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| 11. |  | RENZ, T. E.; NEUFELDT, H.; AYARZA, M. A.; RESCK, D. V. S.; ZECH, W. Microbial biomass, microbial activity, and carbon pools under different land-use systems in the Brazilian cerrados. In: THOMAS, R.; AYARZA, M.A., ed. Sustainable land management for the oxisols of the Latin American savannas: dynamics of soil organic matter and indicators of soil quality. Cali: CIAT, 1999. p.187-197.| Biblioteca(s): Embrapa Cerrados. |
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| 16. | | FUHRMANN, S.; NEUFELDT, H.; WESTERHOF, R.; AYARZA, M. A.; SILVA, J. E. da; ZECH, W. Soil organic carbon, carbohydrates, amino sugars, and potentially mineralizable nitrogen under different land-use systems in oxisols of the Brazilian cerrados. In: THOMAS, R.; AYARZA, M.A., ed. Sustainable land management for the oxisols of the Latin American savannas: dynamics of soil organic matter and indicators of soil quality. Cali: CIAT, 1999. p.110-122.| Biblioteca(s): Embrapa Cerrados. |
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| 19. | | AYARZA, M. A.; THOMAS, R.; ZECH, W.; NEUFELDT, H.; WESTRHOF, R. LILIENFEIN, J.; FREIBAUER, A.; SILVA, J. E. da. Soil indicators of sustainable agropastoral systems. In: CONGRESSO BRASILEIRO DE CIENCIA DO SOLO, 27., 1999, Brasilia, DF. [Ciencia do solo e qualidade de vida: anais]. [Planaltina: Embrapa Cerrados, 1999]. Sessao de posteres 1. Resumo.| Biblioteca(s): Embrapa Cerrados. |
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| 20. | | LILIENFEIN, J.; FREIBAUER, A.; NEUFELDT, H.; WESTERHOF, R.; AYARZA, M. A.; SILVA, J. E. da; RESCK, D. V. S.; ZECH, W. Influence of land-use on the distribution of water stable aggregates and P status of sandy and clayey cerrado oxisols, Brazil. In: SIMPOSIO SOBRE O CERRADO, 8.; INTERNATIONAL SYMPOSIUM ON TROPICAL SAVANNAS, 1., 1996, Brasilia, DF. Biodiversidade e producao sustentavel de alimentos e fibras nos Cerrados: anais... Planaltina: EMBRAPA-CPAC, 1996. p.323-328.| Biblioteca(s): Embrapa Cerrados. |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Cerrados. Para informações adicionais entre em contato com cpac.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Cerrados. |
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Data corrente: |
15/07/1999 |
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Data da última atualização: |
15/07/1999 |
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Autoria: |
NEUFELDT, H.; RESCK, D. V. S.; AYARZA, M. A.; ZECH, W. |
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Título: |
Soil organic matter in Oxisols of the Brazilian cerrados. |
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Ano de publicação: |
1999 |
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Fonte/Imprenta: |
In: THOMAS, R.; AYARZA, M.A., ed. Sustainable land management for the oxisols of the Latin American savannas: dynamics of soil organic matter and indicators of soil quality. Cali: CIAT, 1999. |
|
Páginas: |
p.89-109. |
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Idioma: |
Inglês |
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Conteúdo: |
Little is known about the sustainability of cultivation systems in the Brazilian savannas, also known as the Cerrados, despite its increasing significance for that country`s agriculture. To characterize management effects and follow alterations of organic compounds in different fractions, we studied wholesoil samples and particle-size separates from clayey and loamy Oxisols under crops, pastures, reforested sites, and savanna. We assessed soil organic carbon (SOC), polysaccharides, and CuO oxidation products (VSC-lignin). Few changes were found in SOC contents of topsoil (0-12 cm) under different land uses after 10-20 years. But organic carbon clearly diminished under continuous cropping on the loamy soil and under reforestation withpine on the clayey soil. Management effects on SOC were more apparent in sand fractions, suggesting that particulate organic matter (POM) was affected most. In the clay fraction, only minor effects were noted. Carbon-normalized polysaccharide contents were enriched under pastures and depleted under pine, but generally followed a similar distribution to that of SOC. Overall, both polysaccharides and VSC-lignin were closely related to soil porosity. Plant-derived polysaccharides and lignin contents were probably regulated by mater availability to soil microbes, so that decomposition was usually more advanced in the clayey soils. Tem years of continuous cropping lowered litter inputs, thus reducing POM, whereas humified organic matter (OM) was unaffected. Planting eucalyptus or well-managed pastures, which produce high amounts of POM, would thus rapidly reverse soil degradation. Continuous cropping does eventually reduce the humified fraction and results in a substantial loss of soil fertility, which is only slowly reversible. In the loamy soils, rotation with a SOC-productive system, such as pastures or eucalyptus, was needed earlier