Suborders of Ultisols

•Aquults•Humults•Udults•Ustults•Xerults

Aquults• water table at or near the surface for most of the year. • Redoximorphic features found in all layers below 25 cm. • Found in; South East United States along the Atlantic Sea

board, South East Asia which includes Indonesia, Malaysia and the Philippines, Upper Amazon River Basin, Congo/Zaire River Basin of Central Africa, and other humid tropic regions with acidic parent materials.

• This suborder of the Ultisols can most likely be found in the inter floodplain.

Humults

• High organic carbon content• Well drained soil, not as wet as Aquults• U.S. found in Willamette Valley of Oregon and into

Washington

Udults

• Found in humid climates• Short periods of dry season• Slightly lower organic content than Humults• Cover vast majority of South Eastern U.S.

Ustults

• Limited moisture• Soil moisture/ availability is seasonally

adequate for at least one crop a year• Found in semiarid and sub humid climates

Xerults

• Temperate Ultisol• Extreme dry summers with moist winters• Sacramento Valley

Suborders of Oxisols

• Aquox• Torrox• Ustox• Perox• Udox

Aquox• Water table at or near the surface for most of the year• wet Oxisols in shallow depressions and in seepage areas at

the base of slopes• A histic epipedon with a hue of 2.5Y or yellower• Found in North Central South America, Central Africa,

Countries close to Equator Globally.• redox concentrations within 50 cm of the mineral soil surface

Aquox Locations

Torrox• These are Oxisols of arid regions• known to occur only Hawaii in the United States

Ustox

• Found in semiarid and subhumid climate• Ustox may be the most extensive suborder,

occurring over a large portion of the interior of South America and in extensive areas of Africa.

Perox

• well drained Oxisols• Found in humid climates where precipitation

exceeds evapotranspiration all year• Poor quality for crops• “Low activity Soils”

Udox

• Found in humid climates• well drained Oxisols• natural rainfall in normal years is abundant

and are areas are dry in some parts for less than 90 days,

Vertisols

• Aquerts• Cryerts• Xererts• Torrerts• Usterts• Uderts

Aquerts

• These soils are typically in low areas, such as glacial lake plains, flood plains, stream terraces, and depressions.

• water table at or near the surface for most of the year

• Manganese oxide gives it dark color• Rice production in Sacramento Valley of

California in winter months

Cryerts

• Cold climates• Usually found at grassland/ forest grassland

transition zones of Canadian praires and possibly in Russia

• Fine textured• periodically shrink and swell, Cracks

commonly open once a year, late in the summer.

Xererts

• Vertisols of Mediterranean climates, which are typified by cool, wet winters and warm, dry summers

• damage to structures and roads is very significant

• Cracks open for atleast 60 consecutive days in both summer and winter seasons

Torrerts

• arid climates

• Found in small quantities in Texas, New Mexico and Arizona, but is the most extensive suborder found in Austrailia.

• closed depressions that can hold ponds from time to time by runoff from the higher areas.

• parent material basalt.

Usderts

• Texas, Australia, Africa, and India

• cracks in normal rainfall years are 5 mm or more wide

• Low rainfall during the summer, tropical and subtropical areas that have two rainy and two dry seasons

• derived from basic igneous rocks

Uderts

• humid areas• gentle slopes and are derived dominantly from

marine shales and alluvium• At one time many of these soils supported

grass, although some support a hardwood or pine forest

Aridisols

• Cryids• Salids• Durids• Gypsids• Argids• Calcids• Cambids

Cryids

• cold desert soils

• high elevations, dominantly in the mountain and basin areas in the United States and Asia

Salids

Salids• common in depressions in the

• Upper boundary within 100 cm of soil surface

• Occur where salts are concentrated near the surface, driven up wards by evaporation

sodium chloride

• Salids are unsuitable for agricultural use

Durids

• have a duripan that has an upper boundary within 100 cm of the soil surface, but most are within 50 cm of the soil surface

• occur dominantly on gentle slopes-Range Land• soils commonly have calcium carbonate

Duripan

Gypsids

• gypsic or petrogypsic horizon within 100 cm of the soil surface

• Accumulation of gypsum takes place initially as crystal aggregates in the voids of the soils

• gypsic horizon occurs as a cemented impermeable layer,

• Gypsids occur in Iraq, Syria, Saudi Arabia, Iran, Somalia, West Asia

Gypsic Soil of Italy

Argids

• do not have a duripan within 100 cm of the soil surface

• high concentration of salts hinder clay illuviation

Calcids

• Found on geologically younger slopes• calcium carbonate in parent materials• extensive in western United States other arid

regions of the world. • Do not have a duripan or a salic, gypsic layer

within 100 cm of the soil surface

Cambids

• Aridisols with lowest soil development

• Weakly developed B horizon

• most common Aridisols in the United States