Softer plinthosols are common in the wet tropics, including in the eastern Amazon basin, the central Congo Basin and parts of Southeast Asia. Dryer areas, including the Sudano-Sahelian zone, Southern African savannah, the Indian subcontinent, and parts of Southeast Asia and northern Australia feature mostly harder pisoliths and petroplinthite.

• Laterite – Product of rock weathering in wet tropical climates rich in iron and aluminium

• IUSS Working Group WRB: World Reference Base for Soil Resources, fourth edition. International Union of Soil Sciences, Vienna 2022. ISBN 979-8-9862451-1-9 ([1]).

• W. Zech, P. Schad, G. Hintermaier-Erhard: Soils of the World. Springer, Berlin 2022, Chapter 10.3.2. ISBN 978-3-540-30460-9

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• Profile photos (with classification) IUSS World of Soils