Adição de areia para dispersão de solos na análise granulométrica

Corá, José Eduardo; Fernandes, Carolina; Beraldo, José Marcos Garrido; Marcelo, Adolfo

doi:10.1590/s0100-06832009000200003

Cited by 15 publications

(9 citation statements)

References 6 publications

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“…Similar results were found by Grohmann & Raij (1977), Oliveira et al (2002), Donagemma et al (2003), Tavares-Filho & Magalhães (2008) and Corá et al (2009), among others. These authors stress that the differences found result from the abrasive action of the sand added to the soil material and/or to the shaking method, since in the case of slow shaking, the soil suspension is subjected to successive falls within the container, leading to aggregate attrition.…”

Section: Resultssupporting

confidence: 90%

Chemical dispersants and pre-treatments to determine clay in soils with different mineralogy

Rodrigues¹,

Oliveira

Silveira

et al. 2011

Rev. Bras. Ciênc. Solo

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Knowledge of the soil physical properties, including the clay content, is of utmost importance for agriculture. The behavior of apparently similar soils can differ in intrinsic characteristics determined by different formation processes and nature of the parent material. The purpose of this study was to assess the efficacy of separate or combined pre-treatments, dispersion methods and chemical dispersant agents to determine clay in some soil classes, selected according to their mineralogy. Two Brazilian Oxisols, two Alfisols and one Mollisol with contrasting mineralogy were selected. Different treatments were applied: chemical substances as dispersants (lithium hydroxide, sodium hydroxide, and hexametaphosphate); pre-treatment with dithionite, ammonium oxalate, and hydrogen peroxide to eliminate organic matter; and coarse sand as abrasive and ultrasound, to test their mechanical action. The conclusion was drawn that different treatments must be applied to determine clay, in view of the soil mineralogy. Lithium hydroxide was not efficient to disperse low-CEC electropositive soils and very efficient in dispersing high-CEC electronegative soils. The use of coarse sand as an abrasive increased the clay content of all soils and in all treatments in which dispersion occurred, with or without the use of chemical dispersants. The efficiency of coarse sand is not the same for all soil classes.

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Section: Resultssupporting

confidence: 90%

Chemical dispersants and pre-treatments to determine clay in soils with different mineralogy

Rodrigues¹,

Oliveira

Silveira

et al. 2011

Rev. Bras. Ciênc. Solo

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“…The clay fraction was determined by the pipette method (Gee and Bauder, 1986) modified by Corá et al (2009) and Suzuki et al (2015), the sand by sieving, and the silt by the difference. In some horizons, due to the difficulty of dispersing the clay, the fraction that was retained in the 53 μm sieve was processed in the manner described above for only the sand fraction to remain in the sieve.…”

Section: Methodsmentioning

confidence: 99%

Characteristics of Soils in Highland Wetlands as a Subsidy to Identifying and Setting their Limits

Warmling

Albuquerque

Almeida

2017

Rev. Bras. Ciênc. Solo

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Palustrine areas and wetlands in particular are fragile ecosystems, with high biodiversity and high ecological productivity, and they provide benefits to society. The aim of this study was to describe and classify the main soils occurring in the wetlands of the Southern Plateau of Santa Catarina, and propose criteria for identification of hydromorphic environments as an aid in demarcation of their boundaries. Soils of four wetlands, in the municipalities of Bom Jardim da Serra, Bom Retiro, Lages, and Painel were described, collected, and taxonomically classified. A transection was demarcated in each one in which soils were analyzed in sites with different degrees of hydromorphism, corresponding to the inner, transition, and outer areas. In hydromorphic areas, the content of organic matter in the soil is higher than in non-hydromorphic areas, which influences the color and classification of the soils. In these soils, Aquents, Aquepts, and Histosols predominate, and Udepts predominate in the outer area. The drainage class and the higher chroma in the subsurface horizons of the Udepts indicate that they are outside the boundaries of the wetlands. The dark color in the surface horizons, along with the greyish colors, associated or not with the presence of mottling in the subsurface horizons, were the most obvious characteristics of a hydromorphic condition, indicating that the soil is located in the transitional and inner areas of the wetlands.

