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Mudanças na estrutura do solo avaliada com uso de tomografia computadorizada PAB
Pires,Luiz Fernando; Bacchi,Osny Oliveira Santos.
O objetivo deste trabalho foi avaliar, em escala milimétrica, a modificação da densidade e da porosidade de amostras deformadas de solo submetidas a ciclos de umedecimento e secamento (U-S), por meio da tomografia computadorizada de raios gama. Amostras com 98,1 cm³ foram preparadas procedendo ao peneiramento do solo em malha de 2 mm e acondicionamento de forma homogênea em tubos de PVC. As amostras de solo foram submetidas a um, dois e três ciclos de U-S. As amostras controle não foram submetidas a nenhum ciclo de U-S. Após a aplicação dos ciclos de U-S, a porosidade das amostras diminuiu e as camadas de solo se adensaram. Os dados de tomografia computadorizada permitiram análise contínua da densidade do solo e de sua porosidade, em camadas milimétricas...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Análise de imagens; Atenuação de raios gama; Ciclos de umedecimento e secamento; Densidade do solo; Porosidade do solo.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2010000400007
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Radiological impact of phosphogypsum surface application in a no-till system in Southern Brazil PAB
Dias,Nivea Maria Piccolomini; Caires,Eduardo Fávero; Pires,Luiz Fernando; Bacchi,Márcio Arruda; Fernandes,Elisabete Aparecida de Nadai.
The objective of this work was to determine the impact of phosphogypsum application on 226Ra and 228Ra activities in the soil and on their accumulation in soybean grains. A field experiment was carried out in Paraná state, Brazil, on a loamy Typic Hapludox, under no-till system, with increasing phosphogypsum rates: 4, 8, and 12 Mg ha-1. GammA ray spectrometry was carried out using HPGe detectors with 45 and 10% relative efficiencies, for soybean grains and soil, respectively. No increment of 226Ra and 228Ra activities was observed due to the increase in phosphogypsum rates in the soil, and a small reduction was noticed in the grains. Average values found for 226Ra and 228Ra activities were 37 and 57 Bq kg-1 in the soil and 1.44 and 3.19 Bq kg-1 in soybean...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Glycine max; Gamma spectrometry; Radioactivity; 226Ra; 228Ra.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2010001200017
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THREE DIMENSIONAL CHARACTERIZATION OF SOIL MACROPOROSITY BY X-RAY MICROTOMOGRAPHY Rev. Bras. Ciênc. Solo
Passoni,Sabrina; Pires,Luiz Fernando; Heck,Richard; Rosa,Jadir Aparecido.
Analysis of the soil pore system represents an important way of characterizing soil structure. Properties such as the shape and number of pores can be determined through soil pore evaluations. This study presents a three-dimensional (3D) characterization of the shape and number of pores of a sub-tropical soil. To do so, a second generation X-ray microtomograph equipped with a plain type detector was employed. A voltage of 120 kV and current of 80 mA was applied to the X-ray tube. The soil samples analyzed were collected at three different depths (0-10, 10-20, and 20-30 cm). The results obtained allowed qualitative (images) and quantitative (3D) analyses of the soil structure, revealing the potential of the microtomographic technique, as well as the study...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Soil structure; Pore size distribution; Soil porosity; Image analysis; Soil microstructural components.
Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000200448
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Experimental Method to Determine Some Physical Properties in Physics Classes Rev. Bras. Ciênc. Solo
Pires,Luiz Fernando; Brinatti,André Maurício; Saab,Sérgio da Costa.
ABSTRACT Particle density, gravimetric and volumetric water contents and porosity are important basic concepts to characterize porous systems such as soils. This paper presents a proposal of an experimental method to measure these physical properties, applicable in experimental physics classes, in porous media samples consisting of spheres with the same diameter (monodisperse medium) and with different diameters (polydisperse medium). Soil samples are not used given the difficulty of working with this porous medium in laboratories dedicated to teaching basic experimental physics. The paper describes the method to be followed and results of two case studies, one in monodisperse medium and the other in polydisperse medium. The particle density results were...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Particle density; Porous medium density; Gravimetric water content; Volumetric water content.
Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000501507
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Changes in the Structure of a Nigerian Soil under Different Land Management Practices Rev. Bras. Ciênc. Solo
Ogunwole,Joshua Olalekan; Pires,Luiz Fernando; Shehu,Bello Muhammed.
Quantification of soil physical quality (SPQ) and pore size distribution (PSD) can assist understanding of how changes in land management practices influence dynamics of soil structure, and this understanding could greatly improve the predictability of soil physical behavior and crop yield. The objectives of this study were to measure the SPQ index under two different land management practices (the continuous arable cropping system and natural bush fallow system), and contrast the effects of these practices on the structure of PSD using soil water retention data. Soil water retention curves obtained from a pressure chamber were fitted to van Genuchten’s equation, setting m (= 1-1/n). Although values for soil bulk density were high, soils under the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Arable cropping; Bush fallow; Soil water retention; Soil physical quality index.
Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000300830
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Funil de haines modificado: curvas de retenção de solos próximos à saturação Rev. Bras. Ciênc. Solo
Cássaro,Fabio Augusto Meira; Pires,Luiz Fernando; Santos,Rosiane Antures dos; Giménez,Daniel; Reichardt,Klaus.
