50 results

SELECTION OF SAMPLING DENSITY BASED ON DATA FROM AREAS ALREADY MAPPED FOR TRAINING DECISION TREE MODELS IN DIGITAL SOIL MAPPING

Tatiane Bagatini, Elvio Giasson, Rodrigo Teske

01/Jul/2015

In order to study sampling techniques useful for digital soil mapping (DSM), we evaluated the effect of changes in sampling density, based on data from areas already mapped by traditional methods, in regard to the accuracy of decision trees models for generating soil maps using DSM. In two watersheds in northwestern Rio Grande do Sul, Brazil, 1:50,000 scale conventional soils maps were used as reference maps. From the ASTER – GDEM Global Digital Elevation Model and the hydrographic network, maps […]

MATHEMATICAL TOOLS ASSOCIATED WITH MAGNETIC SUSCEPTIBILITY AND LANDSCAPE MODELS IN IDENTIFYING AREAS FOR SPECIFIC MANAGEMENT PRACTICES

Sammy Sidney Rocha Matias, José Marques, Gener Tadeu Pereira, Diego Silva Siqueira

01/Jul/2015

The identification of variability patterns through soil properties allows land use and occupation in a sustainable manner. The aim of this study was to ascertain the potential of magnetic susceptibility of the soil and landscape models in defining areas for specific management practices through the use of mathematical tools. The study area is in the municipality of Guariba, SP, Brazil. We chose an area of 110 ha in which three geomorphic surfaces (I, II, and III) had been identified and […]

Spatial Variability and Sampling Density of Magnetic Susceptibility and Soil Properties in Ultisols of the Manicoré Region, AM, Brazil

Ivanildo Amorim de Oliveira, José Marques, Milton César Costa Campos, Renato Eleotério de Aquino, Ludmila de Freitas, Diego Silva Siqueira e, [...]

01/May/2015

The difficulty in finding recent information on the spatial behavior of properties of soils in the Brazilian Amazon region has been a concern of many researchers. Due to the great difficulty and costs in assessing soil properties, alternative methods have been used for prediction, such as magnetic susceptibility. Thus, the objective of this study was to evaluate the spatial variability of magnetic susceptibility and of physical and chemical soil properties in an Argissolo Vermelho (Ultisol) from native forest, Archaeological Black […]

Spatial Variability and Sampling Density of Magnetic Susceptibility and Soil Properties in Ultisols of the Manicoré Region, AM, Brazil

Ivanildo Amorim de Oliveira, José Marques, Milton César Costa Campos, Renato Eleotério de Aquino, Ludmila de Freitas, Diego Silva Siqueira e, [...]

01/May/2015

The difficulty in finding recent information on the spatial behavior of properties of soils in the Brazilian Amazon region has been a concern of many researchers. Due to the great difficulty and costs in assessing soil properties, alternative methods have been used for prediction, such as magnetic susceptibility. Thus, the objective of this study was to evaluate the spatial variability of magnetic susceptibility and of physical and chemical soil properties in an Argissolo Vermelho (Ultisol) from native forest, Archaeological Black […]

Spatial Variability and Sampling Density of Magnetic Susceptibility and Soil Properties in Ultisols of the Manicoré Region, AM, Brazil

Ivanildo Amorim de Oliveira, José Marques, Milton César Costa Campos, Renato Eleotério de Aquino, Ludmila de Freitas, Diego Silva Siqueira e, [...]

01/May/2015

The difficulty in finding recent information on the spatial behavior of properties of soils in the Brazilian Amazon region has been a concern of many researchers. Due to the great difficulty and costs in assessing soil properties, alternative methods have been used for prediction, such as magnetic susceptibility. Thus, the objective of this study was to evaluate the spatial variability of magnetic susceptibility and of physical and chemical soil properties in an Argissolo Vermelho (Ultisol) from native forest, Archaeological Black […]

SOIL ORGANIC MATTER FRACTIONS IN PRESERVED AND DISTURBED WETLANDS OF THE CERRADO BIOME

Ricardo Fernandes de Sousa, Eliana Paula Fernandes Brasil, Cícero Célio de Figueiredo, Wilson Mozena Leandro

01/Jan/2015

Veredas are humid tropical ecosystems, generally associated to hydromorphic soils and a shallow water table. The soils of these ecosystems are affected by the use of the areas around these veredas. The objective of this study was to determine soil organic matter (SOM) fractions in veredas adjacent to preserved (native savanna) and disturbed environments (agricultural areas and pastures) in the Cerrado biome. Soil samples were collected from the 0-10 and 10-20 cm layers along reference lines drawn along the relief […]

USE OF SCALED SEMIVARIOGRAMS IN THE PLANNING SAMPLE OF SOIL PHYSICAL PROPERTIES IN SOUTHERN AMAZONAS, BRAZIL

Renato Eleotério de Aquino, Milton César Costa Campos, José Marques Junior, Ivanildo Amorim de Oliveira, Daniel De Bortoli Teixeira, José Maurício da Cunha

01/Jan/2015

There is a great lack of information from soil surveys in the southern part of the State of Amazonas, Brazil. The use of tools such as geostatistics may improve environmental planning, use and management. In this study, we aimed to use scaled semivariograms in sample design of soil physical properties of some environments in Amazonas. We selected five areas located in the south of the state of Amazonas, Brazil, with varied soil uses, such as forest, archaeological dark earth (ADE), […]

COMPARISON OF SAMPLING PROCEDURES FOR TRAINING PREDICTIVE MODELS IN DIGITAL SOIL CLASS MAPPING

Rodrigo Teske, Elvio Giasson, Tatiane Bagatini

01/Jan/2015

The predictive models used in digital soil mapping (DSM) need to be trained with data that most fully capture the variation of terrain and soil properties in order to generate adequate correlations between environmental variables and the occurrence of soil unities. Several methods have been used in DSM to evaluate the accuracy of these models. The aims of this study were to compare the use of three sampling procedures for training a classification and regression tree (CART) algorithm, and evaluate […]

USE OF SCALED SEMIVARIOGRAMS IN THE PLANNING SAMPLE OF SOIL CHEMICAL PROPERTIES IN SOUTHERN AMAZONAS, BRAZIL

Ivanildo Amorim de Oliveira, Milton César Costa Campos, José Marques Junior, Renato Eleotério de Aquino, Daniel de Bortoli Teixeira, Douglas Marcelo Pinheiro da Silva

01/Jan/2015

The lack of information concerning the variability of soil properties has been a major concern of researchers in the Amazon region. Thus, the aim of this study was to evaluate the spatial variability of soil chemical properties and determine minimal sampling density to characterize the variability of these properties in five environments located in the south of the State of Amazonas, Brazil. The five environments were archaeological dark earth (ADE), forest, pasture land, agroforestry operation, and sugarcane crop. Regular 70 […]

Using numerical classification of profiles based on Vis-NIR spectra to distinguish soils from the Piracicaba Region, Brazil

Rodnei Rizzo, José A. M. Demattê, Fabrício da Silva Terra

01/Apr/2014

Considering that information from soil reflectance spectra is underutilized in soil classification, this paper aimed to evaluate the relationship of soil physical, chemical properties and their spectra, to identify spectral patterns for soil classes, evaluate the use of numerical classification of profiles combined with spectral data for soil classification. We studied 20 soil profiles from the municipality of Piracicaba, State of São Paulo, Brazil, which were morphologically described and classified up to the 3rd category level of the Brazilian Soil […]

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