RESPONSE OF GARLIC (Allium sativum L.) TO LEVELS OF NITROGEN, PHOSPHORUS AND IRRIGATION INTERVAL
RESPONSE OF GARLIC (Allium sativum L.) TO LEVELS OF NITROGEN, PHOSPHORUS AND IRRIGATION INTERVAL
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Date
1999-05
Authors
MIKO, SANI
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Abstract
Field experiments to study the response of garlic (Allium
sativum L.) crop to varying levels of nitrogen, phosphorus and
irrigation interval were conducted during the 1994/95, 1995/96 and
1996/97 dry seasons (November to March) at the Institute for
Agricultural Research, Irrigation farm, Samaru, Zaria (11° 11'N;07°
38'E 686m above sea level). The treatments consisted of four
nitrogen levels (0, 75, 150 and 225KgN/ha), three levels of
phosphorus (0,75, and 150KgP205/ha) and three irrigation intervals
(5,10 and 15 days between irrigations). The experiments were
conducted in a split-plot design with nitrogen levels and
irrigation intervals forming the main treatments while the
phosphorus levels were assigned to the sub-plots. The treatments
were replicated three times in each season.
Results obtained indicated that the application of 75KgN/ha
produced significant increases in all growth and yield characters
compared with control and higher rate of applied nitrogen had no
further influence on these characters. Plots that received no
nitrogen, however, produced significantly shorter plants, lower
leaf number/plant, dry matter/plant and all yield components
compared with the application of 75KgN/ha. Bulb yield and bulb
phosphorus content were observed to increase significantly with
increase in applied N only up to 75KgN/ha. The bulb crude protein
content, however, was found to progressively and significantly
increase with increasing rate of nitrogen up to 225KgN/ha.
Increasing the level of phosphorus from 0 to 75KgP205/ha
significantly increased plant height, dry matter/plant, number of
leaves/plant, CGR and RGR in all the 3 experiments. Similarly, all
other yield components responded significantly to applied
phosphorus only upto 75KgP205/ha. Further, increase in applied
phosphorus beyond 75KgP205/ha did not produce any appreciable
increase. Similar trend was recorded on cured bulb yield/ha. The
bulb phosphorus and protein contents also registered significant
response to applied phosphorus only upto 75kgN/ha.
Growth and yield characters as well as bulb yield, bulb
phosphorus and crude protein contents were significantly decreased
with increase in the number of days between irrigations but only
upto 10-day irrigation interval, while further delay in irrigation
to 15days between irrigations did not affect these characters
appreciably. Generally, the 5-day irrigation interval significantly
out yielded 10 and 15-day interval on all parameters assessed.
Correlation analysis showed positive and significant
associations between bulb yield and all characters assessed in all
seasons, except in 1995/96 where insignificant associations were
registered between bulb yield and average number of leaves/plant;
a negative non-significant correlations between bulb yield and
average clove weight. Dry matter/plant and average bulb weight had
the highest direct individual contributions to bulb yield, while
combinations of plant height and drymatter/plant (1995/96 trial) as
well as bulb weight and bulb size (1994/96) were the highest
contributors to bulb yield. Polynomial response of bulb yield to
nitrogen, phosphorus and irrigation interval indicated quadrati
Description
A dissertation submitted to the Postgraduate School, Ahmadu
Bello University in partial fulfilLment of the requirements for
the award of the degree of Doctor of Philosophy in Irrigation
Agronomy.
DEPARTMENT OF AGRONOMY
FACULTY OF AGRICULTURE
AHMADU BELLO UNIVERSITY
ZARIA, NIGERIA
MAY ,19 9 9
Keywords
RESPONSE,, GARLIC,, (Allium sativum L.),, NITROGEN,, PHOSPHORU,, IRRIGATION,, INTERVAL.