| dc.description.abstract | Intercropping is a farming practice that has recently received attention from
agronomists as a means of improving land use efficiency.
This study was conducted to determine whether manipulating bean density and
planting time could have any effects on the growth and final yield of intercropped
maize and beans. The effects of bean density and planting time on bean
nodulation, soil nitrogen levels, growth and final yields of maize and beans under
intercropping system was investigated at the University of Nairobi, Kabete
campus field station, on reddish brown nitosol clay.
Increasing bean density increased bean height but lowered bean biomass
significantly during both seasons. Increasing bean density to three or more plants
per hill significantly reduced bean nodulation. Planting beans two weeks after
maize increased nodulation significantly. There was high nitrogen levels in the
soil at flowering time in treatments where beans were planted two weeks before
maize as compared to where beans were planted two or four weeks after maize.
Increasing bean density increased bean yields. There was an increase of 116%
and 126% in bean yields in treatments having four bean plants per hill compared
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to those treatments having one bean plant per hill, during the 1993/94 and
1994/95 seasons respectively. The treatments having four bean plants per hill
also had the highest land equivalent ratio (LER) of 1.3 in season one and 1.6 in
season two. High LER of 1.3 in season one and 1.7 in season two were also
obtained in treatments where beans were planted two weeks before maize.
Results during the 1993/94 and 1994/95 seasons showed that bean planting
density and time significantly affected the general development of both maize
and beans. However, the two factors did not significantly affect the final yields of
maize, though that of bean was significantly affected. During the 1993/94
season, beans planted two weeks before maize had the highest yield
(1134.4 kgs/ha), compared to treatments where beans were planted at the same
time with maize (784.4 kg/ha), two weeks after maize (723.3 kg/ha) and four
weeks after maize (402.9 kg/ha) respectively. Beans planted four weeks after
maize had the lowest yields. The trend was similar during the 1994/95 season.
From the results it shows that it is more advantageous to plant beans before
maize in order to obtain higher bean yields. Upto four bean plants per maize
plant can be planted to achieve higher bean yields without affecting maize yield. | en |
