Soil Suborders

OOF

-Alfa

Alfisols

-Ands

Andisols

-Ids

Aridisols

-Ents

Entisols

-NONE

Gelisols

-Ists

Hisosols

-Epts

Inceptisols

-Olls

Mollisols

-OX

Oxisols

-Ods

Spodisols

-Ults

Ultisols

-Erts

Vertisols

Entisols Def.

Very Young Soils from alluvial deposition

Alfisols Def.

Cool, moist climate.

Light Colored

Moderately Acidic

Andisols Def.

Soils derived from volcanic material

Dark color

Fertile

Aridisols Def.

Common Western United States

Thin or no O or A horizon

Often Alkaline

Gelisols Def.

Solis grown in areas with permafrost within 100 cm of surface

Only in Alaska

Histosols Def.

Organic soils

Mostly soils that are commonly called bogs, moors, or peats and mucks

Inceptisols Def.

Young soils

Humid or sub-humid

Horizons that only form quickly

Weak B horizon

Mollisols Def.

Prarie Soils

Dark, thick, with good structure

Low to moderate rainfall

Oxisols Def.

Highly weathered tropical soils

low in weathered material

High in aluminum

Only occur in Hawaii and Puerto Rico

Spodisols Def.

Light-colored

Acid forest

soils in cool regions

generally infertile

Ultisols Def.

Highly weather soils

warm climates

Often leached, acid, and infertile

Common to southeastern U.S.

Vertisols Def.

High in swelling clays

when dry, large, deep cracks form

Found in southern states especially Texas

(Dry Clay Soil)

Particle Size Impacts

Internal Surface Area

• The smaller the particle size, the larger the surface area = higher water-holding capacity

Number and Sizes of pore spaces

Sand

<2 mm but >0.05 mm

Of one mineral

Silt

<0.55 mm but > 0.002 mm

particles not visible

not gritty

Smooth, when wet not sticky

Clay

<0.002 mm

Great specific surface area

Particles stick

Particle Density

Mass per unit of SOLID soil volume

Bulk Density

Function of weight and volume of unit of dry soil

= mass of solids + pores

Soil Porosity

Measure of soil volume that holds air and water

SP = wet weight (g) – dry weight (g) / soil volume cm3
X 100

Soil Permability

Ease which water, air, roots move through
soil