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Artykuły w czasopismach na temat "Soil erosion – Mathematical models"
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Deumlich, D., A. Jha i G. Kirchner. "Comparing measurements, 7Be radiotracer technique and process-based erosion model for estimating short-term soil loss from cultivated land in Northern Germany". Soil and Water Research 12, No. 3 (28.06.2017): 177–86. http://dx.doi.org/10.17221/124/2016-swr.
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Due to changing climate and irregular weather patterns, event-based soil loss and sediment yield have become important issues in the agricultural areas. Several mathematical models and prediction methodologies have been used to estimate event-based soil loss and soil redistribution based on soil types, land management, hydrology and local topography. The use of short-lived beryllium-7 as a means of estimating event-based soil erosion/deposition rates has become an alternative to the traditional soil loss measurement methods. A new erosion model taking into account the movement of <sup>7</sup>Be in soils has been presented recently. In order to direct the attention to the potential offered by this technique (measurements and mathematical model), a two-year study was performed at the erosion plots in Müncheberg, Germany, and twelve individual erosion rates were estimated. This paper presents a systematic comparison of the non-steady state <sup>7</sup>Be model with the process-based erosion model EROSION-3D and measured data. The results demonstrate a close consistency between the erosion rates estimated by erosion models and the estimates provided by the <sup>7</sup>Be model and can therefore be seen as a promising contribution to validating the use of this radionuclide to document short-term soil redistribution within the plot and deposited sediment at the bottom of the plot.
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Gajic, Grozdana, Nikola Zivanovic i Luka Vukic. "Indicators and degradation mechanisam of loess soil". Bulletin of the Faculty of Forestry, nr 114 (2016): 45–54. http://dx.doi.org/10.2298/gsf1614045g.
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Studies that are presented in this paper were carried out to define the formation criteria of loess soil degradation. Erosion stability analysis of this soil type will be carried out on the basis of its physical and mechanical characteristics. To describe the established relationships between the individual parameters of loess soil, the study uses mathematical model, that is based on experimentally obtained results of soils? physical and mechanical characteristics, From the presented results of geotechnical tests, mathematical models and functional relations between water regime and loess soils? resistant characteristics; indicators of internal erosion were defined as well as the mechanism of this process. Effects of the practical application of found results are also analyzed in this paper.
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Bagarello, Vincenzo, Vito Ferro i Dennis Flanagan. "Predicting plot soil loss by empirical and process-oriented approaches. A review". Journal of Agricultural Engineering 49, nr 1 (5.04.2018): 1–18. http://dx.doi.org/10.4081/jae.2018.710.
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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-oriented technology for soil erosion prediction at different spatial scales, is presented. The available criteria to discriminate between acceptable and unacceptable soil loss estimates are subsequently introduced. Finally, some research needs, concerning tests of both empirical and process-oriented models, estimates of the soil loss of given return periods, reliability of soil loss measurements, measurements of rill and gully erosion, and physical models are delineated.
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Vysloužilová, Barbora, i Zdeněk Kliment. "Soil Erosion and Sediment Deposition Modelling at the Small Catchment Scale". Geografie 117, nr 2 (2012): 170–91. http://dx.doi.org/10.37040/geografie2012117020170.
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Water erosion is considered to be the most important factor behind the degradation of agricultural land. Many methods of measuring soil erosion processes, using mathematical models, have been developed in recent years. The most widespread of these, USLE, and its modifications have been used as the basis for new erosion models. Two such models, USPED (Mitášová et al. 1996) and WaTEM/SEDEM (Van Rompaey et al. 2001; Van Oost et al. 2000; Verstraeten et al. 2002), have been utilized to study erosion and deposition processes in the experimental rural catchment of Černičí. River sediment transport is also calculated using the WaTEM/ SEDEM model. The results are discussed with results from USLE and a field survey. The article also presents brief instructions for implementing the models in a GIS environment.
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Svetlitchnyi, А. A., i A. V. Piatkova. "Spatially distributed GIS-realized mathematical model of rainstorm erosion losses of soil". Journal of Geology, Geography and Geoecology 28, nr 3 (10.10.2019): 562–71. http://dx.doi.org/10.15421/111953.
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In connection with the wide and ever increasing spread of erosion degradation of agricultural lands in Ukraine, the task of developing mathematical models and methods for calculating water erosion of soils corresponding to the current level of erosion study and the demands of soil protection practices is becoming increasingly important. The article is devoted to the development of a spatially distributed GIS-implemented mathematical model of rainstorm soil erosion, which accounts for most of the annual soil losses (in the Steppe zone, for example, about 90 %). The development of the model is based on the most theoretically and informationally grounded model for the Steppe and Forest-Steppe of Ukraine , “the logical-mathematical model of rainstorm soil outwash” developed by H. I. Shvebs (1974, 1981), as well as the results of theoretical and field studies and mathematical modeling of the slope runoff and water erosion of soil, carried out at the Department of Physical Geography and Environmental Management of Odessa I. I. Mechnikov National University in the 1990s - 2010s, and also the possibilities of modern geoinformation technologies. For the spatial implementation of the model, a raster model of spatial data and operators of the PCRaster GIS-package (University of Utrecht, the Netherlands) were used, integrated with the Basic programming language into a single system that provides an implementation of the computational algorithm. The developed physical-statistical model of soil erosion-sedimentation takes into account the peculiarities of the formation of slope runoff and soil outwash in conditions of excessive nonstationarity of heavy rainfall, as well as spatial heterogeneity of all major natural and economic factors of water erosion on a slope, including slope steepness, exposure, longitudinal and transverse forms of slopes, soil erodibility, structure of sown areas and anti-erosion measures. Checking the adequacy of the mathematical model was performed using observational data of four experimental catchments ; two runoff plots of the Moldavan water-balance station with total area of 0.08 ha, the Ploska catchment with area of 8.5 ha (Boguslav field experimental base of Ukrainian Hydrometeorological Institute) and the Sukha catchment with area of 63 ha (Veliko-Anadol water-balance station) with observation periods of 17-31 years. Comparison of the calculated average over the catchment area of mean annual values of rainstorm soil losses, with the corresponding values obtained from measurements on these catchments, made on the basis of Nash-Sutcliff efficiency criterion (NS), allowed us to evaluate the quality of the model as good (NS = 0.72).
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Gajic, Grozdana. "Parameters of the occurrence of internal erosion processes in salty-sandy soils". Bulletin of the Faculty of Forestry, nr 92 (2005): 15–29. http://dx.doi.org/10.2298/gsf0592015g.
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The study was aimed at defining the conditions of the occurrence of internal erosion in silty-sandy soils. The susceptibility of this soil to internal erosion depends on the porosity, particle-size composition and hydro-geo-mechanical parameters. Internal erosion stability was analyzed by the introduction of the coefficient of particle composition as the critical particle-size condition, which is in fact the coefficient of internal erosion (Kue). Based on the study results, mathematical models and the functional correlation between water regime and resistant characteristics of silty-sandy soils, we defined the parameters of the occurrence of initial internal erosion and analyzed the effects of the practical application of the study results.
