Fig. 4. Example of a smoothed surface map (Exp. 1, Dooley fine sandy loam) of penetration resistance (PR) on plots that were not subsoiled (NoSS). The bulge in PR at a depth of 
0.15 m corresponds to the depth of a tillage pan.
Fig. 4. Example of a smoothed surface map (Exp. 1, Dooley fine sandy loam) of penetration resistance (PR) on plots that were not subsoiled (NoSS). The bulge in PR at a depth of 0.15 m corresponds to the depth of a tillage pan.