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| Fernandes,Kathleen Lourenço; Ribon,Adriana Aparecida; Marques Junior,José; Bahia,Angélica Santos Rabelo de Souza; Tavares Filho,João. |
| Abstract: The objective of this work was to estimate the iron oxide contents (hematite and goethite) and to characterize the color and the spectral and magnetic signatures of Cerrado soils in the state of Goiás, Brazil. Six Oxisols and one Inceptisol were studied. Spectral and magnetic signatures were determined by diffuse reflectance spectroscopy (DRS) and magnetic susceptibility, respectively. Then, the spectral curves and the second derivative calculations were used to determine hematite and goethite contents, as well as soil color after conversion into tristimulus values. Hematite and goethite contents were also obtained by x-ray diffractometry, and soil color was also defined in the field (Munsell color chart). The values for the isomorphic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diffuse reflectance spectroscopy; Goethite; Hematite; Magnetic susceptibility; Oxisols. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2017001000923 |
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| Mendonça,Patrícia Gabarra; Teixeira,Daniel De Bortoli; Moitinho,Mara Regina; Silva Junior,João Fernandes da; Oliveira,Ismênia Ribeiro de; Martins Filho,Marcílio Vieira; Marques Junior,José; Pereira,Gener Tadeu. |
| ABSTRACT The identification of erosion-susceptible areas is fundamental for the adoption of soil conservation practices. Thus, the best way to estimate the spatial pattern of soil erosion must be identified, in which the process uncertainties are also taken into consideration. The purpose of this study was to evaluate the spatial and temporal uncertainty of soil loss under two scenarios of sugarcane harvest management: green cane (GC) and burnt cane (BC). The study was carried out on a 200-ha area, in Tabapuã, São Paulo State, Brazil. A regular 626-point sampling grid was established in the area, with equidistant intervals of 50 m and a final plant density of about 3.3 samples per ha. The probability that the soil loss would exceed the tolerable limit of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Green cane; Burnt cane; Geostatistics; Indicator kriging. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832018000100512 |
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| Aquino,Renato Eleotério de; Campos,Milton César Costa; Marques Junior,José; Oliveira,Ivanildo Amorim de; Teixeira,Daniel De Bortoli; Cunha,José Maurício da. |
| 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), pasture, sugarcane cropping, and agroforestry. Regular mesh grids were set up in these areas with 64 sample points spaced at 10 m from each other. At these points, we determined the particle size composition, soil resistance to penetration, moisture, soil bulk density and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sample density; Spatial variability; Physical properties; Scaled semivariograms. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000100021 |
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| Oliveira,Ivanildo Amorim de; Marques Junior,José; Campos,Milton César Costa; Aquino,Renato Eleotério de; Freitas,Ludmila de; Siqueira,Diego Silva; Cunha,José Maurício da. |
| A dificuldade em encontrar informações recentes sobre o comportamento espacial dos atributos dos solos na Região Amazônica tem sido preocupação de muitos pesquisadores. Em razão da grande dificuldade e dos custos para avaliar os atributos dos solos, têm-se utilizados métodos alternativos para predição de atributos do solo como a suscetibilidade magnética. Sendo assim, o objetivo deste trabalho foi avaliar a variabilidade espacial da suscetibilidade magnética (SM), os atributos físicos e químicos e determinar a densidade amostral de coleta em Argissolo Vermelho sob floresta nativa, Terra Preta Arqueológica (TPA) sob cultivo, e pastagem na região de Manicoré, Amazonas. Nessas áreas, foram estabelecidas malhas com dimensão de 70 × 70 m e demarcados pontos... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geoestatística; Terra Preta Arqueológica; Semivariograma escalonado. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000300668 |
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| Oliveira,Ivanildo Amorim de; Campos,Milton César Costa; Marques Junior,José; Aquino,Renato Eleotério de; Teixeira,Daniel de Bortoli; Silva,Douglas Marcelo Pinheiro da. |
| 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 × 70 m mesh grids were set up in these areas, with 64 sample points spaced at 10 m distance. Soil samples were collected at the 0.0-0.1 m depth. The chemical properties of pH in water, OM, P, K, Ca, Mg, H+Al, SB, CEC, and V were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Amazonian soils; Archaeological dark earth; Sampling density. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000100031 |
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| Barrios,Mariana dos Reis; Marques Junior,José; Panosso,Alan Rodrigo; Siqueira,Diego Silva; La Scala Junior,Newton. |
| The agricultural potential is generally assessed and managed based on a one-dimensional vision of the soil profile, however, the increased appreciation of sustainable production has stimulated studies on faster and more accurate evaluation techniques and methods of the agricultural potential on detailed scales. The objective of this study was to investigate the possibility of using soil magnetic susceptibility for the identification of landscape segments on a detailed scale in the region of Jaboticabal, São Paulo State. The studied area has two slope curvatures: linear and concave, subdivided into three landscape segments: upper slope (US, concave), middle slope (MS, linear) and lower slope (LS, linear). In each of these segments, 20 points were randomly... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Landforms; Principal component analysis; Cluster analysis. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832012000400002 |
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