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Aeration condition of a clayey oxisol under long-term no-tillage Rev. Bras. Ciênc. Solo
Betioli Junior,Edner; Tormena,Cássio Antônio; Moreira,Wagner Henrique; Ball,Bruce C.; Figueiredo,Getulio Coutinho; Silva,Álvaro Pires da; Giarola,Neyde Fabíola Balarezo.
The hypothesis of this study was that the absence of soil tillage in long-term no-tillage (NT) systems can be detrimental to soil aeration. The objective was to assess the aeration condition of an Oxisol (Rhodic Ferrasol), very clayey texture (750 g kg-1 of clay; 200 g kg-1 of sand), after 30 years of cultivation under NT. The physical property soil air permeability (Ka) is sensitive to changes in the soil pore system. Aside from Ka, the air-filled porosity (ε a) and indices of pore continuity (K1 and N), derived from the relationship between Ka and εa, were used as indices of soil aeration. From the soil layers 0.0-0.1 and 0.1-0.2 m, 240 undisturbed samples were collected along a transect perpendicular to the crop rows, at three sampling positions: corn...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Soil compaction; Air permeability; Air-filled porosity; Pore continuity; Sampling spatial location.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832014000300031
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Assessment of soil physical attributes at sowing row and inter-row under no-till system Rev. Ciênc. Agron.
Blum,Julius; Giarola,Neyde Fabíola Balarezo; Silva,Álvaro Pires da; Guedes Filho,Osvaldo; Silva,Sâmala Glícia Carneiro; Eberhardt,Diogo Néia; Araújo,Suzana Romeiro.
In no-till systems, two different soil conditions are created during the sowing operation: row and inter-row positions. The objectives of this study were to evaluate, using static and dynamic soil attributes, the influence of no-till sowing operation on creating better physical environment for soybean crop growth. A field transect with clay content ranging from 150 to 400 g kg-1 was selected in Ponta Grossa, Paraná State, Brazil, from a Typic Hapludox that has been cultivated under no-till system for 16 years. After soybean harvest, 68 undisturbed soil samples were collected at both sowing row and inter-row positions. The following soil properties were evaluated: saturated hydraulic conductivity, air permeability, bulk density, total porosity, soil...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Soil physical quality; Soil conservation tillage; Soil compaction; Air permeability; Saturated hydraulic conductivity.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902014000500004
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Effect of the hemicellulose in the properties of nanopaper. Repositório Alice
CLARO, F. C.; MATOS, M. de; MAGALHAES, W. L. E..
The foldable, low thermal expansion, and optically transparent are main properties of paper produced with cellulose nanofibers (nanopaper), being able to be used ifl the development of flexible circuit technologies. In this context, this work evaluates the importance of hemicellulose in the properties of nanofiber paper (NFP). The hemicellulose extraction from Pinus sp bleached cellulose pulp was performed with NaOH 17.5% for 1.5 h. Thereafter, the pulp was washed with 8.3% NaOH, then was add 10% acetic acid until neutralization, and washed with water. The nanofibrils were obtained by mechanical defibrillation in a Super Masscoloider Masuko Sangyo mill. The NFP with the grammage of 40 and 50 g/m2 were produced by filtration and drying under pressure. The...
Tipo: Separatas Palavras-chave: Nanofibra; Permeabilidade do ar; Bleached pulp; Air permeability; Hemicelulose; Nanofibers; Hemicellulose; Tensile strength.
Ano: 2017 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1075217
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Influência da hemicelulose na reologia de suspensões de nanocelulose e na formação de filmes de nanofibrilas. Repositório Alice
CLARO, F. C.; MATOS, M. de; MAGALHAES, W. L. E..
É crescente o desenvolvimento de filmes nano-estruturados para uso em embalagens. Nesse contexto, a utilização de celulose nanofibrilada é interessante devido às suas propriedades físicas: como alta resistência, baixa densidade e translucidez, além dos benefícios ecológicos. A polpa celulósica utilizada no processo de obtenção da nanofibrilas apresenta cerca de 15% em massa de hemicelulose, portanto é importante compreender qual o efeito da hemicelulose nas propriedades dos filmes de nanofibras. Para isso, foram produzidas suspensões de nanocelulose uma com hemicelulose e outra na qual a hemicelulose foi extraída com tratamento alcalino. As suspensões foram obtidas pelo método mecânico de desfibrilação. Os filmes foram produzidos com gramaturas de 40 e 50...
Tipo: Separatas Palavras-chave: Reologia; Nanofibra; Resistência à tração; Permeabilidade ao ar; Air permeability; Hemicelulose; Hemicellulose; Rheology; Nanofibers; Tensile strength.
Ano: 2017 URL: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1081393
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Is Structural Quality as Assessed by the "Profil Cultural" Method Related to Quantitative Indicators of Soil Physical Quality? Rev. Bras. Ciênc. Solo
Watanabe,Rafaela; Tormena,Cássio Antonio; Guimarães,Maria de Fátima; Tavares Filho,João; Ralisch,Ricardo; Franchini,Julio; Debiasi,Henrique.
ABSTRACT Soil and crop management systems change the soil structure, thereby affecting soil quality. The “profil cultural” method (PCM) has been used to identify the effects of management systems on soil structure; however, few studies relate the structures identified by the PCM to quantitative indicators of soil structural quality. This study aimed to quantify soil structures using the PCM and relate these structures to bulk density (Bd), critical bulk density (Bdc), soil aeration capacity (εa), least limiting water range (LLWR), and soil air permeability (Ka) under different soil and crop management systems. The study was developed in a long-term experiment (24 years) involving two systems of soil management (no-tillage and conventional tillage) and two...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Least limiting water range; Air permeability; No-tillage; Conventional tillage.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832018000100510
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THE ROLE OF SOIL STRUCTURE ON THE PORE FUNCTIONALITY OF AN ULTISOL J. Soil Sci. Plant Nutr.
Dorner,J; Sandoval,P; Dec,D.
A Typic Hapludult was used to evaluate the effect of soil structure and different bulk densities (reached after the destruction of macro aggregates) on functional characteristics of the pore system. The water retention curve, pore-size distribution, shrinkage curve and index were determined in disturbed and structured samples. To evaluate the effect of soil structure on the continuity of the pore system the air permeability at different matrix potentials was measured. From the relationship between the air permeability and air-filled porosity, pore continuity indexes were calculated. The destruction of the soil structure affects the function of its pores. The amount of air-filled pores increased with the reduction of the bulk density, however, the stability...
Tipo: Journal article Palavras-chave: Soil structure; Pores; Air permeability; Ultisol.
Ano: 2010 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162010000200009
Registros recuperados: 6
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