Loess field in Germany

Surface-water-gley developed in glacial till, Northern Ireland

Soil is the naturally occurring, unconsolidated or loose covering of broken rock particles and decaying organic matter (humus) on the surface of the Earth, capable of supporting life. Humus (Origin 1790–1800 Latin: earth ground) is the organic material in Soil lending it a dark brown or black colouration EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 Soil life or soil biota is a collective term for all the organisms living within the soil ^[1] In simple terms, soil has three components: solid, liquid, and gas. The solid phase is a mixture of mineral and organic matter. Soil organic matter (SOM is the Organic matter component of Soil. Soil particles pack loosely, forming a soil structure filled with voids. ^[2] The solid phase occupies about half of the soil volume. The remaining void space contains water (liquid) and air (gas). ^[3] Soil is also known as earth: it is the substance from which our planet takes its name.

Characteristics

Darkened topsoil and reddish subsoil layers are typical in some regions.

Soil color is the first impression one has when viewing soil. A soil horizon is a specific layer in the Soil which measures parallel to the soil surface and possesses physical characteristics which differ from the layers above and Humid subtropical climate ( Köppen Cfa or Cwa) is a climate zone characterized by hot humid summers and chilly to mild winters Soil color often indicates Soil moisture status and is used for determining Hydric soils Often described by using general terms such as dark brown yellowish brown Striking colors and contrasting patterns are especially memorable. The Red River in Louisiana carries sediment eroded from extensive reddish soils like Port Silt Loam in Oklahoma. For other uses see Red River. The Red River is one of several rivers with that name. The State of Louisiana ( or, État de Louisiane, pronounced) is a state located in the southern region of the United States of America Port Silt Loam is the state soil of Oklahoma. This type of Soil is reddish in color due to the weathering of reddish Sandstones, Siltstones Oklahoma ( is a state located in the South Central region of the United States of America.

Soil color results from chemical and biological weathering. As the primary minerals in parent material weather, the elements combine into new and colorful compounds. Parent material, in Soil science, means the underlying geological material (generally Bedrock or a superficial or drift deposit in which Soil horizons Iron forms secondary minerals with a yellow or red color; organic matter decomposes into brown compounds; and manganese, sulfur and nitrogen can form black mineral deposits. ^[4]

Soil structure is the arrangement of soil particles into aggregates. Soil structure is determined by how individual soil Granules clump or bind together and aggregate and therefore the arrangement of soil pores between them These may have various shapes, sizes and degrees of development or expression. ^[5]

Soil texture refers to sand, silt and clay composition. Soil texture is a Soil property used to describe the relative proportion of different grain sizes of Mineral particles in a soil Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles Silt is Soil or rock derived Granular material of a Grain size between sand and clay Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and Sand and silt are the product of physical weathering while clay is the product of chemical weathering. Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles Clay content is particularly influential on soil behavior due to a high retention capacity for nutrients and water. ^[6]

Formation

Soil formation, or pedogenesis, is the combined effect of physical, chemical, biological, and anthropogenic processes on soil parent material resulting in the formation of soil horizons. Pedogenesis or soil evolution (formation is the process by which Soil is created A soil horizon is a specific layer in the Soil which measures parallel to the soil surface and possesses physical characteristics which differ from the layers above and Soil is always changing. The long periods over which change occurs and the multiple influences of change mean that simple soils are rare. While soil can achieve relative stability in properties for extended periods of time, the soil life cycle ultimately ends in soil conditions that leave it vulnerable to erosion. Little of the soil continuum of the earth is older than Tertiary and most no older than Pleistocene. The chuprichondira geological time interval covers roughly the time span between the demise of the non- avian Dinosaurs and beginning of the most recent Ice Age, approximately The Pleistocene ('plaɪstəsin is the epoch from 18 million to 10000 years BP covering the world's recent period ^[7] Despite the inevitability of soils retrogression and degradation, most soil cycles are long and productive. Soils retrogression and degradation in the French school of pedology are two regressive evolution processes associated with the loss of equilibrium of a stable Soil How the soil "life" cycle proceeds is influenced by at least five classic soil forming factors: regional climate, biotic potential, topography, parent material, and the passage of time.

An example of soil development from bare rock occurs on recent lava flows in warm regions under heavy and very frequent rainfall. Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures In such climates plants become established very quickly on basaltic lava, even though there is very little organic material. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. The plants are supported by the porous rock becoming filled with nutrient bearing water, for example carrying dissolved bird droppings or guano. Guano (from the Quechua 'wanu' via Spanish) is the Feces of Seabirds Bats and seals The developing plant roots themselves gradually breaks up the porous lava and organic matter soon accumulates but, even before it does, the predominantly porous broken lava in which the plant roots grow can be considered a soil.

