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Vertisols of the world A more detailed map of the global distribution of Vertisols. A vertisol is a Soil Order in the USDA soil taxonomy [1] and a Reference Soil Group in the World Reference Base for Soil Resources (WRB). [2] It is also defined in many other soil classification systems. In the Australian Soil Classification it is called ...
Expansive clay, also called expansive soil, is a clay soil prone to large volume changes (swelling and shrinking) directly related to changes in water content. [1] Soils with a high content of expansive minerals can form deep cracks in drier seasons or years; such soils are called vertisols.
A typical phase diagram.The solid green line applies to most substances; the dashed green line gives the anomalous behavior of water. In thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium. [1]
Other soils which have a mollic epipedon are classified as Vertisols because high shrink swell characteristics and relatively high clay contents dominate over the mollic epipedon. These soils are especially common in parts of South America in the Paraná River basin receiving abundant but erratic rainfall and extensive deposition of clay -rich ...
The composition of Ultisol in North Carolina, for reference, is approximately 16% pore space, 2% organic matter and 82% mineral. [8] The use of mulch is widespread in the Piedmont region of the United States as a solution to the high temperatures and saturation of the soil. [9] The addition of mulch helps to make the soil more porous. [10]
The 2:1 layer (TOT) structure consists of two silica (SiO 2) tetrahedral (T) layers which are electrostatically cross-linked via an Al 2 O 3 , or Fe 2 O 3, octahedral (O) central layer. The TOT elementary layers are not rigidly connected to each other but are separated by a free space: the interlayer hosting hydrated cations and water molecules ...
In both the World Reference Base for Soil Resources (WRB) [1] and the USDA soil taxonomy, [2] a Histosol is a soil consisting primarily of organic materials. They are defined as having 40 centimetres (16 in) or more of organic soil material starting within 40 cm from the soil surface.
Gleysoils may be sticky and hard to work, especially where the gleying is caused by surface water held up on a slowly permeable layer. However, some ground-water gley soils have permeable lower horizons , including, for example, some sands in hollows within sand dune systems (known as slacks), and in some alluvial situations.