5.3 - Entisols | Soil Genesis and Development, Lesson 5 - Soil Classification and Geography

This is a very diverse group of soils with one thing in common, little profile (horizon) development. 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.

Key Characteristics: Entisols

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%

U.S. Order Distribution Map for Entisols. *Image courtesy of USDA-NRCS*

**Further Details from the NRCS**

Quiz

Question

The common property found in ALL Entisol soils is:‏

A. Sandy parent material

Incorrect: Though characteristics of this soil order include a wide range of diversity, all Entisols can be expected to show little profile or horizon development.

B. Steep slopes

Incorrect: Though characteristics of this soil order include a wide range of diversity, all Entisols can be expected to show little profile or horizon development.

C. Little horizon development

Correct: Entisols are a very diverse group of soils with one thing in common, little profile (horizon) development. This order includes the soils of floodplains, sand dunes, or those found on steep slopes. Entisols are commonly formed in recently deposited materials, or in parent materials resistant to weathering (E.G., sand). Entisol soils also occur in areas of very dry or cold climate, on steep slopes, or in sandy areas.

D. Cold and/or dry climate

Incorrect: Though characteristics of this soil order include a wide range of diversity, all Entisols can be expected to show little profile or horizon development.

E. Recently deposited parent material

Incorrect: Though characteristics of this soil order include a wide range of diversity, all Entisols can be expected to show little profile or horizon development.

Looks Good! Correct: Entisols are a very diverse group of soils with one thing in common, little profile (horizon) development. This order includes the soils of floodplains, sand dunes, or those found on steep slopes. Entisols are commonly formed in recently deposited materials, or in parent materials resistant to weathering (E.G., sand). Entisol soils also occur in areas of very dry or cold climate, on steep slopes, or in sandy areas.

Question

In the central Great Plains region of the USA, there is a large area of relatively stable sand dunes called the Nebraska Sandhills (see the map of the Entisol distribution above).

What is the probable reason for the formation of this large area of Entisol soils?

A. Dry climate

Incorrect: The name of this area is a clue to the nature of the parent material found here, and its weathering potential.

B. Parent material that is resistant to weathering

Correct: Yes, the quartz sand parent material is very resistant to weathering and does not favor profile development.

C. Grassland vegetation

Incorrect: The name of this area is a clue to the nature of the parent material found here, and its weathering potential.

D. Steep slopes

Incorrect: The name of this area is a clue to the nature of the parent material found here, and its weathering potential.

E. Recently deposited material

Incorrect: The name of this area is a clue to the nature of the parent material found here, and its weathering potential.

Looks Good! Correct: Yes, the quartz sand parent material is very resistant to weathering and does not favor profile development.