 | This article may be confusing or unclear to readers.(October 2009) |
Calcids are a soil suborder in the USDA soil taxonomy. [1] They are aridisols that have accumulated high levels of residual or dryfall calcium carbonate. [2]
| This article may be confusing or unclear to readers.(October 2009) |
Calcids are a soil suborder in the USDA soil taxonomy. [1] They are aridisols that have accumulated high levels of residual or dryfall calcium carbonate. [2]
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 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. Most areas are used as rangeland or wildlife habitat. Some are used as irrigated cropland.
Aridisols 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 clays, calcium carbonate, silica, salts, and CaCO3 tend to be leached from soils of moister climates. Land dominated by Aridisols are used mainly for range, wildlife, 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. [3] [4]
Calcids have the extent of calcium carbonate so they can also known as calcareous soil 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. [5]
These soils are often found in semi-humid to semi-arid regions. Therefore, about 7.89% of Iran is calcidic soil. [7]
Similarly, Calcidic content can be also found in the soils of Rajasthan (India). [8]
There are different forms of calcids-
Out of all the calcids, haplocalcids contain various calcitic pro features. [9]
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. [9]
Within 0.75- 1m of the upper boundaries, calcids soils have no gypsic, hypergypsic or petrogypsic, or salic horizon. [9]
Different kinds of fertilizers and compost can be used to modify the properties of calcidic soils.
A speleothem is a geological formation by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, depending on their depositional history and environment. Their chemical composition, gradual growth, and preservation in caves make them useful paleoclimatic proxies.
Aridisols are a soil order in USDA soil taxonomy. Aridisols form in an arid or semi-arid climate. Aridisols dominate the deserts and xeric shrublands, which occupy about one third of the Earth's land surface. Aridisols have a very low concentration of organic matter, reflecting the paucity of vegetative production on these dry soils. Water deficiency is the major defining characteristic of Aridisols. Also required is sufficient age to exhibit subsoil weathering and development. Limited leaching in aridisols often results in one or more subsurface soil horizons in which suspended or dissolved minerals have been deposited: silicate clays, sodium, calcium carbonate, gypsum or soluble salts. These subsoil horizons can also be cemented by carbonates, gypsum or silica. Accumulation of salts on the surface can result in salinization.
USDA soil taxonomy (ST) developed by the United States Department of Agriculture and the National Cooperative Soil Survey provides an elaborate classification of soil types according to several parameters and in several levels: Order, Suborder, Great Group, Subgroup, Family, and Series. The classification was originally developed by Guy Donald Smith, former director of the U.S. Department of Agriculture's soil survey investigations.
Alfisols are a soil order in USDA soil taxonomy. Alfisols form in semi-arid to humid areas, typically under a hardwood forest cover. They have a clay-enriched subsoil and relatively high native fertility. "Alf" refers to aluminium (Al) and iron (Fe). Because of their productivity and abundance, Alfisols represent one of the more important soil orders for food and fiber production. They are widely used both in agriculture and forestry, and are generally easier to keep fertile than other humid-climate soils, though those in Australia and Africa are still very deficient in nitrogen and available phosphorus. Those in monsoonal tropical regions, however, have a tendency to acidify when heavily cultivated, especially when nitrogenous fertilizers are used.
A soil horizon is a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath. Horizons are defined in many cases by obvious physical features, mainly colour and texture. These may be described both in absolute terms and in terms relative to the surrounding material, i.e. 'coarser' or 'sandier' than the horizons above and below.
In geoscience, paleosol is an ancient soil that formed in the past. The definition of the term in geology and paleontology is slightly different from its use in soil science.
Caliche - - is a sedimentary rock, a hardened natural cement of calcium carbonate that binds other materials—such as gravel, sand, clay, and silt. It occurs worldwide, in aridisol and mollisol soil orders—generally in arid or semiarid regions, including in central and western Australia, in the Kalahari Desert, in the High Plains of the western United States, in the Sonoran Desert, Chihuahuan Desert and Mojave Desert of North America, and in eastern Saudi Arabia at Al-Hasa. Caliche is also known as calcrete or kankar. It belongs to the duricrusts. The term caliche is borrowed from Spanish and is originally from the Latin word calx, meaning lime.
Rendzina is a soil type recognized in various soil classification systems, including those of Britain and Germany as well as some obsolete systems. They are humus-rich shallow soils that are usually formed from carbonate- or occasionally sulfate-rich parent material. Rendzina soils are often found in karst and mountainous regions.