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“…Aparecida, Simões & Andrade (2012), stated that soil texture is based on various combinations of sand, silt and clay, being the particle size distribution of a soil sample defined by relative contents of these fractions. Corá, Fernandes, Beraldo & Marcelo (2009), concluded that stability and size of soil aggregates increase mainly with concentrations of humic and fulvic acids, as well as with an increasing in oxides and hydroxides of Fe and Al. In addition, availability of polyvalent cations, such as Ca 2+ , is an important factor as a binding agent, due to a promotion and formation of cationic bridges between soil organic matter and clay (Bronick & Lal, 2005).…”

Section: Introductionmentioning

confidence: 99%

Particle size distribution by Bouyoucos in slightly alkaline soils from department of Cordoba, Colombia

2018

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The aim of this study was to evaluate the Bouyoucos method, at different stirring times and using two chemical dispersants, for particle size determination and distribution in slightly alkaline soils of Córdoba, Colombia. Eight soils were mechanically dispersed applying a slow stirring; 60 rpm with five stirring times as follows: 2, 4, 6, 10 and 16 hours and a control experiment at 0 h. Chemical dispersion of samples was performed using two dispersants: Calgon (0.058 molL -1 (NaPO 3 ) 6 + 0.075 molL -1 Na 2 CO 3 ) and a mixture of Calgon and 0.1 molL -1 Na 4 P 2 O 7 at pH 9.1, which was proposed by authors. In addition, particle size distribution was determined by Pipette method, which was used as reference method. Tests of means and regression models were performed for sand, silt and clay contents using SAS statistical software. According to the results, significant differences were not found between 10 and 16 h of stirring, therefore maximum state of dispersion had achieved at stirring time of 10 h. Content of sand fraction showed an exponential decreasing which can be described following model given by , with determination coefficients higher than 0.90. Clay fraction showed exponentially increasing behavior of first order given by with determination coefficients greater than 90%. Soil textural classification was performed by Bouyoucos method using the proposed dispersant at 10 h of stirring was 75% similar to that determined by Pipette method whereas for Calgon, was 62.5%.Keywords: Stirring, clay, sand, chemical dispersants, silt, texture, timing. ResumenEl objetivo de este estudio fue evaluar el método de Bouyoucos, a diferentes tiempos de agitación utilizando dos dispersantes químicos, para la determinación de la distribución de tamaño de partícula en suelos ligeramente alcalinos de Córdoba, Colombia. Para ello, ocho suelos fueron sometidos a un proceso de dispersión mecánica, que consistió en una agitación lenta, en un equipo tipo Wagner a 60 rpm con cinco tiempos de agitación 2, 4, 6, 10 y 16 horas y un testigo a 0 h. La dispersión química de las muestras se realizó utilizando dos dispersantes; Calgon ((NaPO 3 ) 6 0.058 M + Na 2 CO 3 0.075 M) y una mezcla compuesta de Calgon más pirofosfato ((NaPO 3 ) 6 + Na 2 CO 3 ) + (Na 4 P 2 O 7 )) 0.1 M a pH 9,1. Además, a las muestras se les determino la granulometría por el método de pipeta. Las pruebas de medias y modelos de regresión de los contenidos de arena, limo y arcilla fueron analizados usando el software estadístico SAS. De acuerdo a los resultados obtenidos, no se encontró diferencias significativas entre las 10 y 16 h de agitación, por lo tanto 10 h son suficientes para obtener un máximo estado de dispersión. El contenido de la fracción arena presentó un decrecimiento exponencial que siguió el modelo , con coeficientes de determinación superiores a 0.90. La fracción de arcilla presentó un comportamiento exponencial creciente de primer orden, con coeficientes de determinación mayores del 90%. La clasificación textural por Bouyoucus con el dispers...

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Adição de areia para dispersão de solos na análise granulométrica

Cited by 15 publications

References 6 publications

Chemical dispersants and pre-treatments to determine clay in soils with different mineralogy

Chemical dispersants and pre-treatments to determine clay in soils with different mineralogy

Characteristics of Soils in Highland Wetlands as a Subsidy to Identifying and Setting their Limits

Particle size distribution by Bouyoucos in slightly alkaline soils from department of Cordoba, Colombia

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