Fig. 2 Quantity–intensity plots for (A) surface and subsurface soils of the Wabasso and Candler sands and (B) the 90- to 100-cm depth horizon of the Wabasso sand. NH₄ is the amount of NH₄ adsorbed or released from the soil and AR_NH4 is the activity ratio, i.e., (NH₄)/(Ca+Mg)^1/2 in solution