Soil recovery at the Meirama opencast lignite mine in northwest Spain: A comparison of the effectiveness of cattle slurry and inorganic fertilizer

Abstract

Effective minesoil recovery requires spoils to be converted to soils of similar quality to those previously existing on that site. The developing minesoil should thus acquire three critical capacities, namely the capacities to a) support plant production, b) degrade organic matter and c) remove contaminants from water. The degree of development of these capacities provides a useful measure of soil quality and thus of the success of a given soil recovery technique. At the Meirama lignite mine in Galicia (northwest Spain), the possibility of using cattle slurry instead of the inorganic fertilizers currently used is being investigated. The results of a number of experiments suggest that cattle slurry is more effective (in terms of the above three critical capacities) than inorganic fertilizer. In slurry-fertilized spoils, rapid increases are observed in vegetation cover, in the relative abundance of self-seeded native plant species, in soil microbial activity and in those physical and chemical properties which affect infiltration and the capacity to remove contaminants from percolating water.