Search results for "Universal Soil Loss Equation"
showing 10 items of 28 documents
Applying the USLE Family of Models at the Sparacia (South Italy) Experimental Site
2016
Soil erosion is a key process to understand the land degradation, and modelling of soil erosion will help to understand the process and to foresee its impacts. The applicability of the Universal Soil Loss Equation (USLE) at event scale is affected by the fact that USLE rainfall erosivity factor does not take into account runoff explicitly. USLE-M and USLE-MM, including the effect of runoff in the event rainfall– runoff erosivity factor, are characterized by a better capacity to predict event soil loss. The specific objectives of this paper were (i) to determine the suitable parameterization of USLE, USLE-M and USLE-MM by using the dataseries of Sparacia experimental site and (ii) to evaluat…
Predicting plot soil loss by empirical and process-oriented approaches. A review
2018
Soil erosion directly affects the quality of the soil, its agricultural productivity and its biological diversity. Many mathematical models have been developed to estimate plot soil erosion at different temporal scales. At present, empirical soil loss equations and process-oriented models are considered as constituting a complementary suite of models to be chosen to meet the specific user need. In this paper, the Universal Soil Loss Equation and its revised versions are first reviewed. Selected methodologies developed to estimate the factors of the model with the aim to improve the soil loss estimate are described. Then the Water Erosion Prediction Project which represents a process-oriente…
A regional analysis of the effects of largest events on soil erosion
2012
A large amount of geomorphic work is caused by a small number of extreme events that are mainly responsible for the time compression of geomorphic processes. The classic approach defines extreme events by their magnitude and they are quantified by certain deviation from a central value. Alternatively, we define extreme events as the largest events sorted by rank, whatever their absolute magnitude. In this case, events with equal rank from two different sites can be responsible for different magnitudes of geomorphic work, e.g., the amount of erosion. The new approach applied to soil erosion is that, whatever the magnitude of soil eroded, erosion is a time compressed process and the percentag…
Predicting maximum annual values of event soil loss by USLE-type models
2017
Abstract Previous experimental investigations showed that a large proportion of total plot soil erosion over a long time period is generally due to relatively few, large storms. Consequently, erosion models able to accurately predict the highest plot soil loss values have practical importance since they could allow to improve the design of soil conservation practices in an area of interest. At present USLE-based models are attractive from a practical point of view, since the input data are generally easy to obtain. The USLE was developed with specific reference to the mean annual temporal scale but it was also applied at the event scale. Other models, such as the USLE-M and the USLE-MM, app…
Testing the USLE-M family of models at the Sparacia experimental site in south Italy
2017
The modified Universal Soil Loss Equation (USLE-M) was empirically deduced by a statistical analysis of the original data set of soil loss measurements used to derive the Universal Soil Loss Equation (USLE). The USLE-M, including the effect of runoffin the event rainfall-runofferosivity factor, is characterized by a better capacity to predict event soil loss. At first, in this paper, using the soil erosion representative variables of USLE-M and the reference condition adopted in the USLE, the dimensional analysis and the self-similarity theory are applied to theoretically deduce a multiplicative equation similar to the USLE-M. Then using the database of the Sparacia experimental site, the a…
Testing the long term applicability of USLE-M equation at a olive orchard microcatchment in Spain
2016
Abstract Universal Soil Loss Equation USLE-based erosion models have been used extensively to complement erosion measurements, to understand the interactions of the different geophysical features into erosion processes and to assess adequate alternative management practices and scenarios analyses. Despite its proved usefulness on different land-uses around the world, there is an urgent need to set up simple tools which do not require an advanced management expertise in terms of both choose of model parameters and calculation ability and which are accurate particularly at the event scale. In this paper the suitability of the Modified USLE (USLE-M) model at the event and the annual scale were…
Analysis of soil loss data from plots of differing length for the Sparacia experimental area, Sicily, Italy
2010
Widely used models of the soil erosion process, such as the empirical universal soil loss equation (USLE) and revised USLE (RUSLE), suggest that soil loss, i.e. the mass of soil lost by water erosion per unit surface area, increases with slope length, λ, although contrasting experimental results may be found in the literature. Experiments were carried out at the Sparacia site, Sicily, to establish the influence of plot length on soil loss. This was tested using data characterised by a high number of replicated, bare plots of different lengths (0.25, 0.4, 1, 2, 5, 11, 22, 33 and 44 m), simultaneously operating in the 1999–2008 period. Event soil losses did not vary significantly with λ or ev…
SW—Soil and Water
2000
Abstract Recent research has directed attention to the properties of the eroded material because of its influence in deposition phenomena and in carrying capacity of pollutant materials. In this paper, the spatial distribution of the content of nitrogen, phosphorus and total organic carbon is firstly deduced using the measurements carried out in 129 soil samples well distributed over the Sicilian Sparacia Basin and a Kriging interpolation method. Then the load of each chemical was calculated at morphological unit and basin scale using the above-mentioned spatial distributions and sediment yield values calculated by a parametric approach such as the revised universal soil loss equation (RUSL…
Predicting unit plot soil loss in Sicily, south Italy
2008
Predicting soil loss is necessary to establish soil conservation measures. Variability of soil and hydrological parameters complicates mathematical simulation of soil erosion processes. Methods for predicting unit plot soil loss in Sicily were developed by using 5 years of data from replicated plots. At first, the variability of the soil water content, runoff, and unit plot soil loss values collected at fixed dates or after an erosive event was investigated. The applicability of the Universal Soil Loss Equation (USLE) was then tested. Finally, a method to predict event soil loss was developed. Measurement variability decreased as the mean increased above a threshold value but it was low als…
Length Slope Factors for applying the Revised Universal Soil Loss Equation at Basin Scale in Southern Italy
2000
In this paper, for a basin divided into morphological units, a distributed model based on the Revised Universal Soil Loss Equation (RUSLE), with different expressions for the topographic factors, and on the sediment delivery ratio of each morphological unit is used. At first, the caesium-137 data available from a Sicilian basin are calibrated with two different models [the Proportional Method (PM), the Simplified Mass Balance (SMB) model] to provide net soil loss data for each morphological unit. Then, for a selected expression of the topographic factor, the slope length exponent is calculated for each morphological unit, equating the calculated sediment yield with the net soil loss. The an…