Resistance of soil organic matter in "humic A horizons" of the mountainous region in the state of Rio de Janeiro.

• Autor(a) principal: FONTANA, A.
• Data de Publicação: 2020
• Outros Autores: PEREIRA, M. G., BALIEIRO, F. de C., CHAGAS, C. da S., DONAGEMMA, G. K., OLIVEIRA, L. S de
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
• Texto Completo: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1121775; http://dx.doi.org/10.1590/2179-8087.009119
• topic: Carbono orgânico; Substâncias húmicas; Composição isotópica; Carbono; Horizonte; Soil organic carbon; Humic substances

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 (C-org) content, total carbon, humic substance fractions contents and natural abundance of (13)Carbon (delta C-13). Low C-org 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 delta C-13 indicated maintenance of original C-org and suggest high resistance of Soil Organic Matter in humic A horizons.