Soil Classification | Soil Genesis and Development, Scenario 3 - Soils and Salts

There is no way anyone could keep track of such a variety of soils without a system – a classification system, similar in some ways to that used to classify organisms in biology. There are 12 general categories of soil called soil Orders. You can read brief descriptions of all of the Orders in the soil Order descriptions, Soil Genesis and Development Lessons 5.2 - 5.14. The three soils we’ve been working with, however, all belong to the same soil Order.

Soil series of saline wetland site.Images courtesy of USDA-NRCS¹ Photo reprinted with permission of the Soil Science Society of America from the Marbut Collection² Photo courtesy of R. Hammer, USDA Natural Resources Conservation Service

Quiz

Question

Question 13: Using the descriptions given in the links (Soil Genesis and Development Lessons 5.2 - 5.14) and your observations from the photos above, which of the soil Orders below are these three soils classified under‏?

To review this concept click on the links: Soil Genesis and Development Lesson 5.2 - 5.14

Entisol

Entisols are very young soils with few horizons.

Alfisol

Alfisols do not have very dark, thick A horizons.

Gelisol

Gelisols are found in areas with permafrost.

Histosol

Histosols are soils composed almost entirely of organic matter.

Mollisol

Mollisols are soils with thick, dark A horizons.

Inceptisol

Inceptisols are fairly young soils with minimal horizon development.

Vertisol

Verstisols are soils with very high clay content which shrink and swell so much they destroy most of their horizons.

Oxisol

Oxisols are very highly weathered, often red, soils.

Ultisol

Ultisols are fairly weathered soils that do not have dark, thick A horizons.

Andisol

Andisols are formed from volcanic ash.

Spodosol

Spodosols are often formed under coniferous vegetation and have strongly-colored red, black, and white horizons.

Aridisol

Aridisols are found in areas with very dry climates and accumulate little organic matter.

Looks Good! Mollisols are soils with thick, dark A horizons.

Quiz

Question

Question 14: Which of the five soil forming factors is most responsible for the similarity of the three soils (Hint: You can eliminate topography – that is what made them different. Also remember that all factors may be similar to some degree, but one more than the others forces the soils to develop in very similar ways).

To review this concept click on the links: Soil Genesis and Development Lessons 3.2 to 3.6

biota

Mollisols are characterized by a thick, dark A horizon which is formed by the growth and death of plants, and the alteration of that organic material into humus.

time

The soil materials were deposited at different times.

climate

While climate is a major reason why certain plants grow on these sites, it is not the immediate cause of the different soil similarities.

parent material

The soils are formed from different parent materials (alluvium and loess), which would differentiate them, especially when they are young. Alluvium (defined)- Sediments deposited by running water of streams and rivers. It may occur on terraces well above present streams, on the present flood plains or deltas, or as a fan at the base of a slope.

Looks Good! Mollisols are characterized by a thick, dark A horizon which is formed by the growth and death of plants, and the alteration of that organic material into humus.

Quiz

Question

Question 15a: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the alfisol order be present there‏?

Yes

Alfisols are formed in temperate climates under hardwood vegetation.

No

Alfisols are formed in temperate climates under hardwood vegetation.

Looks Good! Alfisols are formed in temperate climates under hardwood vegetation.

Question

Question 15b: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the andisol order be present there‏?

Yes

Andisols are formed from volcanic ash.

No

Andisols are formed from volcanic ash.

Looks Good! Andisols are formed from volcanic ash.

Question

Question 15c: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the aridisol order be present there‏?

Yes

Aridisols are formed in areas with very low rainfall.

No

Aridisols are formed in areas with very low rainfall.

Looks Good! Aridisols are formed in areas with very low rainfall.

Question

Question 15d: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the entisol order be present there‏?

Yes

Entisols are very young soils and could form in coastal areas because of constant erosion and redeposition of parent material.

No

Entisols are very young soils and could form in coastal areas because of constant erosion and redeposition of parent material.

Looks Good! Entisols are very young soils and could form in coastal areas because of constant erosion and redeposition of parent material.

Question

Question 15e: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the gelisol order be present there‏?

Yes

Gelisols are soils of very cold climates.

No

Gelisols are soils of very cold climates.

Looks Good! Gelisols are soils of very cold climates.

Question

Question 15f: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the histosol order be present there‏?

Yes

Histosols are organic soils that form under conditions that preserve organic matter, such as where water tables are high.

No

Histosols are organic soils that form under conditions that preserve organic matter, such as where water tables are high.

Looks Good! Histosols are organic soils that form under conditions that preserve organic matter, such as where water tables are high.

