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Runoff erosion

Evelpidou, Niki; Cordier, Stephane; Merino, Agustin; Figueiredo, Tomás de; Centeri, Csaba
Fonte: University of Athens Publicador: University of Athens
Tipo: Livro
ENG
Relevância na Pesquisa
37%
Table of Contents PART I – THEORY OF RUNOFF EROSION CHAPTER 1 - RUNOFF EROSION – THE MECHANISMS CHAPTER 2 - LARGE SCALE APPROACHES OF RUNOFF EROSION CHAPTER 3 - MEASURING PRESENT RUNOFF EROSION CHAPTER 4 - MODELLING RUNOFF EROSION CHAPTER 5 - RUNOFF EROSION AND HUMAN SOCIETIES: THE INFLUENCE OF LAND USE AND MANAGEMENT PRACTICES ON SOIL EROSION PART II - CASE STUDIES CASE STUDIES – INTRODUCTION: RUNOFF EROSION IN MEDITERRANEAN AREA CASE STUDY 1: Soil Erosion Risk And Sediment Transport Within Paros Island, Greece CASE STUDY 2: The Soil Erosion In The Greater Urban Areas (Athens - Budapest) CASE STUDY 3: Site Preparation Impacts On Physical And Chemical Forest Soil Quality Indicators CASE STUDY 4: Integrated Farm-Scale Approach For Controlling Soil Degradation And Combating Desertification In Alentejo, South Portugal - An Example Of Good Farming Practices Towards A Sustainable Land Use In A High Desertification Risk Territory CASE STUDY 5: The Role Of No-Till And Crop Residues On Sustainable Arable Crops Production In Southern Portugal CASE STUDY 6: Runoff And Soil Loss From Steep Sloping Vineyards In The Douro Valley, Portugal: Rates And Fsactyors CASE STUDY 7: Runoff Erosion In Portugal: A Broad Overview CASE STUDY 8: Extraction Of Biomass From Forest Soils - The Main Aspects To Take Into Account To Prevent Soil Degradation

Predição de erosão e capacidade de uso do solo numa microbacia do oeste paulista com suporte de geoprocessamento.; Prediction of erosion and land use capability with geoprocessing support in a watershed located on a western part of the state of São Paulo.

Fujihara, Alberto Kazutoshi
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/04/2002 PT
Relevância na Pesquisa
37.06%
O mapeamento do risco de erosão é uma ferramenta essencial para o planejamento de uso da terra. Este trabalho testa quatro modelos de predição do risco de erosão e capacidade de uso da terra: Risco de Erosão Natural, Risco de Erosão Simulado, Expectativa de Erosão e Capacidade de Uso da Terra. Esses modelos permitem diagnosticar as áreas potenciais e restritas ao uso agrícola em uma microbacia hidrográfica localizada na região do oeste paulista, utilizando recursos de geoprocessamento. O trabalho envolveu as seguintes etapas: i) caracterização da microbacia através de um banco de dados de atributos físicos construído com o auxílio de três sistemas de informações geográfica (SIG): Idrisi, Ilwis e ArcView; ii) elaboração dos mapas de risco de erosão gerados através dos três modelos derivados da Equação Universal de Perdas de Solo (EUPS) e da Capacidade de Uso da Terra; iii) validação do modelo de risco de erosão através da análise comparativa das erosões com os fatores erosivos e o grau de risco indicado pelo modelo. Foram definidos 33 setores para identificar e classificar as áreas mais críticas da microbacia. O risco de erosão foi analisado por 3 índices: de erosão natural (e), de erosão simulado (es) e expectativa de erosão (ee). Foi constatado que o índice de expectativa de erosão não é sensível a valores altos de potencial natural de erosão (PNE). Na microbacia há predomínio das classes de risco de erosão natural moderado a alto em 65...

Estudo do desgaste erosivo-corrosivo de aços inoxidáveis de alto nitrogênio em meio lamacento.; Erosion-corrosion wear of high nitrogen stainless steels in a slurry.