In nature

Biogeography is the study of spatial variations in biological communities. Soils are a restricting factor as to what plants can grow in which environments. Soil scientists survey soils in the hope of understanding controls as to what vegetation can and will grow in a particular location

Geologists also have a particular interest in the patterns of soil on the surface of the earth. Soil texture, color and chemistry often reflect the underlying geologic parent material and soil types often change at geologic unit boundaries. In terms of Soil texture, soil type usually refers to the different sizes of Mineral particles in a particular sample Buried paleosols mark previous land surfaces and record climatic conditions from previous eras. In Soil science, paleosols ( palaeosols in Great Britain and Australia) can have two meanings An unconformity is a buried Erosion surface separating two rock masses or strata of different ages indicating that Sediment deposition was not Paleoclimatology (also Palaeoclimatology) is the study of Climate change taken on the scale of the entire History of Earth. Geologists use this paleopedological record to understand the ecological relationships in past ecosystems. The paleopedological record is essentially the Fossil record of Soils The paleopedological record consists chiefly of Paleosols buried by Flood According to the theory of biorhexistasy, prolonged conditions conducive to forming deep, weathered soils result in increasing ocean salinity and the formation of limestone. The Theory of Biorhexistasy describes climatic conditions necessary for periods of soil formation ( Pedogenesis) separated by periods of Soil erosion.

Geologists use soil profile features to establish the duration of surface stability in the context of geologic faults or slope stability. A soil horizon is a specific layer in the Soil which measures parallel to the soil surface and possesses physical characteristics which differ from the layers above and In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement The field of slope stability encompasses the analysis of static and dynamic stability of slopes of earth and rock-fill dams slopes of other types of embankments excavated slopes An offset subsoil horizon indicates rupture during soil formation and the degree of subsequent subsoil formation is relied upon to establish time since rupture.

Soil examined in shovel test pits is used by archaeologists for relative dating based on stratigraphy (as opposed to absolute dating). A shovel test pit (STP is a standard method for Phase I of an Archaeological survey Absolute dating is the process of determining a specific date for an archaeological or palaeontological site or artifact What is considered most typical is to use soil profile features to determine the maximum reasonable pit depth than needs to be examined for archaeological evidence in the interest of cultural resources management. This article is concerned with cultural resources in the widest sense for traditional archaeological and historic culture specifically see Cultural Heritage Management

Soils altered or formed by man (anthropic and anthropogenic soils) are also of interest to archaeologists. Anthropogenic effects processes objects or materials are those that are derived from Human activities as opposed to those occurring in Natural environments without An example is Terra preta do Indio. Terra preta (“dark soil” in Portuguese) refers to expanses of very dark fertile Anthropogenic Soils found in the Amazon Basin.

Uses

A homeowner tests soil to apply only the nutrients needed.

Due to their thermal mass, rammed earth walls fit in with environmental sustainability aspirations. Rammed earth, also known as cob, pisé de terre or simply pisé, is a type of construction material

A homeowner sifts soil made from his compost bin in background. Compost (ˈkɒmpɒst or US /ˈkɒmpoʊst/ also known as brown manure is the aerobically decomposed remnants of Organic matter. Composting is an excellent way to recycle household and yard wastes.

Soil material is a critical component in the mining and construction industries. Soil serves as a foundation for most construction projects. Massive volumes of soil can be involved in surface mining, road building, and dam construction. Earth sheltering is the architectural practice of using soil for external thermal mass against building walls. Earth sheltering is the architectural practice of using earth against building walls for external Thermal mass, to reduce heat loss and to easily maintain

Soil resources are critical to the environment, as well as to food and fiber production. Soil provides minerals and water to plants. Soil absorbs rainwater and releases it later thus preventing floods and drought. Soil cleans the water as it percolates. Soil is the habitat for many organisms.

Waste management often has a soil component. Waste management is the collection Transport, processing, Recycling or disposal of Waste materials Septic drain fields treat septic tank effluent uses aerobic soil processes. Septic drain fields are used to remove contaminants and impurities from the liquid that emerges from the Septic tank. Description A septic tank generally consists of tanks between the size of 1000 and 2000 gallons (4000 - 7500 litres which is connected to an inlet wastewater pipe at one end and Landfills use soil for daily cover. For other uses see Water treatment and Land reclamation. A landfill, also known as a dump (and historically as Daily cover is the name given to the layer of compressed Soil or earth which is laid on top of a day's deposition of Waste on an operational Landfill site

Organic soils, especially peat, serve as a significant fuel resource. Peat is an accumulation of partially Decayed Vegetation matter.

