Fig. 1. Biomass (dry weight of shoots plus roots) of maize (a), faba bean (b), and P uptake by maize (c) and faba bean (d) supplied with different P forms and grown in various treatments of root barrier between two species for 74 days (Greenhouse Study 1). Bar groups with different capital letters indicate a significant difference (P < 0.05) between forms of phosphorus treatment. Bars with different lowercase letters indicate a significant difference (P < 0.05) among three treatments of root interactions within the same phosphorus form or source. Error bar is a SD (n = 4) (Greenhouse Study 1).