Alfisols - These soils are found in fairly moist areas and are great for crops. Unfortunately, they formed via weathering that leached minerals, specifically clay, into the subsoil. This clay hold moisture and is a key reason why subgrade preparation is essential to the success of your asphalt paving project.
Mollisols - Mollisols are high in organic matter and found in Oklahoma climates with a pronounced arid season. This soil is found across the central part of the state.
Aridisols - This OK panhandle soil is rich in minerals like gypsum and salt because of its location in arid regions of the state.
Ultisols - A soil with very high acid and clay content because of heavy annual rainfall. This material can be found in east Oklahoma.
Entisols - Found in areas throughout Oklahoma, this soil consists of eroded material. This soil is the most common found worldwide and is seen in river valleys and shore deposits.
Vertisols - The extremely high clay content of this soil causes significant shrink/swell with changes in moisture. The majority of this material in Oklahoma is found near the south east border with Texas.
Inceptisols - This soil is typically located in rocky mountainous areas and can be found in west Oklahoma. This material is ideal for asphalt subgrade as there in no accumulation of clay or organic matter.