02150nam a2200277 a 450000100080000000500110000800800410001910000160006024501190007626002140019530000090040952011950041865000260161365000220163965000230166165000170168465300090170165300240171065300240173465300200175870000160177870000200179470000200181470000160183470000220185020559472023-11-16       2016    bl uuuu     u00u1 u    #d1 aLIMA, M. O.  aBurning of tropical brazilian rainforest of sandy soilbdoes it affect soil organic matter?h[electronic resource]  aIn: INTERNATIONAL CONFERENCE OF INTERNATIONAL HUMIC SUBSTANCES SOCIETY, 18., 2016, Kanazawa. Keystone for future Earth: Natural Organic Matter (NOM) in diverse environments: proceedings... Kanazawa: IHSSc2016  a2 p.  aThis study aimed to investigate the impact of vegetation burning on the content and chemical composition of soil organic matter (SOM) along a profile of a sandy Acrisol in Southwestern Amazon, Brazil, within 3 years after experiment beginning(YAB).The study was performed in Rio Branco, Acre State, and the forest burning was performed under controlled conditions. Samples from 6 depth(0-100cm depth)were collected under burned forest (BF) and primary forest (PF) at 1 YAB and 3 YAB. Besides Cand N contents, humic substances and biomarkers were determined. Under PF, the C content decreased with depth from 12 to 2 g kg-1.C/N ratio ranged from 7.6 at the surface to values around 3 at 1 m depth, indicating a predominance of microbial products. Humin fraction was not detected in the whole profile. Burning of vegetation promoted an increase of C and of humic acids only at 0-5 cm. The n-alkane distribution showed a shift towards smaller chains in the 0-5 cm of BF, indicating main contribution of microbial products. Also PAH?s of high molecular weight were detected in this site. Vegetation burning imparts alterations on the SOM composition, but these tend to disappear within 3 years.  aComposição Química  aFloresta Tropical  aMatéria Orgânica  aSolo Arenoso  aAcre  aAmazônia Ocidental  aQueimada controlada  aRio Branco (AC)1 aDICK, D. P.1 aCOSTA, F. de S.1 aCOSTA, J. B. da1 aLARA, L. Z.1 aPERALBA, M. do C.