Search results for "Forestal"
showing 10 items of 1240 documents
Morphometric analysis of two calanchi areas in Sicily (Italy) by exploiting high resolution Digital Elevation Models
2013
In the Mediterranean areas, specifically in Sicily (Italy), irregular rainfalls, strong seasonal changes, scarce vegetation cover and, frequently, outcropping of clayey deposits favor water erosion phenomena. Badland landscapes are the result of severe erosion processes, characterized by steep slopes, sparse vegetation, high drainage density, rapid erosion rates and a shallow or non existing regolith profile. In this investigation we focused on the calanchi badland type, consisting of heavily dissected terrain with steep, unvegetated slopes and channels that rapidly incise and extend headwards. This research was carried out in two calanchi sites located in Sicily. The geometry of 25 badland…
Effective Practices in Mitigating Soil Erosion from Fields
2017
Soil erosion by water is a natural process that cannot be avoided. Soil erosion depends on many factors, and a distinction should be made between humanly unchangeable (e.g., rainfall) and modifiable (e.g., length of the field) soil erosion factors. Soil erosion has both on-site and off-site effects. Soil conservation tries to combine modifiable factors so as to maintain erosion in an area of interest to an acceptable level. Strategies to control soil erosion have to be adapted to the desired land use. Knowledge of soil loss tolerance, T, i.e., the maximum admissible erosion from a given field, allows technicians or farmers to establish whether soil conservation practices need to be applied …
Testing the SEDD model in Sicilian basins
2005
Abstract The Sediment Delivery Distributed (SEDD) model combines the universal soil loss equation (USLE) or the revised universal soil loss equation (RUSLE) with a sediment delivery ratio to predict basin sediment yield. The model was applied to seven Sicilian basins, ranging in size from 20 to 213 km2 . Each basin has a reservoir located at its outlet. The model was applied to each basin using a raster scheme, and a subroutine of ArcInfo software to identify the hydraulic path linking each hillslope cell to the nearest stream cell, and to calculate both the travel time and the sediment delivery ratio of each cell. A procedure for estimating the β coefficient, which appears in the expressio…
Testing a new sampler for measuring plot soil loss
2016
In order to measure soil loss in equipped plots the estimate of the weight of solid material intercepted at their lower end is required. At the experimental area of Sparacia, Sicily, the runoff produced by an erosive event is collected within storage tanks with a capacity of about 1m3. In this paper, the use of a new sampler is proposed to measure easily the weight of solid material eroded from an experimental plot and collected into a storage tank. The sampler is a cylinder having a closing valve at the bottom. Two different series of runs were carried out both to test the reliability of the sampler and to establish a sampling procedure, respectively. An analysis of various sampling config…
Supporting USLE-MM reliability by analyzing soil loss measurement errors
2017
Sampling the collected suspension in a storage tank is a common procedure to obtain soil loss data. A calibration curve of the tank has to be used to obtain actual concentration values from those measured by sampling. However, literature suggests that using a tank calibration curve was not a common procedure in the past. For the clay soil of the Sparacia (Italy) experimental station, this investigation aimed to establish a link between the relative performances of the USLE-M and USLE-MM models, usable to predict plot soil loss at the event temporal scale, and soil loss measurement errors. Using all available soil loss data, lower soil loss prediction errors were obtained with the USLE-MM (e…
USLE-based models: perspectives and limitations in soil erosion modelling
2020
Water soil erosion is a process of detachment and transport of soil particles due to rainfall and runoff and causes the landform modeling on earthʹs surface. The acceleration of soil erosion process through anthropogenic perturbation has severe impacts on soil which becomes qualitatively poor for crop establishment and growth. Planning soil conservation strategies requires prediction technologies of soil loss over a long‐time period. The Universal Soil Loss Equation (USLE), and its revised versions, are widely tested and applied in different environments throughout the world. At present, the USLE continues to be the most applied model for estimating soil loss and still represents the best c…
No-Till Soil Organic Carbon Sequestration Patterns as Affected by Climate and Soil Erosion in the Arable Land of Mediterranean Europe
2022
No-tillage (NT) has been considered an agronomic tool to sequester soil organic carbon (SOC) and match the 4p1000 initiative requirements of conservative soil management. Recently, some doubts have emerged about the NT effect on SOC sequestration, often because observations and experimental data vary widely depending on climate and geographic characteristics. Therefore, a suitable SOC accounting method is needed that considers climate and morphology interactions. In this study, the yearly ratio between SOC in NT and conventional tillage (CT) (RRNT/CT) collected in a previous study for flat (96 samples) and sloping (44 samples) paired sites was used to map the overestimation of SOC sequestra…
Testing a spatially distributed sediment delivery model (SEDD) in a forested basin by cesium-137 technique
2005
The aim of the paper is to validate the sediment delivery distributed (SEDD) model for estimating hillslope sediment yield estimates using net soil erosion values obtained by the cesium-137 technique. The cesium-137 technique provides spatially-distributed measurements useful to verify the predictive capability of a distributed sediment yield model. The application of the cesium-137 technique requires a calibration procedure to convert measurements of 137Cs inventories to estimates of net soil erosion rates. Rainfall and sediment yield data from 1978 to 1994 in a small Calabrian basin forested with eucalyptus trees, were initially used to calibrate, at mean annual temporal scale, the SEDD m…
Sediment delivery processes and chemical transport in a small forested basin
2005
Recent reaserch has directed attention to the properties of the eroded material because of its influence in deposition phenomena and in carrying capacity of pollutant materials
Rill flow velocity and resistance law: A review
2022
Rills caused by runoff concentration on erodible hillslopes generally have very irregular longitudinal profiles and cross-section shapes. Rill erosion directly depends on the hydraulics of flow within the rills which may differ greatly from that in larger and regular channels like streams or rivers. At first, in this paper, a review of the two different approaches to estimate rill flow velocity, based on flow regime and flow resistance laws, is presented. Recent advances in measurements of rill geometry by the three-dimensional photo-reconstruction (3D-PR) technique, which allows one to obtain a Digital Terrain Model (DTM) by low-altitude aerial and terrestrial photogrammetry, are also disc…