because of their higher proportion of POM. Depletion of SOC under pine occured because new litter was not incorporated into the mineral soil, forming a thick moder layer as decomposition continued. After felling trees, the organic layer could be rapidly incorporated into the mineral soil, thus replenishing lost OM. However, the acid litter may reduce soil organic matter quality. MenosLittle is known about the sustainability of cultivation systems in the Brazilian savannas, also known as the Cerrados, despite its increasing significance for that country`s agriculture. To characterize management effects and follow alterations of organic compounds in different fractions, we studied wholesoil samples and particle-size separates from clayey and loamy Oxisols under crops, pastures, reforested sites, and savanna. We assessed soil organic carbon (SOC), polysaccharides, and CuO oxidation products (VSC-lignin). Few changes were found in SOC contents of topsoil (0-12 cm) under different land uses after 10-20 years. But organic carbon clearly diminished under continuous cropping on the loamy soil and under reforestation withpine on the clayey soil. Management effects on SOC were more apparent in sand fractions, suggesting that particulate organic matter (POM) was affected most. In the clay fraction, only minor effects were noted. Carbon-normalized polysaccharide contents were enriched under pastures and depleted under pine, but generally followed a similar distribution to that of SOC. Overall, both polysaccharides and VSC-lignin were closely related to soil porosity. Plant-derived polysaccharides and lignin contents were probably regulated by mater availability to soil microbes, so that decomposition was usually more advanced in the clayey soils. Tem years of continuous cropping lowered litter inputs, thus reducing POM, whereas humified organic matter (OM) was unaff... Mostrar Tudo |
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Thesagro: |
Cerrado; Matéria Orgânica; Oxisol; Solo. |
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Thesaurus NAL: |
Ferralsols; organic matter; soil. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 03040naa a2200253 a 4500
001 1545401
005 1999-07-15
008 1999 bl uuuu u00u1 u #d
100 1 $aNEUFELDT, H.
245 $aSoil organic matter in Oxisols of the Brazilian cerrados.
260 $c1999
300 $ap.89-109.
520 $aLittle is known about the sustainability of cultivation systems in the Brazilian savannas, also known as the Cerrados, despite its increasing significance for that country`s agriculture. To characterize management effects and follow alterations of organic compounds in different fractions, we studied wholesoil samples and particle-size separates from clayey and loamy Oxisols under crops, pastures, reforested sites, and savanna. We assessed soil organic carbon (SOC), polysaccharides, and CuO oxidation products (VSC-lignin). Few changes were found in SOC contents of topsoil (0-12 cm) under different land uses after 10-20 years. But organic carbon clearly diminished under continuous cropping on the loamy soil and under reforestation withpine on the clayey soil. Management effects on SOC were more apparent in sand fractions, suggesting that particulate organic matter (POM) was affected most. In the clay fraction, only minor effects were noted. Carbon-normalized polysaccharide contents were enriched under pastures and depleted under pine, but generally followed a similar distribution to that of SOC. Overall, both polysaccharides and VSC-lignin were closely related to soil porosity. Plant-derived polysaccharides and lignin contents were probably regulated by mater availability to soil microbes, so that decomposition was usually more advanced in the clayey soils. Tem years of continuous cropping lowered litter inputs, thus reducing POM, whereas humified organic matter (OM) was unaffected. Planting eucalyptus or well-managed pastures, which produce high amounts of POM, would thus rapidly reverse soil degradation. Continuous cropping does eventually reduce the humified fraction and results in a substantial loss of soil fertility, which is only slowly reversible. In the loamy soils, rotation with a SOC-productive system, such as pastures or eucalyptus, was needed earlier because of their higher proportion of POM. Depletion of SOC under pine occured because new litter was not incorporated into the mineral soil, forming a thick moder layer as decomposition continued. After felling trees, the organic layer could be rapidly incorporated into the mineral soil, thus replenishing lost OM. However, the acid litter may reduce soil organic matter quality.
650 $aFerralsols
650 $aorganic matter
650 $asoil
650 $aCerrado
650 $aMatéria Orgânica
650 $aOxisol
650 $aSolo
700 1 $aRESCK, D. V. S.
700 1 $aAYARZA, M. A.
700 1 $aZECH, W.
773 $tIn: THOMAS, R.; AYARZA, M.A., ed. Sustainable land management for the oxisols of the Latin American savannas: dynamics of soil organic matter and indicators of soil quality. Cali: CIAT, 1999.
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