02281nab a2200289 i 4500003000900000005001700009008004100026040001800067072000800085072000800093100002100101100003000122100003500152100002800187100003400215100003300249245012100282500007000403520116700473650000901640650001201649650002901661650001401690650002501704773018101729856008101910BR-BrBNA20260512150044.0260512b2020    bl.qr|pooa||| 00| 0 eng |  aBR-BrBNAbeng  aP32  aP33  aFontana, Ademir   aPereira, Marcos Gervasio   aBalieiro, Fabiano de Carvalho   aChagas, Cesar da Silva   aDonagemma, Guilherme Kangussu  aOliveira, Lucienne Silva de   aResistance of Soil Organic Matter in “Humic A Horizons” of the Mountainous Region in the State of Rio De Janeiro  aPublicação on-line; 36 ref.; 2 tables; 3 illus.; Summary (En)  a

ABSTRACT

Soils with high organic carbon content, such as those with “humic A horizon”, occur in different
regions of Brazil. This study aimed to determine the quantitative and qualitative characteristics
of organic matter regarding the humic A horizon under different land uses in Bom Jardim, in Rio
de Janeiro State, Brazil. Samples from forest, pasture, Eucalyptus plantation, coffee cultivation,
olericulture, and also passion fruit soils were sampled and analyzed. In October 2011, undisturbed
samples from humic A horizons, were collected for soil density analysis. In addition, disturbed
samples were collected for the determination of organic carbon (Corg) content, total carbon,
humic substance fractions contents and natural abundance of 13Carbon (δ13C). Low Corg contents
were observed in areas under olericulture, pasture and passion fruit cultivation. The fulvic acid
fraction was higher than other fractions, regardless of land use. The small variability in δ13C
indicated maintenance of original Corg and suggest high resistance of Soil Organic Matter in
humic A horizons.

Keywords: organic carbon, humic substances, isotopic composition.  aSOLO  aCARBONO  aCOMPOSIÇÃO QUÍMICA  aISÓTOPO  aMATÉRIA ORGÂNICA0 02929dRio de Janeiro-RJ Instituto de Florestas - UFRRJ 1994o2025-0455tFloresta e Ambiente (Brazil)x1415-0980  /  ISSN 2179-8087 0nlinegv. 27(1) p. 1-9; (2020)wBR2026001224  uhttps://www.scielo.br/j/floram/a/vSDStL9B9cWqvmH6yvFpGRM/?format=pdf&lang=en