Restauración de suelos de minacontribución a la fijación de carbono en el ecosistema terrestre

Abstract

The restoration and revegetation of minesoils contribute to the enhancement of organic matter in the soil and biomass, and leads to the fixation of atmospheric CO2 . One aim of this study was to evaluate the effects of reclamation treatments in the As Pontes lignite mine (NW Spain) on soil organic matter accumulation, and its particle-size distribution, between 1991 and 2001. In this period, soil organic carbon increased between 3 and 25 MgC/ha in soils with topsoiling treatment (TS) and between 10 and 35 MgC/ha in that without topsoiling (WTS). In TS soils organic matter accumulated mainly in the fine fractions (clay and silt) with a low C/N ratio, while a coarse organic fraction with high C/N ratio dominated the WTS soils. Nevertheless, the latter showed incorporation of the organic matter towards the fine fractions with age, reflecting an organic matter evolution towards more stable fractions. Additionally, the capacity of mine soils to act as sinks for carbon when planted with energetic crops was to evaluate. For this, an experiment was carried out on reclaimed soils whereby productivity and the amount of fixed C in the biomass and the soils was monitored over a period of 3 years. The experiment was carried out using different plant species (Ulex europaeus, Cytisus scoparius, Acacia dealbata, Acacia melanoxilon, Alnus glutinosa and Eucaliptus globulus) and several densities (2, 1 y 0.66 plants per m2 ). Preliminary results indicated that both species and density of plants had a significant effect on production and therefore C fixation in the soil and biomass.