What soil order is characterized by an argillic or glossic horizon?

The correct answer is based on the characteristics of soil orders as defined by the USDA Soil Taxonomy. Alfisols are known for having an argillic horizon, which is a subsurface layer enriched with clay. This feature typically forms in well-drained conditions under moderately weathered environments. The presence of this horizon indicates that the soil has experienced considerable leaching of nutrients and a build-up of clay, reflecting the soil's ability to support productive vegetation.

Alfisols are often found in temperate regions and are valuable for agriculture because they usually contain sufficient nutrients and moisture for crop growth. The glossic horizon, while less common, can also occur in Alfisols, characterized by its shiny appearance due to clay illuviation.

In contrast, other soil orders like Mollisols, Inceptisols, and Entisols have different defining features. Mollisols are characterized by a thick, dark topsoil and are primarily found in grassland environments, while Inceptisols feature a weakly developed profile and typically lack significant clay accumulation. Entisols, on the other hand, have little to no horizon development, making them distinct from Alfisols which have a well-defined layer of clay. Thus, the unique properties of Alf