Agriculture Reference
In-Depth Information
It should be noted that although the information is collected according to the same SOTER
methodology, the speciÝc level of information in each region results in a variable scale of the
end products presented. The soils and terrain database for northeastern Africa, for instance,
contains information at equivalent scales between 1:1 million and 1:2 million, but the soil
proÝle information is not fully georeferenced (reference is done by polygon or mapping unit,
not by latitude and longitude). The same will be true for the soil proÝle information to be
provided by ESB for the European Community, to be released as a SOTER database at 1:5
M. For north and central Eurasia, proÝle information contained in the CD-ROM is very limited.
Fully comprehensive SOTER information is available for South and Central America and the
Caribbean (1:5 M scale), and includes more than 1800 georeferenced soil proÝles. Data are
available from
http://www.isric.nl/SOTER/LACData.zip
and viewable using a viewer program
at
. For Central and Eastern Europe (1:2.5 M scale),
this SOTER database contains more than 600 georeferenced soil proÝles and the results are
also available on CD-ROM (URL:
http://www.isric.nl/SOTER/Viewer102b.exe)
.
Notable gaps in harmonized soil information occur in southern and eastern Asia and in western
and northern Africa. Northern America and Australia are expected to join the program (Figure 12.1).
The effort to harmonize these various formats in a global SOTER product should not be underes-
timated.
It should also be noted that the SOTER methodology and manual are in need of a thorough
review, given the recent developments in remotely sensed technologies and the availability of
high-resolution digital elevation models, which should permit reÝnements and automation of the
physiographic terrain units to be introduced. It has also been recommended that WRB become the
standard classiÝcation to be used for the soil proÝles stored in SOTER, instead of the FAO revised
legend.
Finally, attention should be drawn to the fact that SOTER is not a methodology to carry out
soil surveys or to produce maps, but is in essence a relational database storing, in a systematic
way, related physiographic and soil information. This reÞects the modern practice of digital storage
of existing soil information. On the other hand, when soil information is incomplete or inexistent,
the difÝculties of creating SOTER databases should not be underestimated.
http://www.fao.org/catalog/book_review/giii/x8322-e.htm)
DEVELOPMENT OF THE FAO LEGEND
The FAO Legend (FAO/UNESCO, 1974) for the Soil Map of the World had the following
characteristics:
It was largely based on the diagnostic horizon approach developed under Soil Taxonomy (Soil
Survey Staff, 1960) by the USDA during the 1950s and 1960s. Similar horizons were deÝned, and
where deÝnitions of the diagnostic horizons were slightly simpliÝed, different names were used
for comparable horizons such as the ferralic horizon equivalent to the oxic horizon, or the argic
horizon equivalent to the argillic horizon in Soil Taxonomy.
As the Legend was the outcome of a vast international collaboration of soil scientists, it was
by necessity a compromise. Certain historical soil names were retained to accommodate some
national sensitivities. Examples of these at the highest level were RendzinaÔs, Solonetzes, Solon-
chaks, and Chernozems. Some of the names had a dubious scientiÝc connotation (such as the
Podzoluvisols in which no Podzolization takes place), while others were nearly identical as those
developed in Soil Taxonomy, such as the Vertisols.
In contrast with Soil Taxonomy, climatic characteristics were not retained in the FAO Legend,
although the Xerosols and Yermosols largely coincided with soils developed under an aridic
moisture regime.
The FAO Legend of 1974 recognized 26 Great Soil Groups subdivided in 106 Soil Units, which
were the lowest category recognized on the world soil map. In addition, twelve soil phases were
