Duplex soil
Encyclopedia
With the term “duplex soil”, Northcote defined a primary profile in his Factual Key classification. He described a group of texture contrast soils where the B horizon is dominated by a texture class one and a half (or more) finer than the A horizon. In addition, the clear to sharp change between the two horizons must occur within 0.1 m.
Texture
in duplex soils is highly variable, with the top-soils ranging from coarse sand to clay loam and the subsoils from light
to heavy clay
. Some duplex soils are distinguished by the presence of an A2 bleached horizon, a character also used as a diagnostic key for the distinction between these type of soil
s.
The diagnostic properties used by Northcote for the definition of duplex soils consider only the soil texture
(texture contrast and type of boundary between horizons A and B) and the colour is used for their differentiation (i.e. brown, red and yellow duplex soils). Under the Australian Soil Classification they can be included in different orders such as Podosols, Sodosol, Chromosols or Kurosols.
Texture
Texture
Texture may refer to:* Textures , album of Brian Eno* Textures , a metal band from the Netherlands* Texture , theoretical topological defect in the structure of spacetime...
in duplex soils is highly variable, with the top-soils ranging from coarse sand to clay loam and the subsoils from light
Light clay
Light clay is a natural building material used to infill between a wooden frame in a timber framed building using a combination of clay and straw, woodchips or some other lighter material....
to heavy clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
. Some duplex soils are distinguished by the presence of an A2 bleached horizon, a character also used as a diagnostic key for the distinction between these type of soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
s.
The diagnostic properties used by Northcote for the definition of duplex soils consider only the soil texture
Soil texture
Soil texture is a qualitative classification tool used in both the field and laboratory to determine classes for agricultural soils based on their physical texture. The classes are distinguished in the field by the 'textural feel' which can be further clarified by separating the relative...
(texture contrast and type of boundary between horizons A and B) and the colour is used for their differentiation (i.e. brown, red and yellow duplex soils). Under the Australian Soil Classification they can be included in different orders such as Podosols, Sodosol, Chromosols or Kurosols.