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Petrychenko, V., O. Tarariko i O. Syrotenko. "Space Technologies in Agri-Environmental Monitoring System". Agricultural Science and Practice 1, nr 1 (15.04.2014): 3–12. http://dx.doi.org/10.15407/agrisp1.01.003.
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The contemporary development of the remote space survey syst ems and elements of geoinformation t echnolo gies o ffers the fundamentally new possibilities of control, forecasting and interpretation of the data obtained from agroecological monitoring. Aim. To describe natural and climatic conditions of the various zones within the territory of Ukraine, its agricultural acquirement and risk of the soils’ erosive degradation manifestations in the meaning of climate changes. To determine the factors infl uencing upon the spectral characteristics of the eroded soils for their identifi cation, deciphering, and also the cultivated lands and land tenure systems degradatio n monitoring according to satellite data. Methods. The logical model of water erosion determination and identifi cation according to the data of the Earth remote sensing (ERS) of high spatial resolution is developed on the basis of classifi cation in basic deciphering signs and the procedure of molding of the training samples forming. The materials of the Landsat 8, SPOT, ASTER and RapidEye space surveys, map materials and data of full-scale ground observations on the test objects were used for identifi cation of the processes of sheet and linear erosion. The soil erosion was determined according to two approaches. The fi rst one is based on the plowed soil and the second – on soil covered with plants. The soil erosion class was determined according to the spectral characteristics and humus content, while gully rate – by reference to gullies’ length and square. Results. The humus content in so il was proposed to be determined according to the spatial distribution of spectral characteristics within the limits of uniform regions and corresponding mathematical-statistical models. The opportunities of linear and sheet erosion classifi cation according to the ERS data, and also their use in the system of monitoring and evaluating the ecological state of agrolandscapes and land tenure systems are shown. C onclus ions. The space mo nitoring data of the soils erosive degradation and agrolandscapes in whole provide the opportunity of more effective use of soil resources due to the strategic determination of degradation processes with the subsequent planning and workout the measures for th e optimization of the erosive dangerous agrolandscapes structure, and also introduction of the ground water-guarding systems of soil management.
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Pickup, G., i VH Chewings. "Mapping and Forecasting Soil Erosion Patterns from Landsat on a Microcomputer-based Image Processing Facility." Rangeland Journal 8, nr 1 (1986): 57. http://dx.doi.org/10.1071/rj9860057.
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The paper summarises recent work in the development and implementation of broad scale conceptual and mathematical models of the soil erosion process in flat arid lands. The conceptual model is based on erosion cell behaviour. Its mathematical counterpart is the simultaneous autoregressive random field model recently developed for image modelling.The data used in the mathematical model are derived by transforming standard Landsat MSS data to produce a soil stability index. Practical application of the methods requires the appropriate computer software and an image processing facility. The erosion modelling routines have therefore been implemented as part of a user- friendly microcomputer based image processing package which is now available commercially. The package runs on an IBM XT or AT computer using a Vectrix graphics board and the hardware includes high resolution display and hard copy facilities. Both hardware and software cost less than $30,000 making it ~ossible to decentralise image processing technology to branch offices of government departments or to agricultural consultants.
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HRISSANTHOU, V., i A. PSILOVIKOS. "Distributed modeling of soil erosion and sediment transport". Bulletin of the Geological Society of Greece 34, nr 2 (1.08.2018): 763. http://dx.doi.org/10.12681/bgsg.17354.
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A mathematical model is used for the estimation of the annual sediment yield resulting from rainfall and runoff at the outlet of Nestos River basin (Toxotes, Thrace, Greece), where the ecologically interesting Nestos delta exists. The model is applied to that part of Nestos River basin (838 km2) which lies downstream of three dams. Two dams (Thissavros and Platanovryssi) have been already constructed, while the third one (Temenos) is under construction. The model consists of three sub-models: a rainfall-runoff sub-model, a surface erosion sub-model and a sediment transport sub-model for streams. This model is also capable of computing the annual erosion amount and sediment yield in the individual sub-basins
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Svіtlуchnyi, Oleksandr, i Alla Piatkova. "Problems of spatially distributed quantitative evaluation of soil erosion losses". Visnyk of V.N. Karazin Kharkiv National University, series Geology. Geography. Ecology, nr 56 (1.06.2022): 184–97. http://dx.doi.org/10.26565/2410-7360-2022-56-13.
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Formulation of the problem. Water erosion of soils is the most widespread and dangerous soil degradation process in Ukraine. The development of an effective system of soil protection measures requires the use of spatially distributed mathematical models of soil erosion losses. This, in turn, highlights the problem of spatially distributed source data, which adequately reflect the spatial differentiation of factors of the erosion process, among which the main one is the relief. The purpose of the article. Assessing the adequacy of available spatially distributed source data, including cartographic and freely distributed global digital elevation models (DEMs), for spatially distributed quantitative assessment of soil erosion losses at the local level of territorial coverage is the aim of the article. Assessing from this point of view the scale of the original cartographic data, different global DEMs and their spatial resolution, as well as the degree of spatial generalization of the original data. Materials and methods. The solution of the set tasks was performed by the method of simulation modeling with the use of physical-statistical GIS-realized mathematical model of soil erosion-accumulation, developed at Odessa I. I. Mechnikov National University. Source data arrays were tested with DEMs SRTM90 and SRTM30 with a spatial resolution of 3 and 1 angular seconds, respectively, and AW3D30 with a spatial resolution of 1 angular second, as well as with cartographic DEMs based on topographic maps of scale 1:10000 and 1:25000. For testing the initial data, three test plots with an area of 2.67, 0.59 and 0.21 km2 were selected. The plots are located in the Balta district of Odessa region on the southern spurs of the Podolska upland. Results. It is established that freely distributed global digital elevation models SRTM and AW3D30 in the conditions of flat terrain do not always allow to adequately display the structure of slope runoff and, accordingly, to correctly perform calculations of soil erosion losses. The maximum deviation of the average soil erosion losses calculated for the test plots using global DEMs from the soil losses calculated using the reference DEM for SRTM30 and AW3D30 was 27%, for SRTM90 – almost 70%. The distribution of soil losses over the area of test plots obtained using different global DEMs differs even more. When using DEM based on topographic maps, reducing the scale of the original maps from 1: 10000 to 1: 25000 leads to a decrease in the average value of soil erosion losses by about 20% due mainly to reducing the magnitude and area of distribution of maximum soil losses, and on slopes of complex shape also due to changes in the area of accumulation zones. The degree of spatial generalization of the initial data significantly affects the results of the assessment of soil erosion losses both in relation to the average values and their distribution over the area. For small areas, the use of raster cells larger than 50 m is impractical. Scientific novelty and practical significance. It has been shown for the first time that in the conditions of flat terrain at the local level of spatial coverage, the freely distributed global DEM SRTM and AW3D30 are not always hydrologically correct. The reasons and conditions of violation of this correctness are specified. It has been established that the global DEM AW3D30 has local instrumental errors that may make it impossible to use it. The most realistic values of soil erosion losses are provided by DEM SRTM with a spatial resolution of 1 angular second.