López Ochoa, Diana Maria
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 23/11/2007 PT
Relevância na Pesquisa
37.04%
Os processos de erosão-corrosão são comumente encontrados em tubulações, válvulas e outros componentes usados na indústria química, petroquímica e na exploração de minérios. Quando a corrosão e a erosão atuam conjuntamente, os mecanismos de dano são complexos e em geral as perdas de massa associadas com esta combinação de processos são maiores do que a soma das perdas geradas pela erosão ou a corrosão atuando separadamente. Os aços inoxidáveis são materiais amplamente usados neste tipo de indústrias. A série martensítica é usada quando se necessita de boas propriedades mecânicas e moderada resistência à corrosão, enquanto que a austenítica é usada para condições onde é necessária uma boa resistência à corrosão, ainda que as propriedades mecânicas deste tipo de aço não sejam muito altas. Adições de nitrogênio aos aços inoxidáveis melhoram tanto a resistência à corrosão quanto a resistência mecânica, no entanto, poucos trabalhos têm sido desenvolvidos sobre o sinergismo erosão-corrosão dos aços inoxidáveis de alto nitrogênio. Neste trabalho, estuda-se o efeito da adição de nitrogênio, em solução sólida, na resistência à erosão-corrosão de um aço inoxidável martensítico AISI 410 e um austenítico AISI 304L em lama composta por 3...

Avaliação de novos tratamentos preventivos da erosão e abrasão do esmalte e da dentina; Evaluation of new preventive treatments for erosion and abrasion of enamel and dentin

Silva, Cintia Maria de Souza e
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/07/2013 PT
Relevância na Pesquisa
37.01%
Este trabalho, conduzido na forma de 2 subprojetos, avaliou: 1) o potencial preventivo de pastas à base de hidroxiapatita (nanopartículas de fosfato de cálcio) sobre a erosão e a abrasão do esmalte e dentina bovinos in vitro e in situ e 2) o efeito de um bochecho com solução de lactato de cálcio antes da escovação com dentifrício fluoretado sobre a erosão associada ou não à abrasão do esmalte e dentina bovinos in vitro e in situ. Na fase in vitro do 1o subprojeto, submeteram-se blocos de esmalte e dentina bovinos, por 5 dias, à erosão (coca-cola, pH 2,6, 4x/dia, 90s cada) + abrasão (escova elétrica + solução do dentifrício sem flúor, 10s cada, 2x/dia) e os tratamentos foram realizados após a abrasão, através da aplicação das seguintes pastas sobre os blocos (3 min, 2x/dia): 10% HAP, 10% HAP + 0,2% NaF, 20% HAP, 20% HAP + 0,2% NaF, 20% HAP + 2% NaF, placebo, 0,2% NaF, 2% NaF, MI paste, MI paste plus e controle. Na fase in situ, (4 fases, 5 dias/cada), 12 voluntários utilizaram dispositivo intrabucal palatino contendo 4 blocos de dentina e 4 de esmalte bovinos divididos nas condições: erosão e erosão+abrasão. Em cada fase foi feito tratamento com uma das seguintes pastas: 10% HAP, 10% HAP + 0,2% NaF...

Erosão dentária em adolescentes de Porto Alegre, RS; Dental erosion in adolescents of Porto Alegre, RS

Brusius, Carolina Doege
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
37.01%
Objetivo: O objetivo dessa dissertação foi estudar a prevalência, a incidência, a progressão e os fatores associados à erosão dentária na dentição permanente de adolescentes de Porto Alegre, RS – Brasil. Metodologia: Entre setembro de 2009 e dezembro de 2010, um estudo observacional transversal analítico foi desenvolvido em uma amostra representativa da população de escolares de 12 anos de Porto Alegre. Participaram do estudo 1.528 alunos, aleatoriamente selecionados em 42 escolas, sendo 9 particulares e 33 públicas (taxa de participação de 83,17%). O exame clínico foi realizado nas escolas, após limpeza e secagem dos dentes, por uma única examinadora calibrada. Os incisivos e primeiros molares permanentes foram examinados de acordo com o índice BEWE (Basic Erosive Wear Examination). Medidas antropométricas (peso e altura) foram registradas. Dois questionários foram utilizados: um destinado aos pais/responsáveis legais dos escolares (questões socioeconômicas, acesso a serviços odontológicos, hábitos de higiene oral, saúde geral, etc.) e outro respondido pelos próprios escolares (hábitos alimentares). Entre agosto de 2012 e maio de 2013, após um período de tempo médio de 2,5 anos (±0,35), 801 indivíduos foram reexaminados...

