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Department of Soil and Water Systems

Physical Address:
E. J. Iddings Agricultural Science Laboratory, Rm 242
606 S Rayburn St

Mailing Address:
875 Perimeter Drive MS 2340
Moscow, ID 83844-2340

Phone: 208-885-0111

Email: cals-sws@uidaho.edu

Web: uidaho.edu/cals/sws

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Andisols

Andisols (from Japanese ando, "black soil") are soils that have formed in volcanic ash or other volcanic ejecta. They differ from those of other orders in that they typically are dominated by glass and short-range-order colloidal weathering products such as allophane, imogolite and ferrihydrite. As a result, Andisols have andic properties — unique chemical and physical properties that include high water-holding capacity and the ability to "fix" (and make unavailable to plants) large quantities of phosphorus. They are divided into eight suborders: Aquands, Gelands, Cryands, Torrands, Xerands, Vitrands, Ustands and Udands.

Globally, Andisols are the least extensive soil order and only account for approximately 1 percent of the ice-free land area. They occupy approximately 1.7 percent of the U.S. land area, including some very productive forests in the Pacific Northwest region.

Andisols
Andisols have andic soil properties in layers either: (1) with a cumulative thickness of 36 cm within 60 cm of the mineral soil surface; or (2) comprising at least 60 percent of the depth between the mineral soil surface and a root-restrictive horizon. (USDA-NRCS image)

Contact

Department of Soil and Water Systems

Physical Address:
E. J. Iddings Agricultural Science Laboratory, Rm 242
606 S Rayburn St

Mailing Address:
875 Perimeter Drive MS 2340
Moscow, ID 83844-2340

Phone: 208-885-0111

Email: cals-sws@uidaho.edu

Web: uidaho.edu/cals/sws

Directions