26 research outputs found

    Pedometric Tools Applied to Zoning Management of Areas in Brazilian Semiarid Region

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    Brazilian semi-arid region is a recent frontier in the country for agribusiness. The objective of this study is to apply pedometric tools to zoning areas with distinct potential and limitations to agricultural purposes. The research was set in three main steps: (i) to compile a database with all complete profile data collection; (ii) to analyze the vertical variability of soil properties and select a set of soil key properties useful to define the land potential and limitations; and (iii) to classify the area according to potential for agriculture, considering a medium technological level of the farmers. The quantitative methods applied are supported by geographic information systems (GIS) and spatial statistics. The soil data compilation was based on legacy data, with corresponding topographical data and information from remote sensing images of the area. Tree-based and geostatistical algorithms were applied to predict the spatial variability of the soil key properties. The definition of management zones was based on Iso Cluster and Maximum Likelihood Classification tools. The results pointed three different management zones according to risks of salinization and requirements for irrigation control. The approach showed to be a simple and useful way to select and recommend primarily potential areas for agriculture based on soil properties

    Ferramentas de pedometria para caracterização da composição granulométrica de perfis de solos hidromórficos

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    The objective of this work was to evaluate pedometric tools to characterize the particle size distribution (sand, silt, and clay) and to compare the profiles of hydromorphic soils. The study was carried out in the Guapi-Macacu watershed, in the state of Rio de Janeiro, Brazil. The slice-wise algorithm was applied to slice the profile data at 1-cm intervals, and the equal-area spline function for database harmonization, according to six predefined depth intervals. The analysis of the soil profile collection, using the soil-depth functions (slice‑wise and spline) and the similarity analysis, revealed that Alfisols and Entisols are relatively shallow and have coarse texture in the topsoil layer and a more irregular distribution of clay and silt along the soil profile.These two orders usually occur in the watershed area related to floodplains, valleys, and footslopes. Fluvisols had higher amounts of clay and silt in the topsoil layer, which decrease with soil depth, and they are deeper and occur in alluvial terraces. The approach allowed to characterize the variability of texture along hydromorphical soil profiles and to perform a similarity analysis between soil orders, which can support the differentiation of soil mapping units and the identification of quantitative criteria for soil classification.O objetivo deste trabalho foi avaliar ferramentas pedométricas para caracterização da composição granulométrica (areia, silte e argila) e comparação de perfis de solos hidromórficos. O estudo foi realizado na bacia hidrográfica do rio Guapi-Macacu, RJ. Foram aplicados o algoritmo “slice-wise” para o fatiamento doperfil em intervalos de 1 cm, e a função “spline” para harmonizar o conjunto de dados segundo seis intervalos deprofundidade predefinidos. A análise do conjunto de perfis, por meio das funções de profundidade (slice-wise e spline) e de dendrograma de dissimilaridade, revelou que Planossolos e Gleissolos são relativamente rasos e apresentam camadas arenosas nos horizontes superficiais e teores de argila e silte irregulares em subsuperficie. Essas duas ordens ocorrem na área da bacia hidrográfica geralmente em planícies aluviais, em vales e em sopés de elevação. Os Neossolos Flúvicos apresentaram maiores quantidades de argila e silte em superfície, as quaisdecrescem em profundidade, e são mais profundos e ocorrem nos terraços aluviais. A abordagem permitiu descrever a variabilidade da textura dos solos hidromórficos em perfil e realizar a análise de similaridade entre as ordens, o que pode apoiar a distinção de fases em unidades de mapeamento e a identificação de critérios quantitativos para a classificação dos solos

    Elevation models for obtaining terrain attributes used in digital soil mapping

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    The objective of this work was to evaluate digital elevation models (DEM) obtained by different data sources and to select one of them for deriving morphometric variables used in digital soil mapping. The work was performed in the Guapi‑Macacu river basin, RJ, Brazil. The primary data used in the models generated by interpolation (DEM map and DEM hybrid) were: contour lines, drainage, elevation points, and remote sensor data transformed into points. The obtained models by remote sensing and aero‑restitution (DEM SRTM and DEM IBGE) were used in the comparison. All models showed spatial resolution of 30 m. The elevation model evaluations were based on: the terrain derived attribute analysis (slope, aspect, and curvature); spurious depressions (sink); comparison between features derived from the models and the original ones originated from planialtimetric maps; and the analysis of derived watersheds. The DEM hybrid showed a superior quality than the other models.O objetivo deste trabalho foi avaliar modelos digitais de elevação (MDE), obtidos por diferentes fontes de dados, e selecionar um deles para derivar variáveis morfométricas utilizadas em mapeamento digital de solos. O trabalho foi realizado na Bacia Guapi‑Macacu, RJ. Os dados primários utilizados nos modelos gerados por interpolação (MDE‑carta e MDE‑híbrido) foram: curvas de nível, drenagem, pontos cotados e dados de sensor remoto transformados em pontos. Utilizaram-se, na comparação, modelos obtidos por sensor remoto e por aerorrestituição (MDE SRTM e MDE IBGE). Todos os modelos apresentaram resolução espacial de 30 m. A avaliação dos modelos de elevação foi baseada na análise de: atributos derivados (declividade, aspecto e curvatura); depressões espúrias; comparação entre feições derivadas a partir dos modelos e as originais, oriundas de cartas planialtimétricas; e análise das bacias de contribuição derivadas. O modelo digital de elevação híbrido apresenta qualidade superior à dos demais modelos

    Digital mapping of sand, clay, and soil carbon by Random Forest models under different spatial resolutions