Wind erosion of biochar-amended soil: a wind tunnel experiment; Erosão de solo com biochar: um estudo em túnel de vento

Oliveira, Henrique Balona de Sá
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
37.03%
Biochar application to soils has been reported in the scientific community as a possible means of improving agricultural productivity and, at the same time, as a powerful tool for carbon sequestration and climate change mitigation. However, current knowledge of biochar effects on soil functions and possible environmental threats is still not enough for a full-scale implementation. Erosion is one of the most serious and irreversible threats to soil and there is still no information if biochar may increase or decrease soil erosion rates. Soil erosion by wind is of particular interest for biochar, because of the low particle density and potential human exposure. The purpose of this study was to fill this knowledge gap by investigating the wind erosion potential of biochar-amended soil with a focus on the effect of soil moisture content, using a laboratory wind tunnel. Firstly, experimental tests were implemented in the DAO wind tunnel to define a robust wind erosion methodology in a facility only used for smoke studies. Sediment collecting methods, dust fraction analysis and wind velocity range were the main factors that required investigation. The erosion of biochar-amended soil (10% m m-1) and control soil (sandy soil) was simulated by positioning a tray divided in a sample area and an area for creeping particles...

Understanding and modelling hydrological and soil erosion processes in burnt forest catchments; Estudo e modelação dos processos hidrológicos e erosivos em bacias hidrográficas ardidas

Vieira, Diana Catarina Simões
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
37.06%
Forest fires implications in overland flow and soil erosion have been researched for several years. Therefore, is widely known that fires enhance hydrological and geomorphological activity worldwide as also in Mediterranean areas. Soil burn severity has been widely used to describe the impacts of fire on soils, and has being recognized as a decisive factor controlling post-fire erosion rates. However, there is no unique definition of the term and the relationship between soil burn severity and post-fire hydrological and erosion response has not yet been fully established. Few studies have assessed post-fire erosion over multiple years, and the authors are aware of none which assess runoff. Small amount of studies concerning pre-fire management practices were also found. In the case of soil erosion models, the Revised Universal Soil Loss Equation (RUSLE) and the revised Morgan–Morgan–Finney (MMF) are well-known models, but not much information is available as regards their suitability in predicting post-fire soil erosion in forest soils. The lack of information is even more pronounced as regards post-fire rehabilitation treatments. The aim of the thesis was to perform an extensive research under the post fire hydrologic and erosive response subject. By understanding the effect of burn severity in ecosystems and its implications regarding post fire hydrological and erosive responses worldwide. Test the effect of different pre-fire land management practices (unplowed...

Spatial Variability of Erosion Rates Inferred from the Frequency Distribution of Cosmogenic 3He in Olivines from Hawaiian River Sediments

Meade, Brendan; Mukhopadhyay, Sujoy; Gayer, Eric
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
37%
To constrain the spatial distribution of erosion rates in the Waimea river watershed, on the western side of the island of Kauai, Hawaii, we calculate the frequency distribution of cosmogenic He-3 concentrations ([He-3],) from helium isotopic measurements in olivine grains from a single sample of river sediment. Helium measurements were made in 26 aliquots of similar to 30 olivine grains each. The average [He-3], from the 26 aliquots was used to estimate a basin-wide average erosion rate of 0.056 mm/yr, a value that is similar to erosion rates obtained from geochemical analyses of river sediments from tectonically stable landforms. However, forward models of cosmogenic nuclide production and sediment generation rates are inconsistent with the hypothesis that the observed [He-3], frequency distribution is the result of a homogeneous, basin wide, erosion rate. Instead, a distribution of erosion rates, from similar to 0 to 4 mm/yr, may account for the observed frequency distribution. The distribution of erosion rates can be modeled by both non-linear slope- and curvature-dependent erosion rates with power law exponents ranging from 2.0 to 2.5. However, the spatial distribution of cosmogenic nuclides for slope- and curvature-dependent erosion rates are distinct...

