| dc.description.abstract | This study was undertaken to investigate the variations of
water use efficiency of two varieties of maize (Zea mays L.),
viz. makueni and katumani composite B with planting density.
and meteorological parameters under rainfed conditions. The
study was conducted during the short rains season of 1990 at
Kibwezi Dryland Research Station of the University of Nairobi
in Machakos district, Kenya.
The experimental design comprised two blocks, one for each
maize variety, and three treatments characterised by Low
(24,000 plants/ha), Medium (36,000 plants/ha) and High (83,000
plants/ha). Planting was done manually on 10th of November
1990. Neither manure nor fertilisers were used. Weeding was
also done manually on 1st of December 1990.
Dry matter in kg/ha was· obtained on weekly basis by
harvesting two plants chosen at random from the centre of each
plot. From grain filling stage, the grain dry matter was
separated from the total above-ground dry matter. Harvest
index was computed as a percentage of grain yield dry matter
to total above-ground dry matter. Evapotranspiration was
determined weekly by the water balance approach. Water use
efficiency in g/mm was computed as a ratio of dry matter to
evapotranspiration.
Makueni composite gave higher harvest indices than
katumani composite for all the plots. Medium planting
-xvidensities
gave the highest harvest indices.
Relative dry matter accumulation rates between makueni and
katumani varieties and also planting densities were not
significantly different. Makueni composite was superior to
katumani composite B in absolute dry matter accumulation rate
during grain filling stage.
Makueni composite out yielded katumani composite B in grain
yield by approximately 23.5% and by 14.1% in total aboveground
dry matter.
Katumani composite plots showed higher crop water use than
the corresponding makueni composite plots under the prevailing
meteorological and soil water conditions. Crop water
requirement was maximum during silking period for both
varieties of maize.
Makueni composite exhibited higher water use efficiency than
katumani composite B in both grain and total above-ground dry
matter production. For both yield components, water use
efficiency decreased with increasing plant population.
Although long term studies in the literature recommend a
planting density of 37,000 plants/ha for maize in dryland
areas, this study shows that it is possible to get higher
yields with a planting density of 83,000 plants/ha. | en |
