Fig. 7. Response surface of the objective function [I(t), _SC(z, T)] in the –K_s parameter plane for cumulative infiltraiton at -16-cm supply pressure for the no-tillage surface, Plot 3. All other parameters were set equivalent to the values obtained for the three-parameter fit. At the converged minimum, marked with an "X", error corresponding to the residuals of the infiltration data comprised 75% of the value of [I(t), _SC(z, T)].