Erosão, corrosão, erosão-corrosão e cavitação do aço ABNT 8550 nitretado a plasma; Erosion, Corrosion, Erosion-Corrosion and Cavitation of ABNT 8550 Plasmanitrided Steel

Silva, Flávio José da
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Tese de Doutorado
POR
Relevância na Pesquisa
37%
O aço ABNT 8550 é utilizado na construção de rotores de bombas multifásicas para exploração de petróleo em águas oceânicas profundas, o que justifica um estudo visando o aumento da resistência ao desgaste e à corrosão deste material. Neste trabalho, foram analisadas amostras nitretadas do aço ABNT 8550 com ênfase na resistência à erosão, corrosão, erosão associada à corrosão, e cavitação. Adicionalmente, foram avaliadas amostras nitretadas com deposição adicional de revestimentos aplicados por PVD. O procedimento experimental incluiu: a) produção e caracterização de diferentes tipos de amostras, variando-se a microestrutura do material de base (martensita revenida e ferritaperlita) e os principais parâmetros de nitretação; b) testes de corrosão em água do mar sintética sem escoamento (parada); c) a construção e avaliação de um aparato para simular a erosão e a corrosão, além da ação conjunta destes fenômenos, e d) a realização de testes de cavitação pelo método de vibração ultra-sônica. Os resultados de caracterização das amostras mostraram que um maior tempo de nitretação e maior teor de nitrogênio resultam em maiores espessuras de camadas nitretadas. Com relação à dureza máxima dessas camadas...

Soil erosion in the Three Gorges Reservoir area

Xu, X.; Tan, Y.; Yang, G.; Li, H.; Su, W.
Fonte: CSIRO Publishing Publicador: CSIRO Publishing
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
37.01%
Spatial and temporal change in soil erosion in the Three Gorges Reservoir area since the water storage of the reservoir began filling to 135 m in 2003 is poorly understood. Using a modified soil erosion model, this study quantifies and analyses change in the extent and intensity of soil erosion in the region from 2000 to 2008. MODIS-NDVI remote sensing data (with 250 m spatial resolution) are used in the modelling and analysis of the study. The total amount, area, and intensity of soil erosion in the reservoir region presented a declining trend from 2000 to 2008. Yet there was an anomaly in the trend, in which extreme soil erosion occurred in 2003 and lasted until 2005. The average volume of soil erosion per year decreased by 4.10 × 106 t and the mean area of land experiencing soil erosion reduced by 1129.6 km2 from the pre-storage period (2000–02) to post-storage period II (2006–08). Land suffering soil erosion at high, very high, and severe levels mainly comprises forest and cropland on slopes with gradients ≥15° and is largely distributed in the eastern and south-western sections of the reservoir area. Land experiencing soil erosion at slight or moderate levels mainly involves cropland and forest on slopes with gradients ≥10° in the central section of the reservoir area. The impact of the Three Gorges Project on soil erosion since 2000 has been mainly mediated through three mechanisms: near-resettlement of rural and urban people; increased frequency and severity of geological hazards induced by rising storage of the reservoir; and implementation of ecological projects in the region. Through the former two mechanisms...

Managing post-fire soil erosion in the southern Mount Lofty Ranges.

Morris, Rowena Helen
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2013
Relevância na Pesquisa
37.02%
Post-fire soil erosion is a great concern to land managers due to the potential adverse effects on water quality, the alteration to soil profiles and the detrimental impacts on human communities. To reduce the potential adverse effects of post-fire erosion mitigation actions have been instigated following severe wildfires. Various programs of prescribed burning have been initiated to reduce the risk of wildfires. In order to predict and manage post-fire erosion a clear understanding is needed of the influential environmental variables, associated processes and whether mitigation actions will be effective. In the Southern Mount Lofty Ranges there is a paucity of post-fire erosion data from which to generate evidence-based predictive models and management recommendations. This thesis has the overarching goal of developing evidence-based options for managing post-fire sediment movement in the Southern Mount Lofty Ranges. Evidence-based management of sediment movement from both prescribed fire and wildfire can reduce potential erosion and hence protect regional natural services such as soil profile formation, soil mineral health, the regulation of water quality and maintenance of local landscape character. A case study of the Southern Mount Lofty Ranges is used to produce evidence-based options for managing post-fire erosion in relation to a wildfire at Mount Bold and ten prescribed burns conducted within the Southern Mount Lofty Ranges. Field techniques included visual erosion assessments...

