Soil organic matter molecular composition shifts driven by forest regrowth or pasture after slash-and-burn of Amazon Forest.

Slash-and-burn of Amazon Forest (AF) for pasture establishment has increased the occurrence of AF wildfires. Recent studies emphasize soil organic matter (SOM) molecular composition as a principal driver of post-fire forest regrowth and restoration of AF anti-wildfire ambience. Nevertheless, SOM chemical shifts caused by AF fires and post-fire vegetation are rarely investigated at a molecular level. We employed pyrolysis-gas chromatography-mass spectrometry to reveal molecular changes in SOM (0?10, 40?50 cm depth) of a slash-burn-and-20-month-regrowth AF (BAF) and a 23-year Brachiaria pasture post-AF fire (BRA) site compared to native AF (NAF). In BAF (0-10 cm), increased abundance of unspecific aromatic compounds (UACs), polycyclic aromatic hydrocarbons (PAHs) and lipids (Lip) coupled with a depletion of polysaccharides (Pol) revealed strong lingering effects of fire on SOM. This occurs despite fresh litter deposition on soil, suggesting SOM minimal recovery and toxicity to microorganisms. Accumulation of recalcitrant compounds and slow decomposition of fresh forest material may explain the higher carbon content in BAF (0?5 cm). In BRA, SOM was dominated by Brachiaria contributions. At 40?50 cm, alkyl and hydroaromatic compounds accumulated in BRA, whereas UACs accumulated in BAF. UACs and PAH compounds were abundant in NAF, possibly air-transported from BAF.

Bibliographic Details

Main Authors:	LEAL, O. dos A., JIMÉNEZ-MORILLO, N. T., GONZÁLEZ-PÉREZ, J. A., KNICKER, H., COSTA, F. de S., JIMÉNEZ-MORILLO, P. N., CARVALHO JUNIOR, J. A. de, SANTOS, J. C. dos, DICK, D. P.
Other Authors:	OTÁVIO DOS ANJOS LEAL, INSTITUTE OF BIO AND GESOCIENCE AGROSPHERE; NICASIO T. JIMÉNEZ-MORILLO, UNIVERSIDADE DE ÉVORA /I NSTITUTO DE RECURSOS NATURALES Y AGROBIOLOGÍA DE SEVILLA; JOSÉ A. GONZÁLEZ-PÉREZ, INSTITUTO DE RECURSOS NATURALES Y AGROBIOLOGÍA DE SEVILLA; HEIKE KNICKER, INSTITUTO DE RECURSOS NATURALES Y AGROBIOLOGÍA DE SEVILLA; FALBERNI DE SOUZA COSTA, CPAF-AC; PEDRO N. JIMÉNEZ-MORILLO, UNIVERSIDAD PABLO DE OLAVIDE; JOÃO ANDRADE DE CARVALHO JÚNIOR, UNIVERSIDADE ESTADUAL PAULISTA; JOSÉ CARLOS DOS SANTOS, INSTITUTO NACIONAL DE PESQUISAS ESPACIAIS; DEBORAH PINHEIRO DICK, UNIVESIDADE FEDERAL DO RIO GRANDE DO SUL.
Format:	Artigo de periódico biblioteca
Language:	Ingles English
Published:	2023-02-17
Subjects:	Derruba-e-queima, Slash-and-burn agriculture, Western Amazon, Asentamiento humano, Acrisoles, Regeneración natural, Materia orgánica del suelo, Pastizales, Química del suelo, Molecular composition, Composição molecular, Composición molecular, Nitroalkanes, Nitroalcanos, Van Krevelen 3D diagram, Analytical pyrolysis, Assentamento Santa Luzia (AC), Cruzeiro do Sul (AC), Acre, Amazônia Ocidental, Amazonia Occidental, Sistema de Cultivo, Cultivo Migratório, Regeneração Natural, Pastagem, Brachiaria, Química do Solo, Solo, Matéria Orgânica, Human settlements, Shifting cultivation, Acrisols, Natural regeneration, Soil organic matter, Pastures, Soil chemistry,
Online Access:	http://www.alice.cnptia.embrapa.br/alice/handle/doc/1151856 https://doi.org/10.3390/ijerph20043485
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