Agriculture Reference
In-Depth Information
Table 9.5 (continued)
Examples of Special-purpose Soil Classification Systems in Australia
Practical issue
(Classification/Soil Classes)
Reference
(Section in Text)
Soil and Other Attributes Used
Urban planning.
Soil properties: depth, permeability, shrink-swell
potential, Gilgai, bearing strength, drainage
properties, erodibility, salinity, and pH.
Terrain properties: mass movement, watertables,
subsidence and flooding.
Hicks and Hird (2002)
Capability, limitations. (5
primary classes, and several
subclasses).
Urban planning
.
Similar to above
Sheard and Bowman
(1996)
Soil sampling medium for
mineral exploration
Saline seepages, acid sulfate soils (ASS), iron- and
aluminium-rich precipitates, sulfidic material,
mottles in sulfuric horizons, salinity, pH,
geochemical analyses.
Skwarnecki et al. (2002)
. (6 soil
classes or materials).
(1995). The formation of minesoils has proceeded in response to varying times of exposure (i.e.,
ranging from days to up to 20 years) of the materials to the surface weathering environment, and to
varying rates of weathering depending on the nature of the rock types, in climates ranging from
tropical to arid and Mediterranean. This information, together with proposed amendments to Soil
Taxonomy (Smith and Sobek, 1978; Fanning and Fanning, 1989), has been used to develop preliminary
proposals to modify both the Australian Soil ClassiÝcation (Isbell, 1996) and Soil Taxonomy (Soil
Survey Staff, 1999).
Minesoils generally have high contents of weathered rock fragments (ranging from 10% to
>30%), a thin friable vesicular surface crust (5 to 10 mm), very weakly developed A and B
horizons (100 mm thick and usually at depths of 50 to 500 mm) with silty-sandy-clay loam to
silty light clay textures and saline to sodic properties. The following four broad categories of
minesoils have been identiÝed: lithosolic minesoils with minimal pedogenic development,
stony/gravelly lags, vesicular crusts, and weak development of B horizons (e.g., Lithic and
Typic Ustispolents/Xerispolents); polysequal soils indicative of erosion events (e.g., Fluventic
and Aeric Ustispolents/Xerispolents); acid sulfate soils characteristic of waterlogged situations
(e.g., SulÝc Spolaquents and SulÝc Ustispolents); and soils characteristic of seasonally water-
logged situations (e.g., Aquic Ustispolents). Major factors that inÞuence the use of minesoils
in rehabilitation strategies are stoniness, impermeable crust formation, and acid sulfate, saline,
or sodic conditions.
ClassiÝcation of the different types of minesoils using the proposed amendments to Soil
Taxonomy has been undertaken (Fitzpatrick and Hollingsworth, 1995). As a result, suggestions for
updating the classiÝcation of minesoils at subgroup level (Spolic, Anthromorphic Anthroposols) in
the Australian Soil ClassiÝcation (Isbell, 1996) have also been generated. This information can be
used as the basis to construct a user-friendly technical soil classiÝcation for mine-site rehabilitation.
The classiÝcation so proposed can include management-related properties.
Saline Soils
Several workers (e.g., Williams and Bullock, 1989) have attempted to categorize the wide range
of dryland saline soils using hydrology (presence or absence of groundwater) and water status
(natural or primary as opposed to induced or secondary status). Based on the Williams and Bullock
(1989) system and newly acquired morphological, hydrological, and chemical information about
saline soil-landscapes across Australia, a new classiÝcation has been developed to categorize saline
soils using hydrological, soil water, and soil chemical status (sodicity or type of soluble salt)
(Fitzpatrick et al., 2001; Tables 9.5 and 9.6). The important soil chemical features are halitic (sodium
chloride dominant), gypsic (gypsum or calcium sulfate dominant), sulÝdic (pyrite dominant),
sulfuric (sulfuric acid dominant), and sodic (high exchangeable sodium on clay surfaces). Most of
these terms are deÝned in Isbell (1996). Current general-purpose classiÝcation systems (e.g., Isbell,
