Resumen

CORTES, Helen E.; BALLESTEROS, María I.  y  ZAMUDIO, Adriana M.. OPTIMIZATION OF A METHODOLOGY FOR THE HUMIN EXTRACTION OF AN COLOMBIAN OXISOL. FRACTIONATION AND PHISICOCHEMICAL CHARACTERIZATION. Rev.Colomb.Quim. [online]. 2007, vol.36, n.3, pp.335-348. ISSN 0120-2804.

The colombian Amazonia is a natural reserve that needs to be conserved without change and organic matter is an important component of the soil for supplying nutrients to plants. The soil humin has been very little taken in to account in this ecosystem, however the humin role is considered to be very important in the soil dynamics, for this reason needs to be evaluated. The objective of this work, is considered the evaluation of the experimental conditions for the extraction and the fractionation of the humin of the A and BA horizons of an Oxisol of the Amazonia zone. This is related to the relation soil-extractant, number of extractions and the characterization of the fractions obtained by means of elemental analysis of C, H and N; E4/E6 relation and thermal differential analysis (TDA). It was found that the optimal conditions of extraction the relation soil-extractant 1:40 in the smaller soil fraction of 50 μm, the shaking time was one hour, with 4 successive extractions for the soil of the horizon A and a single one for the BA horizon, due to the high decrease on the of organic matter content. They were found lower nitrogen percentage and degree of aromaticity, with respect to humic acids. Nevertheless, when comparing the different fractions from humin, the insolubilization extractable humin and the humin bound to iron, showed greater degree of aromaticity and condensation that the insolubilization nonextractable humin. Respect to the thermal differential analysis (TDA), appreciable differences did not appear, all the fractions were more stable than humic acids, with a flat band between 490 °C and 600°C.

Palabras clave : Humic substances; humin; humin characterization; oxisol; TDA.

        · resumen en Español | Portugués     · texto en Español     · Español ( pdf )