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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 International Union of Soil Sciences (IUSS). WRB, 4th edition (2022) Background History Since the 19th century, several countries developed national soil classification systems. During the 20th century, the need for an international soil classification system became more and more obvious. From 1971 to 1981, the Food and Agriculture Organization (FAO) and UNESCO published the Soil Map of the World, 10 volumes, scale 1 : 5 M). The Legend for this map, published in 1974 under the leadership of Rudi Dudal, became the FAO soil classification. Many ideas from national soil classification systems were brought together in this worldwide-applicable system, among them the idea of diagnostic horizons as established in the '7th approximation to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Classification
Soil classification deals with the systematic categorization of soils based on distinguishing characteristics as well as criteria that dictate choices in use. Overview Soil classification is a dynamic subject, from the structure of the system, to the definitions of classes, to the application in the field. Soil classification can be approached from the perspective of soil as a material and soil as a resource. Inscriptions at the temple of Horus at Edfu outline a soil classification used by Tanen to determine what kind of temple to build at which site. Ancient Greek scholars produced a number of classification based on several different qualities of the soil. Engineering Geotechnical engineers classify soils according to their engineering properties as they relate to use for foundation support or building material. Modern engineering classification systems are designed to allow an easy transition from field observations to basic predictions of soil engineering properties and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technosol
A Technosol in the World Reference Base for Soil Resources is a Reference Soil Group that combines soils whose properties and pedogenesis are dominated by their technical origin. They contain either a significant amount of artefacts (something in the soil recognizably made or extracted from the earth by humans), some sort of geotechnical liner, or are sealed by technic hard rock (hard material created by humans, having properties unlike natural rock). They include soils from wastes (landfills, sludge, cinders, mine spoils and ashes), pavements with their underlying unconsolidated materials, soils with geomembranes and constructed soils in human-made materials. However, Technosols can also refer to a situation in which normal soil, such as a Chernozem, has been moved to a new location to act as a fill. If this fill is less than 50 cm, then the soil is called a Technosol. If fill material is greater than 50 cm deep, then the fill is designated by the original soil used to c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planosol
A Planosol in the World Reference Base for Soil Resources is a soil with a light-coloured, coarse-textured, surface horizon that shows signs of periodic water stagnation and abruptly overlies a dense, slowly permeable subsoil with significantly more clay than the surface horizon. In the US Soil Classification of 1938 used the name Planosols, whereas its successor, the USDA soil taxonomy, includes most Planosols in the ''Great Groups'' Albaqualfs, Albaquults and Argialbolls. These soils are typically in seasonally waterlogged flat lands. They occur mainly in subtropical and temperate, semi-arid and subhumid regions. Planosols are formed mostly in clayey alluvial and colluvial deposits. Geological stratification and/or a pedogenetic process of destruction and removal of clay has resulted in the relatively coarse-textured, light-coloured surface soil abruptly overlying finer textured subsoil; impeded downward percolation of water causes temporarily reducing conditions with a stagn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plinthosol
Plinthosols are iron-rich soils characterized by the presence of plinthite, petroplinthite or pisoliths. Distribution Softer plinthosols are common in the wet tropics, including in the eastern Amazon basin, the central Congo Basin The Congo Basin (french: Bassin du Congo) is the sedimentary basin of the Congo River. The Congo Basin is located in Central Africa, in a region known as west equatorial Africa. The Congo Basin region is sometimes known simply as the Congo. It con ... and parts of Southeast Asia. Dryer areas, including the Sudano-Sahelian zone, Southern African savannah, the Indian subcontinent, and parts of Southeast Asia and northern Australia feature mostly harder pisoliths and petroplinthite. See also * References * IUSS Working Group WRB: World Reference Base for Soil Resources, fourth edition. International Union of Soil Sciences, Vienna 2022. . Further reading * W. Zech, P. Schad, G. Hintermaier-Erhard: Soils of the World. Springer, Berlin 2022, Chapter 10. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Podzol
In soil science, podzols are the typical soils of coniferous or boreal forests and also the typical soils of eucalypt forests and heathlands in southern Australia. In Western Europe, podzols develop on heathland, which is often a construct of human interference through grazing and burning. In some British moorlands with podzolic soils, cambisols are preserved under Bronze Age barrows (Dimbleby, 1962). Term Podzol means "under-ash" and is derived from the Russian под (pod) + зола́ (zola); the full form is "подзо́листая по́чва" (podzolistaya pochva, "under-ashed soil"). The term was first given in middle of 1875 by Vasily Dokuchaev. It refers to the common experience of Russian peasants of plowing up an apparent under-layer of ash (leached or E horizon) during first plowing of a virgin soil of this type. Characteristics Podzols can occur on almost any parent material but generally derive from either quartz-rich sands and sandstone or sedimentary debri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allophane