Rozprawy doktorskie na temat "Soil erosion – Mathematical models"
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Lopes, Vicente Lucio 1952. "A numerical model of watershed erosion and sediment yield". Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/191125.
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A physically based, distributed parameter, event oriented, nonlinear, numerical model of watershed response is developed to accommodate the spatial changes in topography, surface roughness, soil properties, concentrated flow patterns and geometry, and land use conditions. The Green and Ampt equation with the ponding time calculation for an unsteady rain is used to compute rainfall excess rates. The kinematic wave equations are used to describe the unsteady one-dimensional overland and channel flow. The unsteady and spatially varying erosion/deposition process on hillslopes and channel systems is described dynamically using simultaneous rates of sediment entrainment and deposition rather than the conventional approach using steady state sediment transport functions. To apply the model the watershed is represented by a simplified geometry consisting of discrete overland flow planes and channel elements. Each plane or channel is characterized by a length, width, and a roughness parameter. For channel elements, a cross-section geometry is also needed. A modular computer program called WESP (Watershed Erosion Simulation Program) is developed to provide the vehicle for performing the computer simulations. Rainfall simulator plots are used to estimate infiltration parameters, hydraulic roughness, and soil erodibility parameters for raindrop impact and overland flow. The ability of the model to simulate watershed response (hydrograph and sedigraph) to a variety of rainfall inputs and antecedent soil moisture conditions is verified using data collected on two small watersheds. The good agreement between the simulated watershed response and the observed watershed response indicates that the governing equations, initial and upper boundary conditions, and structural framework of the model can describe satisfactorily the physical processes controlling watershed response.
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Zheng, Tingting. "Mathematical modeling of soil erosion by rainfall and shallow overland flow". Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/9144.
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New analytical and numerical solutions are developed to both the kinematic approximation to the St Venant equations and the Hairsine-Rose (HR) soil erosion model in order to gain a better physical understanding of soil erosion and sediment transport in shallow overland flow. The HR model is unique amongst physically based erosion models in that it is the only one that: considers the entire distribution of the soil s sediment size classes, considers the development of a layer of deposited non-cohesive sediment having different characteristics to the original underlying cohesive soil and considers separately the erosion processes of rainfall detachment, runoff entrainment and gravitational deposition. The method of characteristics and the method of lines were used to develop both the analytical and numerical solutions respectively. These solutions were obtained for boundary and initial conditions typical of those used in laboratory flume experiments along with physically realistic constant and time dependent excess rainfall rates. Depending on the boundary and initial conditions, interesting new solutions of the kinematic wave equation containing expansion waves, travelling shocks as well as solutions which split into an upslope and downslope drying profiles were found. Numerical solutions of the HR model were applied to the experimental flume data of Polyakov and Nearing (2003) obtained under flow conditions which periodically cycled between net erosion and net deposition conditions. While excellent agreement was found with suspended sediment data, the analysis suggested that an additional transport mechanisms, traditionally not included in soil erosion models, was occurring. While the inclusion of bed-load transport improved the ii overall model prediction, it was still not sufficient. Subsequent asymptotic analysis then showed that the interaction of the flow with an evolving bed morphology was in fact far more important than bed load transport. A very interesting finding from this work showed that the traditional criterion of validating sediment transport model based solely on suspended sediment data was not sufficient as reliable predictions could be obtained even when important transport mechanisms were neglected. Experimental plots of sediment discharge or suspended sediment concentration against water discharge in overland flow have been shown to contain significant hysteresis between the falling and rising limbs of the discharge hydrograph. In the final Chapter, the numerical solution developed for the complete system of soil erosion and kinematic flow was used to show that it was possible for the HR model to simulate three of the four hysteresis loops identified in the literature. Counter clock-wise loops, clock-wise loops and figure 8 loops could all be produced as a result of starting with different initial conditions, being mi(x; 0) = 0, mi(x; 0) = pimt and mi(x; 0) = 0:5pimt respectively. This is the first time that these types of hysteresis loops have been produced by any erosion model. The generation of these hysteresis loops are physically explainable in terms of sediment availability and is consistent with data obtained on the field scale.
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Barchyn, Thomas Edward, i University of Lethbridge Faculty of Arts and Science. "Field-based aeolian sediment transport threshold measurement : sensors, calculation methods, and standards as a strategy for improving inter-study comparison". Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Geography, 2010, 2010. http://hdl.handle.net/10133/2616.
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Aeolian sediment transport threshold is commonly defined as the minimum wind speed (or shear stress) necessary for wind-driven sediment transport. Threshold is a core parameter in most models of aeolian transport. Recent advances in methodology for field-based measurement of threshold show promise for improving parameterizations; however, investigators have varied in choice of method and sensor. The impacts of modifying measurement system configuration are unknown. To address this, two field tests were performed: (i) comparison of four piezoelectric sediment transport sensors, and (ii) comparison of four calculation methods. Data from both comparisons suggest that threshold measurements are non-negligibly modified by measurement system configuration and are incomparable. A poor understanding of natural sediment transport dynamics suggests that development of calibration methods could be difficult. Development of technical standards was explored to improve commensurability of measurements. Standards could assist future researchers with data syntheses and integration.xi, 108 leaves : ill. ; 29 cm
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Navarro, Hernan Ricardo. "Flume Measurements of Erosion Characterstics of Soil at Bridge Foundations in Georgia". Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/7267.
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Shelby tube sediment samples collected from the foundations of ten (10) bridges located in the state of Georgia were tested in the laboratory to find their erosional behavior and the correlation of erosion parameters with sediment properties in order to improve the prediction of scour around bridge foundations. These sites were spatially distributed in order to fall into different major river basins and in different physiographic regions. A description of the Valley and Ridge, Blue Ridge, Piedmont, and Coastal Plain physiographic regions of Georgia is included, and the erosion parameters found from flume measurements are associated with their respective regions. Flume measurements were performed using a rectangular, tilting, recirculating flume located in the hydraulics lab in the School of Civil and Environmental Engineering at Georgia Tech. Velocities up to 1.7 m/s and bed shear stresses up to 21 Pa can be achieved in the flume. Regression analysis was performed on erosion rates as a function of applied shear stress to determine the parameters of the erosion function. The resulting parameters, the critical shear stress and the erosion rate constant, were correlated with soil properties and physiographic regions.
Experimental methodology was chosen to approach this problem because the involvement of interparticle forces for fine-grained materials makes it difficult to deal with the erosion phenomenon through other means. Nevertheless, analytical description of the erosion phenomenon was included in order to provide a better understanding of it.
