Agriculture Reference
In-Depth Information
Table 19.6
Correlation between WRB (1998) and Soil Taxonomy (1999)
WRB
Soil Taxonomy
Histosols
Cryosols
Anthrosols
Leptosols
Ver tisols
Fluvisols
Solonchaks
Gleysols
Andosols
Podzols
Plinthosols
Ferralsols
Solonetz
Planosols
Chernozems
Kastanozems
Phaeozems
Gypsisols
Durisols
Calcisols
Albeluvisols
Alisols
Nitisols
Acrisols
Luvisols
Lixisols
Umbrisols
Cambisols
Arenosols
Regosols
Histosols pp
*
*
.
Gelisols pp.
Inceptisols pp., Plaggepts
Entisols, Lithic subgroups pp.
Ver tisols
Entisols - Fluvents
Aridisols - Salorthids pp.
Inceptisols - Aquepts pp., Entisols - Aquents pp.
Andisols
Spodosols
Oxisols - Plinthaquox pp.
Oxisols pp.
Aridisols - Natrargids pp.
Alfisols - Abruptic Albaqualf pp., Ultisols - Abruptic Albaquults pp.
Mollisols - Borolls pp.
Mollisols - Ustolls, Xerolls pp.
Mollisols - Udolls pp.
Aridisols - Gypsids pp.
Aridisols - Durids pp.
Aridisols - Calcids pp.
Alfisols - Fraglossudalfs
Ultisols - Udults pp.
Oxisols - Kandiudox pp., Ultisols - Kandiudults pp.
Ultisols - Udults, Ustults, Haplustalfs pp.
Alfisols pp.
Alfisols - Paleustalfs, Ustalfs, Udalfs, Ustalfs pp.
Inceptisols pp.
Inceptisols pp.
Entisols - Psamments pp.
Entisols pp.
* pp. =
pro parte
¤
In Soil Taxonomy, climatic factors are used to differentiate at Soil Order level (e.g., Gelisols,
Aridisols) as indicated by Ópp.Ô (pro parte) in Table 19.6. WRB avoids climatic criteria and argues
that an overlay with precise climatic information (as result of modelling) may result in a more
accurate analysis for the purpose of land evaluation.
¤
Another reason for the less than complete match between Soil Taxonomy and the WRB is that the
WRB distinguishes 30 Reference Soil Groups at the highest categorical level, whereas Soil
Taxonomy differentiates between 12 Soil Orders. For instance, the Mollisols of Soil Taxonomy
cover the WRB Reference Soil Groups of the Chernozems, Kastanozems, and Phaeozems.
¤
WRB uses only two categorical levels, whereas Soil Taxonomy comprises six levels.
¤
WRB uses more diagnostic horizons, properties, and materials than does Soil Taxonomy.
¤
Though there is great similarity between names of diagnostic horizons in Soil Taxonomy and
WRB, the differences in deÝnition are sometimes large (e.g., argic and salic horizons). WRB has
made a special effort to simplify analytical requirements to classify soils. It should also be noted
that WRB recognizes at the highest level processes such as prolonged hydromorphy or intense
man-made changes, whereas these are recognized at the second level only in Soil Taxonomy.
THE RANKING OF WRB QUALIFIERS
A rather comprehensive list of lower level names for the World Reference Base has been arrived
at after reviewing the uses that have been made of a second level by FAO (1988), Soil Survey Staff
(1999), and WRB (ISSS-ISRIC-FAO, 1994), and at the third level in soil classiÝcations of Botswana
(Remmelzwaal and Verbeek, 1990), northeastern Africa (FAO, 1998), Bangladesh (Brammer et al,
1988), and the European Union (CEC, 1985), and by reclassifying a large number of typifying