Both humans in many cultures and animals occasionally eat soil. Geophagy is the practice of eating earthy or soil-like substances such as Clay, and Chalk, in order to obtain essential nutrients such as sulfur and phosphorus from

Degradation

Land degradation is a human induced or natural process which impairs the capacity of land to function. Land degradation are a concept in which the value of the Biophysical environment is affected by one or more combination of human-induced processes acting upon the land Land in Economics comprises all naturally occurring resources whose supply is inherently fixed (i Soils are the critical component in land degradation when it involves acidification, contamination, desertification, erosion, or salination.

While soil acidification of alkaline soils is beneficial, it degrades land when soil acidity lowers crop productivity and increases soil vulnerability to contamination and erosion. Soil acidification is the buildup of Hydrogen Cations also called Protons in the Soil. Soils are often initially acid because their parent materials were acid and initially low in the basic cations (calcium, magnesium, potassium, and sodium). Parent material, in Soil science, means the underlying geological material (generally Bedrock or a superficial or drift deposit in which Soil horizons In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Acidification occurs when these elements are removed from the soil profile by normal rainfall or the harvesting of crops. Soil acidification is accelerated by the use of acid-forming nitrogenous fertilizers and by the effects of acid precipitation. Acid rain is Rain or any other form of precipitation that is unusually Acidic It has harmful effects on plants aquatic animals and infastructure

Soil contamination at low levels are often within soil capacity to treat and assimilate. Soil contamination is caused by the presence of man-made chemicals or other alteration in the natural soil environment Many waste treatment processes rely on this treatment capacity. Exceeding treatment capacity can damage soil biota and limit soil function. Derelict soils occur where industrial contamination or other development activity damages the soil to such a degree that the land cannot be used safely or productively. A derelict soil is a Soil that has been damaged by industrial or other development activity and which is currently unused Remediation of derelict soil uses principles of geology, physics, chemistry, and biology to degrade, attenuate, isolate, or remove soil contaminants and to restore soil functions and values. Generally remediation means providing a Remedy, so environmental remediation deals with the removal of Pollution or Contaminants from environmental Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit Techniques include leaching, air sparging, chemical amendments, phytoremediation, bioremediation, and natural attenuation. Phytoremediation describes the treatment of environmental problems ( Bioremediation) through the use of Plants The word's etymology comes from Bioremediation can be defined as any process that uses Microorganisms Fungi, green plants or their Enzymes to return the natural environment altered

Desertification is an environmental process of ecosystem degradation in arid and semi-arid regions, or as a result of human activity. Desertification is the degradation of land in arid and dry sub-humid areas resulting primarily from human activities and influenced by climatic variations It is a common misconception that droughts cause desertification. A drought is an extended period of months or years when a region notes a deficiency in its water supply Droughts are common in arid and semiarid lands. Well-managed lands can recover from drought when the rains return. Soil management tools include maintaining soil nutrient and organic matter levels, reduced tillage and increased cover. These help to control erosion and maintain productivity during periods when moisture is available. Continued land abuse during droughts, however, increases land degradation. Increased population and livestock pressure on marginal lands accelerates desertification.

Soil erosional loss is caused by wind, water, ice, movement in response to gravity. Erosion is the carrying away or displacement of solids ( Sediment, Soil, rock and other particles usually by the agents of currents such as wind Gravitation is a natural Phenomenon by which objects with Mass attract one another Although the processes may be simultaneous, erosion is distinguished from weathering. Weathering is the decomposition of earth rocks, Soils and their Minerals through direct contact with the planet's Atmosphere. Erosion is an intrinsic natural process, but in many places it is increased by human land use. Land use' is also often used to refer to the distinct land use types in Zoning. Poor land use practices include deforestation, overgrazing, and improper construction activity. Deforestation is the conversion of Forested areas to non-forest land for use such as Arable land, Pasture, urban use logged area or wasteland Overgrazing occurs when plants are exposed to Livestock Grazing for extended periods of time or without sufficient recovery periods Improved management can limit erosion using techniques like limiting disturbance during construction, avoiding construction during erosion prone periods, intercepting runoff, terrace-building, use of erosion suppressing cover materials and planting trees or other soil binding plants. In Agriculture, a terrace is a leveled section of a Hilly cultivated area designed as a method of Soil conservation to slow or prevent the rapid

Sediment in the Yellow River.

