A Phaeozem in the World Reference Base for Soil Resources (WRB) is a dark soil with a high base status, but without a secondary carbonates within one metre of the soil surface. Phaeozems correlate with the Udolls and Aquolls (Mollisols) of the USDA soil taxonomy.
These soils are found mainly in humid and sub-humid tall-grass steppes; there are extensive areas of them in the United States, Argentina and China. Phaeozems form from unconsolidated sediments such as loess and glacial till and typically have organic matter contents of about 5% and a pH of 5–7.
- IUSS Working Group WRB: World Reference Base for Soil Resources 2014, Update 2015. World Soil Resources Reports 106, FAO, Rome 2015. ISBN 978-92-5-108369-7 (PDF 2,3 MB).
- Delvaux, B.; Brahy, V. "Mineral Soils conditioned by a Wet (Sub)Tropical Climate". FAO. Retrieved 14 June 2014.
- Major Soils of the World. ISRIC Wageningen, The Netherlands, 2001