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Effect Of Introducing Garden Egg To Fluted Pumpkin In A Relay Intercrop On Sole And Combined Growth Of The Crop Mixtures
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Types of intercropping (spatial and temporal patterns)
Several types
of intercropping, all of which vary the temporal and spatial mixture to
some degree, have been described (Andrews and Kassam, 1976). The degree
of spatial and temporal overlap in the component crops can vary
somewhat, but both requirements must be met for a cropping system to be
an intercrop. Thus, there are several different modes of component crops
(Willey, 1985). Yield advantage occurs because growth resources such as
light, water, and nutrients are more completely absorbed and converted
to crop biomass by the intercrop over time and space as a result of
differences in competitive ability for growth resources between the
component crops, which exploit the variation of the mixed crops in
characteristics such as rates of canopy development, final canopy size
(width and height), photosynthetic adaptation of canopies to irradiance
conditions, and rooting depth (Midmore, 1993; Morris and Garrity, 1993;
Tsubo et al., 2001). Regularly intercropped pigeon pea or cowpea can
help to maintain maize yield to some extent when maize is grown without
mineral fertilizer on sandy soils in sub-humid zones of Zimbabwe
(Waddington et al., 2007). Intercropping maize with cowpea has been
reported to increase light interception in the intercrops, reduce water
evaporation, and improve conservation of the soil moisture compared with
maize alone (Ghanbari et al., 2010). This yield advantage occurs when
the component crops do not compete for the same ecological niches and
the interspecific competition for a given resource is weaker than the
intraspecific competition. Normally, complementary use of resources
occurs when the component species of an intercrop use qualitatively
different resources or they use the same resources at different places
or at different times (Tofinga et al., 1993). In ecological terms,
resource complementarity minimizes the niche overlap and the competition
between crop species, and permits crops to capture a greater range and
quantity of resources than the sole crops. Improved resource use gives
in most cases a significant yield advantage, increases the uptake of
other nutrients such as P, K, and micronutrients, and provides better
rooting ability and better ground cover as well as higher water use
efficiency (Midmore, 1993; Morris and Garrity, 1993). Thus, selection of
crops that differ in competitive ability in time or space is essential
for an efficient intercropping system as well as decisions on when to
plant, at what density, and in what arrangement. Although in this way
cropping management decisions specify the design of intercropping
systems, intercrop performance is governed largely by the availability
of and the competition for the environmental resources. Research has
shown that intercrops are most productive when component crops differ
greatly in growth duration (Wien and Smithson, 1981; Smith and Francis,
1986; Fukai and Trenbath, 1993; Keating and Carberry, 1993). For
example, when a long duration pigeon pea cultivar was grown in mixture
with three cereal crops of different growth durations, i.e. setaria,
pearl millet, and sorghum, the Land Equivalent Ratio was highest with
the quick-maturing setaria and lowest with the slow-maturing sorghum
(Rao and Willey, 1980). It must be noted here that Land Equivalent Ratio
shows the efficiency of intercropping for using the environmental
resources compared with monocropping with the value of unity to be the
critical value. When the Land Equivalent Ratio is greater than one
(unity) the intercropping favours the growth and yield of the species,
whereas when the Land Equivalent Ratio is lower than one the
intercropping negatively affects the growth and yield of the plants
grown in mixtures (Willey, 1979; Willey and Rao, 1980). Asynchrony in
resource demand ensures that the late maturing crop can recover from
possible damage caused by a quick-maturing crop component and the
available resources, e.g. radiation capture over time, are used
thoroughly until the end of the growing season (Keating and Carberry,
1993). By contrast, when the component crops have similar growth
durations their peak requirements for growth resources normally occur
about the same time and the competition for the limiting growth
resources is intense (Fukai and Trenbath, 1993).
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ABSRACT - [ Total Page(s): 1 ]The effect of introducing garden egg (Solanum aethiopicum) to fluted pumpkin (Telfairia occidentalis) in a relay intercrop on the growth of crop mixture under rainfed conditions (September to November, 2014) was investigated at the Faculty of Agriculture University of Benin, Benin City Nigeria.Garden egg and a local variety of fluted pumpkin were sown sole and intercrop. Garden egg and fluted pumpkin were planted sole and intercropped to evaluate their interaction effect on growth parameters suc ... Continue reading---
