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Registro Completo |
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Biblioteca(s): |
Embrapa Pantanal. |
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Data corrente: |
15/02/1995 |
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Data da última atualização: |
04/04/2017 |
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Autoria: |
ELLIOTT, E. T.; CAMBARDELLA, C. A. |
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Título: |
Physical separation on soil organic matter. |
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Ano de publicação: |
1991 |
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Fonte/Imprenta: |
Agriculture, Ecosystems and Environment, v.34, p.407-419, 1991. |
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Idioma: |
Inglês |
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Conteúdo: |
The distribution of organic matter within physical fractions of the soil can be assessed by disruption of the soil structure, followed by the separation of physical fractions based on particle size or density. Disruption of the soil structure can be accomplished by physical or chemical methods, or some combination of the two. The most commonly used methods of physical disruption are shaking and sonication. Dhaking is the more gentle method with the advantage of being able to obtain a wide range of disrupting energies relatively easily. Sonication can impart more energy to the soil a shorter period of time. The greatest potential problem associated with the use of sonication is the redistribution of organic matter among size/density fractions. Chemical extraction methods are commonly used prior to disruption of soil for particle size analysis. Some chemical dispersants can selectively solubilize organic matter. This specificity can be used to determine the kinds and amounts of organic matter that bind particles into agregates. Three methods of physical separation of soil have been used, sieving, sedimentation and densiometry. Sieving separates soil particles based strictly on size and is used primarily for aggregate separation of non-disrupted soil samples. Sedimentation separates particles based on an equivalent spherical diameter, which may vary in size, shape and density. It is most often used in conjunction with a disruption pretreatment to obtain fine fractions. Densitometry separates particles based on the weight per unit volume, independent of size and shape, and is used to separate lighter from heavier fractions. It is possible to combine any or all of these separation methods in order to isolate, for instance, organic matter from a particular size fraction that has a specific density. MenosThe distribution of organic matter within physical fractions of the soil can be assessed by disruption of the soil structure, followed by the separation of physical fractions based on particle size or density. Disruption of the soil structure can be accomplished by physical or chemical methods, or some combination of the two. The most commonly used methods of physical disruption are shaking and sonication. Dhaking is the more gentle method with the advantage of being able to obtain a wide range of disrupting energies relatively easily. Sonication can impart more energy to the soil a shorter period of time. The greatest potential problem associated with the use of sonication is the redistribution of organic matter among size/density fractions. Chemical extraction methods are commonly used prior to disruption of soil for particle size analysis. Some chemical dispersants can selectively solubilize organic matter. This specificity can be used to determine the kinds and amounts of organic matter that bind particles into agregates. Three methods of physical separation of soil have been used, sieving, sedimentation and densiometry. Sieving separates soil particles based strictly on size and is used primarily for aggregate separation of non-disrupted soil samples. Sedimentation separates particles based on an equivalent spherical diameter, which may vary in size, shape and density. It is most often used in conjunction with a disruption pretreatment to obtain fine fractions. Densitom... Mostrar Tudo |
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Thesagro: |
Matéria Orgânica; Solo. |
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Thesaurus Nal: |
organic matter; soil. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02297naa a2200181 a 4500
001 1783889
005 2017-04-04
008 1991 bl --- 0-- u #d
100 1 $aELLIOTT, E. T.
245 $aPhysical separation on soil organic matter.
260 $c1991
520 $aThe distribution of organic matter within physical fractions of the soil can be assessed by disruption of the soil structure, followed by the separation of physical fractions based on particle size or density. Disruption of the soil structure can be accomplished by physical or chemical methods, or some combination of the two. The most commonly used methods of physical disruption are shaking and sonication. Dhaking is the more gentle method with the advantage of being able to obtain a wide range of disrupting energies relatively easily. Sonication can impart more energy to the soil a shorter period of time. The greatest potential problem associated with the use of sonication is the redistribution of organic matter among size/density fractions. Chemical extraction methods are commonly used prior to disruption of soil for particle size analysis. Some chemical dispersants can selectively solubilize organic matter. This specificity can be used to determine the kinds and amounts of organic matter that bind particles into agregates. Three methods of physical separation of soil have been used, sieving, sedimentation and densiometry. Sieving separates soil particles based strictly on size and is used primarily for aggregate separation of non-disrupted soil samples. Sedimentation separates particles based on an equivalent spherical diameter, which may vary in size, shape and density. It is most often used in conjunction with a disruption pretreatment to obtain fine fractions. Densitometry separates particles based on the weight per unit volume, independent of size and shape, and is used to separate lighter from heavier fractions. It is possible to combine any or all of these separation methods in order to isolate, for instance, organic matter from a particular size fraction that has a specific density.
650 $aorganic matter
650 $asoil
650 $aMatéria Orgânica
650 $aSolo
700 1 $aCAMBARDELLA, C. A.
773 $tAgriculture, Ecosystems and Environment$gv.34, p.407-419, 1991.
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