In the western half of north america, ultisols are most commonly found in which precipitation range?

Ultisols are most usually found in which precipitation range is 60 inches and over in the western half of north America. Ultisols is define as soils with sub apparent clay accumulations that retain low native fertility and are frequently red hued in line for the existence of iron oxides. Originate in humid tropical and subtropical climates. The controlling factors are climate, time and organisms, the percentage of global ice free land surface is ~8% and the percentage of US ice free land surface is ~9%.