Final answer:
Ultic soils commonly occur in regions with acidic conditions, like the Central Uplands and the humid tropics, as well as in areas with agricultural practices that increase soil acidity, including regions within the U.S.
Step-by-step explanation:
Ultic soils are frequently found in regions where acidic conditions prevail, predominantly due to the solubilization of aluminum at low pH levels, which is detrimental to plant growth. For instance, the Central Uplands in Southern Germany, adjacent to the main Alps, showcase such soil conditions that could potentially develop Ultic soil characteristics. This region is known for mixed deciduous-coniferous forests and a moderate climatic pattern with four distinct seasons. Furthermore, like in the humid tropics accounting for a significant portion of acid soils globally, the U.S. agriculture also faces challenges with acidic soils, especially those intensified by agricultural practices such as the use of nitrogen fertilization. Regions with temperature extremes, such as the eastern steppe of Ukraine or areas in the U.S. like eastern Montana, could also be probable zones for the occurrence of Ultic soils.