STUDIES ON WEED INTERFERENCE AND CONTROL IN COTTON (Gossypium hirsutum L.)/COWPEA (unquiculata L. (Walp.)] MIXTURE AT SAMARU, NIGERIA
STUDIES ON WEED INTERFERENCE AND CONTROL IN COTTON (Gossypium hirsutum L.)/COWPEA (unquiculata L. (Walp.)] MIXTURE AT SAMARU, NIGERIA
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Date
1994-12
Authors
DADARI, SALIHU ADAMU
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Abstract
Field experiments were conducted during the 1987, 1988
and 1989 cropping seasons on the farm of the Institute for
Agricultural Research, Samaru (11°, 111N; 07° 381E) , to
evaluate the effects of period of weed-interference and weed
control on the performance; of 3:1 replacement population
cotton/cowpea mixture.
The losses caused by weed-infestation throughout the life
cycle of the crops in the three seasons were averaged at 96.2%
for seed cotton and 90.1% for cowpea grain yields, compared
with those kept weed-free throughout. Weed-infestation
throughout the crop life cycle also reduced the yield
components, namely flower and boll counts of cotton, by 85 to
94.8%, pod count of cowpea by about 80.4%, as well as dry
matter of cotton and cowpea crops by about 78.2% and 82.0%,
respectively.
Regression of cotton/cowpea mixture's yields on weed dry
matter indicated that, every 1 kg increase in weed weight,
reduced seed cotton and cowpea grain yields by 0.19 kg/ha and
0.2kg/ha, respectively.
The critical period of weed competition in cotton/cowpea
mixture was between 3 and 6 weeks after sowing cotton (WASC)
using cotton as top canopy crop grown in the traditional
"Gicci" system. The most effective herbicide treatment in
this mixture was alachlor plus diuron at 1.0 + 0.4 kg a.i./ha
followed by (fb) supplementary hoe-weeding (SHW) at 6 WASC,
which out-yielded two hoe-weedings by 9.1% and the weedy check
by 90.3% in terms of seed cotton yield. This treatment,
however, resulted in seed cctton yield that was 13% lower than
that of three hoe-weedings. In component cowpea, alachlor
plus diuron at 1.0 + 0.4 kg a.i./ha fb SHW gave grain yield
that was higher than those of two
and three hoe-weedings,and the weedy check by 27.5%, 16.2%
and 80.6%, respectively.
Revenue realised in excess of chemical weed control cost
was N7,685/ha, compared with N6,215.00 for three hoe-weedings,
and N5,495.00, for two hoe-weedings.
Description
A Thesis submitted to the Post-graduate School,
Ahmadu Bello University, Zaria in partial fulfillment
of the requirements for the Degree of Doctor of Philosophy in Agronomy
DEPARTMENT OF AGRONOMY
FACULTY OF AGRICULTURE
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA
DECEMBER, 1994
Keywords
STUDIES,, WEED,, INTERFERENCE,, CONTROL,, COTTON,, (Gossypium hirsutum L.), COWPEA,, (unquiculata, L. (Walp.)], MIXTURE,, SAMARU,, NIGERIAN.