Seed (grain) yield responses of faba bean (Vicia faba L.
cv. Fiord) to applications of fertiliser phosphorus (0, 5, 10, 20 and 40 kg
P/ha as triple superphosphate) and zinc (0, 0.5, 1 and 2 kg Zn/ha as
zinc oxide) were measured in 3 field experiments conducted in 1997 and 1998 on
neutral to alkaline soils in south-western Australia. Additions of fertiliser
phosphorus significantly (P<0.001) increased grain
yields by about 50 and 100% in 2 experiments, but in the third
experiment differences in grain yield due to applications of fertiliser
phosphorus were not significant (P>0.05). Increases
in grain yields due to zinc fertiliser were small (<10%) and were
only significant (P<0.05) in 1 experiment. This
suggests the 3 sites chosen had adequate soil zinc for grain production of
faba bean. In 1 experiment the increase in grain yield due to addition of
phosphorus fertiliser was due to an increase in the number of pods per plant;
numbers of seed per pod and mean seed weight were unaffected by additions of
phosphorus and zinc fertiliser. Adding phosphorus and zinc fertiliser
increased concentrations of both elements in grain, but had no effect on the
concentrations of other nutrient elements (N, K, S, Ca, Mg, Na, Cu, Mn, Fe)
measured in grain. These findings support results of a previous study in
Western Australia indicating that phosphorus is the major nutrient element
deficiency for grain production of faba bean in neutral to alkaline soils.