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Múltiplas técnicas no mapeamento digital de solos; Multiple techniques in the digital soil mapping

Alves, Marcelo Rodrigo
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 29/01/2009 Português
Relevância na Pesquisa
66.27%
A busca por elevados índices de produtividade agrícola, bem como a demanda constante pelo uso da terra tem cada vez mais realçado a importância do conhecimento do solo e de suas propriedades, o que se dá, principalmente, através dos levantamentos de solo. No entanto, a obtenção destas informações não é direta, sendo dispendiosa, morosa e pouco atrativa, refletindose na carência de profissionais especializados e, conseqüentemente, na ausência de levantamentos de solos em níveis detalhados. A continuidade na execução de levantamentos, em quaisquer níveis, depende principalmente do emprego de novas técnicas, sobretudo das técnicas de mapeamento digital. Essencialmente por este recurso oferecer agilidade e acuracidade, despertando também o interesse de novos pesquisadores. Inúmeros estudos em levantamentos de solos têm abordado e indicado o uso de dados geoespaciais (modelo digital de elevação, geomorfologia, entre outros) e produtos de sensoriamento remoto espectral (espectrorradiometria aos níveis de laboratório, campo e/ou orbital), porém não há trabalhos unindo estas técnicas de forma concisa, apurada e científica. Neste contexto, este trabalho visa, fundamentalmente, determinar um método que identifique e espacialize classes de solos utilizando múltiplas ferramentas...

Pedologia quantitativa: espectrometria VIS-NIR-SWIR e mapeamento digital de solos; Quantitative pedology: VIS-NIR-SWIR spectrometry and digital soil mapping

Ramírez López, Leonardo
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 17/06/2009 Português
Relevância na Pesquisa
66.33%
Para a avaliação das características do solo relacionadas com o potencial uso dos solos, assim como para a avaliação da fertilidade, as análises químicas e físicas de rotina são os métodos convencionalmente usados. Estes são bastante custosos e demorados o que tem representado no Brasil uma dificuldade no seu uso por parte de pequenos agricultores, além da aplicabilidade da agricultura de precisão no manejo de solos. Atualmente a pedometria está fornecendo a possibilidade de incorporar em ciência do solo técnicas bastante sofisticadas que podem ajudar a diminuir o custo na obtenção da informação e compreender melhor o funcionamento dos processos do solo. Entre os tópicos mais recentes que estão incluídos na pesquisa relacionada com pedometria está a espectroscopia de reflectância. Embora se tenha demonstrado que uma grande quantidade de atributos podem ser estimados a partir da resposta espectral do solo via sensoriamento, ainda não se têm atingido níveis de acurácia ótimos em relação às metodologias convencionais, sobretudo no referente a atributos químicos. Para tanto, o presente trabalho foi desenvolvido com a finalidade de responder basicamente os seguintes questionamentos: a. Existem faixas espectrais específicas das bases trocáveis ou se estas podem mudar em função do argilomineral fornecedor da capacidade de troca de cátions?; b. A calibração de modelos usando unicamente algumas faixas espectrais específicas pode melhorar o desempenho destes?; c. Qual é a influência dos níveis de acurácia dos modelos espectrais sobre mapas construídos com atributos estimados a partir destes?; d. Como os tamanhos dos grupos de amostras de calibração influenciam a acurácia dos modelos?; e. Como a calibração de atributos relacionados com o intemperismo podem auxiliar no mapeamento de classes de solo?; The routine soil analysis is traditionally used on the evaluation of soil attributes related to land use potential...

