THE EFFECTS OF PERIOD OF WEED INTERFERENCE AND WEED CONTROL ON COWPEA (Vigna unquiculata (L.) walp)
THE EFFECTS OF PERIOD OF WEED INTERFERENCE AND WEED CONTROL ON COWPEA (Vigna unquiculata (L.) walp)
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Date
1988-09
Authors
TIMOTHY, TSUWE SULE
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Abstract
Two field experiments were conducted during the
1987 wet season at Samaru in the Northern Guinea
savanna ecological :Zone of Nigeria to study the effects
of period of weed interference and weed control on
cowpea (Vigna unguiculata (L,) Walp).
In the study, weed interference for 3 WAS did
not adversely affect crop growth, yield and yield
attributes. Cowpea was critically adversely affected
by weeds between 3 and 9 WAS Once kept weed-free
for 9 WAS no significant reduction in seed yield
occured compared with the crop kept weed-free throughout,
although maximum yield occured with the crops
kept weed-free for 15 weeks.
In the weed control experiment, all the herbicide
treatments significantly reduced weed infestation until
9 WAS Among the weed control treatments, metolachlor
plus metobromuron at 1.5+1.5 kg a.i/ha followed by
supplementary hoe-weeding at 6 WAS gave effective weed
control and resulted in vigorous cowpea growth and
significantly higher cowpea yield than the hoe-weeded
controls Pre-emergence mixtures of diuron with
metolachlor and alachlor each at 0.8+1.5 kg a.i/ha,
each followed by post-emergence imazaquin at 0.2 kg
a.i/ha at 3 WAS, resulted in comparable cowpea seed
yield to the highest obtained with metolachlor plus
metobromuron followed by supplementary hoe-weeding .
Plots hoe-weeded twice and those treated with alachlor
plus diuron at 1.5+0.8 kg a.i/ha followed by supplementary
hoe-weeding at 6 WAS had higher seed yield than
the untreated control. With the exception of metolachlor
plus diuron, all the other plots treated with half
the rate of the pre-emergence herbicide mixtures only
produced cowpea seed yield that were comparable to those
1 of the untreated control.
The pre-emergence herbicide treatments differentially
depressed various aspects of cowpea growth like
vigour, plant height, leaf dry weight and leaf area.
Uncontrolled weed growth throughout the crop
life-cycle resulted in significant depression of cowpea
growth parameters such as crop vigour, plant height,
leaf production and caused cowpea seed yield reduction
by 74.2% in the weed interference and 74,5% in the
weed control trials.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT
OF THE REQUIREMENT FOR THE DEGREE OF
MASTER OF SCIENCE IN AGRONOMY
DEPARTMENT OF AGRONOMY
FACULTY OF AGRICULTURE
AHMADU BELLO UNIVERSITY
ZARIA, NIGERIA,,
SEPTEMBER, 1988
Keywords
EFFECTS,, PERIOD,, WEED,, INTERFERENCE,, WEED,, CONTROL,, COWPEA,, (Vigna unquiculata (L.) walp).