EFFECTS OF NITROGEN, PERIOD OF WEED INTERFERENCE AND HERBICIDES ON THE PERFORMANCE OF KENAF (Hibiscus caimahinus L.) IN THE NORTHERN GUINEA SAVANNA OF NIGERIA
EFFECTS OF NITROGEN, PERIOD OF WEED INTERFERENCE AND HERBICIDES ON THE PERFORMANCE OF KENAF (Hibiscus caimahinus L.) IN THE NORTHERN GUINEA SAVANNA OF NIGERIA
No Thumbnail Available
Date
1998-05
Authors
KUCHINDA, NOVEMBER CHIROMA
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Field experimenfewere conducted during the 1993 to 1995 wet seasons to study the
effects of period of weed interference and herbicides on the yield performance of kenaf
(Hibiscus cannabinus L.) grown under varying N levels at the Institute for Agricultura
Research, Samaru (11° ll'N; 07° 38'E).
The results showed that N application significantly increased wood, fibre and seed yields
of kenaf. This was as a result of the increase in growth parameters, viz crop vigour score,
plant height and butt diameter. Nitrogen fertilizer application also caused early flowering
in kenaf. Application of 90 kg N/ha at 12 WAS in 1994 and 45 and 90 kg N/ha at 9 WAS
in 1995 in the weed control trials caused singificant reduction of weed cover score in the
crop.
a
Initial weed infestation for 6 WAS and beyond depressed crop growth and yields
compared to the weed-free control. The growth and yields of the crop kept weed-free for
6 WAS and beyond were however comparable to the maximum in the trial and the weedfree
control. The critical period of weed competition in kenaf was between 3 and 6 WAS.
Metolachlor and alachlor each at 1.50 kg and the mixtures with ametryne at 1.0 +
1.0 kg consistently depressed weed cover score. Similar results were obtained by fusilade
at 0.75 kg and its mixture with ametryne at 0.50 + 1.0 kg, although the treatments were
fairly phytotoxic to the crop. The weed control treatments with exception of metolachlor
in 1995 and fusilade in 1994 and 1995 resulted in greater crop vigour score than the weedy
check at 6-12 WAS in 1993 and 1995 and 9-12 WAS in 1994. Alachlor and its mixture
with ametryne increased wood yield over the weedy check and was comparable to hoev
weeding at 3 and 6 WAS in 1995. A similar result on ribbon yield was obtained by the
mixture with fusilade in 1993. Alachlor and mixtures containing metolaehlor and alachlor
increased fibre yield in 1995. Alachlor + ametryne and fluazifop-butyl (fusilade) in 1993,
mixture with alachlor and metolaehlor alone in 1994 and fusilade + ametryne in 1995
increased the number of capsules per plant. Weed infestation throughout the crop growth
cycle caused 28.2% to 53.0% wood yield, 26.5% to 55.3% fibre yield and 21.9% to
63.8% seed yield reductions compared to the highest yields obtained in 1993, 1994 and
1995, respectively.
Seed and fibre weights per plant were positively correlated with crop vigour score,
plant height, butt diameter and number of capsules per plant. Seed weight was positively
correlated with 100-seed weight. Seed and fibre yields were however, negatively
correlated with the number of days to first flowering, weed cover score and weed dry
weight. Wood yield was a major contributor to fibre yield, while butt diameter was a
major contributor to seed yield.
Description
A Dissertation submitted to the Postgraduate School, Ahmadu Bello
University 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
MAY, 1998
Keywords
EFFECTS,, NITROGEN,, PERIOD,, WEED,, INTERFERENCE,, HERBICIDES,, PERFORMANCE,, KENAF., (Hibiscus caimahinus L.),, NORTHERN,, GUINEA,, SAVANNA,, NIGERIA.