J. Helenius et K. Jokinen, YIELD ADVANTAGE AND COMPETITION IN INTERCROPPED OATS (AVENA-SATIVA L)AND FABA BEAN (VICIA-FABA L) - APPLICATION OF THE HYPERBOLIC YIELD-DENSITY MODEL, Field crops research, 37(2), 1994, pp. 85-94
Both monocrops and intercrops of oats (Avena sativa L.) and faba bean
(Vicia faba L.) were cultivated over a range of sowing densities in a
field experiment of randomized complete blocks design. The hyperbolic
yield-density model was applied to phytomass and seed yield. Predictio
ns and parameters of the model were used to quantify intra- and inter-
specific competition, and to evaluate yield potential of the mixtures.
The model accounted for 93% and 85% of the variation in phytomass and
in seed yield, respectively. In both species intraspecific competitio
n was more severe than interspecific competition. Oats was relatively
the stronger of the two competitors, e.g. substitution rates were 0.33
plants of oats for a plant of bean with respect to oat seed yield, an
d 0.72 plants of bean for a plant of oats with respect to bean seed yi
eld. Oats bad a greater yield potential than bean. The mixture sown in
densities of 400 oats/m2 and 40 beans/m2 out-yielded the most product
ive monoculture with respect to seed yield. Land equivalent ratios (LE
R) of this mixture, 1.05 for phytomass and 1.06 for seed yield, indica
ted yield advantage. The greatest LER obtained for seed yield was 1.10
. The predicted yield curves demonstrated that the maximum (asymptotic
) combined yields, 13 t/ha of phytomass and 6 t/ha of seeds might be o
btained by planting bean and oats in 1:1 ratio. Land equivalent ratios
of this mixture were 1.23 for phytomass and 1.31 for seed yield. Both
the actual results and the model predictions suggest potential of int
ercropped oats and faba bean.