In both the

World Reference Base for Soil Resources The World Reference Base for Soil Resources (WRB) is an international soil classification system for naming soils and creating legends for soil maps. The currently valid version is the fourth edition 2022. It is edited by a working group of the I ...

(WRB) and 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 ...

, a Histosol is 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 ...

consisting primarily of

organic material Organic matter, organic material or natural organic matter is the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come fro ...

s. They are defined as having or more of organic soil material starting within 40 cm from the soil surface. In Soil Taxonomy, Gelisols key out before Histosols, and in WRB, Histosols key out before Cryosols. Therefore, organic

permafrost Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below ...

soils belong to the Histosols in WRB (Cryic Histosols) and to the Gelisols (Histels) in Soil Taxonomy. Organic soil material has an organic carbon content (by

weight In science and engineering, the weight of an object is a quantity associated with the gravitational force exerted on the object by other objects in its environment, although there is some variation and debate as to the exact definition. Some sta ...

) of 12 percent or more (Soil Taxonomy) or 20 percent or more (WRB). These materials include muck ( sapric soil material), mucky peat (hemic soil material), or

peat Peat is an accumulation of partially Decomposition, decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, Moorland, moors, or muskegs. ''Sphagnum'' moss, also called peat moss, is one of the most ...

( fibric soil material). Many Histosols show aquic conditions or artificial drainage, some (Folists in Soil Taxonomy and Folic Histosols in WRB) developed under terrestrial conditions. Organic material and therefore Histosols have very low

bulk density In materials science, bulk density, also called apparent density, is a material property defined as the mass of the many particles of the material divided by the bulk volume. Bulk volume is defined as the total volume the particles occupy, includ ...

. Many are

acidic An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the ...

and very deficient in major

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

nutrient A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

s, especially the raised bogs, which are saturated by rainwater and lack connection to nutrient-containing groundwater. Histosols are known by various other names in other countries, such as

or muck. In the

Australian Soil Classification The Australian Soil Classification is the classification system currently used to describe and classify soils in Australia. It is a general-purpose, hierarchical classification Hierarchical classification is a system of grouping things accordin ...

, Histosols are called Organosols. Histosols form whenever organic matter forms at a more rapid rate than it is destroyed. This occurs because of restricted

drainage Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess water. The internal drainage of most agricultural soils can prevent severe waterlogging (anaerobic conditions that harm root gro ...

precluding aerobic decomposition, and the remains of plants and

animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...

s remain within the soil. Thus, Histosols are very important

ecologically Ecology () is the natural science of the relationships among living organisms and their environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere levels. Ecology overlaps with the closely re ...

because they, and Gelisols, store large quantities of organic

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

. If accumulation continues for a long enough period,

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

forms. Most Histosols occur in

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

Scandinavia Scandinavia is a subregion#Europe, subregion of northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. ''Scandinavia'' most commonly refers to Denmark, Norway, and Sweden. It can sometimes also ...

, the

West Siberian Plain The West Siberian Plain () is a large plain that occupies the western portion of Siberia, between the Ural Mountains in the west and the Yenisei, Yenisei River in the east, and the Altai Mountains on the southeast. Much of the plain is poorly d ...

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

and

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

. Smaller areas are found in other parts of

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

, the

Russian Far East The Russian Far East ( rus, Дальний Восток России, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in North Asia. It is the easternmost part of Russia and the Asia, Asian continent, and is coextensive with the Far Easte ...

(chiefly in

Khabarovsk Krai Khabarovsk Krai (, ) is a federal subjects of Russia, federal subject (a krai) of Russia. It is located in the Russian Far East and is administratively part of the Far Eastern Federal District. The administrative centre of the krai is the types of ...

and

Amur Oblast Amur Oblast () is a federal subject of Russia (an oblast), located on the banks of the Amur and Zeya rivers in the Russian Far East. The oblast borders Heilongjiang province of the People's Republic of China (PRC) to the south. The administrati ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

and other areas of permanent

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

land.

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

Histosols are known from the earliest extensive land

vegetation Vegetation is an assemblage of plants and the ground cover they provide. It is a general term, without specific reference to particular Taxon, taxa, life forms, structure, Spatial ecology, spatial extent, or any other specific Botany, botanic ...

in the

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

. Histosols are generally very difficult to cultivate because of the poor drainage and often low chemical

fertility Fertility in colloquial terms refers the ability to have offspring. In demographic contexts, fertility refers to the actual production of offspring, rather than the physical capability to reproduce, which is termed fecundity. The fertility rate ...

. However, Histosols formed on very recent

glacial A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

lands can often be very productive when drained and produce high-grade

pasture Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Types of pasture Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, c ...

for dairying or

beef cattle Beef cattle are cattle raised for meat production (as distinguished from dairy cattle, used for milk (production)). The meat of mature or almost mature cattle is mostly known as beef. In beef production there are three main stages: cow-calf opera ...

. They can sometimes be used for

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

if carefully managed, but there is a great risk of the organic matter becoming dry powder and eroding under the influence of drying

wind Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heatin ...

s. A tendency towards shrinkage and compaction is also evident with

crop A crop is a plant that can be grown and harvested extensively for profit or subsistence. In other words, a crop is a plant or plant product that is grown for a specific purpose such as food, Fiber, fibre, or fuel. When plants of the same spe ...

s. Like Gelisols, Histosols have greatly restricted use for

civil engineering Civil engineering is a regulation and licensure in engineering, professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads ...

purposes because heavy

structure A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...

s tend to subside in the wet soil. In

, Histosols are subdivided into: * Folists – Histosols that are not saturated with water for long periods of time during the year. * Fibrists – Histosols that are primarily made up of only slightly decomposed organic materials, often called peat. * Hemists – Histosols that are primarily made up of moderately decomposed organic materials. * Saprists – Histosols that are primarily made up of highly decomposed organic materials, often called muck. * Wassists - Histosols that have a field observable water table 2 cm or more above the soil surface for more than 21 hours of each day in all years.

Taxonomy. Principal qualifiers

Histosols are classified into: *Muusic/ Rockic/ Mawic *Cryic *Thionic *Folic *Floatic/ Subaquatic/ Tidalic *Fibric/ Hemic/ Sapric *Leptic *Murshic/ Drainic *Ombric/ Rheic *Hyperskeletic/ Skeletic *Andic *Vitric *Calcic *Dystric/ Eutric

References

* *

External links

profile photos (with classification)
WRB homepage
profile photos (with classification)
IUSS World of Soils {{Authority control Pedology Types of soil

Taxonomy. Principal qualifiers

See also

References

Further reading

External links