Data/hora: 07/06/2024 16:05:13

Biblioteca(s): | Embrapa Solos.
Data corrente: | 09/12/2008
Data da última atualização: | 27/10/2021
Autoria: | SONG, G.; NOVOTNY, E. H.; SIMPSON, A. J.; CLAPP, C. E.; HAYES, M. H. B.
Afiliação: | G. SONG, University of Limerick; ETELVINO HENRIQUE NOVOTNY, CNPS; A. J. SIMPSON, University of Toronto; C. E. CLAPP, University of Minnesota; M. H. B. HAYES, University of Limerick.
Título: | Sequential exhaustive extraction of a Mollisol soil, and characterizations of humic components, including humin, by solid and solution state NMR.
Ano de publicação: | 2008
Fonte/Imprenta: | European Journal of Soil Science, Oxford, v. 59, n. 3, p. 505-516, Jun. 2008.
DOI: | https://doi.org/10.1111/j.1365-2389.2007.01006.x
Idioma: | Inglês
Conteúdo: | A comprehensive sequential extraction procedure was applied to isolate soil organic components using aqueous solvents at different pH values, base plus urea (base-urea), and finally dimethylsulfoxide (DMSO) plus concentrated H2SO4 (DMSO-acid) for the humin-enriched clay separates. The extracts from base-urea and DMSO-acid would be regarded as 'humin' in the classical definitions. The fractions isolated from aqueous base, base-urea and DMSO-acid were characterized by solid and solution state NMR spectroscopy. The base-urea solvent system isolated ca. 10% (by mass) additional humic substances. The combined base-urea and DMSO-acid solvents isolated ca. 93% of total organic carbon from the humin-enriched fine clay fraction (<2 ?m). Characterization of the humic fractions by solid-state NMR spectroscopy showed that oxidized char materials were concentrated in humic acids isolated at pH 7, and in the base-urea extract. Lignin-derived materials were in considerable abundance in the humic acids isolated at pH 12.6. Only very small amounts of char-derived structures were contained in the fulvic acids and fulvic acids-like material isolated from the base-urea solvent. After extraction with base-urea, the 0.5 m NaOH extract from the humin-enriched clay was predominantly composed of aliphatic hydrocarbon groups, and with lesser amounts of aromatic carbon (probably including some char material), and carbohydrates and peptides. From the combination of solid and solution-state NMR spectroscopy, it is clear that the major components of humin materials, from the DMSO-acid solvent, after the exhaustive extraction sequence, were composed of microbial and plant derived components, mainly long-chain aliphatic species (including fatty acids/ester, waxes, lipids and cuticular material), carbohydrate, peptides/proteins, lignin derivatives, lipoprotein and peptidoglycan (major structural components in bacteria cell walls). Black carbon or char materials were enriched in humic acids isolated at pH 7 and humic acids-like material isolated in the base-urea medium, indicating that urea can liberate char-derived material hydrogen bonded or trapped within the humin matrix.
Palavras-Chave: | Extração sequencial; Solo Mollisol; Substâncias húmicas.
Categoria do assunto: | P Recursos Naturais, Ciências Ambientais e da Terra
Registro original: | Embrapa Solos (CNPS)
Exemplares: | CNPS - (13576-1) - UPC - AP - DD -  -  - 2008.00056 - DIS