University of Idaho College of Agricultural and Life Sciences Plant, Soil & Entomological Sciences Soil & Land Resources
Soil Orders
Soil Links
  Gelisols    Histosols    Spodosols    Andisols    Oxisols    Vertisols    Aridisols    Ultisols    Mollisols    Alfisols    Inceptisols    Entisols


Spodosols (from Greek spodos, "wood ash") are acid soils characterized by a subsurface accumulation of humus that is complexed with Al and Fe. These photogenic soils typically form in coarse-textured parent material and have a light-colored E horizon overlying a reddish-brown spodic horizon. The process that forms these horizons is known as podzolization.

Spodosols often occur under coniferous forest in cool, moist climates. Globally, they occupy ~4% of the ice-free land area. In the US, they occupy ~3.5% of the land area.

Many Spodosols support forest. Because they are naturally infertile, Spodosols require additions of lime in order to be productive agriculturally.

Spodosols are divided into 5 suborders: Aquods, Gelods, Cryods, Humods, and Orthods. Click here for more information about these suborders. Click here to view a map of their distribution in the US.

Click on map to view larger image

Click on map to view larger image
<< back to Soil Orders list Spodosol example #1 >> 
1. Aeric Alaquod
North Carolina
2. Durorthod landscape
northern Michigan
3. Typic Durorthod
northern Michigan
4. Haplocryod landscape
northern Idaho
5. Andic Haplocryod
northern Idaho
6. Haplocryod landscape
northern Idaho
7. Aquic Haplocryod
northern Idaho

8. Kauri landscape
New Zealand

9. Egg-cup Spodosol
New Zealand
If you have any comments, suggestions, or questions about the 12 Soil Orders web site,
please contact
Dr. Paul McDaniel  at the Soil Science Division,
University of Idaho, Moscow, ID 83844-2339.