Fig. 2. Root length density of maize at anthesis as a function of soil depth, tillage systems, and starter fertilizer banding in Zollikofen and Schafisheim in 1997 and 1999. Circles indicate side of plant row with fertilizer band, triangles indicate opposite side, filled symbols indicate no-tillage (NT), and open symbols indicate conventional tillage (CT); *, **, and *** indicate significance at the P < 0.05, 0.01, and 0.001 probability levels, respectively; blank is not significant.