Técnicas espectroscópicas e atributos do terreno no mapeamento digital de solos; Spectroscopic techniques and terrain attributes on digital soil mapping

Rizzo, Rodnei
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 04/04/2011 Português
Relevância na Pesquisa
56.39%
O conhecimento dos atributos do solo e de sua variabilidade espacial são essenciais para a aplicação de um manejo racional, promovendo altas produtividades e baixo impacto ambiental. Dentre as informações mais utilizadas para o planejamento e tomadas de decisão na atividade agrícola, observa-se o mapa pedológico. Este indica de maneira simplificada uma série de atributos, tais como a textura, as condições químicas e a morfologia. Em contrapartida, estes mapas são escassos, desatualizados ou mesmo apresentam-se em escala inadequada, resultando em um entrave no desenvolvimento agrícola sustentável. Desta forma, surge a necessidade de ferramentas que auxiliem no processo de levantamento e mapeamento de solos, reduzindo custos e tempo de execução. Duas técnicas capazes de atenuar tal problemática são a espectroscopia de reflectância e o mapeamento digital de solos. Diversos trabalhos indicam o potencial das curvas espectrais para determinar atributos como teor de argila e carbono, no entanto, há carência de estudos avaliando relações entre classes taxonômicas e o comportamento espectral. Da mesma forma, não se encontra na literatura pesquisas que conciliaram o mapeamento digital de solos e o espectro eletromagnético. Sendo assim...

Comparação entre mapas de solos obtidos pelos métodos convencional e digital numa área complexa; Comparison between soil maps obtained by conventional and digital methods in complex area

Bazaglia Filho, Osmar
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 16/04/2012 Português
Relevância na Pesquisa
56.41%
Mapas de solos são essenciais para o desenvolvimento de áreas agrícolas de maneira economicamente viável e ambientalmente correta. Até o momento, o Brasil conta apenas com mapas de solos de escala pequena (1:250.000 a 1:1.000.000), cuja utilização é limitada para planejamento agrícola e ambiental a nível de propriedade rural. Apesar de sua importância, no Brasil poucos mapeamentos têm sido realizados pelos órgãos públicos competentes, principalmente por restrições orçamentárias e falta de pedólogos. Além disso, o 5º e 6º níveis categóricos do Sistema Brasileiro de Classificação de Solos (SiBCS), que devem ser utilizados em levantamentos detalhados, não estão definidos. Dessa forma, pouco se sabe a respeito da qualidade/similaridade dos mapas desse nível que vem sendo executados no país. Os principais motivos para essa situação são: elevado custo, mão-de-obra e tempo requeridos nos trabalhos de mapeamento. Uma alternativa para redução desses entraves é o mapeamento digital de solos (MDS). Sendo assim, objetivou-se: (i) comparar quatro mapas de solos convencionais de uma mesma área complexa, de mesma escala (1:10.000), elaborados por diferentes pedólogos de maneira independente, e (ii) comparar estes com um mapa de solos obtido por técnica de MDS. Para tanto...

Estratégias de mapeamento digital de solos por redes neurais artificiais baseadas na relação solo-paisagem; Strategies for digital soil mapping by artificial neural networks based on soil-landscape

Arruda, Gustavo Pais de
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 14/05/2012 Português
Relevância na Pesquisa
56.32%
A escassez de informações do solo que permitam o seu uso adequado, seja para fins agrícola, ambiental ou de projeto urbanos, pode ser minimizada com soluções provenientes do desenvolvimento de novas tecnologias. Nesse sentido, o presente estudo teve como objetivo aplicar duas estratégias digitais para obtenção de mapas de solos preliminares em áreas onde não foram realizados levantamentos pedológicos convencionais. As estratégias foram executadas com base em variáveis ambientais que estabelecem relações entre ocorrência de solos e suas posições na paisagem. A área de estudo compreendeu o município de Barra Bonita-SP, totalizando 11.072 ha. Para uso na predição dos solos pela técnica de Redes Neurais Artificiais (RNA) foram utilizadas as variáveis: declividade, elevação, perfil de curvatura, plano de curvatura e índice de convergência derivados de um Modelo Digital de Elevação (MDE), além das informações de geologia e das superfícies geomórficas identificadas na região. Na primeira estratégia, por meio de uma análise de agrupamento (Fuzzy k-médias) das variáveis, foram escolhidas cinco áreas chaves distribuídas na área de estudo, nas quais foi realizado levantamento de solos de nível semidetalhado para reconhecimento das unidades de mapeamento. Na estratégia 2...

