Search results for "Surface Processes"

Changes in soil hydrodynamic parameters during intermittent rainfall following tillage

2023

The changes in the soil hydrodynamic properties following soil tillage were investigated in rainfall simulation trials of intermittent rain at the Masse experimental station (Soil Erosion LABoratory, SERLAB) in central Italy. The experiments were designed to build a database as representative as possible of situations that may occur in nature. The data collected during the experiments were used to determine the saturated soil hydraulic conductivity, Ks, the soil sorptivity at the antecedent soil–water matric potential Ψi, S, and the flow-weighted mean pore size at Ψi, λm. It was also verified if the energy content of total rainfall after tillage explained the short-term temporal variability…

Laboratory testing of Beerkan infiltration experiments for assessing the role of soil sealing on water infiltration

2018

Abstract Soil surface sealing is a major cause of decreased infiltration rates and increased surface runoff and erosion during a rainstorm. The objective of this paper is to quantify the effect of surface sealing on infiltration for 3 layered soils with different textures for the upper layer and investigate the capability of BEST procedure to catch the formation of the seal and related consequences on water infiltration. Rainfall experiments were carried out to induce the formation of the seal. Meanwhile, Beerkan infiltration runs were carried out pouring water at different distances from the soil surface (BEST-H versus BEST-L runs, with a High and Low water pouring heights, respectively) f…

2014

Abstract. Biogenic NOx emissions from natural and anthropogenically influenced soils are currently estimated to amount to 9 Tg a−1, hence a significant fraction of global NOx emissions (45 Tg a−1). During the last three decades, a large number of field measurements have been performed to quantify biogenic NO emissions. To study biogenic NO emissions as a function of soil moisture, soil temperature, and soil nutrients, several laboratory approaches have been developed to estimate local/regional NO emissions by suitable upscaling. This study presents an improved and automated laboratory dynamic chamber system (consisting of six individual soil chambers) for investigation and quantification of…

Spatial Distribution of Soil Hydrological Properties in the Kilombero Floodplain, Tanzania

2017

Analysis and interpretation of soil properties dynamics is a keystone in understanding the hydrologic responses and yield potential of floodplain wetlands. This study characterizes the distribution and spatial trends of selected soil physical properties in the Kilombero floodplain, Tanzania. A total of 76 composite soil samples were taken from 0 to 20 cm and 20 to 40 cm depth in a regular grid design across three hydrological zones, related to flooding intensity defined as fringe, middle, and riparian during the rainy season of 2015. The samples were analyzed for soil texture, bulk density, organic carbon, and saturated hydraulic conductivity. Seasonal soil moisture content was monitored at…

Short-term changes in soil Munsell colour value, organic matter content and soil water repellency after a spring grassland fire in Lithuania

2014

Abstract. Fire is a natural phenomenon with important implications on soil properties. The degree of this impact depends upon fire severity, the ecosystem affected, topography of the burned area and post-fire meteorological conditions. The study of fire effects on soil properties is fundamental to understand the impacts of this disturbance on ecosystems. The aim of this work was to study the short-term effects immediately after the fire (IAF), 2, 5, 7 and 9 months after a low-severity spring boreal grassland fire on soil colour value (assessed with the Munsell colour chart), soil organic matter content (SOM) and soil water repellency (SWR) in Lithuania. Four days after the fire a 400 m2 plo…

Biodiversity dynamics and their driving factors during the Cretaceous diversification of Spatangoida (Echinoidea, Echinodermata)

2004

Abstract Variations in recorded diversity over time present a scrambled signal that is modulated by a large number of variables: the potential of particular life forms to generate evolutionary innovations, external constraints induced by the environment in its broad sense, the heterogeneity of the fossil record and the analytical artefacts due to sampling bias. A key question is how to characterise and quantify the separate input of any given factor in the overall diversity signal. This paper explores the structure of diversity data for spatangoid heart urchins and the sensitivity of recorded diversity to different factors of analytical bias (length of geological periods, proportion of pala…

Sulfuric acid speleogenesis (SAS) close to the water table: Examples from southern France, Austria, and Sicily

2016

Caves formed by rising sulfuric waters have been described from all over the world in a wide variety of climate settings, from arid regions to mid-latitude and alpine areas. H2S is generally formed at depth by reduction of sulfates in the presence of hydrocarbons and is transported in solution through the deep aquifers. In tectonically disturbed areas major fractures eventually allow these H2S-bearing fluids to rise to the surface where oxidation processes can become active producing sulfuric acid. This extremely strong acid reacts with the carbonate bedrock creating caves, some of which are among the largest and most spectacular in the world. Production of sulfuric acid mostly occurs at or…

Sulfuric acid caves of Italy: A review

2019

Abstract In Italy, especially along the Apennine Chain, numerous active and inactive sulfuric acid speleogenetic (SAS) caves have been documented in the last two decades. Here we present an overview of these peculiar hypogene systems, illustrating their main geomorphological and mineralogical features, and the microbial signatures observed in the active underground environment. SAS caves are widely distributed in the northern and central Apennines, whereas they are less abundant in the southern Apennines, in the Apulian foreland, in Sicily and in Sardinia. Their location is significantly influenced by lithological and structural rock properties, as they occur in carbonate areas where acidic…

Determining the potential impacts of fire and different land uses on splash erosion in the margins of drylands

2021

Abstract This research aimed to estimate the splash erosion and its evolution during the first months in specific land uses after a forest fire. The study area was located in Congosto (North-West Spain), in the margins of Spanish drylands, after a wildfire occurred in May 2012, which burned 15.56 ha of scrubland and Pinus reforestation. Two different burned land uses were selected and compared to control areas: i) burned pine forest; and, scrublands. Rainfall intensity and the number, sizes and speed of raindrops were measured by an optical disdrometer and soil loss by funnels. Moreover, infiltration, soil moisture content, aggregate stability, water repellence, pH and organic matter were a…

Effectiveness of carbon isotopic signature for estimating soil erosion and deposition rates in Sicilian vineyards

2015

Abstract Traditional methods for measurement of soil erosion provide information on erosion rates and mechanisms but fail to determine the spatial distribution of sediment redistribution. Recent studies have used carbon (C) stable isotopes to trace sediment and to monitor soil organic carbon (SOC) redistribution. The difference in δ 13 C values in a slope-transect or in a watershed provides information about the source of suspended organic matter and sediment removal and deposition, but miss enough information to quantify sediment loss. The objective of this research was to develop a method to estimate soil erosion using the natural discrimination of δ 13 C-SOC with soil depth, comparing δ …