Abstract

LOPEZ-SALAZAR, Rubén et al. Humic and fulvic acid extraction method and characterization by infrared spectrophotometry. Rev. Mex. Cienc. Agríc [online]. 2014, vol.5, n.spe8, pp.1397-1407. ISSN 2007-0934.

Organic extracts are now widely accepted by farmers mainly because of cost and success of their applications in crops, in order to obtain an organic-mineral complex or humate as an alternative for efficient delivery of nutrients to crops, an organic fossil mineral was collected from a mine, humic acid (HA) and fulvic (FA) fractions were extracted in the laboratory. The pH of these acids was adjusted with chemical fertilizers. For humic and fulvic acids pH 6, 7, 8 and 4, 6, 7 was handled respectively and finally solidified. Functional groups of these acids were characterized by an infrared spectrometer (IR). Results show that humic and fulvic acids have similar functional groups but different amount, the organo-mineral mixture of HA and FA showed a similar behavior in adsorption of the added element, however both HA and FA at pH 7 showed the highest Ca and Fe adsorption, since they are pH dependent compounds and complex formation is due to the cation exchange reaction by free radicals.

Keywords : organic extracts; functional groups; organic-mineral.

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