Geoscience Reference
In-Depth Information
Publius Vergilius Maro, also known as Virgil (70-19 BC), who wrote
two series of plays in verse: the Eclogues (42-39 BC) and the Georgics
(39-29 BC). After him, Lucius Iunius Moderatus Columella, also called
Columella (AD first century), authored De Re Rustica (Agriculture). Lastly,
Rutilius Taurus Aemilianus Palladius , usually called Palladius , wrote
a treatise on agriculture also titled De Re Rustica . The exact date is
unknown, but is estimated between AD 460 and 480. We give two
examples:
' All soils cannot bear all produce ' (Virgil).
' Here are some indicators by which we can identify that a soil is rich. If,
after wetting a small clod of that soil with soft water and kneading it by hand,
we note that it is sticky and that its parts are adhering to each other, that is a
definite proof that it contains richness in itself ' (Palladius).
Later on, farmers gave to their soils vernacular names that went back
to the toponymy of the country concerned. For example, the 'Aubues' in
France are bleached soils (Latin ' alba ' = 'white').
4.1.2 The Classification of Dokuchaev
For proposing a valid system of classification of soils, it is necessary to
have examined many soil profiles and then to have done a cartographic
exercise. But to make a correct map, we must have a proper system to
identify the soils found! In the early days of pedology, cartographic
studies and classification systems were developed together. The basic
impetus was given by Dokuchaev and his group, as we had indicated
in Chapter 1. The first classification of the master of pedology was
published in 1886 (USDA 1960). But its final version was to appear in
1900, to be presented in French in Paris on the occasion of the World
Fair (Table 4.1).
Table 4.1 The Dokuchaev classification presented at the World Fair in Paris
in 1900, reproduced verbatim. But the table has been trimmed of its right-hand
portion that presented the factors of soil formation in the different climatic zones
identified. Thus the table lacks the columns giving 'terrains' (parent material),
climate, vegetation, (soil) fauna and relief.
Zones
Soil types
Principal features and weathering processes
BOREAL ZONE
Tundra soils
Very weak weathering processes in general,
(brown)
especially lessivage. Great accumulation of
coarse, acid humus, chiefly in the sod horizon.
Permanently frozen soil below 50 or 100 cm.
Table 4.1 Contd...
 
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