Water erosion prediction by stochastic and empirical models in the Mediterranean: A case study in Northern Sicily (Italy); Prognose der Bodenerosion im Mittelmeerraum anhand statistischer und empirischer Modelle: Eine Fallstudie in Nordsizilien (Italien)

Angileri, Silvia Eleonora
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
Relevância na Pesquisa
37.07%
The present thesis aimed to explore the methodological advantages as well as limitations in applying different modelling approaches to predict water soil erosion in Mediterranean environments. The research was accomplished in the central northern part of Sicily (Italy), considering this region to be representative of Mediterranean environmental conditions. In this region soil degradation problems, due to water erosion are becoming more and more serious. Consequently, defining models being able to predict erosion susceptibility and to discriminate environmental factors causing erosion is important to protect soil resources. The prediction of the spatial distribution of soil erosion processes was carried out by means of GIS tools and multivariate statistical analysis. A stochastic gradient boosting model (TreeNet) was proposed to classify erosion and mass wasting processes and to define the functional relationship between spatial data sets of driving factors and response variables. The TreeNet method allowed identifying a susceptibility model that accurately fits the relationship between a set of several attributes and the activity of different erosion processes with a high resistance to over-training. Moreover, a better understanding of the prediction model was provided by the evaluation of the relative overall importance of the predictive variables in the tree construction. In order to estimate the overall prediction skill of the model...

Use of 7Be to document soil erosion associated with a short period of extreme rainfall

Fonte: Elservier Science BV Publicador: Elservier Science BV
Tipo: Artículo de Revista
EN
Relevância na Pesquisa
37.02%
Intensification and expansion of agricultural production since the 1970s have increased soil erosion problems in south-central Chile. Quantitative information on soil loss is needed for erosion risk assessment and to establish the effectiveness of improved land management practices. Since information from traditional sources, such as erosion plots, is limited, attention has been directed to the use of environmental radionuclides for documenting erosion rates. Cs-137 has been successfully utilised for this purpose, but only provides information on medium-term erosion rates. There is also a need to document event-related soil erosion. This paper outlines the basis for using 7Be measurements to document short-term erosion and reports its successful use for quantifying the erosion that occurred within an arable field, as a result of a period of heavy rainfall (400 mm in 27 days) occurring in May 2005. The study field had been under a no-till, no-burning system for 18 years, but immediately prior to the period of heavy rainfall the harvest residues were burnt. The erosion recorded therefore reflected both the extreme nature of the rainfall and the effects of the burning in increasing surface runoff and erosion. The sampled area corresponded to that used previously by the authors to document the medium-term erosion rates associated with both conventional tillage and the subsequent switch to a no-till system. Comparisons between the erosion documented for the period of heavy rainfall in 2005 with these medium-term erosion rates permits some tentative conclusions regarding the importance of extreme events and the impact of burning in increasing the erosion associated with the no-till system.

Soil Erosion in a Highly Dynamic, Terraced Environment - The Effect of the Three Gorges Dam in China

Schönbrodt-Stitt, Sarah
Fonte: Universität Tübingen Publicador: Universität Tübingen
Tipo: Dissertation; info:eu-repo/semantics/doctoralThesis
EN
Relevância na Pesquisa
37.09%
Worldwide, soil erosion is one of the most pressing environmental problems of present times. Particularly, soil erosion triggered by overland flow and runoff seriously affects the productivity and stability of ecosystems. The loss of fertile topsoil and soil's water storage capacity, and the discharge of sediments and associated contamination of waterbodies due to diffuse matter transport of particle-bounded agrochemicals from cropland highly elicit call a for action to combat soil erosion for a future securing of food supply and high drinking water quality. Globally, China belongs to one of those countries most affected by soil erosion. Technical problems as well as high economic off-site damages and costs resulting from reservoir siltation and thus, reduced project's lifespan due to soil erosion are typical for numerous large-scale dam projects in China. In addition to the natural disposition to soil erosion, especially, anthropogenic impacts associated to the dam construction distinctly affect the soil erosion risk potential in the adjacent ecosystems. This can be exemplarily seen at the currently worldwide largest dam project, the Three Gorges Dam at the Yangtze River in Central China. This megaproject has been controversially discussed since its planning...

