Fig. 1. Leaf area (LA) per plant as a function of topsoil bulk density (BD_top) and P concentration (P_top) at the two- and the three-leaf stage of maize. Treatments followed by the same letter are not significantly different at = 0.05. Vertical bars are standard errors. ANOVA: *, **, and *** indicate significance at = 0.05, 0.01, and 0.001, respectively. NS, not significant.