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All publications of “Élvio Giasson”

12 results

A Regional Legacy Soil Dataset for Prediction of Sand and Clay Content with Vis-Nir-Swir, in Southern Brazil

Elisângela Benedet Silva ORCID logo , Élvio Giasson ORCID logo , André Carnieletto Dotto ORCID logo , Alexandre ten Caten ORCID logo , José Alexandre Melo Demattê ORCID logo , Ivan Luiz Zilli Bacic ORCID logo , [...]

12/Aug/2019

ABSTRACT The success of soil prediction by VIS-NIR-SWIR spectroscopy has led to considerable investment in large soil spectral libraries. The aims of this study were 1) to develop a soil VIS-NIR-SWIR spectroscopy approach using legacy soil samples to improve spectral soil information in a regional scale; (2) to compare six spectral preprocessing techniques; and (3) to compare the performance of linear and non-linear multivariate models for prediction of sand and clay content. A total of 1,534 legacy soil samples, stored […]

Visual Abstract

Selection of Environmental Covariates for Classifier Training Applied in Digital Soil Mapping

Alcinei Ribeiro Campos, Elvio Giasson, José Janderson Ferreira Costa, Israel Rosa Machado, Elisângela Benedet da Silva, Benito Roberto Bonfatti

26/Nov/2018

ABSTRACT A large number of predictor variables can be used in digital soil mapping; however, the presence of irrelevant covariables may compromise the prediction of soil types. Thus, algorithms can be applied to select the most relevant predictors. This study aimed to compare three covariable selection systems (two filter algorithms and one wrapper algorithm) and assess their impacts on the predictive model. The study area was the Lajeado River Watershed in the state of Rio Grande do Sul, Brazil. We […]

Spatial Disaggregation of Multi-Component Soil Map Units Using Legacy Data and a Tree-Based Algorithm in Southern Brazil

Israel Rosa Machado, Elvio Giasson, Alcinei Ribeiro Campos, José Janderson Ferreira Costa, Elisângela Benedet da Silva, Benito Roberto Bonfatti

02/Mar/2018

ABSTRACT Soil surveys often contain multi-component map units comprising two or more soil classes, whose spatial distribution within the map unit is not represented. Digital Soil Mapping tools supported by information from soil surveys make it possible to predict where these classes are located. The aim of this study was to develop a methodology to increase the detail of conventional soil maps by means of spatial disaggregation of multi-component map units and to predict the spatial location of the derived […]

PRODUCTION OF A SOIL MAP ASSOCIATING COMMON DIGITAL SOIL MAPPING TECHNIQUES WITH HAND DELINEATION OF SOIL MAPPING UNITS

Rodrigo Teske, Elvio Giasson, Tatiane Bagatini

01/Jul/2015

The production of soil maps through digital soil mapping (DSM) techniques may be hampered due to the lack of traditional reference soil maps. In these situations, the tacit knowledge of the field soil scientist can be used for manual delineation of soil mapping units (MUs) based on generation of a map of occurrence of soil types predicted by DSM. The objective of this study was to evaluate and to compare soil maps generated by two methods. One method, called “direct […]

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 […]

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 […]

Characterization of legacy soil maps: use of indicators in maps at different cales in Rio Grande do Sul

Eliana Casco Sarmento, Elvio Giasson, Eliseu José Weber, Carlos Alberto Flores, David Goodrich Rossiter, Heinrich Hasenack

01/Dec/2014

Conventional soil maps have acquired increasing importance as inputs for various applications, often without regard to their quality. The aim of this study was to assess and compare soil maps using easily determinable quantitative indicators. Nine soil maps (at different scales, from Rio Grande do Sul) and ArcGIS software were used. Effective scale number (NSN), polygons smaller than the minimum legible delineation (MLD), shape complexity index (S), number of taxonomic classes, soil types, mapping units, and proportion of areas with […]

Comparison of the use of digital elevation models in digital mapping of soils of Dois Irmãos, RS, Brazil

Rodrigo Teske, Elvio Giasson, Tatiane Bagatini

01/Oct/2014

Digital elevation models (DEM) are fundamental sources for correlating the occurrence and distribution of soils in the landscape by digital soil mapping (DSM). The influence of the types and resolutions of DEMs on the predictive capability of prediction models of soil classes has not been greatly studied. This study evaluated and compared the effects of different DEMs on the prediction of occurrence of soil mapping units (MU). Twelve predictor variables derived from different DEMs were correlated with the occurrence of […]

Chemical and mineralogical changes in a Brazilian Rhodic Paleudult under different land use and managements

Jessé Rodrigo Fink, Alberto Vasconcellos Inda, Jaime Antonio de Almeida, Carlos Alberto Bissani, Elvio Giasson, Paulo César do Nascimento

01/Aug/2014

Changes in land use and management can affect the dynamic equilibrium of soil systems and induce chemical and mineralogical alterations. This study was based on two long-term experiments (10 and 27 years) to evaluate soil used for no-tillage maize cultivation, with and without poultry litter application (NTPL and NTM), and with grazed native pasture fertilized with cattle droppings (GrP), on the chemical and mineralogical characteristics of a Rhodic Paleudult in Southern Brazil, in comparison with the same soil under native […]

Potential use of century model and gis to evaluate the impact of agriculture on regional soil organic carbon stocks

Elisandra Solange Oliveira Bortolon, João Mielniczuk, Carlos Gustavo Tornquist, Fabíola Lopes, Élvio Giasson, Homero Bergamaschi

01/Jun/2012

The land use and land use and management changes are among the main determinants of the stocks of soil organic carbon (SOC). The spatially explicit dynamic modeling is a technique that has been successfully used in evaluations of regional SOC stocks changes. Thus, this study aimed to use the Century 4.0 model associated with geoprocessing and remote sensing techniques to evaluate the effects of agricultural use and soil management changes on dynamics of soil organic carbon (SOC) on farms in […]

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