Mapeamento digital de classes de solos : características da abordagem brasileira; Digital soil mapping : characteristics of the brazilian approach

Ten Caten, Alexandre; Dalmolin, Ricardo Simão Diniz; Mendonça-Santos, Maria de Lourdes; Giasson, Elvio
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
Relevância na Pesquisa
56.39%
O solo é cada vez mais reconhecido como tendo um importante papel nos ecossistemas, assim como para a produção de alimentos e regulação do clima global. Por esse motivo, a demanda por informações relevantes e atualizadas em solos é crescente. Pesquisadores em ciência do solo estão sendo demandados a gerar informações em diferentes resoluções espaciais e com qualidade associada dentro do que está sendo chamado de Mapeamento Digital de Solos (MDS). Devido ao crescente número de trabalhos relacionados ao MDS, faz-se necessário reunir e discutir as principais características dos estudos relacionados ao mapeamento digital de classes de solos no Brasil, o que irá possibilitar uma perspectiva mais ampla dos caminhos, além de nortear trabalhos e demandas futuras. O mapeamento de classes de solos empregando técnicas de MDS é recente no país, com a primeira publicação em 2006. Entre as funções preditivas utilizadas, predomina o emprego da técnica de regressões logísticas. O fator de formação relevo foi empregado na totalidade dos estudos revisados. Quanto à avaliação da qualidade dos modelos preditivos, o emprego da matriz de erros e do índice kappa têm sido os procedimentos mais usuais. A consolidação dessa abordagem automatizada como ferramenta auxiliar ao mapeamento convencional passa pelo treinamento dos jovens pedólogos para a utilização de tecnologias da geoinformação e de ferramentas quantitativas dos aspectos de variabilidade do solo.; Soil is increasingly being recognized as having an important role in ecosystems...

Soil digital mapping with reduced soil samples under agro-silvo-pastoral systems.

Alexandre, Carlos; Nunes, Jorge; Cortez, Nuno
Fonte: European Confederation of Soil Science Societies Publicador: European Confederation of Soil Science Societies
Tipo: Aula
Português
Relevância na Pesquisa
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Soil depth (SD), clay content (SCC) and soil organic carbon (SOC) determine land use systems response but are quite expensive to be mapped in high definition. This study uses proximal sensing, tree canopy influence and cokriging (CK) to explore soil sampling reduction in soil digital mapping for low income land use systems. It applies to 5.34 ha of “montado” in central-south of Portugal with rolling morphology and mostly Regosols, Cambisols and Leptosols. Soil probing followed stratified random sampling of areas outside (OC) and under tree canopy (UC), giving 70, 79 and 64 points for SD, SCC(0-50 cm) and SOC(0-30 cm). Soil was surveyed with Dualem1 for ECa. Correlation between ECa, SD, SCC and SOC were 0.687, 0.586 and 0.448. SOC averages differ significantly for UC and OC (83 Mg/ha and 41 Mg/ha). Cokriging with ECa as auxiliary variable was performed for subsamples (N=32, 16, 8 and 4) and results were validated with complementary subsamples (N=32). Completely random and stratified subsampling were applied (slope position and tree canopy influence for SOC). Averaging seven replicas, CK reduced RRMSE (Root Mean Square Error/mean) by less than 0.05 relatively to OK. However, CK allows just a limited increase in RRMSE (<0.05) for SD and SOC when soil subsamples are reduced to N=8...

