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96 Cards in this Set
- Front
- Back
Alfisols
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Soils with clay B horizons and a high base status
• Moderately leached forest soils that have relatively high native fertility • These soils are well developed and contain a subsurface horizon in which clays have accumulated (E horizon – clay rich layer) • Mostly found in temperate humid and subhumid regions of the world (wet and dry seasons) • Found in Mississippi Valley and east Texas |
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Aridisols
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Soils of arid regions
• Are calcite-containing soils of arid regions that exhibit at least some subsurface horizon development • They are characterized by being dry most of the year • They contain subsurface horizons in which clays, calcium carbonate, silica salts, and/or gypsum have accumulated • They are used mainly for range land, 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 |
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Entisols
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Recently formed soils
• Soils of recent origin • The central concept is soils developed in unconsolidated parent material with usually no genetic horizons except an A-Horizon • All soils that do not belong in any of the other orders belong here • They are characterized by great diversity, both in environmental setting and land use • Many are found in steep, rocky settings, however Entisols of large river valleys provide croplands and habitat for millions of people of the world • Most extensive soil order, occupying 16.2% of the world’s ice-free land area |
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Histosols
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Peats
• Soils that are composed mainly of organic materials • They contain at least 20-30% organic matter by weight and are more than 40cm thick • Bulk densities are often quite low • Most form in settings where restricted drainage inhibits the decomposition of plant and animal remains, allowing these organic materials to accumulate over time • They are ecologically important because of the large quantities of carbon that they contain • These are often referred to as peats and mucks and have physical properties that restrict their use for engineering purposes • They are mined for fuel and horticultural products • Swamps, marshes, bogs |
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Inceptisols
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Soils without contrasting horizons (new soils)
• Soils that exhibit minimal horizon development • They are more developed than Entisols, but still lack the features that are characteristic of other soil orders • Inceptisols are widely distributed and occur under a wide range of ecological settings • They are often found on fairly steep slopes, young geomorphic surfaces, and on resistant parent materials • Many are found in mountainous areas and are used for forestry, recreation, and watersheds |
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Mollisols
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Soils with mull humus
• Soils of grassland ecosystems; soils of the north America plains • They are characterized by a thick, dark surface horizon • Fertile surface horizon results from the long-term addition of organic materials derived from plant roots • Occur primarily in middle latitudes and are extensive in prairie regions, such as the Great Plains of the U.S. • Mollisols are among some of the most important and productive agricultural soils in the world and are extensively used for this purpose |
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Oxisols
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Sesquioxide-rich, highly weathered soils
• Very highly weathered soils that are found primarily in intertropical regions of the world o Thick O-Horizon • These soils contain few weatherable minerals and are often rich in iron and aluminum oxide minerals • These soils are characterized by extremely low native fertility, resulting from very low nutrient reserves, and high phosphorous retention by oxide minerals, and low cation exchange capacity • Most nutrients in oxisol ecosystems are contained in the standing vegetation and decomposing plant material • Despite low fertility, oxisols can be quite productive with inputs of lime and fertilizers |
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Spodosols
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Soils with iron and hums in the B horizon
• Acids oils characterized by a subsurface accumulation of humus that is complexed with aluminum and iron • These photogenic soils typically form in coarse-textured parent material that have light-colored E-Horizon overlying a redish-brown spodic horizon • Spodosols often occur under coniferous forests in cool, moist climates • Many support forests, but because they are naturally infertile, they require additions of lime in order to be productive agriculturally |
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Ultisols
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Soils with clay B horizons and low base status
• Strongly leached, acid forest soils with relatively low native fertility • They are found primarily in humid temperate and tropical areas of the world, typically in older, stable landscapes • Intense weathering of primary minerals has occurred, and much of the ca, Mg and K has been leached from these soils • Ultisols have a subsurface horizon in which clays have accumulated, often with strong yellowish or reddish colors resulting from the presence of iron oxides • Because of favorable climate regimes in which they are typically found Ultisols often support productive forests • Because of their acidity and relatively low quantities of plant-available Ca, Mg and K. Ultisols are poorly suited for agriculture without the use of fertilizer and lime |
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Vertisols
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Shrinking and swelling clay soils
• Clay-rich soils that shrink and swell with changes in moisture content • During dry periods, the soil volume shrinks, and deep wide cracks form • The soil volume expands as it gets wet • The shrink/swell action creates serious engineering problems and generally prevents the formation of distinct, well-developed horizons. • Vertisols occupy 2.0% of the US land area and occur primarily in Texas |
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Gelisols
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• Soils of very cold climates that contain permafrost within 2 meters of the surface
• These soils are limited geographically to high-latitude polar regions and high mountain elevations • Low soil temperatures cause soil-forming processes such as decomposition of organic materials to proceed very slowly o Holds a lot of organic material • Gelisols store large quantities of organic carbon • They surpass swamps and marsh ecosystems |
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Andisols
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• Soils that have formed in volcanic ash and other volcanic ejcta
• These soils differ from those of other suborders in that they are typically dominated by glass and poorly crystalline colloidal (gell) materials • Possess many unique chemical and physical properties including high water-holding capacity and the ability to fix large quantities of phosphorus |
