Andosol

Andosols are soils found in volcanic areas formed in volcanic tephra. In some cases Andosols can also be found outside active volcanic areas.[1] Andosols cover an estimated 1–2% of earth's ice-free land surface. Andosols are a Reference Soil Group of the World Reference Base for Soil Resources (WRB).[2] They are closely related to other types of soils such as Vitrosols, Vitrandosols, Vitrons and Pumice Soils that are used in different soil classification systems. Poorly developed Andosols are often rich in vitreous materials and are therefore also called Vitric Andosols. The name comes from Japanese an (暗 'dark') and do (土 'soil'), synonymous with kuroboku (黒ぼく).[3] In the USDA soil taxonomy, Andosols are known as Andisols.[4]

Andosol
an Andosol profile
Used inWRB
WRB codeAN
ProfileABwC
Parent materialtephra
Climatevarious

Andosols are usually defined as soils containing high proportions of glass and amorphous colloidal materials, including allophane, imogolite and ferrihydrite.[5] Because they are generally quite young, Andosols typically are very fertile except in cases where phosphorus is easily fixed (this sometimes occurs in the tropics). They can usually support intensive cropping, with areas used for wet rice in Java supporting some of the densest populations in the world. Other Andosol areas support crops of fruit, maize, tea, coffee or tobacco. In the Pacific Northwest USA, Andosols support very productive forests.

Andosols occupy ~1% of global ice-free land area. Most occur around the Pacific Ring of Fire, with the largest areas found in central Chile, Ecuador, Colombia, Mexico, the Pacific Northwest US, Japan, Java and New Zealand's North Island. Other areas occur in the East African Rift, Italy, Iceland and Hawaiʻi. They are the most common type of soil in the Azores.[6]

Fossil Andosols are known from areas far from present-day volcanic activity and have in some cases been dated as far back as the Precambrian 1.5 billion years ago.[7][8]

Suborders
  • Aquands – Andosols with a water table at or near the surface for much of the year.
  • Gelands – Andosols of very cold climates (mean annual temperature <0 °C).
  • Cryands – Andosols of cold climates.
  • Torrands – Andosols of very dry climates.
  • Ustands – Andosols of semiarid and sub humid climates.
  • Udands – Andosols of humid climates.
  • Xerands – temperate Andosols with very dry summers and humid winters.
  • Vitrands – relatively young Andosols that are coarse-textured and dominated by glass.


See also

References
  1. Andosols by Olafur Arnalds in Encyclopedia of Soil Science, pp. 39–26.
  2. IUSS Working Group WRB (2022). "World Reference Base for Soil Resources, fourth edition" (PDF). International Union of Soil Sciences, Vienna.
  3. Pavel Vladimirovich Krasilʹnikov (2009). A Handbook of Soil Terminology, Correlation and Classification. Earthscan. p. 376. ISBN 978-1-84977-435-2. Retrieved 30 August 2013.
  4. Major Soils of the World. ISRIC Wageningen, The Netherlands. 2001 Archived 2014-10-23 at the Wayback Machine
  5. "Andisols". National Resource Conservation Service. United States Department of Agriculture. Archived from the original on 9 May 2006. Retrieved 2006-05-14.
  6. "Caracterização e Diagnóstico da Ilha do Pico" (PDF). servicos-sraa.azores.gov.pt. p. 62. Retrieved 7 May 2021.
  7. Grunwald, Sabine. "Andisols". Soil & Water Sciences. University of Florida. Retrieved 2006-05-14.
  8. "Andisols". Soil and Land Sciences Division. University of Idaho. Archived from the original on 2009-03-09. Retrieved 2006-05-14.

Further reading
  • W. Zech, P. Schad, G. Hintermaier-Erhard: Soils of the World. Springer, Berlin 2022, Chapter 11.3.3. ISBN 978-3-540-30460-9
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