1. Entisols
“Baby Soils”
Linda Peterson

2. Entisols are soils of recent origin
Entisols are 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 fit into one of the other 11 orders are Entisols. Thus, they are characterized by great diversity, both in environmental setting and land use.
The order entisol includes soils that are so weakly developed they may have only a thin ochric epipedon over a C horizon. There are two reasons why these soils lack greater development: 1. the parent material consists of such highly resistant minerals that the rate of weathering is very slow; for example, droughty sands remain poorly developed because they contain an abundance of quartz; or 2. The exposed land surface is young as a result of erosion or burial under new material brought in by wind or some other agent.

3. Unprotected soils on slopes are subject to water erosion, and on more-level plains wind may erode the topsoil, thus exposing new material below and keeping this so young. The opposite process keeps alluvial and wetland soils young. New material is added layer by layer as floodwater moves over the soils or temporary ponds spread across them.

4. General characteristics
Formative Element: Time
Description: Young, thin, relatively underdeveloped soils
Common Master Horizon(s): A and C
NO Common Subhorizons
Description of genetic horizons: thin A horizon over parent material
FAO translation: Fluvisols, Lithosols, Arenosols, Regosols
% of U.S. land area: 16.2% (12.3%)
% of World land area: 17.9% (18%)

5. Typical Environments
Many Entisols are found in steep, rocky settings. However, Entisols of large river valleys and associated shore deposits provide cropland and habitat for millions of people worldwide. This also includes the soils of unstable environments, such as floodplains, sand dunes, or those found on steep slopes. Entisols are commonly found at the site of recently deposited materials (e.g., alluvium), or in parent materials resistant to weathering (e.g. sand). Entisol soils also occur in areas where a very dry or cold climate limits soil profile development. Productivity potential of Entisols varies widely, from very productive alluvial soils found on floodplains, to low fertility/productivity soils found on steep slopes or in sandy areas.

6. Globally Entisols are the most extensive of the soil orders, occupying ~18% of the Earth's ice-free land area. In the US, Entisols occupy ~12.3% of the land area.
Entisols are divided into 6 suborders: Wassents, Aquents, Arents, Psamments, Fluvents, and Orthents.
Entisols have no diagnostic horizons. Some Entisols have steep, actively eroding slopes, and others are on flood plains or glacial outwash plains that receive new deposits of alluvium at frequent intervals.

7. Suborders
Wassents - Entisols that are submerged for more than 21 hours every day
Aquents - Entisols with a water table at or near the surface for much of the year
Arents - Entisols that have been disturbed and contain fragments of diagnostic horizons that are not arranged in any discernable order
Psamments - very sandy Entisols
Fluvents - alluvial Entisols commonly found on floodplains
Orthents - common Entisols that don't meet criteria of other suborders
Wassents - Entisols that are submerged for more than 21 hours every day
Aquents - Entisols with a water table at or near the surface for much of the year
Aquents, or the wet Entisols, are widely distributed. They dominate some of the delineations along the southern Atlantic and gulf coasts and on the flood plains along the Mississippi River and along other rivers and streams. Some Aquents are forming, mostly in sandy deposits, in other parts of the country. Most of the soils are forming in recent sediments. They support vegetation that tolerates permanent or periodic wetness. They are used mostly as pasture, cropland, forest, or wildlife habitat.
Arents - Entisols that have been disturbed and contain fragments of diagnostic horizons that are not arranged in any discernable order
Arents do not have diagnostic horizons because they have been deeply mixed by plowing, spading, or other methods of moving by humans. They are important soils for irrigated crop production in California. Small areas also occur throughout the country. Arents are used mostly as cropland, urban land, or pasture. Some are used as wildlife habitat.
Psamments - very sandy Entisols
Psamments occur throughout the country. Some of the largest areas are in Nebraska, California, Minnesota, Wisconsin, Michigan, Arizona, and Florida. These soils are sandy in all layers. They are among the most productive rangeland soils in some arid and semiarid climates. Some Psamments that are nearly bare are subject to soil blowing and drifting and provide poor support for wheeled vehicles. Psamments are used mostly as rangeland, pasture, or wildlife habitat.
Fluvents - alluvial Entisols commonly found on floodplains
Fluvents are the more or less freely drained Entisols that formed in recent water-deposited sediments on flood plains, fans, and deltas along rivers and small streams throughout the country. Some of the largest areas are on the flood plains along the Mississippi River. Most Fluvents are frequently flooded, unless they are protected by dams or levees. Stratification of the materials is normal. Most Fluvents are used as rangeland, forest, pasture, or wildlife habitat. Some are used as cropland.
Orthents - common Entisols that don't meet criteria of other suborders
Orthents are mainly in the Western States. They are commonly on recent erosional surfaces. Orthents are used mostly as rangeland, pasture, or wildlife habitat.

9. Typic Udifluvent SW Wisconsin
The dynamic nature of fluvial landscapes is responsible for the characteristics seen in this and other Fluvents. Periodic deposition of new sediment creates the numerous stratified layers of mineral and organic matter seen in this profile. This upbuilding process limits expression of the soil-forming processes seen in other soil orders.
Note the presence of a thick buried A horizon at depth in this profile. A feature of this and many other Fluvents is an irregular decrease in organic carbon with depth.

10. Loamy-skeletal, mixed, superactive, nonacid, mesic Lithic Xerorthent
These soils have formed from basalt residuum and are very shallow to bedrock.The 10-cm-thick A horizon represents the extent of soil formation on this steeply sloping landscape position.
The shallow nature of these soils severely limits their use. The most common uses are rangeland and gravel quarries.

11. Udipsamment landscape Northern Michigan
This glacial outwash plain in northern Michigan is dominated by sandy soils. Mean annual precipitation is ~30" (760 mm). Low fertility is a severe limitation to use of these soils. Native vegetation consists of Jack Pine, white oak, and scrub oak. Where cleared, successful agricultural production requires lime and fertilizer inputs.

12. Typic Udipsamment
This soil occurs in glacial outwash on outwash plains in northern Michigan. The B horizon has a slight accumulation of illuvial sesquioxides and thin coatings of illuvial organic matter, but not sufficient quantities to qualify as a Spodosol. The sand textures also prevent the Bw horizon from qualifying as a cambic diagnostic horizon in Soil Taxonomy..

13. Coarse-silty, mixed, superactive, calcareous, mesic Typic Torriorthent
The parent material for this soil is silty alluvium derived from calcareous lacustrine sediments, and it has undergone very little alteration as a result of soil-forming processes. Horizon formation is limited to the light-colored A horizon, where a slight accumulation of organic matter has aided the development of some soil structure. Because of the arid climate, there has been limited leaching and considerable calcium carbonate is still present in the upper horizons.

14. Entisol Recap Soils with little profile development
Many different parent materials contribute to varied soil properties of this order.
Often found in very dry or cool locations
Geographically extensive, commonly found with aridisols.
Widely varied productivity potential
Extent of world ice-free land area: 16%
Not a state soil

15. Work Cited
McDaniel, Paul, Dr. "Entisols Home." Entisols Home. University of Idaho, n.d. Web. 07 Nov
"Soil Genesis and Development, Lesson 5 - Soil Classification and Geography." Plant and Soil Sciences ELibrary. USDA, n.d. Web. 07 Nov
Eash, Neal Samuel., Mary C. Bratz, and Milo I. Harpstead. Soil Science Simplified.
Ames, IA: Blackwell Pub., Print.