Question

Question 15g: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the inceptisol order be present there‏?

Yes

Inceptisols are fairly young soils so could form in coastal areas that are not constantly churned by erosion and redeposition.

No

Inceptisols are fairly young soils so could form in coastal areas that are not constantly churned by erosion and redeposition.

Looks Good! Inceptisols are fairly young soils so could form in coastal areas that are not constantly churned by erosion and redeposition.

Question

Question 15h: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the mollisol order be present there‏?

Yes

Mollisols are soils formed in fairly dry climates under prairie grasses.

No

Mollisols are soils formed in fairly dry climates under prairie grasses.

Looks Good! Mollisols are soils formed in fairly dry climates under prairie grasses.

Question

Question 15h: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the oxisol order be present there‏?

Yes

Oxisols are very old soils and would not be found in unstable coastal areas.

No

Oxisols are very old soils and would not be found in unstable coastal areas.

Looks Good! Oxisols are very old soils and would not be found in unstable coastal areas.

Question

Question 15j: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the spodosol order be present there‏?

Yes

Spodosols are found in some Florida locations with alternating water table depths, but not in coastal areas subject to erosion and flooding.

No

Spodosols are found in some Florida locations with alternating water table depths, but not in coastal areas subject to erosion and flooding.

Looks Good! Spodosols are found in some Florida locations with alternating water table depths, but not in coastal areas subject to erosion and flooding.

Question

Question 15k: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the ultisol order be present there‏?

Yes

Ultisols are fairly old soils and would not be found in unstable coastal areas.

No

Ultisols are fairly old soils and would not be found in unstable coastal areas.

Looks Good! Ultisols are fairly old soils and would not be found in unstable coastal areas.

Question

Question 15l: Nebraska is an unusual location for a saline wetland. Suppose we were looking at a saline soil formed in a coastal marsh in Florida. Will soils from the vertisol order be present there‏?

Yes

Vertisols are soils formed from marine (ocean) sediments that have been raised above sea level. They shrink and swell greatly when dry or wet.

No

Vertisols are soils formed from marine (ocean) sediments that have been raised above sea level. They shrink and swell greatly when dry or wet.

Looks Good! Vertisols are soils formed from marine (ocean) sediments that have been raised above sea level. They shrink and swell greatly when dry or wet.

To review this concept click on the link: Soil Genesis and Development Lesson 5.2 to 5.14

Quiz

Question

Question 16a: Saline soils can form in other locations besides just wetlands. Is topography responsible for accumulation of salt in a soil?

Yes

Low areas close to a water table may accumulate salts from the water present.

No

Low areas close to a water table may accumulate salts from the water present.

Looks Good! Low areas close to a water table may accumulate salts from the water present.

Question

Question 16b: Saline soils can form in other locations besides just wetlands. Is parent material responsible for accumulation of salt in a soil?

Yes

Some parent materials may be saline and so contribute to forming a saline soil.

No

Some parent materials may be saline and so contribute to forming a saline soil.

Looks Good! Some parent materials may be saline and so contribute to forming a saline soil.

Question

Question 16c: Saline soils can form in other locations besides just wetlands. Is time responsible for accumulation of salt in a soil?

Yes

The passage of time by itself will not cause salt to accumulate unless other factors are involved.

No

The passage of time by itself will not cause salt to accumulate unless other factors are involved.

Looks Good! The passage of time by itself will not cause salt to accumulate unless other factors are involved.

Question

Question 16d: Saline soils can form in other locations besides just wetlands. Is biota responsible for accumulation of salt in a soil?

Yes

Unique salt-tolerant plants and animals may be found on a saline soil, but they do not cause the salt to accumulate.

No

Unique salt-tolerant plants and animals may be found on a saline soil, but they do not cause the salt to accumulate.

Looks Good! Unique salt-tolerant plants and animals may be found on a saline soil, but they do not cause the salt to accumulate.

Question

Question 16e: Saline soils can form in other locations besides just wetlands. Is climate responsible for accumulation of salt in a soil?

Yes

High evaporation of soil water may cause salts to accumulate, especially at the soil surface, leaving a crust of salt. This assumes that rainfall is insufficient to wash the accumulated salts back below the surface.

No

High evaporation of soil water may cause salts to accumulate, especially at the soil surface, leaving a crust of salt. This assumes that rainfall is insufficient to wash the accumulated salts back below the surface.

Looks Good! High evaporation of soil water may cause salts to accumulate, especially at the soil surface, leaving a crust of salt. This assumes that rainfall is insufficient to wash the accumulated salts back below the surface.

To review this concept click on the links: Soil Genesis and Development Lessons 3.1 to 3.6