An appropriate data set size for digital soil mapping in Erechim, Rio Grande do Sul, Brazil

Caten,Alexandre ten; Dalmolin,Ricardo Simão Diniz; Pedron,Fabrício de Araújo; Ruiz,Luis Fernando Chimelo; Silva,Carlos Antônio da
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2013 Português
Relevância na Pesquisa
56.34%
Digital information generates the possibility of a high degree of redundancy in the data available for fitting predictive models used for Digital Soil Mapping (DSM). Among these models, the Decision Tree (DT) technique has been increasingly applied due to its capacity of dealing with large datasets. The purpose of this study was to evaluate the impact of the data volume used to generate the DT models on the quality of soil maps. An area of 889.33 km² was chosen in the Northern region of the State of Rio Grande do Sul. The soil-landscape relationship was obtained from reambulation of the studied area and the alignment of the units in the 1:50,000 scale topographic mapping. Six predictive covariates linked to the factors soil formation, relief and organisms, together with data sets of 1, 3, 5, 10, 15, 20 and 25 % of the total data volume, were used to generate the predictive DT models in the data mining program Waikato Environment for Knowledge Analysis (WEKA). In this study, sample densities below 5 % resulted in models with lower power of capturing the complexity of the spatial distribution of the soil in the study area. The relation between the data volume to be handled and the predictive capacity of the models was best for samples between 5 and 15 %. For the models based on these sample densities...

Solum depth spatial prediction comparing conventional with knowledge-based digital soil mapping approaches

Menezes,Michele Duarte de; Silva,Sérgio Henrique Godinho; Mello,Carlos Rogério de; Owens,Phillip Ray; Curi,Nilton
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2014 Português
Relevância na Pesquisa
56.41%
Solum depth and its spatial distribution play an important role in different types of environmental studies. Several approaches have been used for fitting quantitative relationships between soil properties and their environment in order to predict them spatially. This work aimed to present the steps required for solum depth spatial prediction from knowledge-based digital soil mapping, comparing the prediction to the conventional soil mapping approach through field validation, in a watershed located at Mantiqueira Range region, in the state of Minas Gerais, Brazil. Conventional soil mapping had aerial photo-interpretation as a basis. The knowledge-based digital soil mapping applied fuzzy logic and similarity vectors in an expert system. The knowledge-based digital soil mapping approach showed the advantages over the conventional soil mapping approach by applying the field expert-knowledge in order to enhance the quality of final results, predicting solum depth with suited accuracy in a continuous way, making the soil-landscape relationship explicit.

Digital soil mapping approach based on fuzzy logic and field expert knowledge

Menezes,Michele Duarte de; Silva,Sérgio Henrique Godinho; Owens,Phillip Ray; Curi,Nilton
Fonte: Editora da Universidade Federal de Lavras Publicador: Editora da Universidade Federal de Lavras
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2013 Português
Relevância na Pesquisa
66.32%
In Brazil, soil surveys in more detailed scale are still scarce and necessary to more adequately support the decision makers for planning soil and environment activities in small areas. Hence, this review addresses some digital soil mapping techniques that enable faster production of soil surveys, beyond fitting continuous spatial distribution of soil properties into discrete soil categories, in accordance with the inherent complexity of soil variation, increasing the accuracy of spatial information. The technique focused here is knowledge-based in expert systems, under fuzzy logic and vector of similarity. For that, a contextualization of each tool in the soil types and properties prediction is provided, as well as some options of knowledge extraction techniques. Such tools have reduced the inconsistency and costs associated with the traditional manual processes, relying on a relatively low density of soil samples. On the other hand, knowledge-based technique is not automatic, and just as the traditional soil survey, the knowledge of soil-landscape relationships is irreplaceable.

Applying conditional latin hypercube (cLHS) for selecting soil sampling location for digital soil mapping at Parque Estadual da Mata Seca, MG, Brazil.

