At each of the eleven south-facing slopes three experiments were carried out. A total of 33 plots were selected for the experiments; located in the Galilee and Carmel Mountains (Israel), Crete (Greece) and Alicante (Spain). Simulated rainfall was used in order to measure time to ponding and runoff, steady-state in…
Use of BEST Procedure to Assess Soil Physical Quality in the Baratz Lake Catchment (Sardinia, Italy)
2016
Conversion of Mediterranean maquis and/or natural forest into agro-pastoral lands is a cause of soil degradation in many Mediterranean areas. Indicators of soil physical quality (SPQ) quantitatively linked to soil hydraulic properties are a valuable tool to assess the effect of land use changes. In this investigation, the Beerkan Estimation of Soil Transfer parameters (BEST) procedure for soil hydraulic characterization was used to estimate SPQ indicators. Four areas of the Baratz Lake watershed, Sardinia, Italy, characterized by both typical natural vegetation (holm oak [ Quercus ilex L.] forest and high maquis) and degraded vegetation (grassland established after fire or clearing of the m…
Causes and underlying processes of measurement variability in field erosion plots in Mediterranean conditions
2007
Published online 25 May 2006
Soil wettability, runoff and erodibility of major dry-Mediterranean land use types on calcareous soils
2007
This study examines six land uses (pine woodland, long unburnt scrubland, recently burnt scrubland, orange grove, olive grove and cereal crop), typical for calcareous soils in a dry-Mediterranean region such as eastern Spain, with regard to soil surface water repellency occurrence, hydrological response and erodibility. For each land use, we performed water drop penetration time (WDPT) tests and rainfall simulations respectively on in situ soils at ten replicate plots for extremely dry antecedent conditions in summer 2002 and for wet winter conditions, in early 2003 in the Canyoles river valley. In contrasts to what might have been expected, water repellency was absent or subcritical (WDPT …
Magnitude-frequency analysis of water redistribution along a climate gradient in Spain
1999
Abstract Banded patterns in soils and vegetation form part of important discontinuities on semi-arid slopes in Spain. At fine scales (
Influence of the rainfall measurement interval on the erosivity determinations in the Mediterranean area
2006
Summary The single-storm erosion index, EI, of the USLE and RUSLE models may vary appreciably with the rainfall measurement interval, Δ t . However, the effect of Δ t on EI has not been investigated in the Mediterranean area. Approximately 700 erosive events and 1.5 years of rainfall energies measured by a rainfall impact measurement device were used to evaluate the effect of the rainfall measurement interval (5 min ⩽ Δ t ⩽ 60 min) on the erosivity determinations in the Mediterranean semi-arid area of Sicily. According to both literature and practical considerations, a reference time interval equal to 15 min was used in this investigation. Hourly rainfall data led to an appreciable underes…
Spatial and temporal variations of water repellency and probability of its occurrence in calcareous Mediterranean rangeland soils affected by fires
2013
Abstract Water repellency (WR) is a common soil property in many fire-affected ecosystems, but it also occurs in long-unburned terrain. It can vary in space at different scales (between point and pedon or slope and catchment) and time (during the same day, between seasons or years, or with a post-fire recovery period). This paper: i) reports on the occurrence and persistence of WR in fire-affected calcareous forest soils under Mediterranean climatic conditions, examining its spatial variability at macro-, meso- and micro-scales, and monthly changes with soil moisture content; and ii) develops exploratory models to estimate the probability of the natural background (not fire-induced) WR to o…
The impact of cotton geotextiles on soil and water losses from Mediterranean rainfed agricultural land
2010
High soil erosion risk of Mediterranean cultivated soils is due to steep slopes, high rainfall intensities and low vegetation cover. Traditional land management as ploughing and herbicides give rise to high soil erosion rates. This paper reports on the use of a cotton geotextiles to control soil and water losses on agricultural land under Mediterranean climatic conditions. Eight paired plots (1, 2, 4 and 16 m2) were studied during 1-year period under natural rainfall. Forty rainfall simulations under wet and dry climatic conditions, and water drop penetration time (WDPT) tests, were carried out in order to analyze the effect of a geotextile on soil and water losses on a typical rainfed orch…
Plot-scale measurement of soil erosion at the experimental area of Sparacia (southern Italy)
2004
Obtaining good quality soil loss data from plots requires knowledge of the factors that affect natural and measurement data variability and of the erosion processes that occur on plots of different sizes. Data variability was investigated in southern Italy by collecting runoff and soil loss from four universal soil-loss equation (USLE) plots of 176 m2, 20 ‘large’ microplots (0·16 m2) and 40 ‘small’ microplots (0·04 m2). For the four most erosive events (event erosivity index, Re ≥ 139 MJ mm ha−1 h−1), mean soil loss from the USLE plots was significantly correlated with Re. Variability of soil loss measurements from microplots was five to ten times greater than that of runoff measurements. D…
Soil degradation and its impact on desertification: A research design for Mediterranean environments
1988
Summary Much is said but little is known of the processes and linkages of soil degradation with desertification. With particular emphasis on South-East Spain, a research design is proposed to characterize the processes, their dynamics and effect on productivity. Through detailed monitoring of plot experiments at three slope positions, changes in soil physical and chemical parameters and analyses of runoff and eroded sediments will be related to induced destruction of the vegetation. Knowing the cause and process will lead to the identification of management techniques that may protect vulnerable Mediterranean environments.