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    O objetivo deste trabalho foi avaliar a influência da resolução espacial do modelo digital de elevação e da eficiência de modelos Random Forest sobre a predição dos teores de areia, argila e carbono orgânico, com uso de número reduzido de amostras. O trabalho foi realizado em área de Cerrado com diversidade litológica, no Estado do Mato Grosso do Sul, tendo-se utilizado atributos morfométricos, dados do sensor TM Landsat 5 e litologia como covariáveis preditoras. Dados da camada superficial (0,0–0,2 m) de 175 perfis de solos (0,009perfis km-2) e de 26 covariáveis preditoras foram utilizados com resolução espacial de 30 (conjunto 1) e 90 m (conjunto 2). A análise realizada pelo Random Forest mostrou que as covariáveis de nível de base do canal de drenagem, da elevação e da litologia foram as mais importantes para explicar a variabilidade. A validação dos modelos apresentou similaridade entre os conjuntos quanto à predição de areia, argila e carbono orgânico, o que explica os seguintes valores de variabilidade espacial, respectivamente: 44, 40 e 33%, para a resolução de30 m; e de 45, 46 e 33%, para a resolução de 90 m. A resolução espacial das covariáveis preditoras tem pouca influência sobre a predição dos atributos, e a abordagem por Random Forest apresenta potencial de utilizaçãopara estimar atributos do solo. The objective of this work was to evaluate the effect of the digital elevation model spatial resolution and of the efficiency of Random Forest models on the prediction of sand, clay, and organic carbon contents, using few soil samples. The study was carried out in a Cerrado area with lithological diversity, in the state of Mato Grosso do Sul, Brazil, using morphometric attributes, TM Landsat 5 sensor data, and lithology aspredictive covariates. The surface layer data (0.0–0.2 m) of 175 soil profiles (0,009 profiles km-2) and of 26 predictor covariates were used with 30 (set 1) and 90-m (set 2) spatial resolutions. The performed analysis by Random Forest models showed that channel base level, elevation, and lithology were the most important ones to explain the variability. The validation of the models showed similarity among sets for the prediction of sand,clay, and organic carbon contents, which explains the following values of spatial variability, respectively: 44, 40, and 33%, for the spatial resolution of 30 m; and 45, 46, and 33%, for the spatial resolution of 90 m. The spatial resolution of the predictive covariates has little effect on attribute predictions, and the Random Forest approach has potential use for estimating soil properties

    Statement of Second Brazilian Congress of Mechanical Ventilarion : part I

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    ATLANTIC EPIPHYTES: a data set of vascular and non-vascular epiphyte plants and lichens from the Atlantic Forest

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    Epiphytes are hyper-diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non-vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer-reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non-vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non-vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events. © 2019 The Authors. Ecology © 2019 The Ecological Society of Americ

    Integração de dados do quickbird e atributos do terreno no mapeamento digital de solos por redes neurais artificiais

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    No presente estudo, foi realizada uma avaliação de diferentes variáveis ambientais no mapeamento digital de solos em uma região no norte do Estado de Minas Gerais, utilizando redes neurais artificiais (RNA). Os atributos do terreno declividade e índice topográfico combinado (CTI), derivados de um modelo digital de elevação, três bandas do sensor Quickbird e um mapa de litologia foram combinados, e a importância de cada variável para discriminação das unidades de mapeamento foi avaliada. O simulador de redes neurais utilizado foi o "Java Neural Network Simulator", e o algoritmo de aprendizado, o "backpropagation". Para cada conjunto testado, foi selecionada uma RNA para a predição das unidades de mapeamento; os mapas gerados por esses conjuntos foram comparados com um mapa de solos produzido com o método convencional, para determinação da concordância entre as classificações. Essa comparação mostrou que o mapa produzido com o uso de todas as variáveis ambientais (declividade, índice CTI, bandas 1, 2 e 3 do Quickbird e litologia) obteve desempenho superior (67,4 % de concordância) ao dos mapas produzidos pelos demais conjuntos de variáveis. Das variáveis utilizadas, a declividade foi a que contribuiu com maior peso, pois, quando suprimida da análise, os resultados da concordância foram os mais baixos (33,7 %). Os resultados demonstraram que a abordagem utilizada pode contribuir para superar alguns dos problemas do mapeamento de solos no Brasil, especialmente em escalas maiores que 1:25.000, tornando sua execução mais rápida e mais barata, sobretudo se houver disponibilidade de dados de sensores remotos de alta resolução espacial a custos mais baixos e facilidade de obtenção dos atributos do terreno nos sistemas de informação geográfica (SIG)

    Predição de Classes de Solos de Paisagens Montanhosas da Serra do Mar, com o Uso de Redes Neurais Artificiais (RNAs)

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    The objective of this study was to apply artificial neural networks for the prediction of soil classes, using as source of data products of orbital remote sensors, information of local geology and attributes of the land derived from a digital elevation model, aiming to evaluate the use of this boarding for execution of the process of generation of soil map, in mountainous areas with varied lithology in Serra do Mar. For the prediction of soil classes were tried different combinations between the selected discriminant variables: elevation, slope angle, aspect, curvature, plan of curvature, profile of curvature, combined topographical index, solar radiation, factor LS, geology and indices derived from an image of sensor ETM+ of the LANDSAT 7, ndvi, clay mineral and iron oxid. The best results were obtained with all the discriminants variables, reaching global exactness between 93,2 and 95.6%, excluding the variable profile of curvature, the reached global exactness oscillated between 93,9 and 95,4%. The maps delineated for the classifier for artificial neural networks, have shown sufficient coherent and similar to the conventional soil map, presenting more space details. Index terms: artificial neural networks, terrain attributes, classification of soils.Pages: 3916-392
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