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Engineering Properties of Soils
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1. Soil strength
2. Soil sensitivity 3. Soil Compressibility 4. Erodibility 5. Hydrualic Conductivity 6. Corrosive Potential 7. Ease of Excavation |
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O - Horizon
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-Organic horizon, or Humus
-Dead and decaying organic materials -This layer, in tropical forests, supports the vegetation |
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A - Horizon
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(True 1st layer of soil) – Oldest soil most altered from its parent material
-Zone of Leaching -Residue – non dissolvable material -Principally affected by chemical weathering |
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B - Horizon
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-Zone of Accumulation
-Beginning form as soil-proper -Chemical and physical weathering |
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C - Horizon
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-Partially decomposed parent material
-Mainly physical decomposition |
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D/R - Horizon
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No longer soil
-Unaltered parent material |
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E - Horizon
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Root resistant layer either too hard or burns the roots
-Light colored layer -Present in some soils as part of the Zone of Leaching -Composed of clay, calcium, magnesium, and iron An E – Horizon – Specially adapted trees (cedars) or just grass and shrubs; found in dryer environments |
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Contour Plowing
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o Plow perpendicular to the slope
o Each rill serves to keep water, and sediment from running downhill o One of the most widely used methods |
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No-till Agriculture
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o Eliminates plowing, which loosens the soil and makes it more susceptible to erosion
o This method may include “punching holes” in the soil and injecting the seeds at the same time o This is part of an integrated plan to control weeds and pests |
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Terracing Slopes
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o Producing a flat surface on a slope and adding a lip
o Water collects on each of the terraces. If it overruns the lip of the terrace, it will be trapped on the next level o This methods has been used for hundred (or more) years in the mountains of the Far East |
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Polyculture Agriculture
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o There are row crops (corn, wheat, etc.) and cover crops (strawberry, melons, etc.)
o Row crops protect from the wind, but they tend to leave the ground exposed to water erosion o Cover crops protect from the water, but not as much from the wind. o By planting several types of crops, ether in the same area, or in alternating strips, you get the best of both worlds o Of course, leaving the ground alone would be the best method |
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• Moderately leached forest soils that have relatively high native fertility
• These soils are well developed and contain a subsurface horizon in which clays have accumulated (E horizon – clay rich layer) • Mostly found in temperate humid and subhumid regions of the world (wet and dry seasons) • Found in Mississippi Valley and east Texas |
Alfisols
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• Moderately leached forest soils that have relatively high native fertility
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Alfisols
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These soils are well developed and contain a subsurface horizon in which clays have accumulated (E horizon – clay rich layer)
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Alfisols
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Mostly found in temperate humid and subhumid regions of the world (wet and dry seasons)
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Alfisols
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Found in Mississippi Valley and east Texas
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Alfisols
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• Soils that have formed in volcanic ash and other volcanic ejecta
• These soils differ from those of other suborders in that they are typically dominated by glass and poorly crystalline colloidal (gell) materials • Possess many unique chemical and physical properties including high water-holding capacity and the ability to fix large quantities of phosphorus |
Andisols
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Soils that have formed in volcanic ash and other volcanic ejecta
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Andisols
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These soils differ from those of other suborders in that they are typically dominated by glass and poorly crystalline colloidal (gell) materials
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Andisols
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Possess many unique chemical and physical properties including high water-holding capacity and the ability to fix large quantities of phosphorus
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Andisols
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• Are calcite-containing soils of arid regions that exhibit at least some subsurface horizon development
• They are characterized by being dry most of the year • They contain subsurface horizons in which clays, calcium carbonate, silica salts, and/or gypsum have accumulated • They are used mainly for range land, 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
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Are calcite-containing soils of arid regions that exhibit at least some subsurface horizon development
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Aridisols
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They are characterized by being dry most of the year
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Aridisols
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They contain subsurface horizons in which clays, calcium carbonate, silica salts, and/or gypsum have accumulated
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Aridisols
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They are used mainly for range land, wildlife, and recreation
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Aridisols
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Because of the dry climate in which they are found, they are not used for agricultural production unless irrigation water is available
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Aridisols
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• Soils of recent origin
• The central concept is soils developed in unconsolidated parent material with usually no genetic horizons except an A-Horizon • All soils that do not belong in any of the other orders belong here • They are characterized by great diversity, both in environmental setting and land use • Many are found in steep, rocky settings, however Entisols of large river valleys provide croplands and habitat for millions of people of the world • Most extensive soil order, occupying 16.2% of the world’s ice-free land area |
