Adição de areia para dispersão de solos na análise granulométrica
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Data
2009-04-01
Autores
Corá, José Eduardo [UNESP]
Fernandes, Carolina [UNESP]
Beraldo, José Marcos Garrido [UNESP]
Marcelo, Adolfo Valente [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Ciência do Solo
Resumo
A acurácia da análise granulométrica depende da obtenção de suspensões de solo completamente dispersas e estáveis para possibilitar a separação das suas frações granulométricas. O objetivo do presente trabalho foi avaliar a eficácia da adição de quantidades e tamanhos de grãos de areia na fase de dispersão da análise granulométrica de solos, visando à maior acurácia na obtenção dos resultados da análise granulométrica. Os solos utilizados foram: Latossolo Vermelho eutroférrico (LVef), LatossoloVermelho acriférrico (LVwf), Latossolo Vermelho eutrófico (LVe), Argissolo Vermelho-Amarelo eutrófico (PVAe) e Nitossolo Vermelho eutroférrico (NVef). A dispersão das amostras dos solos foi realizada por meio da adição de hidróxido de sódio e agitação rotativa (60 rpm) por 16 h. O delineamento experimental adotado foi o inteiramente casualizado, com esquema fatorial 6 x 2, com três repetições. Os tratamentos foram constituídos por seis quantidades (0, 5, 10, 15, 20 e 25 g) e dois diâmetros (2,0-1,0 e 1,0-0,5 mm) de areia, adicionados na fase de dispersão da análise granulométrica dos solos. de acordo com as equações ajustadas, a adição de areia com diâmetro entre 1,0 e 0,5 mm nas quantidades de 21,4 g para LVef, 19,6 g para LVwf e 25,8 g para NVef proporciona, respectivamente para esses solos, aumentos de 50, 38 e 14,5 % nos teores de argila. No LVe e no PVAe não se justifica a adição de areia na análise granulométrica, pois esses solos não apresentaram problemas de dispersão. Os resultados demonstram que a adição de 25 g de areia, com diâmetro entre 1,0 e 0,5 mm, na fase de dispersão da análise granulométrica de solos argilosos com altos teores de óxidos de Fe e com dificuldades de dispersão, é eficiente para promover efetiva dispersão das partículas primárias do solo.
The accuracy of mechanical analysis depends on the complete dispersion and stability of the soil suspension in order to make the separation of the soil fractions possible. The purpose of this study was to evaluate the efficacy of adding sand in different amounts and particle sizes in the dispersion phase of the soil textural analysis in attempt to improve the accuracy of results. The soils used were Rhodic Eutrudox (oxidic) (LVef), Anionic Rhodic Acrudox (LVwf), Rhodic Eutrudox (kaolinitic) (LVe), Arenic Hapludalf (PVAe) and Rhodic Kandiudox (NVef). Sodium hydroxide and rotation shaking (60 rpm) for 16 hours with addition of sand were used in the dispersion phase. The experiment was set up in a complete randomized design, arranged in a factorial 6 x 2, with three replications. The amounts of sand particles used in the dispersion phase were: 5, 10, 15, 20 and 25 g and the sand particle diameters were 2.0 to 1.0 mm and 1.0 to 0.5 mm. According to the adjusted model, the addition of sand particles (diameter 1.0-0.5 mm) at amounts of 21.4 g to LVef, 19.6 g to LVwf and 25.8 g to NVef increased the soil clay content by 50, 38, and 14.5 %, respectively. No sand was added to LVe and PVAe, since clay dispersion was not a problem in these soils. Results indicated that the addition of 25 g of sand (particle diameter 0.5-1.0 mm), during the dispersion phase of the soil granulometric analysis of clayey soils with high iron oxide content and limited dispersion, is efficient to disperse the soil fractions.
The accuracy of mechanical analysis depends on the complete dispersion and stability of the soil suspension in order to make the separation of the soil fractions possible. The purpose of this study was to evaluate the efficacy of adding sand in different amounts and particle sizes in the dispersion phase of the soil textural analysis in attempt to improve the accuracy of results. The soils used were Rhodic Eutrudox (oxidic) (LVef), Anionic Rhodic Acrudox (LVwf), Rhodic Eutrudox (kaolinitic) (LVe), Arenic Hapludalf (PVAe) and Rhodic Kandiudox (NVef). Sodium hydroxide and rotation shaking (60 rpm) for 16 hours with addition of sand were used in the dispersion phase. The experiment was set up in a complete randomized design, arranged in a factorial 6 x 2, with three replications. The amounts of sand particles used in the dispersion phase were: 5, 10, 15, 20 and 25 g and the sand particle diameters were 2.0 to 1.0 mm and 1.0 to 0.5 mm. According to the adjusted model, the addition of sand particles (diameter 1.0-0.5 mm) at amounts of 21.4 g to LVef, 19.6 g to LVwf and 25.8 g to NVef increased the soil clay content by 50, 38, and 14.5 %, respectively. No sand was added to LVe and PVAe, since clay dispersion was not a problem in these soils. Results indicated that the addition of 25 g of sand (particle diameter 0.5-1.0 mm), during the dispersion phase of the soil granulometric analysis of clayey soils with high iron oxide content and limited dispersion, is efficient to disperse the soil fractions.
Descrição
Palavras-chave
texture analysis, clay, mechanical dispersion, iron oxide soil, microaggregation, análise textural, Argila, dispersão mecânica, Oxidos de ferro, microagregação
Como citar
Revista Brasileira de Ciência do Solo. Sociedade Brasileira de Ciência do Solo, v. 33, n. 2, p. 255-262, 2009.