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Pseudogley
A Stagnosol in the World Reference Base for Soil Resources (WRB) is soil with strong mottling of the soil profile due to redox processes caused by stagnating surface water. Stagnosols are periodically wet and mottled in the topsoil and subsoil, with or without concretions and/or bleaching. The topsoil can also be completely bleached (albic horizon). A common name in many national classification systems for most Stagnosols is pseudogley. In the USDA soil taxonomy, many of them belong to the Aqualfs, Aquults, Aquents, Aquepts and Aquolls. They are developed in a wide variety of unconsolidated materials like glacial till, and loamy aeolian, alluvial and colluvial deposits and physically weathered siltstone. Stagnosols occur on flat to gently sloping land in cool temperate to subtropical regions with humid to perhumid climate conditions. The agricultural suitability of Stagnosols is limited because of their oxygen deficiency resulting from stagnating water above a dense subsoil. Th ...
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Pseudogley
A Stagnosol in the World Reference Base for Soil Resources (WRB) is soil with strong mottling of the soil profile due to redox processes caused by stagnating surface water. Stagnosols are periodically wet and mottled in the topsoil and subsoil, with or without concretions and/or bleaching. The topsoil can also be completely bleached (albic horizon). A common name in many national classification systems for most Stagnosols is pseudogley. In the USDA soil taxonomy, many of them belong to the Aqualfs, Aquults, Aquents, Aquepts and Aquolls. They are developed in a wide variety of unconsolidated materials like glacial till, and loamy aeolian, alluvial and colluvial deposits and physically weathered siltstone. Stagnosols occur on flat to gently sloping land in cool temperate to subtropical regions with humid to perhumid climate conditions. The agricultural suitability of Stagnosols is limited because of their oxygen deficiency resulting from stagnating water above a dense subsoil. Th ...
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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 ...
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Weathering
Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), and so is distinct from erosion, which involves the transport of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity. Weathering processes are divided into ''physical'' and ''chemical weathering''. Physical weathering involves the breakdown of rocks and soils through the mechanical effects of heat, water, ice, or other agents. Chemical weathering involves the chemical reaction of water, atmospheric gases, and biologically produced chemicals with rocks and soils. Water is the principal agent behind both physical and chemical weathering, though atmospheric oxygen and carbon dioxide and the activities of biological organisms are also important. Chemical weathering by biological action is also known as biological wea ...
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Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, smaller islands. With an area of , Australia is the largest country by area in Oceania and the world's List of countries and dependencies by area, sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. It is a Megadiverse countries, megadiverse country, and its size gives it a wide variety of landscapes and climates, with Deserts of Australia, deserts in the centre, tropical Forests of Australia, rainforests in the north-east, and List of mountains in Australia, mountain ranges in the south-east. The ancestors of Aboriginal Australians began arriving from south east Asia approximately Early human migrations#Nearby Oceania, 65,000 years ago, during the Last Glacial Period, last i ...
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North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the west and south by the Pacific Ocean. Because it is on the North American Plate, North American Tectonic Plate, Greenland is included as a part of North America geographically. North America covers an area of about , about 16.5% of Earth's land area and about 4.8% of its total surface. North America is the third-largest continent by area, following Asia and Africa, and the list of continents and continental subregions by population, fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 579 million people in List of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's population. In Americas (terminology)#Human ge ...
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Central Europe
Central Europe is an area of Europe between Western Europe and Eastern Europe, based on a common historical, social and cultural identity. The Thirty Years' War (1618–1648) between Catholicism and Protestantism significantly shaped the area's history. The concept of "Central Europe" appeared in the 19th century. Central Europe comprised most of the territories of the Holy Roman Empire and those of the two neighboring kingdoms of Poland and Hungary. Hungary and parts of Poland were later part of the Habsburg monarchy, which also significantly shaped the history of Central Europe. Unlike their Western European (Portugal, Spain et al.) and Eastern European (Russia) counterparts, the Central European nations never had any notable colonies (either overseas or adjacent) due to their inland location and other factors. It has often been argued that one of the contributing causes of both World War I and World War II was Germany's lack of original overseas colonies. After World War ...
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Western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean world, the Roman Empire (Western Roman Empire and Eastern Roman Empire), and medieval "Christendom" (Western Christianity and Eastern Christianity). Beginning with the Renaissance and the Age of Discovery, roughly from the 15th century, the concept of ''Europe'' as "the West" slowly became distinguished from and eventually replaced the dominant use of "Christendom" as the preferred endonym within the region. By the Age of Enlightenment and the Industrial Revolution, the concepts of "Eastern Europe" and "Western Europe" were more regularly used. Historical divisions Classical antiquity and medieval origins Prior to the Roman conquest, a large part of Western Europe had adopted the newly developed La Tène culture. As the Roman domain ...
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Fertile Soil
Soil fertility refers to the ability of soil to sustain agricultural plant growth, i.e. to provide plant habitat and result in sustained and consistent yields of high quality.Bodenfruchtbarkeit
Retrieved on 2015-11-09.
It also refers to the soil's ability to supply plant/crop nutrients in the right quantities and qualities over a sustained period of time.A fertile soil has the following properties: * The ability to supply essential plant nutrients and water in adequate amounts and proportions for plant growth and reproduction; and * The absence of toxic substances which may inhibit plant growth e.g Fe^2+ which leads to nutrient toxicity. The following properties contribute to soil fertilit ...
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Hydraulic Conductivity
Hydraulic conductivity, symbolically represented as (unit: m/s), is a property of porous materials, soils and rocks, that describes the ease with which a fluid (usually water) can move through the pore space, or fractures network. It depends on the intrinsic permeability (, unit: m) of the material, the degree of saturation, and on the density and viscosity of the fluid. Saturated hydraulic conductivity, , describes water movement through saturated media. By definition, hydraulic conductivity is the ratio of volume flux to hydraulic gradient yielding a quantitative measure of a saturated soil's ability to transmit water when subjected to a hydraulic gradient. Methods of determination There are two broad categories of determining hydraulic conductivity: *''Empirical'' approach by which the hydraulic conductivity is correlated to soil properties like pore size and particle size (grain size) distributions, and soil texture *''Experimental'' approach by which the hydraulic conducti ...
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Porosity
Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface (cf. closed-cell foam). There are many ways to test porosity in a substance or part, such as industrial CT scanning. The term porosity is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, petrophysics, hydrology, earth sciences, soil mechanics, and engineering. Void fraction in two-phase flow In gas-liquid two-phase flow, the void fraction is defined as the fraction of the flow-channel volume that is occupied by the gas phase or, alternatively, as the fraction of the cross-sectional area of the channel that is occupied by the gas phase. Void fraction usually varies from location to location in the flow ch ...
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Gleysols
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 extensiv ...
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Oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is Earth's most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula . Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. Many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as ...
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