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| Combatt-Caballero,Enrique Miguel; Palencia-L,Manuel; Borja-M.,Katerine. |
| Abstract 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 (NaPO3)6 + 0.075 molL-1 Na2CO3) and a mixture of Calgon and 0.1 molL-1 Na4P2O7 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... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Stirring; Clay; Sand; Chemical dispersants; Silt; Texture; Timing. |
| Ano: 2018 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-28122018000100126 |
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| Chiba, Marcio Koiti; IAC; Natale, William; UNESP; Cruz, Mara Cristina Pessôa da; UNESP; Teixeira, Luiz Antonio Junqueira; IAC; Centurion, José Frederico; UNESP. |
| Este trabalho teve por objetivo estudar a distribuição de formas não-trocáveis de potássio, em frações texturais de um Latossolo cultivado com bananeira, por dois anos, em dois regimes hídricos (parcelas principais), e doses de potássio (0, 300, 600 e 900 kg há-1) (subparcelas), seguindo delineamento em blocos casualizados, com parcelas subdivididas. Verificou-se que os maiores teores de potássio (trocável e não-trocável) estão contidos nas frações mais finas: argila e silte. Neste sistema de cultivo e com a aplicação dos adubos na superfície, a movimentação do nutriente, nas camadas estudadas, esteve associada à presença e movimentação da água no perfil do solo. A irrigação desempenhou papel relevante na distribuição das formas do K. Nas parcelas... |
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Palavras-chave: 5.01.00.00-9 Agronomia irrigação; Argila; Silte; Areia; K-trocável; K não-trocável. irrigation; Clay; Silt; Sand; Exchangeable K; Non-exchangeable K. |
| Ano: 2008 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/5321 |
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| Broch,Djulia Taís; Klein,Vilson Antonio. |
| ABSTRACT: Degradation that occursin agricultural soils causes compaction.Soil density (DS) analysis has been reported to be an unreliable method of measuring the extent of soil compaction, because it varies with the soil granulometric composition and organic matter (OM)content. However, soil relative density (DR) is a good indicator that facilitates the measurement of the degree of compaction and thus, soil comparison and management techniques. Quotient between the DS and its maximum density (Dsmax) gives the DR. This study aimed to assess the effect of the granulometric composition on the physical-hydrological properties of the high-silt containing soils,under no tillage. Samples from disturbed and undisturbed structures of 18 soils were collected from... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Proctor test; Silt; Relative density. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782017001200251 |
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