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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.
Water-reactive substances [1] are those that spontaneously undergo a chemical reaction with water, often noted as generating flammable gas. [2] Some are highly reducing in nature. [ 3 ] Notable examples include alkali metals , lithium through caesium , and alkaline earth metals , magnesium through barium .
Soils with this shrink-swell capacity fall under the soil order of Vertisols. [6] As these soils dry, deep cracks can form on the surface, which then allows water to penetrate to deeper levels of the soil. [7] This can cause the swelling of these soils to become cyclical, with periods of both shrinking and swelling.
ions) compensating the negative electrical charges of the TOT layers and with water molecules causing the interlayer expansion. The main cations in the smectite interlayers are Na + and Ca 2+. The sodium cations are responsible for the highest swelling of smectite while calcium ions have lower swelling properties. Calcium smectite has ...
A soil family category is a group of soils within a subgroup and describes the physical and chemical properties which affect the response of soil to agricultural management and engineering applications. The principal characteristics used to differentiate soil families include texture, mineralogy, pH, permeability, structure, consistency, the ...
Cation-exchange capacity (CEC) is a measure of how many cations can be retained on soil particle surfaces. [1] Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the surrounding soil water. [2]
Many dryland crops are grown on fluvisols, normally with some form of water control. On tropical Fluvisols with satisfactory irrigation and drainage paddy rice cultivation is widespread. Some coastal lowlands have fluvisols with sulphidic material within the profile (a thionic horizon).