Linear, exponential and power regression mathematical models for erosion rate were compared, and the two best-fit regression models of erosion rate as a function of shear stress are proposed to formulate a methodology intended to characterize the behavior of a soil exposed to erosive flow conditions. One of them is a linear model to calculate critical shear stresses and low erosion rates. The second model, which is exponential, has the advantage of describing the erosion rate response for a wider range of shear stress values. It is shown that one of the most relevant predictors for the critical shear stress and erosion rate constant in the regression models is the fine material content present in the sample, which is an indirect indicator of the contribution of interparticle forces to the erosion process. Applying the described methodology, a more case-specific calculation of the erosion at bridge foundations can be performed taking into account the actual material in situ.
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Segarra, Eduardo. "A dynamic analysis of the crop productivity impacts of soil erosion: an application to the Piedmont area of Virginia". Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/51930.
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This study was born out of the desire to analyze the complex soil management problem faced by individual economic agents as well as society. The focus of this study, however, was on the theoretical formulation and estimation of partial equilibrium dynamic economic models directed toward optimizing the private use of the soil resource. In particular, four empirical representative farm models were formulated.
Solutions to the four representative farm models showed that sizable reductions in topsoil loss, which contributes to non-point source pollution, and aggravates the crop productivity impacts of soil erosion, can be accomplished by adopting alternative support practices. Because of the change in support practices, reductions in the present value of net returns are expected, but this decrease in return was found to be minimal when compared to reductions in topsoil loss. Policy implications as well as several policy recommendations stemming from those results, with respect to soil conservation, are outlined and analyzed.Ph. D.
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Mengler, Faron. "Gully erosion on rehabilitated bauxite mines". University of Western Australia. School of Earth and Geographical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0176.
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[Truncated abstract] Landforms rehabilitated after bauxite mining can be vulnerable to soil loss by water erosion processes. On most rehabilitated sites, management controls such as deep ripping, contour mounding and landscaped sub-catchments limit erosion. Despite these measures, severe gully erosion that is anecdotally associated with steep slopes can damage rehabilitated areas and affect downstream drinking water resources. A review of erosion dynamics reveals that gullies develop episodically and in a non-linear manner. They often initiated as a near surface process and are influenced by natural climatic drivers. Despite this, local site characteristics including soil and landform can predispose an area to gully erosion. Moreover, erosion models, becoming more-widely utilized within the mining industry, may provide useful tools with which to measure, analyse, and manage gully erosion. One of these models, SIBERIA was tested to determine its suitability for application a tool to help manage erosion risk. We first surveyed 26 eroding and erosion-prone rehabilitated hillslopes to determine the common form and setting for gully erosion on these rehabilitated bauxite mines. A conceptual model was developed to include and explore the interplay between the common causes of the gullies surveyed. The conceptual model accounts for slope steepness but suggests that additionally, certain triggers and threshold effects operating under different site conditions are as influential (or even more influential) than slope steepness as determinants of gully erosion occurrence and severity. ... Soil properties and soil erodibility had some subtle influence on landform stability and erosion risk. The most-erodible media occurred where either: mine floor material was mixed with topsoil/ overburden; and/or the topsoil/overburden layer was thin or its coverage is patchy resulting in slaking subsoil, hardsetting soil and surface crusts. When erodible surface media were combined with steeper (>8[degrees]) or longer (>50 m) slopes or with any major erosion trigger, rill and gully development was greatly intensified. The SIBERIA simulation model was calibrated and its simulated outputs were compared to known locations of gully erosion on a steep, rehabilitated pit from the Willowdale mine. At a resolution of one metre, SIBERIA was able to simulate the approximate dimensions of gullies. However, SIBERIA could not simulate the exact location of individual gully headcuts. Additionally, SIBERA was able to simulate the effect of different microtopographic surface treatments but this was only achieved by increasing the grid resolution to 25 cm and reducing the size of the area simulated due to model constraints. Locations of gully headcuts were overlain onto a grid-based, Digital Elevation Model (DEM) using a Geographic Information System (GIS). The spatial distribution of gully headcut locations was compared to DEM derivatives such as slope and flow accumulation. Positive, and predictive relationships allow between the steepness of the slope of the pre-mining landform and the cell count of the area contributing to flow (catchment), as determined by GIS, may allow a mine scale indication of erosion risk using simple GIS desktop analysis.
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Cox, Christopher 1967. "Watershed master planning for St. Lucia using geographic information systems". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27303.
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A method for estimating long-term average annual soil loss under different land management scenarios from the Marquis and Soufriere watersheds on St. Lucia is presented. The Revised Universal Soil Loss Equation (RUSLE) was used, and a GIS was employed to generate the required input parameters. Model execution and results were also generated within the GIS. Modelling soil loss for the different land management scenarios was based upon a land capability classification and associated conservation treatments. Soil losses under current agricultural land-use patterns were analyzed and compared to potential soil losses under conservation treatments following the criteria specified in the land capability classification. The model predicted substantial declines in soil loss where conservation treatments were assigned, as compared to soil loss under current land-use patterns. It was found that predicted soil losses from the Soufriere watershed were four times that predicted for the Marquis watershed for all the land management scenarios modelled. Of the input parameters in the model, slope steepness was most highly correlated to predicted soil loss. It is anticipated that the findings of this study will be used in the development of a decision support system for agricultural and forestry land planning on St. Lucia.
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Castro, Luciana Gomes. "Dinâmica da água em terraços de infiltração". Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-26062002-145103/.
