Agriculture Reference
In-Depth Information
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Lixic
intergrade with Lixisols
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Umbric
intergrade with Umbrisols
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Arenic
intergrade with Arenosols
Secondary characteristics qualiÝers directly related to diagnostic horizons, properties or
soil materials:
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Endostagnic
stagnic properties between 50 and 100 cm
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Humic
strongly humic properties
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Ferric
presence of a ferric horizon within 100 cm
Secondary characteristics qualiÝers not directly related to deÝned diagnostic horizons,
properties, or soil materials:
¤Vetic
ECEC
of less than 6 cmolc/kg
clay
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Alumic
Al saturation (ECEC) of 50% or more
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Hypereutric
Having a base saturation of 80% or more
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Hyperdystric
Having a base saturation of less than 50% in all parts between 20 and 100 cm
and less than 20% in some part
QualiÝers related to soil colors:
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Rhodic
ferralic horizon with hue redder than 5YR, etc
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Xanthic
ferralic horizon with hue of 7.5YR or yellower, etc.
ÑRemaining characteristicsÒ qualiÝer:
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Haplicother ferralic horizons
one would go down the list of qualiÝers and note that qualiÝer #2
applies. Therefore, the soil is classiÝed as a Geric Ferralsol. On the basis of available information
on clay distribution (clay increase meets minimum speciÝcations of an argic horizon) and base
saturation (less than 50% in at least part of the ferralic B horizon) that is available (qualiÝer #9),
one would further classify this soil as an Acri-Geric Ferralsol. If more than two qualiÝers apply,
these can be added between brackets behind the standard name. If, for instance, the Ferralsol
discussed also features strongly humic properties (qualiÝer #14) and a dark red color (qualiÝer
#20), the soil would be named an Acri-Geric Ferralsol (Humic, Rhodic).
In addition, the Soil Unit name might express the depth (from shallow to deep: Epi, Endo,
Bathi) and intensity (from weak to strong: Proto, Para, Hypo, Ortho, and Hyper) of features,
important for management interpretations. In poly-sequential soil proÝles, the qualiÝers Cumuli or
Thapto can be used to indicate accumulation or burial.
For each Reference Soil Group there is a deÝned list of qualiÝers available, with suggested
qualiÝer ranking. For a comprehensive discussion of qualiÝers, reference is made to the FAO World
Soil Resources Reports Number 84 (FAO et al., 1998). Note that the issue of qualiÝer ranking is
still a point of debate (Nachtergaele et al., 2001).
To classify a Ferralsol
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CORRELATION: THE WRB (1998) WITH USDA'S SOIL TAXONOMY (1999)
Table 19.6 correlates the WRB (1998) Reference Groups and Soil Orders/Suborders of Soil
Taxonomy (1999). The table demonstrates that international consensus on soil naming is growing;
near-perfect correlation exists for many groups such as Histosols, Vertisols, Andosols, and Podzols.
Evidently the match can only be partial for several reasons:
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