Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols
The occurrence of Umbric Ferralsols with thick umbric epipedons (> 100 cm thickness) in humid Tropical and Subtropical areas is a paradox since the processes of organic matter decomposition in these environments are very efficient. Nevertheless, this soil type has been reported in areas in the So...
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Sociedade Brasileira de Ciência do Solo
2011-02-01
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| Series: | Revista Brasileira de Ciência do Solo |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832011000100003&lng=en&tlng=en |
| _version_ | 1818918467872489472 |
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| author | Flávio Adriano Marques Márcia Regina Calegari Pablo Vidal-Torrado Peter Buurman |
| author_facet | Flávio Adriano Marques Márcia Regina Calegari Pablo Vidal-Torrado Peter Buurman |
| author_sort | Flávio Adriano Marques |
| collection | DOAJ |
| description | The occurrence of Umbric Ferralsols with thick umbric epipedons (> 100 cm thickness) in humid Tropical and Subtropical areas is a paradox since the processes of organic matter decomposition in these environments are very efficient. Nevertheless, this soil type has been reported in areas in the Southeast and South of Brazil, and at some places in the Northeast. Aspects of the genesis and paleoenvironmental significance of these Ferralsols still need a better understanding. The processes that made the umbric horizons so thick and dark and contributed to the preservation of organic carbon (OC) at considerable depths in these soils are of special interest. In this study, eight Ferralsols with a thick umbric horizon (UF) under different vegetation types were sampled (tropical rain forest, tropical seasonal forest and savanna woodland) and their macromorphological, physical, chemical and mineralogical properties studied to detect soil characteristics that could explain the preservation of high carbon amounts at considerable depths. The studied UF are clayey to very clayey, strongly acidic, dystrophic, and Al-saturated and charcoal fragments are often scattered in the soil matrix. Kaolinites are the main clay minerals in the A and B horizons, followed by abundant gibbsite and hydroxyl-interlayered vermiculite. The latter was only found in UFs derived from basalt rock in the South of the country. Total carbon (TC) ranged from 5 to 101 g kg-1 in the umbric epipedon. Dichromate-oxidizable organic carbon represented nearly 75 % of TC in the thick A horizons, while non-oxidizable C, which includes recalcitrant C (e.g., charcoal), contributed to the remaining 25 % of TC. Carbon contents were not related to most of the inorganic soil variables studied, except for oxalate-extractable Al, which individually explained 69 % (P < 0.001) of the variability of TC in the umbric epipedon. Clay content was not suited as predictor of TC or of the other studied C forms. Bulk density, exchangeable Al3+, Al saturation, ECEC and other parameters obtained by selective extraction were not suitable as predictors of TC and other C forms. Interactions between organic matter and poorly crystalline minerals, as indicated by oxalate-extractable Al, appear to be one of the possible organic matter protection mechanisms of these soils. |
| first_indexed | 2024-12-20T00:50:26Z |
| format | Article |
| id | doaj.art-0fb662e58dcd4087b5ed7787041b0fc1 |
| institution | Directory Open Access Journal |
| issn | 1806-9657 |
| language | English |
| last_indexed | 2024-12-20T00:50:26Z |
| publishDate | 2011-02-01 |
| publisher | Sociedade Brasileira de Ciência do Solo |
| record_format | Article |
| series | Revista Brasileira de Ciência do Solo |
| spelling | doaj.art-0fb662e58dcd4087b5ed7787041b0fc12022-12-21T19:59:15ZengSociedade Brasileira de Ciência do SoloRevista Brasileira de Ciência do Solo1806-96572011-02-01351254010.1590/S0100-06832011000100003S0100-06832011000100003Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsolsFlávio Adriano Marques0Márcia Regina Calegari1Pablo Vidal-Torrado2Peter Buurman3UEPUniversidade Estadual do Oeste do ParanáUniversidade de São PauloWageningen UniversityThe occurrence of Umbric Ferralsols with thick umbric epipedons (> 100 cm thickness) in humid Tropical and Subtropical areas is a paradox since the processes of organic matter decomposition in these environments are very efficient. Nevertheless, this soil type has been reported in areas in the Southeast and South of Brazil, and at some places in the Northeast. Aspects of the genesis and paleoenvironmental significance of these Ferralsols still need a better understanding. The processes that made the umbric horizons so thick and dark and contributed to the preservation of organic carbon (OC) at considerable depths in these soils are of special interest. In this study, eight Ferralsols with a thick umbric horizon (UF) under different vegetation types were sampled (tropical rain forest, tropical seasonal forest and savanna woodland) and their macromorphological, physical, chemical and mineralogical properties studied to detect soil characteristics that could explain the preservation of high carbon amounts at considerable depths. The studied UF are clayey to very clayey, strongly acidic, dystrophic, and Al-saturated and charcoal fragments are often scattered in the soil matrix. Kaolinites are the main clay minerals in the A and B horizons, followed by abundant gibbsite and hydroxyl-interlayered vermiculite. The latter was only found in UFs derived from basalt rock in the South of the country. Total carbon (TC) ranged from 5 to 101 g kg-1 in the umbric epipedon. Dichromate-oxidizable organic carbon represented nearly 75 % of TC in the thick A horizons, while non-oxidizable C, which includes recalcitrant C (e.g., charcoal), contributed to the remaining 25 % of TC. Carbon contents were not related to most of the inorganic soil variables studied, except for oxalate-extractable Al, which individually explained 69 % (P < 0.001) of the variability of TC in the umbric epipedon. Clay content was not suited as predictor of TC or of the other studied C forms. Bulk density, exchangeable Al3+, Al saturation, ECEC and other parameters obtained by selective extraction were not suitable as predictors of TC and other C forms. Interactions between organic matter and poorly crystalline minerals, as indicated by oxalate-extractable Al, appear to be one of the possible organic matter protection mechanisms of these soils.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832011000100003&lng=en&tlng=enLatossolossolos tropicaiscarbono totalcarbono orgânico do solocarvão do solocarbono pirogênicohorizonte A húmico |
| spellingShingle | Flávio Adriano Marques Márcia Regina Calegari Pablo Vidal-Torrado Peter Buurman Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols Revista Brasileira de Ciência do Solo Latossolos solos tropicais carbono total carbono orgânico do solo carvão do solo carbono pirogênico horizonte A húmico |
| title | Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols |
| title_full | Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols |
| title_fullStr | Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols |
| title_full_unstemmed | Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols |
| title_short | Relationship between soil oxidizable carbon and physical, chemical and mineralogical properties of umbric ferralsols |
| title_sort | relationship between soil oxidizable carbon and physical chemical and mineralogical properties of umbric ferralsols |
| topic | Latossolos solos tropicais carbono total carbono orgânico do solo carvão do solo carbono pirogênico horizonte A húmico |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832011000100003&lng=en&tlng=en |
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