FIG. 1. The pressure head is plotted vs. the radius (clay soil, medium root density, high transpiration rate) for the numerical solution (solid line) at different times after the start of water extraction (Fig. 14a in de Jong van Lier et al. [2006]). The results at the moment of first occurrence of limiting hydraulic conditions at the root surface are indicated by the dashed lines (numerical = black, incorrect analytical = red); in addition, the correct analytical solution (dots) is given.