03468naa a2200673 a 450000100080000000500110000800800410001902200460006002400480010610000200015424501520017426000090032652013870033565000130172265000220173565000250175765000130178265000250179565000190182065000240183965000150186365000240187865000230190265000130192565000210193865000260195965000230198565000090200865300090201765300140202665300240204065300240206465300250208865300240211365300340213765300270217165300270219865300250222565300210225065300320227165300260230365300170232965300170234665300150236365300230237865300260240165300310242765300280245865300190248670000280250570000280253370000160256170000200257770000280259770000300262570000220265570000160267777301010269321518562023-05-17       2023    bl uuuu     u00u1 u    #d  a1661-7827 (impresso) / 1660-4601 (online)7 ahttps://doi.org/10.3390/ijerph200434852DOI1 aLEAL, O. dos A.  aSoil organic matter molecular composition shifts driven by forest regrowth or pasture after slash-and-burn of Amazon Forest.h[electronic resource]  c2023  aSlash-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.  aAcrisols  aHuman settlements  aNatural regeneration  aPastures  aShifting cultivation  aSoil chemistry  aSoil organic matter  aBrachiaria  aCultivo Migratório  aMatéria Orgânica  aPastagem  aQuímica do Solo  aRegeneração Natural  aSistema de Cultivo  aSolo  aAcre  aAcrisoles  aAmazonia Occidental  aAmazônia Ocidental  aAnalytical pyrolysis  aAsentamiento humano  aAssentamento Santa Luzia (AC)  aComposição molecular  aComposición molecular  aCruzeiro do Sul (AC)  aDerruba-e-queima  aMateria orgánica del suelo  aMolecular composition  aNitroalcanos  aNitroalkanes  aPastizales  aQuímica del suelo  aRegeneración natural  aSlash-and-burn agriculture  aVan Krevelen 3D diagram  aWestern Amazon1 aJIMÉNEZ-MORILLO, N. T.1 aGONZÁLEZ-PÉREZ, J. A.1 aKNICKER, H.1 aCOSTA, F. de S.1 aJIMÉNEZ-MORILLO, P. N.1 aCARVALHO JUNIOR, J. A. de1 aSANTOS, J. C. dos1 aDICK, D. P.  tInternational Journal of Environmental Research and Public Healthgv. 20, n. 4, 3485, Feb. 2023.