Abstract. CO2 efflux has been measured in the development of a retrospective analysis of limestne quarries rehabilitation in Catalonia. Rehabilitation treatments have been grouped into different categories according to soil application, soil amendment, sowing and plantation. CO2 fluxes were usually below 1 g CO2 m-2 h-1. Our analysis shows that the type of rehabilitation treatment has a major importance in the recuperation of the soil biological activity. This was especially true when rainfall was low (below 525 mm y-1) and in soils with unbalanced textures. In these cases, there were not significant differences between soils where biosolids have been applied as organic amendment (1,127±0,227 g CO2 m-2 h-1) and reference undisturbed soils (1,071±0,130 g CO2 m-2 h-1). For organic amendment treatments, comparison between plots of different age suggests that the effect of the fresh organic matter addition on CO2 flux is not transient.
Key words: Biological activity, CO2 efflux, limestone quarries, soil restoration