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O terraceamento é uma prática de conservação do solo que visa reduzir a perda de água e solo pela interceptação de enxurradas que ocorrem quando a intensidade da chuva supera a capacidade de infiltração de água no solo. Atualmente, o dimensionamento dos terraços tem sido feito com base em conhecimento empírico; no entanto, um conhecimento mais detalhado da física dos processos que regem o funcionamento dos terraços possibilitaria otimizar o dimensionamento dos terraços. No presente estudo foi avaliada a capacidade de infiltração de água no canal de um terraço em nível pelos métodos da densidade de fluxo e da armazenagem de água em diferentes condições de manejo agrícola (solo nu, solo gramado e solo sob preparo convencional e plantio direto para a implantação da cultura de milho) num Latossolo vermelho com declividade média de 0,08 m m-1. Em cada tratamento foram instaladas sondas de TDR em três pontos de observação no centro do canal do terraço (distanciados de 4 m entre si e considerados como repetições), nas rofundidades de 0,05, 0,10, 0,20, 0,40, 0,60 e 0,80 m. Nestas mesmas profundidades amostras indeformadas de solo foram retiradas para determinação da densidade e curva de retenção de água no solo. As leituras das guias de onda do TDR foram feitas automaticamente e a intensidade de chuva monitorada por um pluviômetro automatizado. Ao final de cada evento de chuva erosiva a deposição de solo foi medida por meio de 14 pontos de observação dispostos ao longo do centro do canal do terraço de cada tratamento. Durante a estação seca (julho-agosto), a condutividade hidráulica do solo não saturado foi determinada em cada repetição nas mesmas profundidades, utilizando o método do perfil instantâneo. Os resultados demonstraram que os manejos agrícolas influenciam na deposição de água e solo sobre o canal do terraço e estas na formação de selo superficial e na capacidade de infiltração de água do canal. Conclui-se que a alta variação comumente obtida entre as repetições de determinação da condutividade hidráulica implica em dificuldades quando se objetiva detectar pequenas diferenças nas densidades de fluxo entre tratamentos. Assim, mostrou ser inviável utilizar densidades de fluxo calculadas pela equação de Darcy-Buckingham para encontrar diferenças em taxas de infiltração em terraços em nível. Essa conclusão reforça-se devido às condições superficiais altamente variáveis encontradas em canais de terraços em nível devido a deposições irregulares do material erodido. Uma metodologia para se realizar medições da umidade nas deposições sobre o canal deve ser desenvolvida para aumentar a acurácia da medida da armazenagem. A taxa de infiltração de água no canal do terraço não pode ser estimada pela variação da armazenagem da água no solo somente, devido ao papel importante da drenagem profunda e, possivelmente, da absorção de água pela camalhão do terraço. Uma adequada estimativa da taxa de infiltração no canal do terraço, imprescindível para seu dimensionamento, deve aliar um grande número de repetições, além da medição da umidade no interior da camada de material depositado sobre o canal ao longo do tempo.Terracing is a soil conservation practice that aims to reduce water and soil loss by interception of runoff that occurs when rainfall intensities exceed infiltration capacity. Actually, dimensions of terraces are being determined in an empirical way; however, a more detailed understanding of the physics behind the hydrological functions of terraces would allow an optimized dimensioning of terraces. In this study the infiltration capacity of a level terrace was evaluated by the methods of flux density and water storage, under different management conditions (bare soil, pasture, conventionally tilled maize and zero-tillage maize) on an oxisol with a slope of 0.08 m m-1. In each treatment TDR sensors were installed at three observation points in the middle of the terrace canal (distance between points: 4 m; considered to be repetitions) at the depths of 0.05, 0.10, 0.20, 0.40, 0.60 and 0.80 m. At the same depths, undisturbed soil samples were taken to determine soil density and soil water retention curve. TDR readings were made automatically and a rainfall gauge automatically monitored rainfall intensity. At the end of each rainfall event, soil deposition was measured at 14 locations in the terrace canal in each treatment. During the dry season (July-August), unsaturated hydraulic conductivity was determined at each repetition at the same depths by the instantaneous profile method. The results showed that agricultural management influenced water and soil deposition in the terrace canal and these affected surfaced sealing and infiltration capacity. It was concluded that the high variation usually obtained between repetitions of the hydraulic conductivity determinations makes the detection of small differences between flux densities difficult. Therefore, it showed to be impossible to use flux densities calculated by Darcy-Buckingham equation in the order to prove existence of different infiltration rates in level terraces. This conclusion was reinforced due to the highly variable surface conditions in the terrace canal. A methodology to measure water contents within the depositions in the canal should be developed to increase the precision of water storage estimation. Infiltration rates in the terrace canal cannot be estimated by storage variation alone, due to the important role of drainage and, possibly, ascension of water in the terrace hill. A correct estimate of the infiltration rate in the canal, necessary for its dimensioning, should combine a high number of repetitions with the measurement of water content within the layer of deposits over the terrace canal surface along time.
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Galdino, Sérgio. "Estimativa da perda de terra sob pastagens cultivadas em solos arenosos da bacia hidrográfica do alto Taquari - MS/MT". [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256830.
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Orientadores: Mara de Andrade Marinho, Edson Eiji MatsuraTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola
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Resumo: O assoreamento do rio Taquari constitui grave problema ambiental e socioeconômico do Pantanal Brasileiro e decorre principalmente da erosão acelerada do solo ocupado com pastagens degradadas na parte alta da bacia. Um dos modelos mais utilizado para estimar a perda média anual de solo é a Equação Universal de Perda de Solo (USLE). Novas pesquisas foram realizadas para melhorar as estimativas do modelo, originando a Equação Universal de Perda de Solo Revisada (RUSLE). A principal mudança foi na forma de determinação do fator de uso e manejo do solo (C). Na USLE o fator C é obtido a partir do monitoramento constante da perda de solo em parcelas experimentais durante vários anos, constituindo sério empecilho a sua determinação, principalmente no Brasil. Na RUSLE o fator C para pastagens é estimado mais rapidamente, a partir de levantamentos de parâmetros do solo e da vegetação. O objetivo geral do trabalho foi ajustar os fatores da RUSLE às condições locais da bacia do alto Taquari (BAT) e estimar as taxas de perda de solo por erosão, para posterior estudo de cenários de manejo e identificação das práticas mais protetoras dos solos na bacia. O estudo compreendeu áreas de pastagens cultivadas em solos arenosos da BAT. Os parâmetros necessários para estimativas da razão de perda de solo (SLR) e fator C da RUSLE foram levantados em nove parcelas (pastagens) em duas épocas do ano. Análise da SLR e do fator C identificaram valores de C representativos de pastagem não degradada e com níveis de degradação; baixo/médio e alto. Na espacialização do fator C na BAT utilizou-se o modelo linear de mistura espectral. Para a estimativa das perdas de solo nas áreas de pastagens também foram espacializados os demais fatores da RUSLE. A erosividade das chuvas (Fator R) foi estimada a partir de registros mensais e anuais de precipitação de postos pluviométricos localizados na BAT e entorno. Na estimativa da erodibilidade do solo (Fator K) foram utilizados parâmetros físico-químicos do solo levantados no campo. O fator topográfico (LS da RUSLE) foi obtido empregando algoritmo de contribuição de área a montante e modelo digital de elevação do Banco de Dados Geomorfométricos do Brasil (TOPODATA). O fator de práticas conservacionistas do solo (Fator P) foi considerado unitário na estimativa da perda de solo atual na BAT. Também foram estimadas as perdas de solo para dois cenários futuros de manejo adequado do solo e da pastagem. Resultado evidenciou que os valores do fator C estimados pela RUSLE para pastagens se assemelham àqueles determinados pela USLE. A média da perda de solo nas pastagens da BAT em 2010 foi estimada em 9,638 Mg ha-1 ano-1. O estudo de cenários permitiu uma redução em até 75,97% das taxas de perda de solo por erosão com a implementação de manejo adequado do solo e da pastagem. Conclui-se que a RUSLE apresenta bom potencial de estimativa do fator de uso e cobertura do solo, e que se ajustou bem às condições locais da BAT na estimativa da perda de solo
Abstract: The river siltation Taquari constitutes serious environmental and socioeconomic problem of the Brazilian Pantanal and arises principally from accelerated erosion of land occupied by degraded pastures in the upper basin. One of the models used to estimate the average annual soil loss is the Universal Soil Loss Equation (USLE). New research has been done to improve the model estimates, yielding the Revised Universal Soil Loss Equation (RUSLE). The main change was in the method determines the use and soil management factor (C). With USLE, the C factor is obtained from the constant monitoring of soil loss in plots for several years, constituting serious impediment to their determination, especially in Brazil. With RUSLE, the C factor for pastures is estimated sooner, using surveys of soil parameters and vegetation. The overall goal of this work was to adjust RUSLE factors to upper Taquari basin (UTB) local conditions and to estimate soil loss rates due to erosion, for further management scenarios studies and more protective soil identification practices in the basin. The study included pastures grown on sandy soils of the UTB. The required parameters for soil loss ratio estimates (SLR) and the RUSLE C factor were raised in nine plots (pastures) in two seasons. Further SLR analysis identified C factor values for non-degraded, low, medium and highly degraded pasture levels. C factor spatialization for the UTB used the linear spectral mixture model. To estimate soil loss in grazing areas other RUSLE factors were also spatialized. The rainfall erosivity factor (R) was estimated from records of monthly and annual precipitation of rain gauge stations located in and around the UTB. For soil erodibility (K factor) estimation, physic-chemical soil parameters collected in the area were used. The topographic factor (LS RUSLE) was obtained using algorithm contribution of the upstream area and Brazilian geomorphometric digital elevation model data from TOPODATA. The soil conservation practices factor (P) unit was considered estimating soil loss in the UTB. Two future soil loss scenarios were also estimated. Results showed that the C factor values estimated by RUSLE for pastures resemble those determined by USLE. The average soil loss in the pastures of the UTB in 2010 was estimated at 9.638 Mg ha-1 yr-1. The scenario study allowed for a reduction up to 75.97% in the rates of soil loss due to erosion by implementing proper soil and pasture management. We conclude that the RUSLE estimation shows good potential for land use techniques, which fits well into the UTB local conditions and in the estimation of soil loss
Doutorado
Planejamento e Desenvolvimento Rural Sustentável
Doutor em Engenharia Agrícola
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Dissart, Jean-Christophe. "The economics of erosion and sustainable practices : the case of the Saint-Esprit watershed". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0006/MQ44158.pdf.
