The soil unit was classified according to the legend of the FAO-Unesco soil map (1989).
Although a newer system is developed, called WRB (World Reference Base) it seems
adequate to use the older FAO system because it works well and the staff has during many
years experiences from the national soil survey. However, it should be stressed that the FAO
system is not the only used system within NAFRI. The MSEC programme use the Soil
Taxonomy System from USDA. There are advantages and disadvantages with both systems
but in general soils can be translated from one system into the other.