| Texto completo | |
| Autor(es): |
Ruiz, Francisco
;
Rumpel, Cornelia
;
Dignac, Marie-France
;
Baudin, Francois
;
Ferreira, Tiago Osorio
Número total de Autores: 5
|
| Tipo de documento: | Artigo Científico |
| Fonte: | SOIL BIOLOGY & BIOCHEMISTRY; v. 187, p. 12-pg., 2023-10-27. |
| Resumo | |
In this study, we combined Rock-Eval (R) analysis, analytical pyrolysis, and wet-chemical extractions, assisted by Fourier transform infrared spectroscopy (FTIR), and measurements of soil heterotrophic respiration. Our objective was to assess the biological and thermal stability of mixed-nature soil organic matter (SOM) derived from grass litter and kerogen. We studied a Technosol constructed with Ca, Mg and kerogen-rich waste rock (black shales), which has been under pasture cultivation for 20 years. We compared the results with those from black shales and an adjacent natural soil under long-term pasture cultivation, both used as endmembers representing kerogen and plant-derived SOM, respectively. Analytical pyrolysis and FTIR analyses revealed a mixed composition of SOM in the Technosol. Predominantly, polysaccharides, lignin, lipids and N-compounds were originated from plant-derived SOM, while (poly)aromatic and most aliphatic compounds were traced back to kerogen. Rock-Eval analysis showed that 58% of SOM in Technosol was kerogen-derived, which was poorly accessible to soil microbiota, as evidenced by heterotrophic respiration. In addition, an important portion of plant-derived SOM (>70%) was only released during the Rock-Eval oxidation stage. The impact of chemical recalcitrance of kerogen compounds on short-term biological stability was remarkable and demonstrated a strong correlation with the thermal indices derived from the Rock-Eval pyrolysis stage. Conversely, the parameters from Rock-Eval oxidation stage showed a positive correlation with the amount of SOM involved in mineral-organic associations, particularly with Ca2+ and Mg2+ (i.e., cation bridging). Thus, to disentangle the contribution of chemical recalcitrance and mineral-organic associations to SOM stability, we recommend the assessment of all Rock-Eval thermograms (from pyrolysis and oxidation stages) in combination with chemical and biological assessments, especially when studying soils containing mixed-nature SOM. (AU) | |
| Processo FAPESP: | 19/18324-3 - Qualidade do solo e estabilização da matéria orgânica em tecnossolos construídos com rejeitos de mineração de calcário |
| Beneficiário: | Francisco Ruiz |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |
| Processo FAPESP: | 21/10382-4 - Interações organo-minerais em pedogênese incipiente: um estudo de caso com Tecnossolo |
| Beneficiário: | Francisco Ruiz |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Doutorado |