Pełny tekst źródłaKsiążki na temat "Soil erosion – Mathematical models"
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Paris, S. Erosion hazard model: (modified SLEMSA). Wyd. 2. [Lilongwe]: Malawi Govt. Ministry of Agriculture, Land Husbandry Branch, 1990.
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Forum on Erosion Productivity Impact Estimators (1985 Alexandria, Va.). Forum on Erosion Productivity Impact Estimators. [Washington, D.C.?]: U.S. Dept. of Agriculture, Soil Conservation Service, Assessment and Planning, 1986.
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Forum, on Erosion Productivity Impact Estimators (1985 Alexandria Va ). Forum on Erosion Productivity Impact Estimators. [Washington, D.C.?]: U.S. Dept. of Agriculture, Soil Conservation Service, Assessment and Planning, 1986.
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Hessel, Rudi. Modelling soil erosion in a small catchment on the Chinese Loess Plateau: Applying LISEM to extreme conditions. Utrecht: Koninklijk Nederlands Aardrijkskundig Genootschap, 2002.
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Hebel, Bernd. Validierung numerischer Erosionsmodelle in Einzelhang- und Einzugsgebiet-Dimension. Basel: Geographisches Institut der Universität Basel, 2003.
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Mainam, Félix. Modelling soil erodibility in the semiarid zone of Cameroon: Assessment of interrill erodibility parameters for mapping soil erosion hazard by means of GIS techniques in the Gawar area = Modellering van de erosiegevoeligheid van de bodem in het Semi-aride gebied van Kameroen : bepaling van de parameters van vlakte erosie voor het in kaart brengen van het risiko van bodemerosie door middel van GIS technieken in het Gawar gebied. Enschede, the Netherlands: ITC, 1999.
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Pingcang, Zhang, i Yang Qinke, red. Qu yu shui tu liu shi tu rang yin zi yan jiu: Quyu shuitu liushi turang yinzi yanjiu. Beijing: Di zhi chu ban she, 2003.
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Kerzhent︠s︡ev, A. S. Modelirovanie ėrozionnykh prot︠s︡essov na territorii malogo vodosbornogo basseĭna. Moskva: Nauka, 2006.
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Putman, John W. The erosion-productivity impact calculator as formulated for the Resource Conservation Act appraisal. [Washington, DC]: U.S. Dept. of Agriculture, Economic Research Service, Natural Resource Economics Division, 1987.
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Putman, John W. The erosion-productivity impact calculator as formulated for the Resource Conservation Act appraisal. [Washington, DC]: U.S. Dept. of Agriculture, Economic Research Service, Natural Resource Economics Division, 1987.
Znajdź pełny tekst źródłaCzęści książek na temat "Soil erosion – Mathematical models"
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Wickenkamp, V., R. Duttmann i T. Mosimann. "A Multiscale Approach to Predicting Soil Erosion on Cropland Using Empirical and Physically Based Soil Erosion Models in a Geographic Information System". W Soil Erosion, 109–34. Berlin, Heidelberg: Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/978-3-662-04295-3_7.
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Evans, R. "Field Data and Erosion Models". W Modelling Soil Erosion by Water, 313–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-58913-3_23.
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Le Bissonnais, Y., D. Fox i L. M. Bresson. "Incorporating Crusting Processes in Erosion Models". W Modelling Soil Erosion by Water, 237–46. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-58913-3_18.
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Rose, Calvin W. "Developments in Soil Erosion and Deposition Models". W Advances in Soil Science, 1–63. New York, NY: Springer New York, 1985. http://dx.doi.org/10.1007/978-1-4612-5088-3_1.
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Botterweg, Peter. "Snowmelt and Frozen Soils in Simulation Models". W Modelling Soil Erosion by Water, 365–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-58913-3_27.
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Nicks, A. D. "The Use of USLE Components in Models". W Modelling Soil Erosion by Water, 377–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-58913-3_28.
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Kirkby, Mike. "Modelling Across Scales: The Medalus Family of Models". W Modelling Soil Erosion by Water, 161–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-58913-3_12.
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Rudra, R. P., W. T. Dickinson i G. J. Wall. "Problems Regarding the Use of Soil Erosion Models". W Modelling Soil Erosion by Water, 175–89. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-58913-3_13.
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Brazier, R. E., C. J. Hutton, A. J. Parsons i J. Wainwright. "Scaling Soil Erosion Models in Space and Time". W Handbook of Erosion Modelling, 98–116. Chichester, UK: John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781444328455.ch6.
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Burt, T. P. "Infiltration for Soil Erosion Models: Some Temporal and Spatial Complications". W Modelling Soil Erosion by Water, 213–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-58913-3_16.
