Although there are good arguments to limit soil survey and mapping to identifiable
stable soil areas with a certain thickness, the WRB has taken the more comprehensive
approach to name any object forming part of the epiderm of the earth (Sokolov, 1997;
Nachtergaele, 2005). This approach has a number of advantages; notably that it allows
for the tackling environmental problems in a systematic and holistic way, and avoids
sterile discussion on a universally agreed definition of soil and its required thickness
and stability. Therefore, the object classified in the WRB is: any material within 2 m of
the Earth’s surface that is in contact with the atmosphere, excluding living organisms,
areas with continuous ice not covered by other material, and water bodies deeper than
2 m1. If explicitly stated, the object classified in the WRB includes layers deeper than
2 m