Allophane is an amorphous to poorly crystalline hydrous aluminium silicate clay mineraloid. Its chemical formula is Al2O3·(SiO2)1.3-2·(2.5-3)H2O. Since it has short-range atomic order, it is a mineraloid, rather than a mineral, and can be identified by its distinctive infrared spectrum and its X-ray diffraction pattern. It was first described in 1816 in Gräfenthal, Thuringia, Germany. Allophane is a weathering or hydrothermal alteration product of volcanic glass and feldspars and sometimes has a composition similar to kaolinite but generally has a molar ratio of Al:Si = 2. It typically forms under mildly acidic to neutral pH (5–7). Its structure has been debated, but it is similar to clay minerals and is composed of curved alumina octahedral and silica tetrahedral layers.Smalley, I.J. 1979. A spherical structure for allophane. Nature 281, 339 only Transmission electron micrographs show that it is generally made up of aggregates of hollow spherules ~3–5 nm in diameter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andosol
Andosols are soils found in volcanic areas formed in volcanic tephra. In some cases Andosols can also be found outside active volcanic areas. Andosols cover an estimated 1–2% of earth's ice-free land surface. Andosols are a Reference Soil Group of the World Reference Base for Soil Resources (WRB). They are closely related to other types of soils such as Vitrosols, Vitrandosols, Vitrons and Pumice Soils that are used in different soil classification systems. Poorly developed Andosols are often rich in vitreous materials and are therefore also called Vitric Andosols. The name comes from Japanese ( 'dark') and ( 'soil'), synonymous with (). In the USDA soil taxonomy, Andosols are known as Andisols. Andosols are usually defined as soils containing high proportions of glass and amorphous colloidal materials, including allophane, imogolite and ferrihydrite. Because they are generally quite young, Andosols typically are very fertile except in cases where phosphorus is easily fixed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology. Typically, groundwater is thought of as water flowing through shallow aquifers, but, in the technical sense, it can also contain soil moisture, perma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gleysol
A gleysol is a wetland soil (hydric soil) that, unless drained, is saturated with groundwater for long enough to develop a characteristic colour pattern. The pattern is essentially made up of reddish, brownish, or yellowish colours at surfaces of soil particles and/or in the upper soil horizons mixed with greyish/blueish colours inside the peds and/or deeper in the soil. Gleysols are also known as ''Gleyzems'', ''meadow soils'', ''Aqu''-suborders of Entisols, Inceptisols and Mollisols (USDA soil taxonomy), or as ''groundwater soils'' and ''hydro-morphic soils''. Gleysols occur within a wide range of unconsolidated materials, mainly fluvial, marine and lacustrine sediments of Pleistocene or Holocene age, having basic to acidic mineralogy. They are found in depression areas and low landscape positions with shallow groundwater. Wetness is the main limitation on agriculture of virgin gleysols; these are covered with natural swamp vegetation and lie idle or are used for extensive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solonchak
Solonchak (Russian and Ukrainian: Солончак) is a Reference Soil Group of the World Reference Base for Soil Resources (WRB). It is a pale or grey soil type found in arid to subhumid, poorly drained conditions. The word is Russian for "salt marsh" in turn from Russian ''sol'' (соль), "salt". Ukrainian folk word "солончак" in turn from Ukrainian "salty" (солоний) + "чак"—suffix; designation of an object that has the property. In Ukraine there is a village Solonchaky. See also * Chott *Salt marsh *Soil salinity *Solonetz *Takir Takir (takyr) (russian: такыр, originally from Kazakh or another Turkic language) meaning "smooth, even, or bare", is a type of relief occurring in the deserts of Central Asia, similar to a salt flat in the southwestern United States. A ta ... * Salt pan References * IUSS Working Group WRB: World Reference Base for Soil Resources, fourth edition. International Union of Soil Sciences, Vienna 2022. . Further reading ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertisol
A vertisol, or vertosol, is a soil type in which there is a high content of expansive clay minerals, many of them known as montmorillonite, that form deep cracks in drier seasons or years. In a phenomenon known as argillipedoturbation, alternate shrinking and swelling causes ''self-ploughing'', where the soil material consistently mixes itself, causing some vertisols to have an extremely deep A horizon and no B horizon. (A soil with no B horizon is called an ''A/C soil''). This heaving of the underlying material to the surface often creates a microrelief known as ''gilgai''. Vertisols typically form from highly basic rocks, such as basalt, in climates that are seasonally humid or subject to erratic droughts and floods, or that impeded drainage. Depending on the parent material and the climate, they can range from grey or red to the more familiar deep black (known as "black earths" in Australia, "black gumbo" in East Texas, "black cotton" soils in East Africa, and "vlei soils" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solonetz
Solonetz ( uk, Солонець, rus, Солоне́ц, p=səlɐˈnʲɛts) is a Reference Soil Group of the World Reference Base for Soil Resources (WRB). They have, within the upper 100 cm of the soil profile, a so-called "natric horizon" ("natrium" is the Latin term for sodium). There is a subsurface horizon (subsoil), higher in clay content than the upper horizon, that has more than 15% exchangeable sodium. The name is based on the Russian соль (sol, meaning salt). Ukrainian folk word "solontsi" means salty soil. In Ukraine there are many villages that are called Solontsі. Solonetz zones are associated with Gleysols, Solonchaks and Kastanozems. In USDA soil taxonomy, Solonetz corresponds to sodium-rich Alfisols. See also *Chott *Salt marsh *Soil salinity *Solonchak *Takir Takir (takyr) (russian: такыр, originally from Kazakh or another Turkic language) meaning "smooth, even, or bare", is a type of relief occurring in the deserts of Central Asia, similar to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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