Incremento da exatidão da análise granulométrica do solo por meio da coleta da suspensão (Silte + Argila)

Ruíz, Hugo Alberto

doi:10.1590/s0100-06832005000200015

Cited by 168 publications

(96 citation statements)

References 2 publications

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“…For physical characterization, soil samples were collected at depths of 0.0-0.30 m and 0.30-0.60 m, for particle size analysis, using the pipette method and 0.1 mol L -1 of NaOH (Ruiz 2005). The clay fraction was separated by sedimentation, total sand by sieving, and silt was calculated based on the difference between them.…”

Section: Methodsmentioning

confidence: 99%

Heavy metal contents in Latosols cultivated with vegetable crops1

Silva

Galindo

Nascimento

et al. 2016

Pesqui. Agropecu. Trop.

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Heavy metals are naturally found in soils, but their levels may increase as a result of anthropogenic actions. This study aimed at determining the concentrations of Cd, Cu, Mn, Ni, Pb and Zn in Yellow Latosol from vegetable crops areas, as well as the influence of the cultivation and position in the landscape on the accumulation of these elements. Soil samples were collected from five farming areas and four areas with natural vegetation, which served as a reference. Soil was collected along the planting rows from three transect positions (upper, middle and lower sections of the slope), as well as from the upper portion of forest areas, at three depths (0.0-0.10 m, 0.10-0.30 m and 0.30-0.60 m). The results from the chemical analyses indicated that Cd, Cu, Mn, Pb and Zn levels in the soil increased as a result of cultivation. Only Cd and Cu concentrations were above the quality reference values for the Pernambuco State. The multivariate analysis techniques used were efficient at separating the environments and at differentiating the origin of the metals. Soils from forest areas were clearly separated from croplands, demonstrating the effect of agricultural practices on the metal contents in the soils. The principal component analysis indicated a predominantly anthropogenic origin (phosphate fertilizing) for Cd, in more superficial soil samples.

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Section: Methodsmentioning

confidence: 99%

Heavy metal contents in Latosols cultivated with vegetable crops1

Silva

Galindo

Nascimento

et al. 2016

Pesqui. Agropecu. Trop.

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“…A fração silte foi obtida por diferença entre duas pipetagens, sendo na primeira recolhido silte + argila e, na segunda, apenas argila, considerando o tempo de sedimentação segundo a equação de Stokes, levando-se em conta a densidade de partículas (Embrapa, 1997) de cada solo em estudo. As frações texturais foram calculadas conforme proposta apresentada por Ruiz (2005).…”

Section: Methodsunclassified

Dispersantes químicos na análise granulométrica de latossolos

Mauri¹,

Ruíz

Fernandes

et al. 2011

Rev. Bras. Ciênc. Solo

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RESUMOA completa dispersão da amostra e a manutenção da estabilidade da fase dispersa são condições fundamentais para obtenção de maior acurácia na análise textural de amostras de solo. Para isso, foram testados compostos de Na + e Li + como dispersantes químicos alternativos, frente à solução de NaOH 10 mmol L -1 , com o objetivo de lograr dispersão mais efetiva e minimizar a presença de pseudocomponentes, fundamentalmente pseudossilte, na análise granulométrica de Latossolos. O trabalho foi realizado utilizando amostras de oito Latossolos do Estado de Minas Gerais, selecionados por apresentarem diferentes materiais de origem e teores de óxidos de ferro. Os tratamentos foram dispostos segundo um delineamento em blocos casualizados, correspondendo a um arranjo fatorial 8 x 2 x 7, com três repetições. Os fatores em estudo foram as amostras dos oito Latossolos, retiradas nos horizontes A e B, e sete dispersantes. O NaOH foi usado como dispersante de referência, testando-se alternativamente soluções de LiOH, NaClO, [NaClO + NaOH], [HCl + NaOH], (NaPO 3 ) n e [(NaPO 3 ) n + NaOH]. Utilizando a maior proporção de argila para identificar a efetividade dos dispersantes, nenhum deles igualou-se ao NaOH. Empregando o sinal > para indicar maior efetividade, a sequência determinada foi: NaOH > [(NaPO 3 ) n + NaOH] > [HCl + NaOH] > [NaClO + NaOH] > LiOH > (NaPO 3 ) n > NaClO. Dentre os dispersantes alternativos, destacouse a solução de [(NaPO 3 ) n + NaOH], com resultados próximos aos do dispersante de referência, evidenciando a importância da elevação do pH até valores próximos de 12. A efetividade das outras soluções sódicas com pH elevado, [NaClO+NaOH] e [HCl+NaOH], foi reduzida pela elevação da pressão osmótica da solução,

