Fig. 1. Correlation between the fraction of hydrophilic prosulfuron sorption (f_hydrophilic) and the ratio of the absolute value of anion exchange capacity (AEC, cmol kg^–1) to cation exchange capacity (CEC, cmol kg^–1) at the pH of the prosulfuron isotherm study. The line is a linear regression fit set to intercept zero and r² is the associated goodness of fit. Soils include four highly weathered subsurface Oxisols (A1, A2, A3, and DRC) collected from Brazil, three subsurface Andisols (K1, K2, and K3) from South Korea, two weathered surface Ultisols (4R and 8R) from Costa Rica, and one moderately weathered surface Alfisol (Toronto) from Indiana.