Calcids are a

soil 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 definitions distinguish dirt from ''soil'' by re ...

suborder in the

USDA soil taxonomy USDA soil taxonomy (ST) developed by the United States Department of Agriculture and the National Cooperative Soil Survey provides an elaborate Soil classification, classification of soil types according to several parameters (most commonly their p ...

. They are aridisols that have accumulated high levels of residual or dryfall

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

Background

Calcids have a calcic or petrocalcic horizon and have carbonated materials in any above layers. The parent materials are high in content of carbonate, or carbonates were added as dust, or both.

Precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...

has been insufficient to remove the carbonates or even move them to great depths. These soils are often found in the western states of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. Most areas are used as rangeland or wildlife habitat. Some are used as irrigated cropland.

Aridisols Aridisols (or desert soils) are a soil order in USDA soil taxonomy. Aridisols (from the Latin ''aridus'', for "dry", and ''solum'') form in an arid or semi-arid climate. Aridisols dominate the deserts and xeric shrublands, which occupy about on ...

are CaCO₃ containing soils of arid regions that exhibit at least some sub-surface horizon development. They are characterized by being dry most of the year, and exhibit limited leaching. Aridisols contain sub-surface horizon in which

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 ...

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...

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). ...

, and CaCO₃ tend to be leached from soils of moister climates. Land dominated by Aridisols are used mainly for range,

wildlife Wildlife refers to domestication, undomesticated animals and uncultivated plant species which can exist in their natural habitat, but has come to include all organisms that grow or live wilderness, wild in an area without being species, introdu ...

, and recreation. Because of the dry climate in which they are found, they are not used for agricultural production unless irrigation water is available. Aridisols are divided into 8 suborders: Cryids, Salids, Durids, Gypsids, Argids, Calcids, Orthids and Cambids.

Chemical nature of calcid

Calcids have the extent of calcium carbonate so they can also known as

calcareous soil Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an adje ...

or calcisols. Due to high calcium content, coarse texture, undulating surface, and even due to unsuitable climate, calcids are not suitable for fruit tree and crop cultivation. So, if these kinds of soils are irrigated and cultivated then micronutrient deficiency is normal. However, fine, loamy, textured calcids are good for agriculture.

Other locations of Calcid

These soils are often found in semi-humid to semi-arid regions. Therefore, about 7.89% of

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

is calcidic soil. Similarly, Calcidic content can be also found in the soils of

Rajasthan Rajasthan (; Literal translation, lit. 'Land of Kings') is a States and union territories of India, state in northwestern India. It covers or 10.4 per cent of India's total geographical area. It is the List of states and union territories of ...

(India).

Classification of calcid

There are different forms of calcids- * Salicalcids * Gypsicalcids
Petrocalcids
* Hypercalcids
Haplocalcids.
Out of all the calcids, haplocalcids contain various calcitic pro features.

Horizons

In terms of horizons, Calcids have a calcic
hypercalcic
or petrocalcic horizon with its/their upper boundary within 1.0 m of the soil surface. Within 0.75- 1m of the upper boundaries, calcids soils have n
gypsic
hypergypsic o
petrogypsic
or salic horizon.

Reaction with other components

Different kinds of fertilizers and compost can be used to modify the properties of calcidic soils. * Sulfur compost enhances the chemical properties for example- CEC, OM, and available micro and micronutrients, and increases the productivity of calcareous soil. * In contrast,

biochar Biochar is a form of charcoal, sometimes modified, that is intended for organic use, as in soil. It is the lightweight black remnants remaining after the pyrolysis of biomass, consisting of carbon and ashes. Despite its name, biochar is steril ...

s even worsen the properties and productivity of calcids by increasing pH, and hence limiting crop productivity.

References

{{reflist Types of soil