| Registro completo |
| Provedor de dados: |
Scientia Agricola
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| País: |
Brazil
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| Título: |
Comparison of carbon and nitrogen determination methods for samples of a Paleudult subjected to no-till cropping systems
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| Autores: |
Dieckow,Jeferson
Mielniczuk,João
Knicker,Heike
Bayer,Cimélio
Dick,Deborah Pinheiro
Kögel-Knabner,Ingrid
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| Data: |
2007-10-01
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| Ano: |
2007
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| Palavras-chave: |
Walkley-Black
Kjeldahl
Wet combustion
Dry combustion
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| Resumo: |
Organic carbon (C) concentration evaluated by the Walkley-Black method, and total nitrogen(N)concentration determined by Kjeldahl method, were compared with corresponding results of C and N concentrations obtained through the dry combustion method (Elementar Vario EL analyzer), using samples of ten soil layers down to the depth of 107.5 cm of a kaolinitic Typic Paleudult (220-418 g clay kg-1 along the profile) subjected to no-till cropping systems [fallow bare soil, pigeon pea (Cajanus cajan L. Millsp.) plus maize, and lablab (Lablab purpureum L. Sweet) plus maize]. A close correlation (R² > 0.96) was observed between the C results of the Walkley-Black and dry combustion methods, but a correction was suggested to be applied to C results of Walkley-Black (C = 1.05C W.Black + 0.47). A close correlation (R² > 0.96) was also found between results of Kjeldahl-N and dry combustion-N, but no correction was necessary to be applied. The relationships between results of Walkley-Black and dry combustion and between results of Kjeldahl and dry combustion did not change among soil samples from different management systems, in disagreement to findings of a previous study where results of analytical C recovery were influenced by samples from different managements, supposedly because changes in lability or recalcitrance of organic matter might have affected the wet combustion reactions. A poor correlation (R² = 0.42) was found between the C:N ratios based on Walkley-Black and Kjeldahl analysis and the C:N ratios based on dry combustion analysis. The methods for C and N determination did not affect the interpretation of the effects of management systems on soil C and N stocks.
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162007000500011
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| Editor: |
São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
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| Relação: |
10.1590/S0103-90162007000500011
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| Formato: |
text/html
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| Fonte: |
Scientia Agricola v.64 n.5 2007
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| Direitos: |
info:eu-repo/semantics/openAccess
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