Brazilian latosols and their B horizon microstructure as long-term biotic constructs
Autor(a) principal: | |
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Data de Publicação: | 2001 |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | LOCUS Repositório Institucional da UFV |
Texto Completo: | http://go.galegroup.com/ps/i.do?p=AONE&u=capes&id=GALE|A79547384&v=2.1&it=r&sid=AONE&asid=65cd4e79 http://www.locus.ufv.br/handle/123456789/23809 |
Resumo: | This paper discusses micropedological evidence for the biological formation of microstructure in tropical soils, placing emphasis on latosol (oxisol) formation promoted by termite activity. The microstructure of selected latosols from Brazil was investigated using standard chemical and physical methods, optical microscopy, and high resolution scanning electron microscopy coupled with energy-dispersive X-ray analysis to provide microchemical analysis of discrete microaggregates in thin section. The results showed that, in spite of great variability of parent materials, the B horizon of these soils displayed uniform microgranular structure, with little lithodependence and no apparent relationship to particle-size. Lithorelicts of oval pellets of 100-1000 mm diameter, similar to those in the B horizon, were observed in the upper parts of the C horizon (saprolite). In addition, microparticles of charcoal ([is less than] 50 [micro]m) were found in the inner microaggregates. The basic skeleton of the inner microaggregates was formed of quartz grains, generally smaller than 100 mm diameter. In contrast, the quartz grains of the soil skeleton ranged between 30 and 5000 mm. These microaggregates were not distinguishable from those built by termites on shallow saprolite. I present a general model of latosol genesis, which considers the close interdependence between the advent of angiosperm-dominated landscapes, neotectonics, and the synchronous appearance of termites and latosols on tropical land, dating back to late Cretaceous/early Tertiary times. The microaggregation of latosols is viewed as a long-term strategy favouring physical characteristics to counteract the irreversible trend of increasing nutrient losses. The degree of microaggregation appears related to high gibbsite and Feoxide concentrations, although these minerals are not responsible for microaggregate formation. However, it is postulated that gibbsite and Fe-oxides are associated only with the persistence of microaggregates in tropical soils. Because of a tendency to form face-to-face structures, kaolinite does not favour the microaggregation phenomenon, and hence, highly kaolinitic latosols display coalesced aggregates. |
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Schaefer, Carlos E. R.2019-03-07T14:21:28Z2019-03-07T14:21:28Z2001-090004-9573http://go.galegroup.com/ps/i.do?p=AONE&u=capes&id=GALE|A79547384&v=2.1&it=r&sid=AONE&asid=65cd4e79http://www.locus.ufv.br/handle/123456789/23809This paper discusses micropedological evidence for the biological formation of microstructure in tropical soils, placing emphasis on latosol (oxisol) formation promoted by termite activity. The microstructure of selected latosols from Brazil was investigated using standard chemical and physical methods, optical microscopy, and high resolution scanning electron microscopy coupled with energy-dispersive X-ray analysis to provide microchemical analysis of discrete microaggregates in thin section. The results showed that, in spite of great variability of parent materials, the B horizon of these soils displayed uniform microgranular structure, with little lithodependence and no apparent relationship to particle-size. Lithorelicts of oval pellets of 100-1000 mm diameter, similar to those in the B horizon, were observed in the upper parts of the C horizon (saprolite). In addition, microparticles of charcoal ([is less than] 50 [micro]m) were found in the inner microaggregates. The basic skeleton of the inner microaggregates was formed of quartz grains, generally smaller than 100 mm diameter. In contrast, the quartz grains of the soil skeleton ranged between 30 and 5000 mm. These microaggregates were not distinguishable from those built by termites on shallow saprolite. I present a general model of latosol genesis, which considers the close interdependence between the advent of angiosperm-dominated landscapes, neotectonics, and the synchronous appearance of termites and latosols on tropical land, dating back to late Cretaceous/early Tertiary times. The microaggregation of latosols is viewed as a long-term strategy favouring physical characteristics to counteract the irreversible trend of increasing nutrient losses. The degree of microaggregation appears related to high gibbsite and Feoxide concentrations, although these minerals are not responsible for microaggregate formation. However, it is postulated that gibbsite and Fe-oxides are associated only with the persistence of microaggregates in tropical soils. Because of a tendency to form face-to-face structures, kaolinite does not favour the microaggregation phenomenon, and hence, highly kaolinitic latosols display coalesced aggregates.engAustralian Journal of Soil Researchvolume 39, Issue 5, Pages 909-926, 2001CSIRO Publishinginfo:eu-repo/semantics/openAccessFerrosolsOxisolsLateritesTermitesMicroaggregatesBiological activityBrazilian soilsBrazilian latosols and their B horizon microstructure as long-term biotic constructsinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfreponame:LOCUS Repositório Institucional da UFVinstname:Universidade Federal de Viçosa (UFV)instacron:UFVORIGINALartigo.pdfartigo.pdfTexto completoapplication/pdf2647878https://locus.ufv.br//bitstream/123456789/23809/1/artigo.pdfb49fe260cf09dec6d66fd137abf4976eMD51LICENSElicense.txtlicense.txttext/plain; charset=utf-81748https://locus.ufv.br//bitstream/123456789/23809/2/license.txt8a4605be74aa9ea9d79846c1fba20a33MD52123456789/238092019-03-07 11:23:01.506oai:locus.ufv.br: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Repositório InstitucionalPUBhttps://www.locus.ufv.br/oai/requestfabiojreis@ufv.bropendoar:21452019-03-07T14:23:01LOCUS Repositório Institucional da UFV - Universidade Federal de Viçosa (UFV)false |