MENDONÇA-SANTOS, M. L.; DART, R. O.; BERBARA, R. L. L.
Fonte: In: GLOBAL WORKSHOP ON DIGITAL SOIL MAPPING, 3,, 30 Sept.- Oct. 3, 2008, Logan, Utah. Bridging research, production, and environmental applications: papers. Publicador: In: GLOBAL WORKSHOP ON DIGITAL SOIL MAPPING, 3,, 30 Sept.- Oct. 3, 2008, Logan, Utah. Bridging research, production, and environmental applications: papers.
Tipo: Resumo em anais de congresso (ALICE) Formato: 6 p.
Português
Relevância na Pesquisa
66.3%
The use of the Conditional Latin Hypercube (cLHS) to select soil samples location to be used in the prediction of soil properties as soil organic carbon seems to be an important tool to decrease costs and subjectivity of sampling schemes. The main objective of this work was to test this method in a no sampled area, aiming to evaluate its efficiency in Digital Soil Mapping (DSM) procedures. The results show that this method was able to significantly increase the reliability in the spatial distribution of the sampled points in Parque Estadual da Mata Seca (PEMS). The study area is located in the North of Minas Gerais State, Brazil, in Tropical Dry Forest (TDF) ecosystems mainly. In this study, the cLHS algorithm developed by Minasny & McBratney (2006) was used, in addition to some ancillary data as Land Use/Land Cover and Normalized Difference Vegetation Index (NDVI), in order to select 60 soil sampling location to the study of soil organic carbon and others soil properties. The cLHS will be further analyzed in its performance to select representative points to be sampled and how this method could be helpful for DSM.; 2008

Modelling and digital soil mapping of the organic carbon stock in the topsoil (0-10 cm) of Rio de Janeiro State, Brazil.

MENDONÇA-SANTOS, M. L.; SANTOS, H. G.; COELHO, M. R.
Fonte: In: GLOBAL WORKSHOP ON DIGITAL SOIL MAPPING, 3, 30 Sept. - Oct. 3, 2008, Logan, Utah. Bridging research, production, and environmental applications: papers. Publicador: In: GLOBAL WORKSHOP ON DIGITAL SOIL MAPPING, 3, 30 Sept. - Oct. 3, 2008, Logan, Utah. Bridging research, production, and environmental applications: papers.
Tipo: Artigo em anais de congresso (ALICE) Formato: 10 p.
Português
Relevância na Pesquisa
86.4%
A soil database with 431 soil profiles of Rio de Janeiro State was used in the scope of a research project entitled ?Quantifying the magnitude, spatial distribution and organic carbon in soils of Rio de Janeiro State, using quantitative modeling, GIS and database technologies? (Projeto Carbono_RJ, funded by FAPERJ - Carlos Chagas Filho Foundation for Research Support in Rio de Janeiro State). Considering that these soil data were collected to other purpose, there was only a few sparse data to soil bulk density, which is essential to estimate of soil organic carbon (SOC) stock. To face this problem, pedotransfer functions (PTFs) were estimated to be used in the modeling of organic soil carbon of topsoil (0-10 cm), using s.c.o.r.p.a.n model. The following environmental correlates were used as predictor variables: satellite data, lithology and soil maps, DEM (Digital Elevation Model) and its derivatives as source of information for these variables. This dataset, that represents the best organized soil dataset in Brazil, is working as a trial for learning/teaching of Digital Soil Mapping (DSM) using a variety of methods for predicting soil classes and their properties. The "f" of the equation was modeled by means of multilinear analysis and regression-kriging. Seven different models were built and compared through statistical methods. In a general way...

The Use of GIS and Digital Elevation Model in Digital Soil Mapping: a case study from São Paulo, Brazil.

