International Journal of Horticulture 2016, Vol.6, No.1, 1
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pineapple in the late season of 2012.
Pineapple fruit yield of 12.8 t/ha obtained when cowpea
was sown at the time of transplanting pepper was 71.4,
69.8, 72.8 and 71.4% lower than fruit yield obtained
when cowpea was sown at 3, 6 and 9 WAT and in sole
crop of pineapple, respectively. The time of sowing
cowpea into pineapple pepper intercrops in the rainy
season of 2012 did not result in significant decreases in
pineapple yield (Fig.1). However, sowing cowpea early
at transplanting pepper and at 3 WAT pepper reduced
fruit yield by 25.1 and 12.8 %, respectively. The yield
of 78.5 t/ha of pineapple fruit recorded in sole
pineapple was not significantly higher than fruit yield
in the pineapple-pepper intercrop alone and
pineapple-pepper intercrops with cowpea sown at
transplanting and at 3 WAT pepper in the late season of
2011 (Fig. 1). About 17.5 % yield reduction occurred
when cowpea was sown at time of transplanting pepper
into pineapple in the late season of 2011. Yield
reduction of 39.2 % was however recorded when
cowpea was sown at the time of transplanting pepper
into pineapple in the late season of 2012.
Fig. 1 Effect of time of sowing cowpea into pineapple-pepper
intercrops on fruit yield of pineapple (2011 and 2012: rainy and
late season planting).
The temporal effect of the presence of cowpea on fruit
yield of pineapple in pineapple-pepper-cowpea
intercrop is described by polynomial functions (Fig. 1).
The relationships were characterised by variable R
2
in
the 2011 and 2012 rainy and late season experiments
Rainy season of 2011: y = – 2.9482x
2
+ 25.782x –
5.2556, R
2
= 0.82**
Late season of 2011: y = 0.55x
2
– 2.1176x + 68.872,
R
2
= 0.54*
Rainy season of 2012: y = 0.258 x
2
+ 1.2463x +
44.311, R
2
= 0.50*
Late season of 2012: y = – 1.9363x
2
+ 20.254x +
44.311, R
2
= 0.94**
3 Discussion
The decline observed in the growth indicator (area of
d-leaf) of pineapple when intercropped with pepper
and cowpea resulted from shading effect of pepper
and cowpea on pineapple as explained by
Bartholomew et al
.
(2003). The effects of shade and
competition was more noticeable when cowpea was
sown early especially at the transplanting pepper in
the rainy season planting of 2011. The lack of
significant differences in growth and biomass
accumulation obtained for this treatment can be due to
the initial slow growth of pineapple during the
establishment phase which coincides with phase of
intercropping with pepper and cowpea. Lower values
of pineapple d-leaf area recorded for the late-season
planting could be attributed to unfavourable weather
condition of this season on the establishment of
pineapple. The late season is characterized by low
rainfall, high temperature and low relative humidity
which cumulate in terminal drought situation (Agele
et al., 2008).
The number of days to 50% flowering in pineapple
was prolonged when cowpea was sown at the time of
transplanting pepper during the rainy season and could
be attributed to the shading by the biomass and
canopy of the more vigorous cowpea. However, the
number of days to 50% flowering was not
significantly prolonged in the late-season crop due to
shorter duration of the arable intercropped. Py et al.
(1987) reported that the state of the crop species
population density enhanced competition at the period
of flowering is of profound significance.
The lower yield of pineapple fruits obtained when