A serious and long-running water erosion problem is in China, on the middle reaches of the Yellow River and the upper reaches of the Yangtze River. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National The Yellow River or Huang He / Hwang Ho ( Hatan Gol Queen river) is the second-longest river in China (after the Yangtze River) and the From the Yellow River, over 1.6 billion tons of sediment flow each year into the ocean. To help compare different orders of magnitude, the following list describes various Mass levels between 10&minus36&thinsp kg and 1053&thinspkg The sediment originates primarily from water erosion in the Loess Plateau region of northwest China. Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of The Loess Plateau ( also known as the Huangtu Plateau is a Plateau that covers an area of some 640000 km² in the upper and middle of China 's

Soil piping is a particular form of soil erosion that occurs below the soil surface. It is associated with levee and dam failure as well as sink hole formation. Turbulent flow removes soil starting from the mouth of the seep flow and subsoil erosion advances upgradient. ^[8] The term sand boil is used to describe the appearance of the discharging end of an active soil pipe. ^[9]

Soil salination is the accumulation of free salts to such an extent that it leads to degradation of soils and vegetation. Soil salinity is the salt content in the soil Salt affected soils are caused by excess accumulation of salts typically most pronounced at the soil surface Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants Consequences include corrosion damage, reduced plant growth, erosion due to loss of plant cover and soil structure, and water quality problems due to sedimentation. Salination occurs due to a combination of natural and human caused processes. Aridic conditions favor salt accumulation. This is especially apparent when soil parent material is saline. Irrigation of arid lands is especially problematic. All irrigation water has some level of salinity. Irrigation, especially when it involves leakage from canals, often raise the underlying water table. Rapid salination occurs when the land surface is within the capillary fringe of saline groundwater. Salinity control involves flushing with higher levels of applied water in combination with tile drainage. Salinity control relates to controlling the problem of soil salinity and reclaiming salinized agricultural land ^[10].

See also

• Geohumus
• Geoponic
• Humus
• Manure
• Mud
• Red Mediterranean soil
• Soil contamination
• Soil erosion
• Soil functions
• Soil mechanics

References

Further reading

• Adams, J. A. 1986. Dirt. College Station, Texas : Texas A&M University Press ISBN 0890963010
• Soil Survey Staff. (1975) Soil Taxonomy: A basic system of soil classification for making and interpreting soil surveys. Year 1975 ( MCMLXXV) was a Common year starting on Wednesday (link will display full calendar of the Gregorian calendar. USDA-SCS Agric. Handb. 436. U. S. Gov. Print. Office. Washington, DC.
• Soil Survey Division Staff. (1999) Soil survey manual. Year 1999 ( MCMXCIX) was a Common year starting on Friday (link will display full 1999 Gregorian calendar) Soil Conservation Service. U. S. Department of Agriculture Handbook 18.
• Logan, W. B. , Dirt: The ecstatic skin of the earth. 1995 ISBN 1-57322-004-3
• Faulkner, William. Plowman's Folly. New York, Grosset & Dunlap. 1943. ISBN 0-933280-51-3
• Jenny, Hans, Factors of Soil Formation: A System of Quantitative Pedology 1941
• Why Study Soils?
• Soil notes
• 97 Flood. USGS. Retrieved on 2006-05-31. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1279 BC - Rameses II (The Great (19th dynasty becomes pharaoh of Ancient Egypt. Photographs of sand boils.
• Oregon State University's Soils (wiki)
• Soil-Net.com A free schools-age educational site teaching about soil and its importance.
• LandIS Soils Data for England and Wales a pay source for GIS data on the soils of England and Wales and soils data source; they charge a handling fee to researchers.
• LandIS Free Soilscapes Viewer Free interactive viewer for the Soils of England and Wales
• Geo-technological Research Paper, IIT Kanpur, Dr P P Vitkar - Strip footing on weak clay stabilized with a granular pile http://pubs.nrc-cnrc.gc.ca/cgi-bin/rp/rp2_abst_e?cgj_t78-066_15_ns_nf_cgj4-78

External links

• Soil Science Society of America
• Percolation Test Learn about Soil, Percolation, Perc and Perk Tests.
• USDA-NRCS Web Soil Survey Inventory of the soil resource across the U. S.
• European Soil Portal EUSOILS (wiki)
• OpenAg. info's Soil Science Encyclopedia (wiki)
• Wossac the world soil survey archive and catalogue.
• "Soil texture tests