The effect of inoculation by arbuscular mycorrhizal fungi (AMF) and indigenous AMF populations on biomass production and phosphorus (P) uptake by leek and on its utilization of P in Kola apatite and bone meal was studied in field soils. Arbuscular mycorrhiza (AM) did not enhance P uptake from Kola apatite, which had no clear effect on P uptake by leek within one growing season, either in the field or in pots. AM increased P uptake from bone meal by 62% in a pot experiment. Inoculation did not increase the effect in unsterile soil as compared with the indigenous AMF populations. The results demonstrate a key role for AM in utilization of organic P.