Population density and intercropping of sorghum (sorghum
bicolour
(L) and
Soybean {
Glycine max Merril
(L)} may alter their growth and yield
patterns through responses to light and physiological attributes as compared to
their performance in standard densities and monocultures. There is limited field
information on this hypothesis. Thus the objective of this study was to
determine the influence of intercropping and population density on protein and
oil yield components, photosynthesis of sorghum and Soybean at the canopy
closure. The study was conducted at the University of Nairobi farm during the
long rains. There was a significant increase in the number of Soybean pods per
plant between the low density and normal density populations followed by a
decline at high plant populations. Whereas population density increased the
protein seed yield of Soybean, intercropping hardly altered it. In contrast,
both population density and intercropping significantly decreased Soybean seed
oil content. The observed protein and oil content is explained by the
photosynthetic responses of partial shaded and fully exposed leaves. There was a
significant decrease and increase of Soybean photosynthetic rates of both
non-shaded and partially shaded leaves respectively within the intercrops,
whereas population density caused a significant decline in non-shaded and
partially shaded leaves. The interactive effects between population density and
intercropping caused an increase in percent Soybean seed protein and decreases
in its percent oil content and photosynthetic rates of partially shaded sorghum
and Soybean leaves. These results demonstrate that population density and
intercropping may be a viable alternative of manipulating the productivity of
these crops through their changes in physiological processes.