Integrated techniques for slope erosion modelling and badland monitoring in key sites of Central Italy; Tecniche integrate di modellazione della denudazione dei versanti e monitoraggio dell’erosione accelerata in siti chiave dell’Italia centrale

VERGARI, FRANCESCA
Fonte: La Sapienza Universidade de Roma Publicador: La Sapienza Universidade de Roma
Tipo: Tese de Doutorado
EN
Relevância na Pesquisa
37.11%
The growing interest in studying badland dynamics reflects the need to increase knowledge of geomorphologic processes and dynamics in subhumid badland areas, particularly because of their importance in generating extremes of water and sediment production. Field studies of soil erosion are expensive, time-consuming and data needs to be collected over many years. Though providing detailed understanding of the erosion processes, field studies have limitations because of the complexity of interactions and the difficulty of generalising from the results. Cost-efficient methods of estimating erosion over whole catchments are required as ways of predicting erosion after disturbance or following various erosion management strategies. Thus, the indirect estimation and the prevision of erosion rates is still one of the main research topics of the scientific community in the field of geomorphology and is far from solved. This Ph.D. research project is aimed at defining an integrated methodology of denudation intensity estimation and prevision, for areas greatly affected by badlands, and it is based on both quantitative geomorphic analysis and multivariate statistical investigations, in order to deepen the relationships between the main denudation effects and the potential causal factors favoring geomorphologic instability in badlands areas. The research have allowed to propose a statically based method for water erosion hazard assessment...

Spatially distributed modelling of soil erosion and sediment yield at regional scales in Spain

Vente, Joris de; Poesen, Jean; Verstraeten, Gert; Van Rompaey, Anton; Govers, Gerard
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
Relevância na Pesquisa
37.07%
Initiated by the need to quantify erosion rates and the impacts of global changes on erosion, several attempts have been made to apply erosion models at regional scales. However, these models have often been directed towards on-site soil erosion estimates, emphasising sheet and rill erosion processes, and disregarding gully erosion, channel erosion and sediment transport. These models are therefore of limited use for the assessment of sediment yield, off-site impacts of erosion, and for the development of environmental management to control these impacts at regional scale. This study analyses and compares three spatially distributed models for the prediction of soil erosion and/or sediment yield at regional scales: the WATEM-SEDEM model that is based on the empirical Revised Universal Soil Loss Equation (RUSLE) in combination with a sediment transport equation, the physics-based Pan European Soil Erosion Risk Assessment model (PESERA), and a newly developed Spatially Distributed Scoring model (SPADS). The three models were applied to 61 Spanish drainage basins and model predictions were evaluated against data on measured reservoir sedimentation rates. Global data sets on land use, climate, elevation and soil characteristics were used as model input for WATEM-SEDEM and SPADS...

Root characteristics of representative Mediterranean plant species and their erosion-reducing potential during concentrated runoff

Baets, S. de; Poesen, Jean; Knappen, A.; González Barberá, Gonzalo; Navarro-Cano, J. A.
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 579917 bytes; image/jpeg
ENG
Relevância na Pesquisa
37.06%
Gully erosion is an important soil degradation process in Mediterranean environments. Revegetation strategies for erosion control rely in most cases on the effects of the above-ground biomass on reducing water erosion rates, whereas the role of the below-ground biomass is often neglected. In a Mediterranean context, the above-ground biomass can temporally disappear because of fire or overgrazing and when concentrated flow erosion occurs, roots can play an important role in controlling soil erosion rates. Unfortunately, information on root characteristics of Mediterranean plants, growing on semi-natural lands, and their effects on the topsoil resistance to concentrated flow erosion is lacking. Therefore, typical Mediterranean grass, herb, reed, shrub and tree root systems of plants growing in habitats that are prone to concentrated flow erosion (i.e. in ephemeral channels, abandoned fields and steep badland slopes) are examined and their erosion-reducing potential was evaluated. Root density (RD), root length density (RLD) and root diameters are measured for 26 typical Mediterranean plant species. RD values and root diameter distribution within the upper 0.10–0.90 m of the soil profile are then transformed into relative soil detachment rates using an empirical relationship in order to predict the erosion-reducing effect of root systems during concentrated runoff. Comparing the erosion-reducing potential of different plant species allows ranking them according to their effectiveness in preventing or reducing soil erosion rates by concentrated flow. RD in the 0.10 m thick topsoil ranges between 0.13 kg m−3 for Bromus rubens (L.) and 19.77 kg m−3 for Lygeum spartum (L.)...

