Search results for "soil"
showing 10 items of 3493 documents
Influence of vegetation recovery on soil hydrology and erodibility following fire: an 11-year investigation
2005
The present study investigates long-term changes in soil hydrological properties and erodibility during the regrowth of different types and densities of vegetation following a severe wildfire in the Serra Grossa Range, eastern Spain. Twelve plots of similar slope and soil characteristics, naturally recolonized by four different plant species (trees, herbs, shrubs and dwarf shrubs) were examined using rainfall simulations during an 11-year period. The mean erosion rate was 80 g m−2 h−1, 6 months after the fire under wet-winter conditions, declining to 30 g m−2 h−1 in the following summer and reaching <10 g m−2 h−1 after 2 years. Considerable variation under the different vegetation types …
The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period
2008
Abstract Hillslopes are thought to be most susceptible to enhanced surface runoff and erosion immediately following wildfire due to removal of protective vegetation and litter cover, and in many cases a fire-induced reduction in soil wettability. This enhanced susceptibility declines as vegetation and litter layer recover. For logistical reasons, however, few studies have been able to examine the responses of burnt terrain immediately following burning and little is therefore known about the effect of the wettable ash layer that often covers the ground until it is redistributed or removed by wind or water erosion. Here we quantify the effects of ash and needle cast ground cover on surface r…
Contribution of the largest events to suspended sediment transport across the USA
2010
This work analyses the contribution of the largest events to suspended sediment transport on the continental scale. The analysis is based on the United States Geological Survey (USGS) Suspended Sediment and Ancillary database. Data were obtained from 1314 catchments, comprising more than 2 500 000 daily events. The total number of days in the dataset amounts to 10 000 years. Catchments are of different sizes and belong to distinct climatic environments; they are distributed for the analysis according to USA hydrological divisions (HDs). The main objective of the research is to examine the effect of the n-largest event on the total suspended sediment load over recorded periods, and to discus…
Shrubland as a soil and water conservation agent in Mediterranean-type ecosystems
2015
John Thornes found that shrubland was a key factor in the control of soil erosion on Mediterranean hillsides. His research inspired many scientists to investigate the impact of shrubland changes and management in semi-arid ecosystems. An example of Professor Thornes’ scientific influence is the experiment carried out on the El Teularet–Sierra de Enguera experimental station since 2003 which showed erosion rates on a 30-year-old abandoned orchard with dense vegetation cover of Ulex parviflorus and Cistus albidus and a 20-year-old fire-affected maquia with Quercus coccifera, Pistacia lentiscus and Juniperus oxycedrus. The measurements demonstrated that the shrubs help create more stable soil …
Response of water and nutrient fluxes to improvement fellings in a tropical montane forest in Ecuador
2009
Abstract Management of natural forests might be one option to reduce the high deforestation rate in Ecuador. We therefore evaluated the response of water and nutrient cycles in a natural tropical montane forest to improvement fellings with the aim of favoring economically valuable target trees which will later be harvested with additional ecosystem impacts not considered here. The study was conducted at ca. 1900–2200 m above sea level in the south Ecuadorian Andes on the east-exposed slope of the east cordillera. In June 2004, one of two paired ca. 10-ha large catchments was thinned by felling 10.2% of the initial basal area (dbh ≥ 10 cm) on 30% of the catchment. The stems remained in situ.…
Changes in the seasonal snow cover of alpine regions and its effect on soil processes: A review
2007
Abstract At its maximum annual development, snow can cover more than half the Northern Hemisphere land area with one-third experiencing seasonal snow cover. The precise conditions that develop during the annual pattern of snowpack development formation have implications for: (i) soil microbiological activity and nutrient transformations; (ii) the capacity of the accumulating snowpack to retain atmospheric derived solutes; (iii) preferential elution and rapid runoff of solutes from the snowpack during periods of thaw; and (iv) leaching of solutes. Long-term records of annual snow accumulation suggest that substantial, regional scale shifts in snowpack characteristics have been occurring. The…
Combined use of eddy covariance and sap flow techniques for partition of ET fluxes and water stress assessment in an irrigated olive orchard
2013
Correct estimation of crop actual transpiration plays a key-role in precision irrigation scheduling, since crop growth and yield are associated to the water passing through the crop. Objective of the work was to assess how the combined use of micro-meteorological techniques (eddy covariance, EC) and physiological measurements (sap flow, SF) allows a better comprehension of the processes involving in the Soil–Plant–Atmosphere continuum. To this aim, an experimental dataset of actual evapotranspiration, plant transpiration, and soil water content measurements was collected in an olive orchard during the midseason phenological period of 2009 and 2010. It was demonstrated that the joint use of …
Exploiting the topographic information in a PDM-based conceptual hydrological model
2014
In this work, a conceptual lumped model was developed to simulate runoff and analyze hydrological processes with the goal of incorporating the morphological information into a probability-distributed model (PDM). PDMs usually describe the process of runoff generation as the result of soil saturation excess caused by precipitation with soil storage capacity represented by a spatially distributed quantity and described by a probability distribution. The proposed model, called topography-based probability distributed model (TOPDM), based on a simple water balance whose components are basin soil moisture storage, precipitation, drainage to groundwater, evapotranspiration, and Dunnian and Horton…
Comparing theoretically supported rainfall-runoff erosivity factors at the Sparacia (South Italy) experimental site
2018
Interpreting rainfall‐runoff erosivity by a process‐oriented scheme allows to conjugate the physical approach to soil loss estimate with the empirical one. Including the effect of runoff in the model permits to distinguish between detachment and transport in the soil erosion process. In this paper, at first, a general definition of the rainfall‐runoff erosivity factor REFe including the power of both event runoff coefficient QR and event rainfall erosivity index EI30 of the Universal Soil Loss Equation (USLE) is proposed. The REFe factor is applicable to all USLE‐based models (USLE, Modified USLE [USLE‐M] and Modified USLE‐M [USLE‐MM]) and it allows to distinguish between purely empirical m…
Anthropogenic processes in the evolution of a soil chronosequence on marly-limestone substrata in an Italian Mediterranean environment
2007
Due to anthropic pressure, many areas of the world are affected by a process of soil “entisolization” that leads to the formation of “anthropogenic soils”. In order to investigate Man's role in soil evolution, a survey was carried out in Southeastern Sicily (Italy), where, for years, there have been wide farming areas with anthropogenic soils. A chronosequence of anthropogenic soils in a vineyard area, cultivated for 22 years, was investigated. The first stage of the chronosequence was made by the original soils which, in the study area, had been undisturbed till the 1980's. These soils, classified as Entic Haploxerolls under the American Soil Taxonomy (ST) or Calcaric Kastanozem according …