The Alfisols

When soil scientists first began studying the soils of the continental U.S. they came across a group rich in aluminum and iron oxides. They named these soils Pedalfers to indicate their higher aluminum (Al) and iron (Fe) contents. Today many of those same soils are called Alfisols.

Alfisols are the non-acid counterparts of Ultisols. Soils in both orders require an accumulation of clay in the subsoil. The importance soil scientists attach to clay movement is reflected in the creation of two soil orders on this property alone.

Alfisols are not extensive in Hawaii, but when they do occur, they are generally associated with the non-acid Oxisols (Eutrustox). When they occur together, the Alfisols are generally found on the steeper slopes near the valley edges.

In Hawaii, Alfisols are fertile soils but require irrigation to support most types of crop production.