Fig. 2. pH dependence on the prosulfuron sorption coefficient (Kd, L kg–1) measured from CaCl2 and Ca(H2PO4)2 solutions (A and B), and the fraction of hydrophilic and hydrophobic prosulfuron sorption (C and D) for the highly weathered subsurface Oxisols A1 and DRC. The terms Kd (Cl) and Kd (P) noted in the legend refer to Kd values measured from 5 mM CaCl2 and Ca(H2PO4)2, respectively.