Entisols
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Soils of recent origin
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Entisols
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The central concept is soils developed in unconsolidated parent material with usually no genetic horizons except an A-Horizon
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Entisols
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All soils that do not belong in any of the other orders belong here
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Entisols
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They are characterized by great diversity, both in environmental setting and land use
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Entisols
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Many are found in steep, rocky settings, however Entisols of large river valleys provide croplands and habitat for millions of people of the world
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Entisols
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Most extensive soil order, occupying 16.2% of the world’s ice-free land area
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Entisols
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• Soils of very cold climates that contain permafrost within 2 meters of the surface
• These soils are limited geographically to high-latitude polar regions and high mountain elevations • Low soil temperatures cause soil-forming processes such as decomposition of organic materials to proceed very slowly • Store large quantities of organic carbon • They surpass swamps and marsh ecosystems |
Gelisols
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Soils of very cold climates that contain permafrost within 2 meters of the surface
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Gelisol
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These soils are limited geographically to high-latitude polar regions and high mountain elevations
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Gelisol
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Low soil temperatures cause soil-forming processes such as decomposition of organic materials to proceed very slowly
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Gelisol
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Store large quantities of organic carbon
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Gelisol
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They surpass swamps and marsh ecosystems
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Gelisol
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• Soils that are composed mainly of organic materials
• They contain at least 20-30% organic matter by weight and are more than 40cm thick • Bulk densities are often quite low • Most form in settings where restricted drainage inhibits the decomposition of plant and animal remains, allowing these organic materials to accumulate over time • They are ecologically important because of the large quantities of carbon that they contain • These are often referred to as peats and mucks and have physical properties that restrict their use for engineering purposes • They are mined for fuel and horticultural products • Swamps, marshes, bogs |
Histosols
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Soils that are composed mainly of organic materials
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Histosol
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They contain at least 20-30% organic matter by weight and are more than 40cm thick
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Histosol
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Bulk densities are often quite low
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Histosol
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Most form in settings where restricted drainage inhibits the decomposition of plant and animal remains, allowing these organic materials to accumulate over time
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Histosol
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They are ecologically important because of the large quantities of carbon that they contain
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Histosol
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These are often referred to as peats and mucks and have physical properties that restrict their use for engineering purposes
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Histosol
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They are mined for fuel and horticultural products
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Histosol
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Swamps, marshes, bogs
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Histosol
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• Soils that exhibit minimal horizon development
• They are more developed than Entisols, but still lack the features that are characteristic of other soil orders • Widely distributed and occur under a wide range of ecological settings • They are often found on fairly steep slopes, young geomorphic surfaces, and on resistant parent materials • Many are found in mountainous areas and are used for forestry, recreation, and watersheds |
Inceptisol
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Soils that exhibit minimal horizon development
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Inceptisol
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They are more developed than Entisols, but still lack the features that are characteristic of other soil orders
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Inceptisol
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Widely distributed and occur under a wide range of ecological settings
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Inceptisol
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They are often found on fairly steep slopes, young geomorphic surfaces, and on resistant parent materials
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Inceptisol
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Many are found in mountainous areas and are used for forestry, recreation, and watersheds
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Inceptisol
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• Soils of grassland ecosystems
• They are characterized by a thick, dark surface horizon • Fertile surface horizon results from the long-term addition of organic materials derived from plant roots • Occur primarily in middle latitudes and are extensive in prairie regions, such as the Great Plains of the U.S. • They are among some of the most important and productive agricultural soils in the world and are extensively used for this purpose |
Mollisol
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Soils of grassland ecosystems
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Mollisol
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They are characterized by a thick, dark surface horizon
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Mollisol
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Fertile surface horizon results from the long-term addition of organic materials derived from plant roots
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Mollisol
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Occur primarily in middle latitudes and are extensive in prairie regions, such as the Great Plains of the U.S.
