Characterization of the edaphic properties in a chronosequence of land rehabilitation, Cerrejón mine, La Guajira, Colombia

Abstract

Carbones del Cerrejon Limited, a coal mining company located in the department of La Guajira, Colombia for more than 25 years has implemented the process of rehabilitating land used for mining once the operations are concluded, closing the mining cycle. The main objective was to characterize the edaphic properties in a chronosequence of land rehabilitation (0, 5, 10, 15, 20 years) and the control. Soil sampling was performed at depths of 0-3, 8-11, 16-19 and 24-27cm; with the following physical properties (bulk density, fine granulometry) and chemical properties (pH, electric conductivity, organic carbon, cationic exchange capacity, Phosphorus, interchangeable cations), following the Agustin Codazzi Geographic Institute protocols. The results indicated that there are significant differences in the behavior of all edaphic parameters except Electric Conductivity. Additionally, it was found that most of the evaluated properties, after 20 years ago, presents conditions close to those of areas not intervened by the mining, giving indications of stability and new pedogenesis, that during the first years of rehabilitation was not possible to detect because of its high variability in the soil layer applied on the sterile rock dump (30cm). Based on this, we conclude that the properties of the rehabilitated soils under the model implemented, in semi-arid environmental conditions and without anthropic pressure, give indications of progressive evolution with similar quality to the undisturbed soils in the area.