sol-, -sol +

(Latin: base, ground, soil, bottom; the lowest part of something; sole of the foot or a shoe)

Soil orders are named by adding the suffix -sol to a root word, as shown in the table of the United States Soil Taxonomy and the soil classification system of the Food and Agriculture Organization, FAO (agency of the United Nations).

Many of the applicable soilwords which are listed and defined in this unit do not use the -sol suffix; however, they are included because they are essential parts of the major listings of the U.S. Soil Taxonomy and the Food and Agriculture Organization presentations.

The soil groups are based on extensive sets of field and laboratory observations and on extensive technical criteria.

Ultisol, Ultisols
1. Strongly leached, acid forest soils with relatively low native fertility.

They are found primarily in humid temperate and tropical areas of the world, typically on older, stable landscapes.

Ultisols have a subsurface horizon in which clays have accumulated, often with strong yellowish or reddish colors that result from the presence of Fe (metal) oxides. The "red clay" soils of the southeastern United States are examples of Ultisols.

With the use of fertilizer and lime, these Ultisols can be very productive for agriculture.

Ultisols are divided into five suborders: Aquults, Humults, Udults, Ustults, and Xerults; all of which are defined in this unit.

2. From the U.S. Soil Taxonomy soil-order classification system.
3. Etymology: from Latin ultimus, "last".
Umbrisol, Umbrisols
1. Soils that are characterized by a surface layer whicht is rich in humus, but not in calcium, and available to plants, owing to high rainfall and extensive leaching that lead to acidic conditions.

They are found under forest cover in high-rainfall regions of western Europe, the Pacific Coast of North America north of California, the southwestern coast of South America, and the Himalayas.

Umbrisols occupy about 0.8 percent of the total continental land area on earth and are related to soils of the Inceptisol order of the U.S. Soil Taxonomy which form under coniferous forest vegetation.

They are the forestland counterpart of Chernozems, Kastanozems, and Phaeozems in exhibiting a humus-rich surface layer.

2. From the classification system of the Food and Agriculture Organization, FAO.
3. Etymology: from Latin umbra, "shade, shadow".
Ustalfs
Alfisols existing in semiarid and subhumid climates.
Ustands
Andisols of semiarid and subhumid climates.
Ustepts
Inceptisols of semiarid and subhumid climates.
Usterts
Vertisols of semiarid and subhumid climates.
Ustolls
Mollisols existing in semiarid and in subhumid climates.
Ustults
Ultisols in semiarid and subhumid climates.
Vertisol, Vertisols
1. Clay-rich soils that shrink and expandl with changes in moisture content.

During dry periods, the soil shrinks, and significant vertical cracking and deep wide cracks form; but, as it gets water, the soil expands.

Typically forming under grassland vegetation in basins or rolling hill landscapes, Vetisols are best suited for use as pastureland and for the cultivation of plants; such as, rice, which thrives in standing surface water.

Vertisols are divided into six suborders: Aquerts, Cryerts, Xererts, Torrerts, Usterts, and Uderts all of which are defined in this unit.

2. From the U.S. Soil Taxonomy soil-order classification system.
3. Etymology: from Latin vertere, "to turn".
Vitrands
Relatively young Andisols that are coarse-textured and dominated with glass.
Wassents
Entisols which are submerged for more than twenty-one hours every day.
Wassists
Histosols which are submerged for more than twenty-one hours every day.
Xeralfs
Temperate Alfisols with very dry summers and wet winters.
Xerands
Temperate Andisols with very dry summers and moist winters.
Xerepts
Temperate Inceptisols with very dry summers and moist winters.

Much of the information presented in this unit was compiled from the following sources:

Encyclopædia Britannica Online; "U.S. Soil Taxonomy"; December 19, 2010.

Soil and Land Resources Division, by Dr. Paul McDaniel;
University of Idaho, Moscow, Idaho; College of Agricultural and Life Sciences;

The National Geographic Desk Reference; A Stonesong Press Book;
National Geographic Society; Washington, D.C.; 1999; pages 224-227.