This is an index of articles relating to soil.
Gypsisols in the World Reference Base for Soil Resources (WRB) are soils with substantial secondary accumulation of gypsum (CaSO4.2H2O). They are found in the driest parts of the arid climate zone. In the USDA soil taxonomy they are classified as Gypsids (USDA Soil Taxonomy), in the Russian soil classification they are called Desert soils (USSR).
Gypcrete or gypcrust is a hardened layer of soil, consisting of around 95% gypsum. Gypcrust is an arid zone duricrust. It can also occur in a semiarid climate in a basin with internal drainage, and is initially developed in a playa as an evaporate. Gypcrete is the arid climate's equivalent to calcrete, which is a duricrust that is unable to generate in very arid climates.
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.
A duripan is a diagnostic soil horizon of the USDA soil taxonomy that is cemented by illuvial silica into a subsurface hardpan. Similar to a fragipan, Petrocalcic Horizon and petrogypsic horizon, it is firmly cemented and restricts soil management. In soil descriptions, they are most often denoted by the symbol Bqm. The closest equivalent in the Canadian system of soil classification is called a duric horizon, although it does not mean exactly the same thing as a duripan in the United States. They form almost exclusively in arid or Mediterranean climates, and can be as hard as concrete, which makes plowing very difficult or impossible. Soils that include duripans are generally used for grazing or wildlife habitat, and are seldom cultivated.
A petrocalcic horizon is a diagnostic horizon in the USDA soil taxonomy (ST) and in the World Reference Base for Soil Resources (WRB). They are formed when secondary calcium carbonate or other carbonates accumulate in the subsoil to the extent that the soil becomes cemented into a hardpan. Petrocalcic horizons are similar to a duripan and a petrogypsic horizon (WRB) in how they affect land-use limitations. They can occur in conjunction with duripans where the conditions are right and there are enough free carbonates in the soil. Calcium carbonates are found in alkaline soils, which are typical of arid and semiarid climates. A common field test for the presence of carbonates is application of hydrochloric acid to the soil, which indicates by fizzing and bubbling the presence of calcium carbonates.
Alkali, or Alkaline, soils are clay soils with high pH, a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate, which causes the soil to swell and difficult to clarify/settle. They derive their name from the alkali metal group of elements, to which sodium belongs, and which can induce basicity. Sometimes these soils are also referred to as alkaline sodic soils. Alkaline soils are basic, but not all basic soils are alkaline.
A Calcisol in the World Reference Base for Soil Resources (WRB) is a soil with a substantial secondary accumulation of lime. Calcisols are common in calcareous parent materials and widespread in arid and semi-arid environments. Formerly Calcisols were internationally known as Desert soils and Takyrs.
Soil management is the application of operations, practices, and treatments to protect soil and enhance its performance. It includes soil conservation, soil amendment, and optimal soil health. In agriculture, some amount of soil management is needed both in nonorganic and organic types to prevent agricultural land from becoming poorly productive over decades. Organic farming in particular emphasizes optimal soil management, because it uses soil health as the exclusive or nearly exclusive source of its fertilization and pest control.
Haplocambids are a type of Aridisol soil which are taxonomically identified as a suborder of Cambid soils. Haplocambids are the most commonly occurring Cambids and are characterized by minimal horizon expression. Soil with 0-5 slopes over 5 °C temperature and loam soil structure is Haplocambids. Almost cold condition and high altitude soil classified into this group. These soil types are the most commonly occurring of the Cambids. The soils are characterized by minimal horizon expression. Most Haplocambids have a redistribution of carbonates below the cambic horizon. The amount of carbonates, however, is insufficient to meet the definition of a calcic horizon, or the upper boundary is more than 100 cm below the soil surface. These soils occur on a variety of landscapes, commonly on those that are younger than late Pleistocene in age. Haplocambids are divided into 22 suborders.
The residual sodium carbonate (RSC) index of irrigation water or soil water is used to indicate the alkalinity hazard for soil. The RSC index is used to find the suitability of the water for irrigation in clay soils which have a high cation exchange capacity. When dissolved sodium in comparison with dissolved calcium and magnesium is high in water, clay soil swells or undergoes dispersion which drastically reduces its infiltration capacity.
Ustic is a class of soil moisture regime. It is one of a range of different soil moisture regimes, such as: aquic moisture regime, aridic moisture regime, udic moisture regime and xeric moisture regime. The ustic moisture regime is intermediate between the aridic regime and the udic regime.
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