Data/hora: 08/06/2024 05:32:30

Biblioteca(s): | Embrapa Solos.
Data corrente: | 29/11/2020
Data da última atualização: | 11/02/2021
Autoria: | SONG, G.; HAYES, M. H. B.; NOVOTNY, E. H.
Afiliação: | GUIXUE SONG, SHANDONG UNIVERSITY; MICHAEL H. B. HAYES, UNIVERSITY OF LIMERICK; ETELVINO HENRIQUE NOVOTNY, CNPS.
Título: | A two-year incubation study of transformations of crop residues into soil organic matter (SOM) and a procedure for the sequential isolation and the fractionation of components of SOM.
Ano de publicação: | 2021
Fonte/Imprenta: | Science of the Total Environment, v. 763, 143034, Apr. 2021.
DOI: | https://doi.org/10.1016/j.scitotenv.2020.143034
Idioma: | Inglês
Conteúdo: | Maize (Zea mays) stover, with its natural C-13 abundance, was incubated for two years in a gravelly brown earth sandy loam soil that had been under long term cultivation to wheat (Triticum aestivum) for more than 30 years. The relative abundances of C-13 in the maize amendment allowed the contributions of the stover to be traced in the components of soil organic matter (SOM) isolated and fractionated using a sequential exhaustive extraction (SEE) process that gave 16 distinct fractions. These were caracterised using elemental, delta C-13, FTIR, and C-13 NMR analyses. Emphasis is placed on results for two years of incubation but to some extent data are compared with those for similar fractions taken after one year of incubation. Amounts of maize-derived organic carbon in the humic (HA) and fulvic (FA) isolates were more than twice those in the fractions after one year of incubation. The NMR results highlighted compositional differences between the fractions and showed increased contributions of lignin to the HAs and FAs (and especially in the cases of the HAs) as pH increased, and it was evident that humification was taking place after two years of incubation. The most recalcitrant humin fraction, isolated in the final solvent in the sequence, dimethylsulphoxide (DMSO) and sulfuric acid, is composed predominantly of methylene moieties, is compositionally and structurally very different from the humic and hydrophilic isolates, but identical to that which did not dissolve in the solvent. That suggests that exhaustively pre-extracting soil with the NaOH/urea solvent system used will allow a truly representative humin to be obtained using the DMSO/acid solvent system.
Palavras-Chave: | FTIR; NMR.
Thesagro: | Extração; Matéria Orgânica; Solo.
Thesaurus Nal: | Humification; Humin; Soil organic matter.
Categoria do assunto: | P Recursos Naturais, Ciências Ambientais e da Terra
Registro original: | Embrapa Solos (CNPS)
Exemplares: | CNPS - (20556-1) - UPC - AP - DD -  -  -  - DIS