Estimación de Erosión Hidrica de Suelos para plan de Manejo del Campo Forestal Aguas Frías, Patagonia Argentina

Dufilho, Ana Cecilia; Universidad Nacional del Comahue. Asentamiento Universitario San Martín de los Andes; Frugoni, María Cristina; Universidad Nacional del Comahue. Asentamiento Universitario San Martín de los Andes; Macchi, Pablo; Universidad Nacion
Fonte: Boletín Geográfico Publicador: Boletín Geográfico
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 25/12/2011 SPA
Relevância na Pesquisa
37.05%
En la Patagonia Argentina existen grandes extensiones de tierras degradadas por sobrepastoreo lo cual favorece la erosión hídrica de los suelos. De éstas existen más de dos millones de hectáreas aptas para la forestación (Gallo et al. 2005), pero con limitaciones ambientales que requieren estudios tendientes a elaborar propuestas de desarrollo y sostenibilidad.El área en estudio situada en la margen derecha del Río Litrán, a 25 km de su desembocadura al Lago Aluminé de la Provincia de Neuquén, es utilizada por comunidades mapuche para realizar su actividad agropecuaria de producción caprina bajo un sistema trashumante y presenta erosión hídrica y eólica muy severa.Unos de los objetivos del plan de manejo del campo forestal es diseñar un conjunto de medidas de control de la erosión que incluyen cierre perimetral, forestación y medidas estructurales para el control de cárcavas.Resulta así necesario, caracterizar la erosión actual y la potencial, que además permitirá realizar el seguimiento de las medidas de control y mitigación a implementar.Con estos fines, para el campo forestal en estudio, se confeccionó un mapa geoedafológico a partir de la fotointerpretación y posterior georeferenciación utilizando un Sistema de Información Geográfica (SIG). La metodología de mapeo de suelos se basa en la Clasificación Jerárquica de Geoformas...

Water erosion prediction at a national scale for South Africa

Le Roux,JJ; Morgenthal,TL; Malherbe,J; Pretorius,DJ; Sumner,PD
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2008 EN
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37.04%
Erosion is a major soil degradation problem in South Africa, confronting both land and water resource management throughout the country. Given the increasing threat of soil erosion, a need to improve techniques of estimating the soil-erosion risk at a national scale was identified by the National Department of Agriculture and forms the basic premise of this study. Principles and components of the Revised Universal Soil Loss Equation are applied here since the model combines sufficient simplicity for application on a national scale with a comprehensive incorporation of the main soil-erosion factors. Indicators of erosion susceptibility of the physical environment, including climate erosivity, soil erodibility and topography were improved over earlier assessments by feeding current available data into advanced algorithms. Two maps are presented: an actual erosion-risk distribution, and a potential erosion-risk map that excludes the vegetation cover factor. Actual soil-erosion risk, which relates to the current risk of erosion under contemporary vegetation and land-use conditions, was accounted for by regression equations between vegetation cover and MODIS-derived spectral index. The area of land with a moderate to severe potential risk is found to total approximately 61 m. ha (50%). Although more than 91 m. (75%) are classified as having only a very low to low actual risk...

KwaZulu-Natal coastal erosion events of 2006/2007 and 2011: A predictive tool?

Smith,Alan; Guastella,Lisa A.; Mather,Andrew A.; Bundy,Simon C.; Haigh,Ivan D.
Fonte: South African Journal of Science Publicador: South African Journal of Science
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 EN
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Severe coastal erosion occurred along the KwaZulu-Natal coastline between mid-May and November 2011. Analysis of this erosion event and comparison with previous coastal erosion events in 2006/2007 offered the opportunity to extend the understanding of the time and place of coastal erosion strikes. The swells that drove the erosion hotspots of the 2011 erosion season were relatively low (significant wave heights were between 2 m and 4.5 m) but of long duration. Although swell height was important, swell-propagation direction and particularly swell duration played a dominant role in driving the 2011 erosion event. Two erosion hotspot types were noted: sandy beaches underlain by shallow bedrock and thick sandy beaches. The former are triggered by high swells (as in March 2007) and austral winter erosion events (such as in 2006, 2007 and 2011). The latter become evident later in the austral winter erosion cycle. Both types were associated with subtidal shore-normal channels seaward of megacusps, themselves linked to megarip current heads. This 2011 coastal erosion event occurred during a year in which the lunar perigee sub-harmonic cycle (a ±4.4-year cycle) peaked, a pattern which appears to have recurred on the KwaZulu-Natal coast. If this pattern proves true...