Fig. 3. Clay percentage in dye-stained and undyed soil. The numbers beside each pair of points represent the number of samples contributing to the mean from dyed and undyed areas within a specific depth range. The mean at 10 cm represents samples from various slice depths within the Ap horizon. Means at lower depths represent samples from slice depths from a 15-cm depth increment. The error bar represents one standard error of the mean. Horizon boundaries indicated on the figure represent typical depths found in the Piedmont region of the southeastern USA.