Pełny tekst źródłaStreszczenia konferencji na temat "Soil erosion – Mathematical models"
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Kavka, P. "COMPARISON OF SOIL EROSION RILLS IDENTIFICATION BY MATHEMATICAL MODELS AND AERIAL PHOTOGRAPHS". W 14th SGEM GeoConference on INFORMATICS, GEOINFORMATICS AND REMOTE SENSING. Stef92 Technology, 2014. http://dx.doi.org/10.5593/sgem2014/b21/s8.066.
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Zhang, Huayong, i Liming Dai. "Surface Runoff and Its Erosion Energy in a Partially Continuous System: An Ecological Hydraulic Model". W ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-10607.
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Plant community and ground surface form a partially continuous ecosystem in conveying surface runoff and its erosion energy. It is one of the mechanisms for maintaining the stable development of a partially continuous ecosystem that the plant community and ground surface dissipate the erosion energy produced by surface runoff so as to control the soil erosion process of the ecosystem. Based on the energy fundamentals of hydraulics and by idealizing the structure of plant community, we obtain an ecological hydraulic model in this paper through a series of mathematical deductions, which includes three equations: (1) the equation on approaching energy balance of surface runoff moving across plant community and ground surface; (2) the equation on the process of dissipating energy of surface runoff by plant community and ground surface in an ecosystem; (3) the equation on the relationship among the pattern of plant community, ground surface and energy dissipation of surface runoff. Theoretically, the ecological hydraulic model can be used to calculate the dynamical process of energy dissipation of surface runoff by plant community and ground surface in a partially continuous ecosystem and to discuss the optimization of plant community pattern in a given section of the ecosystem.
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Liang, Yue, Jiansheng Chen i Liang Chen. "Mathematical Model for Piping Erosion Based on Fluid-Solid Interaction and Soils Structure". W GeoHunan International Conference 2011. Reston, VA: American Society of Civil Engineers, 2011. http://dx.doi.org/10.1061/47628(407)14.
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Salsabilla, A., i E. Kusratmoko. "Assessment of soil erosion risk in Komering watershed, South Sumatera, using SWAT model". W INTERNATIONAL SYMPOSIUM ON CURRENT PROGRESS IN MATHEMATICS AND SCIENCES 2016 (ISCPMS 2016): Proceedings of the 2nd International Symposium on Current Progress in Mathematics and Sciences 2016. Author(s), 2017. http://dx.doi.org/10.1063/1.4991296.
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Kavka, Petr. "SOIL EROSION MODELING IN CZECH REPUBLIC - COMPUTER MODELS IN VARIOUS SCALES". W 13th SGEM GeoConference on WATER RESOURCES. FOREST, MARINE AND OCEAN ECOSYSTEMS. Stef92 Technology, 2013. http://dx.doi.org/10.5593/sgem2013/bc3/s13.026.
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Ramzi, A. A., A. W. Ayu, A. A. Mohm, R. M. Fahmi i O. M. Ibrahim. "Application of experimental soil erosion models (USLE, RUSLE) in Jordan: A review". W 3RD ELECTRONIC AND GREEN MATERIALS INTERNATIONAL CONFERENCE 2017 (EGM 2017). Author(s), 2017. http://dx.doi.org/10.1063/1.5002303.
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Pease, Leonard F., Arich J. L. Fuher, Judith Ann Bamberger i Michael J. Minette. "A Test of Steady State Erosion Models". W ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83392.
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Here we ask the question: how well is the erosion of particle beds in vessels with curved bottoms at industrial scale flow rates represented by models of radial wall jets traversing flat surfaces using the critical shear stress for erosion from the Shields diagram? This mathematical construction has been used successfully to predict the functional forms for the extent of erosion with time using two dimensionless fitting parameters (Pease, et al., 2017). However, the direct prediction of the curves without fitting and scaling has not been tested quantitatively. Here we evaluate the radial wall jet models of Poreh, et al., (1967) and Rajaratnam (1976) and the expressions for the Shields diagram by Paphitis (2001) and Cao, Pender, and Meng (2006). The use of two models for each element accounts for uncertainty in model selection. The data selected to benchmark these models was obtained in a geometrically scaled version of an industrial scale mixing vessel with 12 jets arrayed in a double ring configuration (Meyer, et al., 2012). These particular jets were operated continuously with observations at steady-state, providing a direct comparison between the long-time erosion fronts and these proposed long-time solutions (i.e., where the applied shear stress equals the critical shear stress for erosion) without interference from transients or parameters that affect transients (e.g., the particle bed thickness). We find experimentally that the extent of the erosion depends significantly on the vessel curvature. Even so, we also find that all of these formulations significantly over predict the extent of erosion observed experimentally. A discussion of model features that may be modified to revise the theory into quantitative agreement is presented.
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Khanina, L. G., M. V. Bobrovsky, V. E. Smirnov, K. V. Ivashchenko, A. I. Zhuravleva i I. V. Zhmaylov. "Comparison of Effects in Linear Models of Soil Variables after a Catastrophic Windthrow in a Quercus Mesic Deciduous Forest". W Mathematical Biology and Bioinformatics. Pushchino: IMPB RAS - Branch of KIAM RAS, 2020. http://dx.doi.org/10.17537/icmbb20.34.
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Maarof, Fauziah, Mohd Adi Faiz Ahmad Fauzi i Shamsiah Mohamed. "Statistical models related to accumulated biomass of Hopea odorata in three soil series of ultisols". W PROCEEDINGS OF THE 21ST NATIONAL SYMPOSIUM ON MATHEMATICAL SCIENCES (SKSM21): Germination of Mathematical Sciences Education and Research towards Global Sustainability. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4887703.
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Casesnoves, Francisco, Maksim Antonov i Priit Kulu. "Mathematical models for erosion and corrosion in power plants. A review of applicable modelling optimization techniques". W 2016 57th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON). IEEE, 2016. http://dx.doi.org/10.1109/rtucon.2016.7763117.
Pełny tekst źródłaRaporty organizacyjne na temat "Soil erosion – Mathematical models"
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Ziegler, Nancy, Nicholas Webb, Adrian Chappell i Sandra LeGrand. Scale invariance of albedo-based wind friction velocity. Engineer Research and Development Center (U.S.), maj 2021. http://dx.doi.org/10.21079/11681/40499.
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Obtaining reliable estimates of aerodynamic roughness is necessary to interpret and accurately predict aeolian sediment transport dynamics. However, inherent uncertainties in field measurements and models of surface aerodynamic properties continue to undermine aeolian research, monitoring, and dust modeling. A new relation between aerodynamic shelter and land surface shadow has been established at the wind tunnel scale, enabling the potential for estimates of wind erosion and dust emission to be obtained across scales from albedo data. Here, we compare estimates of wind friction velocity (u*) derived from traditional methods (wind speed profiles) with those derived from the albedo model at two separate scales using bare soil patch (via net radiometers) and landscape (via MODIS 500 m) datasets. Results show that profile-derived estimates of u* are highly variable in anisotropic surface roughness due to changes in wind direction and fetch. Wind speed profiles poorly estimate soil surface (bed) wind friction velocities necessary for aeolian sediment transport research and modeling. Albedo-based estimates of u* at both scales have small variability because the estimate is integrated over a defined, fixed area and resolves the partition of wind momentum be-tween roughness elements and the soil surface. We demonstrate that the wind tunnel-based calibration of albedo for predicting wind friction velocities at the soil surface (us*) is applicable across scales. The albedo-based approach enables consistent and reliable drag partition correction across scales for model and field estimates of us* necessary for wind erosion and dust emission modeling.