VALLADARES, G. S.; HOTT, M. C.
Fonte: In: HARTEMINK, A. E.; McBRATNEY, A.; MENDONÇA-SANTOS, M. L. (Ed.). Digital Soil mapping with limited data. Netherlands: Springer, 2008. Publicador: In: HARTEMINK, A. E.; McBRATNEY, A.; MENDONÇA-SANTOS, M. L. (Ed.). Digital Soil mapping with limited data. Netherlands: Springer, 2008.
Tipo: Capítulo em livro técnico-científico (ALICE) Formato: p. 349-356.
Português
Relevância na Pesquisa
66.32%
This paper applied pedological mapping in an experimental center of APTA-Frutas in Jundiaí São Paulo, Brazil, using morphometric parameters and GIS tools. The aim of this work was to obtain a preliminary legend of a soil map and to compare the preliminary map with maps made by the traditional soil survey methods. The area has 59 hectares and is located at a mountainous relief in the Atlantic Plateau. The original soil map of this area was made at 1:10 000. A digital elevation model (DEM) was generated with 4m spatial resolution based on a topographical map at 1:10 000 scale, where the level curves are equidistant at 5 m. Based on the DEM we generated altitude, curvature and slope maps. In order to map the hydromorphic soils it was generated a buffer around the hydrography. We also calculated frequency distribution graphics of altitude, curvature and slope maps. After the interpretation of the frequency distribution, we defined classes to predict the soils types. The curvature map was divided into two class intervals (< or = 0 and > 0), the altitude map was divided into four class intervals (690, 703, 704,714, 715, 730, and 731, 757 m), and the slope map was divided into four class intervals (0-9, 10-19, 20-44, and 45-72%). The maps were reclassified and converted to shape files. The shape files were intersected with the others to generate the final preliminary soil map. The methodology was adequate for the preliminary mapping of some types of soils.; 2008

Evaluating hyperspectral imagery for mapping the surface symptoms of dryland salinity

Dutkiewicz, Anna
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 254946 bytes; 3049109 bytes; 2825739 bytes; 111849 bytes; application/pdf; application/pdf; application/pdf; application/pdf
Publicado em //2006 Português
Relevância na Pesquisa
56.42%
Airborne hyperspectral imagery has the potential to overcome the spectral and spatial resolution limitations of multispectral satellite imagery for monitoring salinity at both regional and farm scales. In particular, saline areas that have good cover of salt tolerant plants are difficult to map with multispectral satellite imagery. Hyperspectral imagery may provide a more reliable salinity mapping method because of its potential to discriminate halophytic plant cover from non - halophytes. HyMap and CASI airborne imagery ( at 3m ground resolution ) and Hyperion satellite imagery ( at 30 resolution ) were acquired over a 140 sq km dryland agricultural area in South Australia, which exhibits severe symptoms of salinity, including extensive patches of the perennial halophytic shrub samphire ( Halosarcia pergranulata ), sea barley grass ( Hordeum marinum ) and salt encrusted pans. The HyMap and Hyperion imagery were acquired in the dry season ( March and February respectively ) to maximise soil and perennial vegetation mapping. The optimum time of year to map sea barley grass, an annual species, was investigated through spectral discrimination analysis. Multiple reflectance spectra were collected of sea barley grass and other annual grasses with an ASD Fieldspec Pro spectrometer during the September spring flush and in November during late senescence. Comparing spectra of different species in November attempted to capture the spectral differences between the late senescing sea barley grass and other annual grasses. Broad NIR and SWIR regions were identified where sea barley grass differs significantly from other species in November during late senescence. The sea barley grass was therefore shown to have the potential to be discriminated and mapped with hyperspectral imagery at this time and as a result the CASI survey was commission for November. Other salinity symptoms were characterised by collecting single field and laboratory spectra for comparison to image derived spectra in order to provide certainty about the landscape components that were to be mapped. Endmembers spectra associated with saltpans and samphire patches were extracted from the imagery using automated endmember generation procedures or selected regions of interest and used in subsequent partial unmixing. Spectral subsets were evaluated for their ability to optimise salinity maps. The saltpan spectra contained absorption features consistent with montmorillonite and gypsum. A single gypsum endmember from one image strip successfully mapped saltpans across multiple images strips using the 1750 nm absorption feature as the input to matched filter unmixing. The individual spectra of green and red samphire are dominated by photosynthetic vegetation characteristics. The spectra of green samphire...

