Over the years, there have been numerous attempts to give names
to soils and to group them into natural classes, in much the same
way as plants are named and classified. Classification is important
in order to allow comparison between the soils of different regions,
and to facilitate information transfer and organisation of the
growing knowledge about the main types of soil that occur around
The first true soil classification was produced in the second
half of the 19th century by Dokuchaiev in the USSR. Dokuchaiev
suggested a theory of ‘zonal soils’, where soil types
came from clearly defined geographical and climatic locations.
In 1953, Kubiena produced a system of classification that proved
to be popular and is still widely referred to. His system consisted
of 5 main soil groups (and many sub-groups), arranged according
to specific horizon classes, as well the type of 'humus' present.
Influenced by Kubiena’s ideas and other previous classifications,
two international soil classifications have been developed since
the 1960s, the American ‘7th Approximation’ classification
system published in 1960, and the Food and Agriculture Organisation
classification in the 1970s.
These have been many attempts to provide a unifying classification
as a basis for technology transfer, but this has been hindered
by the use of new, often complex terminology for describing soils.
For example, the American class names in their system include the
terms 'entisols', 'inceptisols', 'aridisols', 'mollisols', 'spodosols',
'alfisols', 'ultisols', 'oxisols' and 'histosols', which to the
layman may not mean very much! Although the American and FAO systems
are widely discussed and referred to, many countries still use
their own national classification systems by preference.
It is incredible to think that there is still so much that is
unknown about soil types, and that new discoveries are continuously
being made all the time. Unfortunately, there is still currently
no universal standard for soil classification, although the recent
World Reference Base (WRB) for soils may address this in the future.