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Agassi, Menahem, Michael J. Singer, Eyal Ben-Dor, Naftaly Goldshleger, Donald Rundquist, Dan Blumberg i Yoram Benyamini. Developing Remote Sensing Based-Techniques for the Evaluation of Soil Infiltration Rate and Surface Roughness. United States Department of Agriculture, listopad 2001. http://dx.doi.org/10.32747/2001.7586479.bard.
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The objective of this one-year project was to show whether a significant correlation can be established between the decreasing infiltration rate of the soil, during simulated rainstorm, and a following increase in the reflectance of the crusting soil. The project was supposed to be conducted under laboratory conditions, using at least three types of soils from each country. The general goal of this work was to develop a method for measuring the soil infiltration rate in-situ, solely from the reflectance readings, using a spectrometer. Loss of rain and irrigation water from cultivated fields is a matter of great concern, especially in arid, semi-arid regions, e.g. much of Israel and vast area in US, where water is a limiting factor for crop production. A major reason for runoff of rain and overhead irrigation water is the structural crust that is generated over a bare soils surface during rainfall or overhead irrigation events and reduces its infiltration rate (IR), considerably. IR data is essential for predicting the amount of percolating rainwater and runoff. Available information on in situ infiltration rate and crust strength is necessary for the farmers to consider: when it is necessary to cultivate for breaking the soil crust, crust strength and seedlings emergence, precision farming, etc. To date, soil IR is measured in the laboratory and in small-scale field plots, using rainfall simulators. This method is tedious and consumes considerable resources. Therefore, an available, non-destructive-in situ methods for soil IR and soil crusting levels evaluations, are essential for the verification of infiltration and runoff models and the evaluation of the amount of available water in the soil. In this research, soil samples from the US and Israel were subjected to simulated rainstorms of increasing levels of cumulative energies, during which IR (crusting levels) were measured. The soils from the US were studied simultaneously in the US and in Israel in order to compare the effect of the methodology on the results. The soil surface reflectance was remotely measured, using laboratory and portable spectrometers in the VIS-NIR and SWIR spectral region (0.4-2.5mm). A correlation coefficient spectra in which the wavelength, consisting of the higher correlation, was selected to hold the highest linear correlation between the spectroscopy and the infiltration rate. There does not appear to be a single wavelength that will be best for all soils. The results with the six soils in both countries indeed showed that there is a significant correlation between the infiltration rate of crusted soils and their reflectance values. Regarding the wavelength with the highest correlation for each soil, it is likely that either a combined analysis with more then one wavelength or several "best" wavelengths will be found that will provide useful data on soil surface condition and infiltration rate. The product of this work will serve as a model for predicting infiltration rate and crusting levels solely from the reflectance readings. Developing the aforementioned methodologies will allow increased utilization of rain and irrigation water, reduced runoff, floods and soil erosion hazards, reduced seedlings emergence problems and increased plants stand and yields.
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Clausen, Jay, Christopher Felt, Michael Musty, Vuong Truong, Susan Frankenstein, Anna Wagner, Rosa Affleck, Steven Peckham i Christopher Williams. Modernizing environmental signature physics for target detection—Phase 3. Engineer Research and Development Center (U.S.), marzec 2022. http://dx.doi.org/10.21079/11681/43442.
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The present effort (Phase 3) builds on our previously published prior efforts (Phases 1 and 2), which examined methods of determining the probability of detection and false alarm rates using thermal infrared for buried object detection. Environmental phenomenological effects are often represented in weather forecasts in a relatively coarse, hourly resolution, which introduces concerns such as exclusion or misrepresentation of ephemera or lags in timing when using this data as an input for the Army’s Tactical Assault Kit software system. Additionally, the direct application of observed temperature data with weather model data may not be the best approach because metadata associated with the observations are not included. As a result, there is a need to explore mathematical methods such as Bayesian statistics to incorporate observations into models. To better address this concern, the initial analysis in Phase 2 data is expanded in this report to include (1) multivariate analyses for detecting objects in soil, (2) a moving box analysis of object visibility with alternative methods for converting FLIR radiance values to thermal temperature values, (3) a calibrated thermal model of soil temperature using thermal IR imagery, and (4) a simple classifier method for automating buried object detection.
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Lieth, J. Heiner, Michael Raviv i David W. Burger. Effects of root zone temperature, oxygen concentration, and moisture content on actual vs. potential growth of greenhouse crops. United States Department of Agriculture, styczeń 2006. http://dx.doi.org/10.32747/2006.7586547.bard.
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Soilless crop production in protected cultivation requires optimization of many environmental and plant variables. Variables of the root zone (rhizosphere) have always been difficult to characterize but have been studied extensively. In soilless production the opportunity exists to optimize these variables in relation to crop production. The project objectives were to model the relationship between biomass production and the rhizosphere variables: temperature, dissolved oxygen concentration and water availability by characterizing potential growth and how this translates to actual growth. As part of this we sought to improve of our understanding of root growth and rhizosphere processes by generating data on the effect of rhizosphere water status, temperature and dissolved oxygen on root growth, modeling potential and actual growth and by developing and calibrating models for various physical and chemical properties in soilless production systems. In particular we sought to use calorimetry to identify potential growth of the plants in relation to these rhizosphere variables. While we did experimental work on various crops, our main model system for the mathematical modeling work was greenhouse cut-flower rose production in soil-less cultivation. In support of this, our objective was the development of a Rose crop model. Specific to this project we sought to create submodels for the rhizosphere processes, integrate these into the rose crop simulation model which we had begun developing prior to the start of this project. We also sought to verify and validate any such models and where feasible create tools that growers could be used for production management. We made significant progress with regard to the use of microcalorimetry. At both locations (Israel and US) we demonstrated that specific growth rate for root and flower stem biomass production were sensitive to dissolved oxygen. Our work also identified that it is possible to identify optimal potential growth scenarios and that for greenhouse-grown rose the optimal root zone temperature for potential growth is around 17 C (substantially lower than is common in commercial greenhouses) while flower production growth potential was indifferent to a range as wide as 17-26C in the root zone. We had several set-backs that highlighted to us the fact that work needs to be done to identify when microcalorimetric research relates to instantaneous plant responses to the environment and when it relates to plant acclimation. One outcome of this research has been our determination that irrigation technology in soilless production systems needs to explicitly include optimization of oxygen in the root zone. Simply structuring the root zone to be “well aerated” is not the most optimal approach, but rather a minimum level. Our future work will focus on implementing direct control over dissolved oxygen in the root zone of soilless production systems.