VERTISOLS

Presented By: Jesse Longtin

Vertisol Characteristics

- Dark clay soils that are formed in warm temperate or tropical regions, but can also be found in areas of the US from Texas to South Dakota.

- Shrink and swell depending on the moisture content. Soil shrinks and

forms deep wide cracks during dry periods, and expands during wetter periods.

- Like this! ------------->

Vertisol Characteristics cont’d

- Occur primarily in Texas. Vertisols occupy around 2.4% of the world’s ice-free land area, and cover about 2.0% of the land area within the US.

- Consists of 6 suborders: Aquerts, Cryerts, Xererts, Torrerts, Usterts, and Uderts.

- When the rains return, if there is sediment between the cracks, they can’t close fully. This action causes a churning motion that moves fresh limy material from the C horizon. This movement helps rejuvenate the topsoil faster than it would be leached.

Vertisol Characteristics- Lens-shaped blocks formed within the soil slide

past one another during this swelling action. This creates a polished surface called a slickenside.

Vertisol Characteristics

Mounds and hollows form as the landscape buckles at the hand of these same forces. This creates a gilgai, which is a form of microtopography. It resembles a small ephemeral lake that is formed from a depression in the soil surface.

South Dakota gilgai Texas gilgai

Vertisol Characteristics

- Well adapted to paddy rice cultures and sugar cane. In regions such as Texas, vertisols are used for pastures, but can be hazardous if stepped in by cattle,other livestock, and people.

- Creates intense engineering stresses because buildings can crack or twist. Soil must remain moist to prevent such damages.

Vertisol Global Distribution:

Mostly in areas of Australia, India, and eastern Africa, primarily Sudan. Also found in some regions of the US and Puerto Rico.

Vertisol Distribution of the US

Mostly in the southern US, such as Texas, but can be found in northwestern Minnesota, Montana, the Dakotas, and in small patches across the western US.

Diagnostic Horizons

Hapludert:<--- Ap

<--- Bss

Moderately well-drained, slowly permeable soil within the Lake Charles series in Texas. Slickensides develop around 10-20 inches and are present throughout the B Horizon

Diagnostic Horizons

Haplustert: <--- Ap

<--- AB

<--- Bss

Soil formed in valley fill composed of pyroclastic material and limestone in Puerto Rico. The shrinking and swelling motion of the clays here creates argillipedoturbation, which is a continuous cycle of mixing. This is evident because of the lack of a visible distinct horizon.

Diagnostic Horizons

Haplustert of south-central Texas:

Formed on flat alluvial surfaces with parent material rich in clay and calcium. Slickensides are present throughout the lower profile.

Diagnostic Horizons

Epiaquert:<--- A<--- AB

<--- Bss1

<--- Bss2

Soils found in flat, smooth enclosed lake plains of Boulder Lake of southern Idaho. Formed from fine-textured lacustrine sediments. Runoff from surrounding soils, not extensive rainfall, causes annual inundation.

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