Wiktionary
n. (plural of alisol English)
Wikipedia
Alisols define a soil group within the World Reference Base for Soil Resources
Properties include having an argic horizon, which has a specific cation exchange capacity; a predominantly alic properties zone between 250mm and 1000 mm from the soil surface; and no diagnostic horizons other than an ochric, umbric, albic, andic, ferric, nitic, plinthic or vertic horizon.
Simply put, alisols are poorly drained soils with a dense subsurface clay layer, which causes a relatively high concentration of aluminum ions in the root zone.
There exist mixed forms, for example 'gleyic alisol', that are mainly alisol, but also contain components that are found in gleysols.
Alisols occur mainly in tropical and humid subtropical climates, though a few are found in unglaciated landscapes as far north as Brittany. Compared to Acrisols and Ferralsols, Alisols have much higher-activity clays and are likely to be found on younger terrains or more geologically active regions such as Kyushu and Chugoku.