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“…Physical and chemical soil properties are listed in table 1. Particle-size analysis was performed with the pipette method adapted by Ruiz (2005) and the C content determined by dichromate oxidation (Yeomans & Bremner, 1988); the total soil N was determined by the Kjehdal method; available P and exchangeable K were extracted by Mehlich-1; Ca, Mg and Al were extracted by 1 mol L -1 KCl and the pH measured in water, at a ratio of 1: 2.5. The P content was determined by colorimetry of the phosphomolybdic complex, as described by Braga & Defelipo (1974); K was determined by flame photometry; Ca and Mg by atomic absorption; and Al by titration (Defelipo & Ribeiro, 1981).…”

Section: Methodsmentioning

confidence: 99%

Competitive sorption and desorption of phosphate and citrate in clayey and sandy loam soils

Souza

Soares²,

Silva³

et al. 2014

Rev. Bras. Ciênc. Solo

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SUMMARYThe increase of organic acids in soils can reduce phosphorus sorption. The objective of the study was to evaluate the competitive sorption of P and citrate in clayey and sandy loam soils, using a stirred-flow system. Three experiments were performed with soil samples (0-20 cm layer) of clayey (RYL-cl) and sandy loam (RYL-sl) Red Yellow Latosols (Oxisols). In the first study, the treatments were arranged in a 2 × 5 factorial design, with two soil types and five combinations of phosphorus and citrate application (only P; P + citrate; and citrate applied 7, 22, 52 min before P); in the second, the treatments were arranged in a 2 × 2 factorial design, corresponding to two soils and two forms of P and citrate application (only citrate and citrate + P); and in the third study, the treatments in a 2 × 2 × 6 factorial design consisted of two soils, two extractors (citrate and water) and six incubation times. In the RYL-cl and RYL-sl, P sorption was highest (44 and 25 % of P application, respectively), in the absence of citrate application. Under citrate application, P sorption was reduced in all treatments. The combined application of citrate and P reduced P sorption to 25.8 % of the initially applied P in RYL-cl and to 16.7 % in RYL-sl, in comparison to P without citrate. Citrate sorption in RYL-cl and RYL-sl was highest in the absence of P application, corresponding to 32.0 and 30.2 % of the citrate applied, respectively. With P application, citrate sorption was reduced to 26.4 and 19.7 % of the initially applied citrate in RYL-cl and RYL-sl, respectively. Phosphorus desorption was greater when citrate was used. Phosphorus desorption with citrate and water was higher in the beginning (until 24 h of incubation of P) in RYL-cl and RYL-sl, indicating a rapid initial phase, followed by a slow release phase. This suggests that according to the contact time of P with the soil colloids, the previously adsorbed P can be released to the soil solution in the presence of O aumento de ácidos orgânicos pode induzir à redução da sorção de P em solos. Este trabalho objetivou avaliar a sorção competitiva de P e citrato em solos de textura muito argilosa e franco-arenosa, utilizando o sistema de fluxo contínuo (stirred-flow). Foram realizados três experimentos com amostras da camada de 0-20 cm de dois Latossolos VermelhoAmarelo, texturas muito argilosa (LVA_arg) e franco-arenosa (LVA_fa). No primeiro, os tratamentos foram definidos por fatorial 2 × 5, sendo dois solos e cinco configurações de aplicação de P e citrato no solo (apenas P, P + citrato e citrato 7, 22, 52 min antes do P); no segundo, os tratamentos foram determinados por fatorial 2 × 2, dois solos e duas formas de aplicação de P e citrato no solo (apenas citrato, citrato + P); e, no terceiro, os tratamentos foram definidos segundo um fatorial 2 × 2 × 6, sendo dois solos, dois extratores (citrato e água) e os seis períodos de incubação. O valor máximo da sorção de P no LVA_arg e LVA_fa foi observado na testemunha sem aplicação de citrato, correspondendo a 44 e 25 % ...

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Incremento da exatidão da análise granulométrica do solo por meio da coleta da suspensão (Silte + Argila)

Cited by 168 publications

References 2 publications

Heavy metal contents in Latosols cultivated with vegetable crops1

Heavy metal contents in Latosols cultivated with vegetable crops1

Dispersantes químicos na análise granulométrica de latossolos

Competitive sorption and desorption of phosphate and citrate in clayey and sandy loam soils

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