The major disadvantage of the Greacen et al. (1968) model is that it requires many laborious measurements of soil mechanical properties. A simpler approach was adopted by Romkens & Miller (1971), who equated the pressure required for void-ratio changes occurring in a cylinder of soil around a root with the pressure required for one-dimensional soil consolidation. The resulting equation was used to predict the rooting densities at which further root radial expansion would be inhibited by the expansion of neighbouring roots. Unfortunately, the Romkens & Miller (1971) model .
