ANDIC SOIL PROPERTIES OF SPODOSOLS IN NONVOLCANIC MATERIALS OF SOUTHEAST ALASKA

Andic properties are typical of soils in volcanic materials, including those in southeast Alaska. Nonvolcanic materials, however, predominat e in southeast Alaska, yet andic properties are common in Spodosols th roughout the area. A well-drained, forested Spodosol was sampled in Ho locene beach deposits with no more than traces of volcanic glass. The pedon has a thin E horizon and a spodic horizon that has andic soil pr operties typical of Spodosols in southeast Alaska. Acid-oxalate-extrac table Al + (Fe/2) is 3.6% in the Bh, 5.8% in the Bhs, and 6.4% in the Bs horizon. Soil bulk densities are low and P retention is >90% in all subhorizons of the spodic horizon. The soil is an Andic Humicryod. Ab out one-third of the Spodosols in nonvolcanic materials of southeast A laska meet the andic or aquandic subgroup requirements of Haplocryods, Humicryods, or Cryaquods. In addition, other Spodosols have andic pro perties in subhorizons of a spodic horizon < 25 cm thick and some are in lithic subgroups. Rapid weathering and leaching, high organic matte r content, and cool temperatures promote the accumulation of amorphous Al and Fe compounds in the perudic soils of southeast Alaska.