Stratigraphical discontinuities, tropical landscape evolution and soil distribution relationships in a case study in SE-Brazil

Cooper, Miguel; Vidal‐Torrado, Pablo; Lepsch, I. F.

doi:10.1590/s0100-06832002000300012

Cited by 9 publications

(9 citation statements)

References 5 publications

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“…The Ferralic Nitisol (Nitossolo Vermelho Eutroférrico latossólico) (Profiles 1 and 2 (P1 and P2)) are situated on the summit. The parent materials for this soil are the Cenozoic red clayey sediments deposited during a Quaternary sedimentation event (Cooper et al, 2002) and the diabase.…”

Section: Resultsmentioning

confidence: 99%

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Origin of microaggregates in soils with ferralic horizons

Cooper

Vidal‐Torrado

Chaplot

2005

Sci. agric. (Piracicaba, Braz.)

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Microaggregates that characterize ferralic soils have been hypothesized to have physical, geochemical and/or biological origins. Despite of many studies, the hierarchy between these processes that form microaggregates has seldom been reported. The objective of this work was to study the genesis of microaggregates in a sequence of Ferralic Nitisols developed on Quaternary red clayey sediments and diabase in Piracicaba (SP), Brazil. This issue was tackled by combining optical microscopy, image analysis, scanning electron microscopy and elemental iron quantifications by X-ray fluorescence. Micromorphological investigations showed three different types of microaggregates: (i) oval microaggregates with well sorted quartz grains in their interior; (ii) oval microaggregates without or with poorly sorted quartz grains in their interior; and (iii) dense polyedric microaggregates. These morphological evidences, together with the elemental iron determinations and scanning electron microscopy, revealed the contribution of more than one process for microaggregate formation: (i) the mechanical action of the mesofauna would form the first type of microaggregates (ii) geochemical and biological processes would form the second type and (iii) the fissuration of the soil matrix by expansion and compression processes would form the third type.

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Section: Resultsmentioning

confidence: 99%

“…The study was conducted on the summit and shoulder segments of a toposequence underlayed by a Cenozoic red clayey deposit and diabase (Cooper et al, 2002). Two excavated pits were used to study the origin of the microaggregates.…”

Section: Methodsmentioning

confidence: 99%

Origin of microaggregates in soils with ferralic horizons

Cooper

Vidal‐Torrado

Chaplot

2005

Sci. agric. (Piracicaba, Braz.)

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“…Disturbed and undisturbed samples were collected from the diagnostic horizon of two soils located in experimental areas of the "Escola Superior de Agricultura Luiz Queiroz" (Esalq/USP), Piracicaba, São Paulo. The soils were classified by Cooper et al (2002) according to the Soil Taxonomy (Soil Survey Staff, 2014) as "Typic Hapludox" (soil 1) and as "Kandiudalfic Eutrudox" (soil 2); according to the Brazilian Soil Classification System, soil 1 is a Latossolo Vermelho amarelo distrófico típico and soil 2 is a Nitossolo Vermelho eutrófico latossólico (Santos et al, 2013).…”

Section: Methodsmentioning

confidence: 99%

Soil Water Retention Curve as Affected by Sample Height

Silva

Libardi

Gimenes

2018

Rev. Bras. Ciênc. Solo

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The soil water retention curve is one of the main instruments to assess the soil physical quality and to improve soil management. Traditionally, the equipment most used in the laboratory to determine the retention curve has been Haines funnels and Richards chambers. An important factor to which little attention has been given in the use of these equipaments is the height of the undisturbed soil sample. This work proposes to evaluate the influence of different heights of undisturbed samples for the determination of the retention curve. For this, undisturbed soil samples were collected in aluminum cylinders of three different heights (S1 = 75 mm; S2 =50mm; S3 =25 mm) and with the same internal diameter (70 mm) from the diagnostic horizons of a Typic Hapludox and a Kandiudalfic Eutrudox (Latossolo Vermelho amarelo distrófico típico and Nitossolo Vermelho eutrófico latossólico, respectively) in experimental areas of "Escola Superior de Agricultura Luiz de Queiroz" (ESALQ/USP), Piracicaba (SP), Brazil. The soil physical characterization was done based on granulometric analysis, bulk density, particle density, porosity, and organic carbon. The retention curves were determined for each sample size using Haines funnels for the tensions of 0.5, 1, 4, 6, and 10 kPa and Richards chambers for 33, 100, and 500 kPa. Data of the curves were estimated, fitted to a model and then the distribution of the soil pore radius was evaluated, differentiating the soil water retention curve. The Typic Hapludox showed a not so remarkable difference between the retention curve with the S3 samples and the retention curve with the S1 samples, in the range 0-1 kPa of tensions, and also between the retention curve with S1 samples and both retention curves with the S2 and S3 samples, in the range 100-500 kPa of tension. This led to a slight difference in the pore distribution curves for the sample heights of this soil. The Kandiudalfic Eutrudox, however, presented not only a remarkable difference of the smaller sample retention curve (S3) in relation to the larger ones (S1 and S2) in the range 0-10 kPa of tension, but also a notable difference in the pore distribution curves, with a reduction of mesopores and increase of micropores with the increase of sample height. Finally, from the results obtained and with the methodology used to determine the soil retention curve, it is not recommended to use undisturbed samples with a height greater than 25 mm.

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“…January is the hottest month (mean 24.4 ºC) and July the coldest (mean 17.4 ºC). The study was conducted on the summit and shoulder segments of a toposequence underlain by a Cenozoic red clayey deposit and diabase (Cooper et al, 2002). …”

Section: Methodsmentioning

confidence: 99%

Soil structure transformations from ferralic to nitic horizons on a toposequence in southeastern Brazil

Cooper¹,

Vidal‐Torrado²,

Grimaldi

2010

Rev. Bras. Ciênc. Solo

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The soil structure transformation from ferralic to nitic horizons was studied in a toposequence on quaternary red clayey sediments and diabase in Piracicaba (SP), Brazil. Morphological and micromorphological studies, image analysis, soil water characteristic curves and monitoring of (total) soil water potential head were used. The presence of polyconcave vughs, clayskins and planar voids shows that the vertical and lateral transition and structural transformation from ferralic to nitic horizons is given by the coalescence of the microaggregates, probably due to tensions created in a drier period in the past. Changes to a more humid climate with a defined dry season and alternate drying and wetting cycles resulted in the fissuration of the previously coalesced material, forming polyhedral aggregates and microaggregates. Simultaneously, clay illuviation filled the voids and together with the compacting action of the biological activity of these soils contributed to the coalescence of microaggregates.

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Stratigraphical discontinuities, tropical landscape evolution and soil distribution relationships in a case study in SE-Brazil

Cited by 9 publications

References 5 publications

Origin of microaggregates in soils with ferralic horizons

Origin of microaggregates in soils with ferralic horizons

Soil Water Retention Curve as Affected by Sample Height

Soil structure transformations from ferralic to nitic horizons on a toposequence in southeastern Brazil

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