Repräsentanz und Data Mining - Konzepte und Methoden der digitalen bodenkundlichen Kartierung; Representativity and Data Mining - Concepts and Methods for Digital Soil Mapping

Schmidt, Karsten
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
Relevância na Pesquisa
56.37%
Im Rahmen dieser Arbeit, die im Sonderforschungsbereich 299 (Landnutzungskonzepte für periphere Regionen) der deutschen Forschungsgemeinschaft angesiedelt ist, wurden Methoden und Konzepte entwickelt, die eine repräsentative Beprobung und hochauflösende Regionalisierung von Bodeneigenschaften in großen Landschaftsräumen (> 1000 km2) ermöglichen. Der Hauptschwerpunkt lag dabei auf der Entwicklung einer mehrstufigen Beprobungsstrategie in Kombination mit speziellen Verfahren aus dem Bereich des Data Mining zur Regionalisierung von Bodeneigenschaften und Bodenformen. Untersuchungsräume waren das Einzugsgebiet der Nidda in Hessen, der Pfälzer Wald in Rheinland Pfalz und eine Region innerhalb der Republik Niger. Im Rahmen der mehrstufigen Beprobungsstrategie wurde das Nidda-Einzugsgebiet im ersten Arbeitsschritt (Manuskript 1) in homogene, nicht fragmentierte Teilräume untergliedert. Die als Grundlage für die Segmentierung vorliegende Bodenkarte 1:50.000 (HLUG) wurde mit Hilfe einer moving-window-basierten Häufigkeitsanalyse ausgewertet und im Anschluss durch eine räumliche k-means Clusteranalyse klassifiziert. Die Anzahl der Cluster, wie auch die Größe des moving-window, wurden semi-automatisch ermittelt. Damit konnten die Bodenlandschaften Vogelsberg...

Sampling design and machine learning optimization for the application of soil sensing data in digital soil mapping; Optimierungen von Stichprobenverfahren und Methoden des Data Minings zur Nutzung geophysikalischer Naherkundungsdaten im Rahmen von Bodenprognosen

Ramirez-Lopez, Leonardo
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
Relevância na Pesquisa
66.34%
The general aim of this thesis was to develop innovative methods to build and optimize empirical soil models based on soil sensing data. The combination of effective sampling schemes with geophysical sensing techniques is an active branch of soil scientific research. This approach aims to provide high resolution soil property data for flood forecasting and protection, agricultural management as well as for developing strategies to adapt to global climate change. This thesis comprises four manuscripts. The first two manuscripts are dedicated to calibration sampling strategies. Sampling design is crucial in predictive modeling, since all results and interpretation are based on the selected samples. Hence, the first manuscript investigates the effect of the calibration set size and the calibration sampling strategy on the generalization error of visible and near infrared (vis–NIR) models. Furthermore, a method useful for identifying the optimal sample set size necessary for calibrating vis–NIR models of soil attributes is developed. Within the context of digital soil mapping, the second manuscript focuses on a comparison of different calibration sampling strategies for building predictive models of soil properties based on soil sensing. An improved version of the well-known conditioned Latin hypercube sampling algorithm...

Continuous Mapping of Soil pH Using Digital Soil Mapping Approach in Europe

GARDI Ciro; YIGINI YUSUF
Fonte: The Eurasian Federation of Soil Science Societies Publicador: The Eurasian Federation of Soil Science Societies
Tipo: Articles in periodicals and books Formato: Online
Português
Relevância na Pesquisa
56.42%
Soil pH is one of the most important chemical parameters of soil, playing an essential role on the agricultural production and on the distribution of plants and soil biota communities. It is the expression of soil genesis that in turns is a function of soil forming factors and influences all the chemical, physical and biological processes that occur in the soil. Thus it shapes the entire soil ecosystem. Due to any of the above reasons, mapping of soil pH becomes very important to provide harmonised soil pH data to policy makers, public bodies and researchers. In order to obtain a continuous mapping of soil pH for Europe, adopting the digital soil mapping approach, a set of continuously distribute covariates, highly correlated with pH, were selected. The estimate of soil pH was realized using a regression procedure, coupled with the kriging of the residuals. More than 30.000 points on top soil pH (CaCl2) were used, and 27 covariates were tested as predictors. The similar approach was already applied with 12.333 samples to produce a pH map of Europe using European Soil Profile Data in 2008 which compiles several databases from 11 different sources (Reuter et al. 2008). Our study was conducted to update the previous data and maps based on LUCAS (EUROSTAT - Land Use/Cover Area frame statistical Survey)...

