Fig. 4. Absolute rates of (A) leaf expansion and (B) root elongation from planting to the three-leaf stage of maize as a function of topsoil temperature (Temp_top) and P concentration (P_top). 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 and 0.01, respectively. NS, not significant.