Ustults are the Ultisols that:
1. Do not have both aquic conditions and the colors defined
for Aquults;
2. Have an ustic moisture regime;
3. Have less than 0.9 percent (by weighted average) organic
carbon in the upper 15 cm of the argillic or kandic horizon,
exclusive of any Ap horizon; and
4. Have less than 12 kg organic carbon in a unit volume