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Mollisol
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They are among some of the most important and productive agricultural soils in the world and are extensively used for this purpose
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Mollisol
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• Very highly weathered soils that are found primarily in intertropical regions of the world
o Thick O-Horizon • These soils contain few weatherable minerals and are often rich in iron and aluminum oxide minerals • These soils are characterized by extremely low native fertility, resulting from very low nutrient reserves, and high phosphorous retention by oxide minerals, and low cation exchange capacity • Most nutrients in oxisol ecosystems are contained in the standing vegetation and decomposing plant material • Despite low fertility, they can be quite productive with inputs of lime and fertilizers |
Oxisol
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Very highly weathered soils that are found primarily in intertropical regions of the world
o Thick O-Horizon |
Oxisol
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These soils contain few weatherable minerals and are often rich in iron and aluminum oxide minerals
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Oxisol
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These soils are characterized by extremely low native fertility, resulting from very low nutrient reserves, and high phosphorous retention by oxide minerals, and low cation exchange capacity
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Oxisol
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Most nutrients in this ecosystems are contained in the standing vegetation and decomposing plant material
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Oxisol
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Despite low fertility, they can be quite productive with inputs of lime and fertilizers
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Oxisol
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• Acids oils characterized by a subsurface accumulation of humus that is complexed with aluminum and iron
• These photogenic soils typically form in coarse-textured parent material that have light-colored E-Horizon overlying a redish-brown horizon • They often occur under coniferous forests in cool, moist climates • Many support forests, but because they are naturally infertile, they require additions of lime in order to be productive agriculturally |
Spodosol
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Acids oils characterized by a subsurface accumulation of humus that is complexed with aluminum and iron
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Spodosol
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Typically form in coarse-textured parent material that have light-colored E-Horizon overlying a redish-brown horizon
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Spodosol
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They often occur under coniferous forests in cool, moist climates
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Spodosol
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Many support forests, but because they are naturally infertile, they require additions of lime in order to be productive agriculturally
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Spodosol
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• Strongly leached, acid forest soils with relatively low native fertility
• They are found primarily in humid temperate and tropical areas of the world, typically in older, stable landscapes • Intense weathering of primary minerals has occurred, and much of the ca, Mg and K has been leached from these soils • They have a subsurface horizon in which clays have accumulated, often with strong yellowish or reddish colors resulting from the presence of iron oxides • Because of favorable climate regimes in which they are typically found they often support productive forests • Because of their acidity and relatively low quantities of plant-available Ca, Mg and K. They are poorly suited for agriculture without the use of fertilizer and lime |
Ultisol
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Strongly leached, acid forest soils with relatively low native fertility
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Ultisol
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They are found primarily in humid temperate and tropical areas of the world, typically in older, stable landscapes
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Ultisol
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Intense weathering of primary minerals has occurred, and much of the ca, Mg and K has been leached from these soils
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Ultisol
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They have a subsurface horizon in which clays have accumulated, often with strong yellowish or reddish colors resulting from the presence of iron oxides
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Ultisol
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Because of favorable climate regimes in which they are typically found they often support productive forests
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Ultisol
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Because of their acidity and relatively low quantities of plant-available Ca, Mg and K. They are poorly suited for agriculture without the use of fertilizer and lime
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Ultisol
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• Clay-rich soils that shrink and swell with changes in moisture content
• During dry periods, the soil volume shrinks, and deep wide cracks form • The soil volume expands as it gets wet • The shrink/swell action creates serious engineering problems and generally prevents the formation of distinct, well-developed horizons. • Occupy 2.0% of the US land area and occur primarily in Texas |
Vertisol
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Clay-rich soils that shrink and swell with changes in moisture content
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Vertisol
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During dry periods, the soil volume shrinks, and deep wide cracks form
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Vertisol
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The soil volume expands as it gets wet
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Vertisol
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The shrink/swell action creates serious engineering problems and generally prevents the formation of distinct, well-developed horizons.
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Vertisol
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Occupy 2.0% of the US land area and occur primarily in Texas
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Vertisol
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