O movimento da água através da matriz do solo é geralmente modelado pelas equações de Darcy, Darcy-Buckingam e Richards, cujo uso está baseado no conhecimento de algumas propriedades físicas do solo, como, por exemplo, a distribuição de poros e a retenção de água pelo solo. A retenção de água pelo solo é conhecida a partir da determinação de sua curva de retenção (CR) ou curva característica. O primeiro objetivo deste trabalho foi apresentar um aparato simples, desenvolvido pela modificação do funil de placa porosa (funil de Haines), para a investigação e o levantamento de CRs detalhadas, em amostras de solos em condições de umidade próximas à saturação e em amostras com potenciais mátricos (ψm) que vão desde 0 kPa a aproximadamente -12 kPa (120 cm de...
Tipo: Info:eu-repo/semantics/report Palavras-chave: Van Genuchten; Curva de retenção; Função capacidade de água.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832008000600032
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Soil physico-hydrical properties resulting from the management in Integrated Production Systems Rev. Ciênc. Agron.
Auler,André Carlos; Miara,Simone; Pires,Luiz Fernando; Fonseca,Adriel Ferreira da; Barth,Gabriel.
Anthropic action, such as the soil use and management systems, promote changes in the soil structure. These changes might hamper the development of plants in soil management practices that involve its mobilization, and the negative effects might be increased due to intensive use. The aim of this study was to evaluate the physico-hydrical properties of a Haplohumox in integrated production systems under different soil managements. The soil superficial (0.0-0.10 m) and sub-superficial (0.10-0.20 m) layers were evaluated in the different systems: conventional tillage (CT), minimum tillage (MT), no-tillage (NT) and chiseled no-tillage (CNT), taking into consideration the annual ryegrass cropped for different uses [cover crop (C), grazing (G) and silage (S)]...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Haplohumox; No-tillage; Soil physical quality; Crop-livestock integration; Agriculture sustainability.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902014000500013
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Field spatial and temporal patterns of soil water content and bulk density changes Scientia Agricola
Timm,Luís Carlos; Pires,Luiz Fernando; Roveratti,Renato; Arthur,Robson Clayton Jacques; Reichardt,Klaus; Oliveira,Júlio Cesar Martins de; Bacchi,Osny Oliveira Santos.
Soil water content (theta) and bulk density (rhos) greatly influence important soil and plant processes, such as water movement, soil compaction, soil aeration, and plant root system development. Spatial and temporal variability of theta and rhos during different periods of the year and different phases of crops are of fundamental interest. This work involves the characterization of spatial and temporal patterns of theta and rhos during different climatic periods of year, aiming to verify whether there are significant temporal changes in rhos at the soil surface layer when submitted to wetting and drying cycles. The field experiment was carried out in a coffee plantation, Rhodic Kandiudalf soil, clayey texture. Using a neutron/gamma surface probe, theta...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Neutron/gamma surface probe; Wetting/drying cycles; Spatial and temporal variability.
Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000100009
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Surface and incorporated liming effects on clay dispersion, water availability, and aeration capacity of a Dystrudept soil Bragantia
Auler,André Carlos; Pires,Luiz Fernando; Caires,Eduardo Fávero.
ABSTRACT Liming represents a management procedure that can affect the soil structure and its thermodynamic processes. In this context, the aims of this study were to assess (i) the effects of the surface and incorporated liming on the clay dispersion, soil water availability, and aeration capacity; (ii) the influence of soil chemical alterations in its physical attributes. For this, a field experiment was installed in a family farming property, located in the southeastern region of the State of Paraná, in a Dystrudept soil. The treatments were 3 application modes (on the surface, incorporated via plowing and incorporated via subsoiling and harrowing), with and without 15 Mg∙ha–1 of lime, aiming to increase the base saturation in the topsoil (0 – 0.20 m) to...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Water field capacity; Soil acidity; Cation exchange capacity; No-tillage system.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052017000300433
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X-ray Microtomography to Quantify Morphological Sandstones Properties BABT
Pires,Luiz Fernando; Melo,Mário Sérgio de; Borges,Jaqueline Aparecida Ribaski; Heck,Richard John; Facin,Paulo Cesar.
Abstract The sandstones of the Furnas Formation in the State of Paraná, south of Brazil, are located in regions with great importance due to the natural heritage found in the rocky forms and associated flora and fauna. This paper presents a detailed analysis of the internal structure of diverse sandstones of the Furnas Formation. X-ray microtomography allowed 3D characterization of the number, pore size and shape distributions of the sandstones. Images with voxel size of 603 µm3 were utilized to evaluate the sandstone’s macroporosity. The main results obtained indicate that higher macroporosities were observed in coarser and some types of silicified sandstones. In general, fine sandstones were characterized by the largest number of pores. As a general...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Image analysis; Porous system; Sandstone structure; 3D analysis; Micromorphology.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132019000100605
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Software Image J to study soil pore distribution Ciência e Agrotecnologia
Passoni,Sabrina; Borges,Fernando da Silva; Pires,Luiz Fernando; Saab,Sérgio da Costa; Cooper,Miguel.
In the soil science, a direct method that allows the study of soil pore distribution is the bi-dimensional (2D) digital image analysis. Such technique provides quantitative results of soil pore shape, number and size. The use of specific softwares for the treatment and processing of images allows a fast and efficient method to quantify the soil porous system. However, due to the high cost of commercial softwares, public ones can be an interesting alternative for soil structure analysis. The objective of this work was to evaluate the quality of data provided by the Image J software (public domain) used to characterize the voids of two soils, characterized as Geric Ferralsol and Rhodic Ferralsol, from the southeast region of Brazil. The pore distribution...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Soil structure; Image analysis; Thin section; Soil porous system; Soil pore size distribution; Ferralsols.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542014000200003
Registros recuperados: 11
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