Instance selection in digital soil mapping: a study case in Rio Grande do Sul, Brazil

Giasson,Elvio; ten Caten,Alexandre; Bagatini,Tatiane; Bonfatti,Benito
Fonte: Universidade Federal de Santa Maria Publicador: Universidade Federal de Santa Maria
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2015 Português
Relevância na Pesquisa
56.34%
A critical issue in digital soil mapping (DSM) is the selection of data sampling method for model training. One emerging approach applies instance selection to reduce the size of the dataset by drawing only relevant samples in order to obtain a representative subset that is still large enough to preserve relevant information, but small enough to be easily handled by learning algorithms. Although there are suggestions to distribute data sampling as a function of the soil map unit (MU) boundaries location, there are still contradictions among research recommendations for locating samples either closer or more distant from soil MU boundaries. A study was conducted to evaluate instance selection methods based on spatially-explicit data collection using location in relation to soil MU boundaries as the main criterion. Decision tree analysis was performed for modeling digital soil class mapping using two different sampling schemes: a) selecting sampling points located outside buffers near soil MU boundaries, and b) selecting sampling points located within buffers near soil MU boundaries. Data was prepared for generating classification trees to include only data points located within or outside buffers with widths of 60, 120, 240, 360, 480...

Prediction of soil distribution on two soilscapes in land type Dc17 east of Bloemfontein, South Africa

Zerizghy,Mussie G.; Le Roux,Pieter; Hensley,Malcolm; van Rensburg,Leon 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 Português
Relevância na Pesquisa
56.31%
The predictive nature of digital soil mapping makes it a labour- and cost-effective way of facilitating soil surveys. A digital elevation model was used to generate terrain attributes that can be used to infer the distribution of soil associations relative to the topography. Two study areas - Gladstone and Potsane -in the Free State Province of South Africa were considered. Slope, aspect, contour and plan curvature, topographic wetness index and topographic morphological unit were used to develop a model for predicting soil associations. Discriminant analysis was employed to develop the model. The model was trained on data obtained from Gladstone and validated on data from Gladstone and Potsane. Predicting soil form was unsatisfactory. Prediction done on soil associations, with soils grouped as deep, shallow and valley-bottom soils (criteria closely related to the suitability for in-field rainwater harvesting), achieved acceptable improvement in prediction accuracy. For Gladstone, when analysis was done using equal prior probability, accuracy percentages of 56.9%, 51.5% and 58.3% were found for calibration, cross-validation and areas suited to in-field rainwater harvesting, respectively. With prior probability set in accordance to sample frequency...

Creating a conceptual hydrological soil response map for the Stevenson Hamilton Research Supersite, Kruger National Park, South Africa

van Zijl,George; Le Roux,Pieter
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2014 Português
Relevância na Pesquisa
56.41%
The soil water regime is a defining ecosystem service, directly influencing vegetation and animal distribution. Therefore the understanding of hydrological processes is a vital building block in managing natural ecosystems. Soils contain morphological indicators of the water flow paths and rates in the soil profile, which are expressed as 'conceptual hydrological soil responses' (CHSR's). CHSR's can greatly aid in the understanding of hydrology within a landscape and catchment. Therefore a soil map could improve hydrological assessments by providing both the position and area of CHSR's. Conventional soil mapping is a tedious process, which limits the application of soil maps in hydrological studies. The use of a digital soil mapping (DSM) approach to soil mapping can speed up the mapping process and thereby extend soil map use in the field of hydrology. This research uses an expert-knowledge DSM approach to create a soil map for Stevenson Hamilton Research Supersite within the Kruger National Park, South Africa. One hundred and thirteen soil observations were made in the 4 001 ha area. Fifty-four of these observations were pre-determined by smart sampling and conditioned Latin hypercube sampling. These observations were used to determine soil distribution rules...