dc.title.en.fl_str_mv |
Brazilian latosols and their B horizon microstructure as long-term biotic constructs |
title |
Brazilian latosols and their B horizon microstructure as long-term biotic constructs |
spellingShingle |
Brazilian latosols and their B horizon microstructure as long-term biotic constructs Schaefer, Carlos E. R. Ferrosols Oxisols Laterites Termites Microaggregates Biological activity Brazilian soils |
title_short |
Brazilian latosols and their B horizon microstructure as long-term biotic constructs |
title_full |
Brazilian latosols and their B horizon microstructure as long-term biotic constructs |
title_fullStr |
Brazilian latosols and their B horizon microstructure as long-term biotic constructs |
title_full_unstemmed |
Brazilian latosols and their B horizon microstructure as long-term biotic constructs |
title_sort |
Brazilian latosols and their B horizon microstructure as long-term biotic constructs |
author |
Schaefer, Carlos E. R. |
author_facet |
Schaefer, Carlos E. R. |
author_role |
author |
dc.contributor.author.fl_str_mv |
Schaefer, Carlos E. R. |
dc.subject.pt-BR.fl_str_mv |
Ferrosols Oxisols Laterites Termites Microaggregates Biological activity Brazilian soils |
topic |
Ferrosols Oxisols Laterites Termites Microaggregates Biological activity Brazilian soils |
description |
This paper discusses micropedological evidence for the biological formation of microstructure in tropical soils, placing emphasis on latosol (oxisol) formation promoted by termite activity. The microstructure of selected latosols from Brazil was investigated using standard chemical and physical methods, optical microscopy, and high resolution scanning electron microscopy coupled with energy-dispersive X-ray analysis to provide microchemical analysis of discrete microaggregates in thin section. The results showed that, in spite of great variability of parent materials, the B horizon of these soils displayed uniform microgranular structure, with little lithodependence and no apparent relationship to particle-size. Lithorelicts of oval pellets of 100-1000 mm diameter, similar to those in the B horizon, were observed in the upper parts of the C horizon (saprolite). In addition, microparticles of charcoal ([is less than] 50 [micro]m) were found in the inner microaggregates. The basic skeleton of the inner microaggregates was formed of quartz grains, generally smaller than 100 mm diameter. In contrast, the quartz grains of the soil skeleton ranged between 30 and 5000 mm. These microaggregates were not distinguishable from those built by termites on shallow saprolite. I present a general model of latosol genesis, which considers the close interdependence between the advent of angiosperm-dominated landscapes, neotectonics, and the synchronous appearance of termites and latosols on tropical land, dating back to late Cretaceous/early Tertiary times. The microaggregation of latosols is viewed as a long-term strategy favouring physical characteristics to counteract the irreversible trend of increasing nutrient losses. The degree of microaggregation appears related to high gibbsite and Feoxide concentrations, although these minerals are not responsible for microaggregate formation. However, it is postulated that gibbsite and Fe-oxides are associated only with the persistence of microaggregates in tropical soils. Because of a tendency to form face-to-face structures, kaolinite does not favour the microaggregation phenomenon, and hence, highly kaolinitic latosols display coalesced aggregates. |
publishDate |
2001 |
dc.date.issued.fl_str_mv |
2001-09 |
dc.date.accessioned.fl_str_mv |
2019-03-07T14:21:28Z |
dc.date.available.fl_str_mv |
2019-03-07T14:21:28Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://go.galegroup.com/ps/i.do?p=AONE&u=capes&id=GALE|A79547384&v=2.1&it=r&sid=AONE&asid=65cd4e79 http://www.locus.ufv.br/handle/123456789/23809 |
dc.identifier.issn.none.fl_str_mv |
0004-9573 |
identifier_str_mv |
0004-9573 |
url |
http://go.galegroup.com/ps/i.do?p=AONE&u=capes&id=GALE|A79547384&v=2.1&it=r&sid=AONE&asid=65cd4e79 http://www.locus.ufv.br/handle/123456789/23809 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartofseries.pt-BR.fl_str_mv |
volume 39, Issue 5, Pages 909-926, 2001 |
dc.rights.driver.fl_str_mv |
CSIRO Publishing info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
CSIRO Publishing |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Australian Journal of Soil Research |
publisher.none.fl_str_mv |
Australian Journal of Soil Research |
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reponame:LOCUS Repositório Institucional da UFV instname:Universidade Federal de Viçosa (UFV) instacron:UFV |
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LOCUS Repositório Institucional da UFV |
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