EFFECT OF WEED CONTROL METHOD AND PERIOD OF WEED INTERFERENCE ON GROWTH AND YIELD OF ROSELLE (Hibiscus sabdariffa L.) IN THE NORTHERN GUINEA SAVANNA OF NIGERIA
EFFECT OF WEED CONTROL METHOD AND PERIOD OF WEED INTERFERENCE ON GROWTH AND YIELD OF ROSELLE (Hibiscus sabdariffa L.) IN THE NORTHERN GUINEA SAVANNA OF NIGERIA
No Thumbnail Available
Date
2021-02
Authors
MOHAMMED, Ramat
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Two field trials were conducted during the wet seasons of 2011 and 2012 at the
experimental Farms of the Institute for Agricultural Research, Samaru (Lat. 110 111,
Long. 070, 381; 686m above sea level) and Federal College of Forestry Mechanization,
Afaka, (Lat 100, 031, Long. 070, 211; 644m above sea level), both in the northern Guinea
savanna of Nigeria. The aim was to evaluate the influence of weed control method and
period of weed interference on growth and yield of roselle (Hibiscus sabdariffa L.).
Experiment I consisted of fourteen treatments (oxadiazon at 1.5 and 2.0 kg a.i. /ha, diuron
at 2.0 and 2.5 kg a.i /ha, metolachlor at 1.5 and 2.0 kg a.i /ha, butachlor at 1.5 and 2.0
kg a.i /ha and pendimethalin at 1.5 and 2.0 kg a.i /ha, hoe weeding at 4; 3 and 6 and 3, 6
and 9 weeks after sowing (WAS) and a weedy check). Experiment II consisted of ten
periods of weed interference in two sets of treatments: In the first set, plots were initially
kept weed free by hoe- weeding for 3, 6, 9 and 12 weeks after sowing (WAS) and left
weed infested thereafter. In the second, plots were left weed infested initially for the
corresponding periods and kept weed free thereafter. There were two controls: plots kept
weed free throughout the crop life cycle and plots left weed infested throughout the crop
life-cycle.Each experiment was laid out in a Randomized Complete Block Design
(RCBD), replicated three times. In Experiment I, the herbicide treatments could not
effectively control the weeds beyond 6WAS, except diuron at 2.0 and 2.5kg a.i /ha and
oxadiazon at 1.5 and 2.0 kg a.i /ha. Application of diuron at 2.5 kg a.i /ha gave
significantly lower weed cover, weed dry matter and highest weed control index than the
other herbicide treatments and were comparable to two hoe-weeding at 3 and 6WAS at
all sampling periods. Highest crop injury was obtained by the application of diuron at 2.5
kg a.i /ha in 2011 at both locations. Among the herbicides, pendimethalin, metolachlor
and butachlor each at 1.5 and 2.0 kg a.i /ha were consistent in combining good weed
control with higher crop growth and yield. Pendimethalin at 2.0 kg a.i /ha gave
significantly higher herbicide efficiency index in both years of trials at the two locations,
more number of leaves, taller plant and thicker stem and more number of primary,
secondary and tertiary branches, compared to other herbicide treatments. As a result of
these, more number of calyx/plant, higher calyx yield/plant and calyx yield, more number
of seeds/capsule, heavier seeds/capsule and greater 100 seed weight were also obtained.
The treatment also gave higher combined yield at both locations, except in 2012 at Afaka,
where metolachlor at 1.5 kg a.i /ha gave higher yield. In experiment II at both locations
in the two years of studies, uncontrolled weed growth throughout the crop life-cycle
significantly depressed the growth and yield of roselle. Keeping the plots weed free
initially for 3WAS only did not prevent suppression in crop growth and yield of roselle;
while initial weed infestation for the first 3WAS had no adverse effect on the crop.
Keeping the plots weed infested for 6WAS and longer depressed various crop growth
characters and calyx yield compared with the crop kept weed free for 6WAS and longer.
The crop was most critically affected by weed between 4 and 6 WAS. Plots left initially
weed infested for 3WAS produced calyx yield comparable to those kept weed free for
6WAS and longer. Number of seeds/capsule, weight of seed/capsule and 100 seed weight
were not significantly affected by any of the factors evaluated in the two experiments in
the two years of studies. Simple correlation matrix among some growth and yield
characters of roselle in the two experiments revealed that plant height, number of leaves,
stem girth and number of primary and secondary branches at 9 WAS and number and calyx weight/plant were positively and strongly correlated with the calyx yield. The
weedy check significantly reduced calyx yield by 72.68%, 24.54% and 59.27%, 45.98%
at Samaru and Afaka, in 2011 and 2012, respectively. The combined yield losses at both
locations were 47.17% and 51.76% in weed control experiment. In the weed interference
experiment, the yield losses were 60.76%, 59.40% and 61.11%, 48.12% in 2011 and
2012 and combined yield losses were 60.01% and 54.62 at Samaru and Afaka,
respectively. The cost benefit analysis for weed control at Samaru in 2011 and 2012
showed that pendimethalin at 1.5 kg a.i /ha gave the best economic returns of
N100,000.00 and N114,000.00 while at Afaka, pendimethalin and metolachlor both at
1. 5 kg a.i /ha gave N 24,800.00 and N53,750 ,00 in 2011 and 2012. Hoe- weeding at 3,
6, 9 WAS gave N96,450.00, N116,150.00 and N27,250.00, N53,350,00 in 2011, 2012 at
Samaru and Afaka, respectively. In experiment II, plots kept weed free for 6WAS gave
best economic returns of N123,800.00 and N141,500.00 in 2011 and 2012, respectively
at Samaru and plots kept weed free for 6WAS and 9WAS gave best economic returns of
ā N41,100.00 and N96,300.00 at Afaka in 2011 and 2012, respectively when compared
with plots kept weed free throughout the crop life-cycle of N108,400.00, N125,000.00 at
Samaru and ā N54,100.00, N85,300.00 at Afaka in both years of study. The nutritional
quality of calyx analyzed in Experiment I included Protein, Fibre, Ash, Iron, Calcium,
Ascorbic acid and Vitamins B1, B2, D and B complex, and treatment had the similar
values. In conclusion, for effective weed control and higher calyx yield, pendimethalin at
1.5 kg a.i /ha or metolachlor at 1.5 kg a.i /ha can be adopted by roselle farmers and
should keep their farm weed free for 6WAS, since the critical period for weed
competition of roselle was found to be between 4 and 6WAS at these locations.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES
AHMADU BELLO UNIVERSITY IN PARTIAL FULFILMENT OF THE
REQUIREMENTS FOR THE AWARD OF DOCTOR OF PHILOSOPHY (Ph.D)
IN AGRONOMY
DEPARTMENT OF AGRONOMY,
FACULTY OF AGRICULTURE,
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA
Keywords
EFFECT,, WEED CONTROL METHOD,, PERIOD,, WEED INTERFERENCE,, GROWTH,, YIELD,, ROSELLE,, (Hibiscus sabdariffaL.),, NORTHERN GUINEA SAVANNA,, NIGERIA