Dispersão da fração argila de um latossolo sob diferentes sistemas de uso e dispersantes

Neto, Eurico Lucas de Sousa; Figueiredo, Luiz Henrique Arimura; Beutler, Amauri Nelson

doi:10.1590/s0100-06832009000300024

Cited by 7 publications

(5 citation statements)

References 7 publications

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“…Thus, it is likely that there are inconsistencies in the classification of soils due to the use of only one quantitative criterion, such as clay content, which is not sensitive to attributes related to the P sorption capacity of the soil. Moreover, with the consolidation and development of the no-tillage system, in which there is an increase of the organic matter content, recurrent problems are observed in routine laboratory assays related to the dispersion of clay in soils under this system (Sousa Neto et al, 2009;Miyazawa and Barbosa, 2011).…”

Section: Introductionmentioning

confidence: 99%

Substitution of Clay Content for P-Remaining as an Index of the Phosphorus Buffering Capacity for Soils of Rio Grande do Sul

Rogeri

Gianello

Bortolon

et al. 2016

Rev. Bras. Ciênc. Solo

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Mehlich-1 soil extract is currently used in Rio Grande do Sul (RS) and Santa Catarina (SC) States, in Brazil, to evaluate soil phosphorus available to plants and Mehlich-1 is sensitive to soil buffering capacity. This limitation is overcome partly by soil separation into buffering classes based on soil clay content. However, soil clay content has some technical and operational limitations, such as the underestimation of soil clay levels in soils under no-till. The aim of this study was to evaluate the remaining phosphorus (P-rem) compared to soil clay content as an index of the buffering capacity in soils of RS. The relationship between P-rem and soil clay content was assessed using 200 soil samples from a wide range of locations across the state. In 20 representative soil types, P-rem, soil clay content, P maximum adsorption capacity, total and pedogenic Fe contents, amount of P 2 O 5 needed to increase soil P in 1 mg kg -1 extracted by Mehlich-1 and -3 methods and P capacity factor were determined. Furthermore, a pot experiment was carried out with plants to determine soil P content extracted by Mehlich-1 and -3 at the maximum technical efficiency (MET) and the maximum absorption efficiency (MEA). Correlation analyses were performed between P-rem and soil clay content and, with the attributes of soils involving the P buffering capacity. The relationship between P-rem and soil clay content was described as a decreasing exponential function; however, the adjustment was not adequate to propose critical levels for P-rem. The P-rem index was superior to soil clay index in practically all relationships with the attributes related to the soil buffering capacity of the soils. In some cases, the indexes were similar; however, P-rem was not lower than the soil clay content in any case. The P-rem is a more reliable index to represent soil buffering capacity than the soil clay content in soils from RS, and P-rem might be used to implement soil classes for Mehlich-1 and Mehlich-3 determinations of soil P.

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Section: Introductionmentioning

confidence: 99%

Substitution of Clay Content for P-Remaining as an Index of the Phosphorus Buffering Capacity for Soils of Rio Grande do Sul

Rogeri

Gianello

Bortolon

et al. 2016

Rev. Bras. Ciênc. Solo

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“…De Sousa, De Figueiredo & Beutler (2009), indicated that knowledge of soil particle size distribution is important due to its close relationship with water dynamics, in addition to its important tool used in soil classification. 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.…”

Section: Introductionmentioning

confidence: 99%

“…Oliveira, Júnior, Vitorino, Ferreira, Sá & Lima (2002), found that slow stirring for 3 h causes a greatest dispersion. De Sousa, De Figueiredo & Beutler (2009), compared different mechanical dispersion methodologies and found that total dispersion of soil samples had achieved using stirring at 50 rpm for 12 hours.…”

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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“…A análise granulométrica do solo requer energia suficiente para vencer a força de ligação dos agregados (Vitorino et al, 2007) e substâncias húmicas, os quais devem ser fragmentados através do choque mecânico (Seta & Karathanasis, 1996;Suzuki et al, 2004;Sousa Neto et al, 2009) e adição de NaOH 0,1 mol L -1 ou Na 4 P 2 O 7 10H 2 O 0,1 mol L -1 (EMBRAPA, 1997). O método mais utilizado se baseia na velocidade de sedimentação das partículas em suspensão aquosa, quando então as partículas maiores decantam rapidamente e as menores permanecem mais tempo em suspensão (EMBRAPA, 1997).…”

Section: Introductionunclassified

Efeitos da agitação mecânica e matéria orgânica na análise granulométrica do solo

Miyazawa

Barbosa

2011

Rev. bras. eng. agríc. ambient.

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RESUMOA parte mineral do solo é classificada conforme a granulometria das partículas em argila, silte e areia (fina e grossa) e sua matéria orgânica pode influir no tamanho e na estabilidade dos agregados. O objetivo deste trabalho foi avaliar os processos de agitação na eficiência de dispersão dos agregados do solo e a interferência da matéria orgânica na análise granulométrica do solo. Várias amostras de solo foram coletadas nas profundidades de 0 a 40 cm. Foram determinados: tempo de agitação da mesa agitadora reciprocante, tipo de agitador, diâmetro do recipiente para agitação reciprocante, efeito do abrasivo na agitação e oxidação da matéria orgânica com H 2 O 2 30% na determinação do teor de argila. Agitação reciprocante com areia grossa foi eficiente na desagregação dos agregados do solo e é indicada para análise em série. A oxidação prévia das substâncias húmicas cimentantes do solo com H 2 O 2 30% não influiu na fragmentação dos agregados. O erro causado pela matéria orgânica do solo no teor de argila pode ser corrigido pelo valor da matéria orgânica determinado por Walkley-Black, dispensando oxidação prévia da amostra com H 2 O 2 30%.Palavras-chave: argila, oxidação da matéria orgânica, dispersão, agregados Effects of mechanical agitation and soil organic matter on soil particle size analysis ABSTRACT The mineral part of soil is classified according to size of clay, silt and sand (fine and coarse) particles. The soil organic matter (OM) can influence the size and stability of clay aggregates. The aims of this study were to evaluate shaking processes on the dispersion efficiency of soil aggregates and to evaluate the influence of soil OM on soil particle size analysis. Samples from 0 to 40 cm depths of several agricultural clay soil were collected. Stirring time on reciprocating shaker, shaker types, diameter of container for reciprocating agitation, effect of abrasive on shaking and oxidation of OM with 30% of H 2 O 2 on clay content determination were evaluated. Reciprocating shaking with coarse sand was efficient in the breakdown of soil aggregates and is suitable for series analysis. Previous oxidation of humic substance in soil with 30% H 2 O 2 did not influence the fragmentation of clay aggregates. Error on clay content caused by soil OM can be corrected by using the value of OM determined by Walkley-Black method and does not require prior oxidation of soil sample with 30% H 2 O 2 .

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Dispersão da fração argila de um latossolo sob diferentes sistemas de uso e dispersantes

Cited by 7 publications

References 7 publications

Substitution of Clay Content for P-Remaining as an Index of the Phosphorus Buffering Capacity for Soils of Rio Grande do Sul

Substitution of Clay Content for P-Remaining as an Index of the Phosphorus Buffering Capacity for Soils of Rio Grande do Sul

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

Efeitos da agitação mecânica e matéria orgânica na análise granulométrica do solo

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