5.11 - Andisols

Soils form in volcanic ash and cinders near or downwind from volcanic activity. Generally lacking in development, they are not extensively weathered, forming in deposits from geologically recent events. Usually of high natural fertility, they tend to accumulate organic matter readily and are of a ‘light’ nature (low bulk density) that is easily tilled. These soils generally have a high productivity potential.

Soil order - Andisols. Image courtesy of USDA-NRCS

Profile example - Andisol Series. Image courtesy of USDA-NRCS

Idaho state soil

USDA details

More information from the University of Idaho


Key Characteristics:  Andisols

  • Form in regions of recent volcanism
  • Volcanic parent materials
  • Generally high in natural fertility
  • ‘Light’ soils that are easily cultivated.
  • Potentially very productive soils
  • Limited geographic distribution
  • Extent of world ice-free land area: 1%

U.S. Order Distribution Map for Andisols. Image courtesy of USDA-NRCS

Further Detail by the NRCS




Andisol soils are formed as a result of what type of geologic activity?‏  

Looks Good! Correct: Andisols are soils forming in ash and cinders near or downwind from volcanic areas.