What feature characterizes Alfisols when compared to other soil orders?

Alfisols are characterized by a base saturation greater than 50%, which distinguishes them from many other soil orders. This high base saturation indicates a significant amount of exchangeable bases such as calcium, magnesium, and potassium, making Alfisols relatively fertile. This feature supports the growth of a variety of plants and contributes to their importance in agriculture.

While higher clay content can be a characteristic of some Alfisols, it is not universally true for this soil order, as they can have a range of textures from sandy to clayey. The presence of a mollic epipedon is specific to Mollisols, not Alfisols, while the origin of the parent material, such as whether the soil developed from granite, does not define the Alfisol category, as they can form from a variety of parent materials. Therefore, the key distinguishing feature of Alfisols is indeed their high base saturation, which plays a critical role in soil fertility and usability in agriculture.