Abstract:
The performance of designed and constructed flame emission
apparatus using liquefied petroleum gas (LPG) was evaluated to control
weeds between ridges in River Nile State. In the first season, different
operative parameters were tested including two types of atmospheric
burners hanged at 12cm height from soil surface, driven forward at 30o and
45 o angle at walking speeds of 11, 18 and 27m/min. The fuel consumption
per hour and temperature for each burner were measured in the laboratory
experiment. In season 2004-05 a field experiment with the combination of
the above parameters was executed to control weeds in faba bean at 4, 5
and 6 weeks after sowing (initiative flowering stage and initiative pod
setting stage).
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From the results of this season, the relation between fuel
consumption (kg hr-1 and kg ha-1) and weeding efficiency were assessed,
using the burner with 1mm orifice diameter directed at 30o angle and
driven at 11m/min. In the following two seasons, an experiment was
conducted to evaluate flame weeding at 4 and 6 weeks after sowing, and
another experiment for comparison with hand weeding and pre-emergence
herbicides. The experiments were arranged in randomized block design
with 6 and 4 replications respectively.
The flaming apparatus showed reasonably high efficiencies, to
control grasses and broad-leaved at 4 weeks after sowing the efficiencies
were 72.4% and 77.8% respectively. Comparison of means of total weeding
efficiency at different weeds developmental stages showed that flaming at 4
weeks after sowing was comparable with hand weeding at the same period
in the first season, and with pre-emergence herbicides; free weed and hand
weeding in the second season. With regards to comparing the flame
weeding with the usually pre-emergence herbicides and hand weeding,
statistical analysis showed no significant difference in total weeding
efficiency in the first season between the three methods, but there was
significant difference (P>0.01) in the second season. This can be attributed
to the large number of grasses which were difficult to be controlled,
compared to broad-leaved weeds. The grain yield of faba bean flamed at 4
weeks after sowing was comparable with the yield of pre-emergence
herbicides and hand weeded plots in the two seasons.
Economic analysis of using flame weeding at 4 weeks after sowing
resulted in 562% and 1094% marginal rate of return in the two seasons,
where herbicides application gave 90% and 314%, the analysis excluded
hand weeding which appeared economically not feasible.
It is apparent that flaming apparatus shows promising results in
terms of weeding efficiency and economic feasibility
