Only the C content of the dominant soils (SEQ = 1 in the data
base query) has been considered to build the map in Fig. 2. The composed
topsoil OC map has been drawn using Surfer Demo SW V9 by
overlapping the different carbon layers taken from the FAO database.
Additionally, soil OC data from topsoils and subsoils were analysed
using ANOVA, for each soil group.