USDA Soil Taxonomy developed by United States Department of Agriculture

United States Department of Agriculture

The United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...

 and the National Cooperative Soil Survey

National Cooperative Soil Survey

The National Cooperative Soil Survey in the United States is a nation-wide partnership of federal, regional, state, and local agencies and institutions...

 provides an elaborate classification

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 :...

 of soil types according to several parameters (most commonly their properties) and in several levels: Order, Suborder, Great Group, Subgroup, Family, and Series

Soil series

Soil series as established by the National Cooperative Soil Survey of the United States Department of Agriculture Natural Resources Conservation Service are a level of classification in the USDA Soil Taxonomy classification system hierarchy. The actual object of classification is the so-called...

.

Example of classification of a soil type

Order: Entisols

Suborder: Fluvents

Great Group: Torrifluvents

Subgroup: Typic Torrifluvents

Family: Fine-loamy, mixed, superactive, calcareous, Typic Torrifluvents

Series: Jocity, Youngston.

Another Example

Order: Alfisols

Alfisols

Alfisols are a soil order in USDA soil taxonomy. Alfisols form in semiarid to humid areas, typically under a hardwood forest cover. They have a clay-enriched subsoil and relatively high native fertility. "Alf" refers to aluminium and iron . Because of their productivity and abundance, the...

Suborder: Xeralfs

Great Group: Durixeralfs

Subgroup: Abruptic Durixeralfs

Family: Fine, Mixed, Active, thermic Abruptic Durixeralfs

Series: San Joaquin (soil)

San Joaquin (soil)

San Joaquin is an officially designated state insignia, the State Soil of the U.S. state of California.The California Central Valley has more than 500,000 acres of San Joaquin soils, named for the south end of that valley. This series is the oldest continuously recognized soil series within the...

Link to Official Series Description: ftp://ftp-fc.sc.egov.usda.gov/NSSC/StateSoil_Profiles/ca_soil.pdf

Orders

• Alfisols
  Alfisols
  Alfisols are a soil order in USDA soil taxonomy. Alfisols form in semiarid to humid areas, typically under a hardwood forest cover. They have a clay-enriched subsoil and relatively high native fertility. "Alf" refers to aluminium and iron . Because of their productivity and abundance, the...
  
   — moderately weathered, form under boreal or broadleaf forests, rich in Fe and Al
• Andisols
  Andisols
  In USDA soil taxonomy, Andisols are soils formed in volcanic ash and defined as soils containing high proportions of glass and amorphous colloidal materials, including allophane, imogolite and ferrihydrite...
  
   — form in volcanic ash
  Volcanic ash
  Volcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact...
  
   and defined as containing high proportions of glass and amorphous colloidal materials, including allophane
  Allophane
  Allophane is a poorly-crystalline hydrous aluminium silicate clay mineraloid. Its chemical formula is Al2O3·1.3-2·2.5-3. 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...
  
  , imogolite
  Imogolite
  Imogolite is an aluminium silicate clay mineral with formula: Al2SiO34. It occurs in soils formed from volcanic ash and was first described in 1962 for an occurrence in Uemura, Kumamoto prefecture, Kyushu Region, Japan. Its name is derived from the Japanese imogo for the brownish yellow soil...
  
   and ferrihydrite
  Ferrihydrite
  Ferrihydrite is a widespread hydrous ferric oxyhydroxide mineral at the Earth's surface, and a likely constituent in extraterrestrial materials. It forms in several types of environments, from freshwater to marine systems, aquifers to hydrothermal hot springs and scales, soils, and areas affected...
  
  
• Aridisols
  Aridisols
  Aridisols are a soil order in USA soil taxonomy. Aridisols form in an arid or semi-arid climate. Aridisols dominate the deserts and xeric shrublands, which occupy about one third of the Earth's land surface...
  
   — (from the Latin aridus, for “dry”) form in an arid or semiarid climate
• Entisols — do not show any profile development other than an A horizon
• Gelisols
  Gelisols
  Gelisols are an order in USDA soil taxonomy. They are soils of very cold climates which are defined as containing permafrost within two meters of the soil surface...
  
   — soils of very cold climates which are defined as containing permafrost within two meters of the soil surface
• Histosols — consist primarily of organic materials
• Inceptisols
  Inceptisols
  Inceptisols are a soil order in USDA soil taxonomy. They form quickly through alteration of parent material. They are older than entisols. They have no accumulation of clays, Iron, Aluminum or organic matter. They have an Ochric or Umbric horizon and a cambic subsurface horizon....
  
   — form quickly through alteration of parent material
• Mollisols
  Mollisols
  Mollisols are a soil order in USDA soil taxonomy. Mollisols form in semi-arid to semi-humid areas, typically under a grassland cover. They are most commonly found in the mid-latitudes, namely in North America, mostly east of the Rocky Mountains, in South America in Argentina and Brazil, and in...
  
   — form in semiarid to semihumid areas, typically under a grassland cover
• Oxisols — best known for their occurrence in tropical rain forest
• Spodosols — typical soils of coniferous or boreal forests
• Ultisols
  Ultisols
  Ultisols, commonly known as red clay soils, are one of twelve soil orders in the United States Department of Agriculture soil taxonomy. They are defined as mineral soils which contain no calcareous material anywhere within the soil, have less than 10% weatherable minerals in the extreme top layer...
  
   — commonly known as red clay soils
• Vertisols — high content of expansive clay

See also

• FAO soil classification
  FAO soil classification
  The Food and Agriculture Organization of the United Nations developed a supra-national classification, also called World Soil Classification, which offers useful generalizations about soils pedogenesis in relation to the interactions with the main soil-forming factors. It was first published in...
  
  
• International Committee on Anthropogenic Soils
  International Committee on Anthropogenic Soils
  The International Committee on Anthropogenic Soils defines its mission as follows. "ICOMANTH is charged with defining appropriate classes in soil taxonomy for soils that have their major properties derived from human activities...
  
   (ICOMANTH)
• Soil classification
  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 :...
  
  
• 1938 USDA soil taxonomy
  1938 USDA soil taxonomy
  The 1938 USDA soil taxonomy was a soil classification system adopted by the United States Department of Agriculture, now obsolete. The classification system used previously was developed and published in 1936 by C.F. Marbut, who was chief of the U.S. Soil Survey at that time. A drastic...
  
  
• Soil
  Soil
  Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
  
  

External links

• USDA / NRCS soil taxonomy webpage
• [ftp://ftp-fc.sc.egov.usda.gov/NSSC/Soil_Taxonomy/tax.pdf Soil taxonomy document]
• A Compendium of On-Line Soil Survey Information: Soil Classification Systems
• USDA-NRCS Web Soil Survey