The adoption of the kandic horizon for use in recognizing the predomin
ance of low activity clay has resulted in reclassification of several
major soil series on the Atlantic Coastal Plain of the Southeastern U.
S. To provide a more definitive basis for predicting the geographic di
stribution of the kandic feature, 41 sites correlated to successive ge
omorphic surfaces in North Carolina were sampled and characterized. Th
e locations represented five defined Coastal Plain surfaces encompassi
ng the Upper, Middle, and Lower Coastal Plain. Well to poorly drained
upland soils were included. Results indicate that both the cation exch
ange capacity 7 and the effective cation exchange capacity requirement
for the kandic horizon were consistently satisfied only in the well d
rained soils on the Upper Coastal Plain surface. Soil with greater wet
ness and soils on lower, younger geomorphic surfaces (Middle and Lower
Coastal Plain) did not consistently satisfy requirements for the kand
ic horizon.