dc.description.abstract | The experiment entitled A Comparison Between
Conservation and Conventional Tillage Systems For Maize
Production was conducted at Kabete (Nairobi, Kenya)
during the short rainy season of 1989/90. A 3x2
factorial experiment consisting of three tillage
treatments (no-tillage, minimum tillage and
conventional tillageJ with two methods of weed control
(manual weed control and chemical weed control J was
used for the experiment. All treatments were replicated
three times on a randomized complete block design.
The results showed that the highest draught
and fuel requirements were obtained from the
conventional tillage treatment; the lowest were from
the no-tillage treatment, w h i Le minimum tillage was
intermediate. As compared to conventional tillage,
minimum tillage and no-tillage saved 47.4% and 59.6%
per hectare in draught requirements respectively.
Moreover, minimum tillage saved 50.3% and no-tillage
saved 78.2% of fuel per hectare as compared to
conventional ti 11 age. The different ti 1 I age systems,
when tested for both draught and fuel requirements,
showed highly significant differences ..
X I V
The most rapid emergence of maize seedl ings,
as indicated by emergence rate index, was obtained from
the minimum tillage treatment where weeds were
control led with chemicals and the slowest was from the
conventional tillage treatment where weeds were also
control led with chemicals. There was, however,
statistically no significant tillage effect and no
significant weed control methods effect on emergence
rate.
The re s u l t s indicated the longest maize plant
growth was for minimum tillage treatment where weeds
were controlled with chemicals, while the shortest
maize plant growth was observed in the no-tillage
treatment where weeds were controlled manually.
However, there was no significant difference among
tillage systems for length of plant growth.
The minimum tillage with manual weed control
plot had the highest yield and the no-tillage with
manual weed control plot had the lowest yield. However,
when tested for statistical difference, ti 1 lage systems
did not significantly affect yield.
The greatest residue mass production was
achieved from the conventional tillage with manual weed
control treatment while the lowest was from the notillage
with manual weed control treatment. Analysis of
variance indicated a significant difference at 5% level
xv
among tillage systems, while there was no significant
difference between weed control methods and no
interaction between tillage systems and weed control
methods on residue production.
The result from economic analysis showed that
the minimum tillage treatment where weeds were manually
controlled was most profitable as compared to al I the
other treatments.
The results of the experiment strongly
indicate that the minimum tillage with manual weed
control system should be employed by farmers in t.he
area during the short rains, as it has been found to
perform better than the other systems. However, it is
recommended that further investigations be carried out
to substantiate the result obtained during the short
rains and t.o see whether they also apply to the long'
rains. | en |