Cambic horizon (''Latin: Cambiare, to change'') is a diagnostic sub-surface

horizon The horizon is the apparent curve that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This curve divides all viewing directions based on whethe ...

of a soil experiencing pedogenic change. Development is minimal and it is cambic if it does not meet the Taxonomic requirements to classify in another

Properties

There are key characteristics that determine a layer of soils classification. Cambic horizons do not consist of appreciable illuviated material such as

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

organic carbon Total organic carbon (TOC) is an analytical parameter representing the concentration of organic carbon in a sample. TOC determinations are made in a variety of application areas. For example, TOC may be used as a non-specific indicator of wa ...

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

, and

aluminum Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

oxyhydroxides Iron(III) oxide-hydroxide or ferric oxyhydroxideA. L. Mackay (1960): "β-Ferric Oxyhydroxide". ''Mineralogical Magazine'' (''Journal of the Mineralogical Society''), volume 32, issue 250, pages 545-557. is the chemical compound of iron, oxygen, ...

carbonate A carbonate is a salt of carbonic acid, (), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group ...

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate Hydrate, dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk ...

, or

soluble salts In chemistry, a salt or ionic compound is a chemical compound consisting of an assembly of positively charged ions (cations) and negatively charged ions (anions), which results in a compound with no net electric charge (electrically neutral). T ...

. These horizons must have a non-sandy texture and occur in poorly drained soils. The particles size must be as finer or finer than

loamy Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–si ...

fine sand or very

fine sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural cl ...

Classification

Cambic horizons are found most in

Mollisols Mollisol is a soil type which has deep, high organic matter, nutrient-enriched surface soil (A horizon), typically between 60 and 80 cm (24-31 in) in depth. This fertile surface horizon, called a mollic epipedon, is the defining diagnosti ...

and

Inceptisols Inceptisols are a soil order in USDA soil taxonomy. They form quickly through alteration of parent material. They are more developed than Entisols. They have no accumulation of clays, iron oxide, aluminium oxide or organic matter. They have an ...

, but can also be found in

Andisols In USDA soil taxonomy, andisols are soils Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific defi ...

where its designation is Bw or Bg in all three. Cambic horizons are designated as Bss or Bssg in Vertisols and Bk in Cambids.

Formation

Cambic horizons form through the soil forming process called

pedogenesis Soil formation, also known as pedogenesis, is the process of soil genesis as regulated by the effects of place, environment, and history. Biogeochemical processes act to both create and destroy order (anisotropy) within soils. These alterations ...

. Influenced primarily by soil forming processes over time, it commonly forms below an albic horizon. It has less clay content than an argillic horizon but is still a visible layer. In the pedogenesis process under a

chronosequence A chronosequence describes a set of ecological sites that share similar attributes but represent different ages. A common assumption in establishing chronosequences is that no other variable besides age (such as various abiotic components and bio ...

, once the soil develops into an alfisol, the Cambic horizon will develop into an argillic (Bt) horizon. They are commonly classified in

floodplains A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high discharge.Goudie, ...

References

{{reflist Pedology