SciELO - Scientific Electronic Library Online

 
vol.32 número3Adsorção de selênio em latossolosFrações da matéria orgânica do solo após três décadas de cultivo de eucalipto no Vale do Rio Doce-MG índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados

Journal

Artigo

Indicadores

Links relacionados

Compartilhar


Revista Brasileira de Ciência do Solo

versão On-line ISSN 1806-9657

Resumo

BALDOTTO, Marihus Altoé et al. Redox properties of humic acids isolated from a soil Under long-term sugarcane cultivation. Rev. Bras. Ciênc. Solo [online]. 2008, vol.32, n.3, pp.1043-1052. ISSN 1806-9657.  http://dx.doi.org/10.1590/S0100-06832008000300013.

Soil organic matter is the largest carbon reservoir in natural systems. In such systems the carbon quality and stability can be estimated based on the increase of humified fractions which, among other factors, is related to the balance between losses and accumulations involving oxidation and reduction reactions of the soil organic matter. The objective of this study was to evaluate the electrochemistry of humic acids isolated from soils cultivated continually with sugar-cane, with or without pre-harvest burning and annual vinasse application using iodimetric redox titrations. The formal electrode potentials of the humic acids had a similar pattern, with values between 0.760 and 0.779 V, at 25 ºC. The oxidation capacity of humic acids varied from 1.01 to 3.44 molc kg-1 at pH 5.0 and from 1.64 to 6.44 molc kg-1 at pH 7.0. Positive and significant correlations were observed between the oxidation capacity and the humic acid contents of phenolic, quinone and semiquinone functional groups.

Palavras-chave : soil chemistry; humic substances; redox potential; oxidation capacity; humification degree.

        · resumo em Português     · texto em Português     · Português ( pdf )

 

Creative Commons License Todo o conteúdo deste periódico, exceto onde está identificado, está licenciado sob uma Licença Creative Commons