They are widely used both in agriculture and forestry, and are generally easier to keep fertile than other humid-climate soils, though those in Australia and Africa are still very deficient in nitrogen and available phosphorus.
In the World Reference Base for Soil Resources (WRB), most Alfisols are classified as Luvisols or Lixisols, but some are classed as Retisols or Nitisols.
They are dominant in many areas, such as the Ohio River basin in the United States, southern and unglaciated Western Europe, the Baltic region and central European Russia, the drier parts of Peninsular India, Sudan in Africa, and many parts of South America.
Probably owing to their fertility, they are the oldest forest soils; vegetation on weathered Oxisols, by contrast, is not known earlier than Middle Permian.
From the fossil wood and spores found in the Aztec Siltstone, there is a strong indication that the trees were Archaeopteris-Callixylon.
[3] In the lower Walton Formation, near Sidney, New York fossils of Archaeopteris macilenta, Callixylon zalesskyi, and Geminospora lemurata have been found.
The tapering geometry of large woody root traces is the most likely cause of the intimate relationship between Argillic horizons, Alfisols, and forests.
The Termitichnus ichnofacies, which included a large array of termite nests and pellets, is found in Oligocene Alfisols, Aridisols, and Oxisols.
All the tetrapod bones and tracks from the paleosol sequences of Late Devonian and Mississippian of New York and Pennsylvania, U.S.A. are found in Aridisols and Alfisols.