Biomass yields, radiation interception and radiation use efficiency as influenced by seed rate in a cereal/legume intercropping system

Int. J. Agr. & Agri. R.
(estimate 0.001023 s.e. 0.0000441 ) awi (estimate
0.03553 s.e. 0.00373 ) and bwi (estimate 0.000828
s.e. 0.0000229)
intercrop BY was quantified using equation 3 (Figure
4). The coefficient of determination for the equation
applied was 83.8 %. For this experiment both the
wheat sole and intercrop, responses were also
quantified using equation 3. Thus, in this experiment
wheat appear to be the more competitive component
in the intercrop as is indicated in Figure 4.
Fig. 6. Effect of wheat seed rate on the reciprocal of
wheat sole crop biomass yield per plant ● (solid line)
for Experiment 3 (spring-sown). See the text for
fitted equation and parameter values.
Fig. 8. Effect of wheat seed rate on biomass yields
(g/m 2 ) for winter wheat (cv. Mallaca) sole crop●
(solid curve), wheat intercrop ○ (broken curve)
and winter faba bean (cv Clipper) ▲ in
Experiment 4. The parameter values for the
Fig. 7. Effect of wheat seed rate on the reciprocal of
wheat intercrop biomass yield per plant ○ (broken
line), for Experiment 3 (spring-sown). See the text
for fitted equation and parameter values.
The total intercrop BY increased with increase in wsr
(P = 0.004 for quadratic wsr, P < 0.001 for the cubic
wsr effect). Bean treatment had no significant effect
on the total intercrop BY (P > 0.05), but there was a
significant interactive effect detected between wsr
and the bean (P = 0.006 for linear wsr x bean effect).
Averaged across wsr, for the mean effects of bean
treatments BY were 527 g/m 2 and 545 g/m 2 for 0
and 40 bean seeds/m 2 respectively (SED 60. 9, DF
15). For the interactive effects, the maximum total
intercrop BY of 808 g/m 2 was obtained at 200
wheat seeds/m 2 , but at that sr wheat sole crop BY
was significantly greater (Figure 4; SED 118, DF
25.7). However, unlike in Experiment 1, from 50-
wheat seeds/m 2 or more both the wheat sole crop
and the total intercrop produce greater BY than the
bean sole crop. Thus, wheat contributed more BY
than the bean in the intercrop (Figure 4). The total
equations 3 applied to the wheat sole crop BY are aw
(estimate 0.03136 s.e 0.00976) and bw (estimate
0.0009508 s.e 0.0000894). Similarly, the parameter
values for the fits of equation 3 to the wheat
intercrop BY are aw (estimate 0.05438 s.e 0.00524)
and bw (estimate 0.001452 s.e 0.0000451).
Responses of the biomass yields to seed rate in
Experiment 3:
In Experiment 3, wheat BY increased with increase
in wsr (P < 0.001 for quadratic wsr). The effect of
intercropping was significant (P < 0.001) but wsr did
not interact significantly with bean treatment (P >
0.05 for wsr x bean treatment effects). Averaged
across wsr, for the mean effect of intercropping,
wheat sole crop produced significantly greater BY
than the intercrop. The BY were 1156 g/m 2 and 896
g/m 2 for the wheat sole crops and intercrops
respectively (SED 38.5, DF 15). For the interactive
effects of wsr and intercropping, equation 3
quantified the response of wheat sole crop BY well
(Figure 5; SED 97.4, DF 24.33). The coefficient of
determination for the equation applied was 93.7%.
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