Abstract:
Onion (Allium cepa L.)
is an important vegetable crop
in Ethiopia.
However, its productivity
is limited because of continuous
cultivation
and inappropriate soil fertility management
practices.
Vermicompost is a new technology widely introduced to the region for the last three
years to
reduce
the challenges.
Nevertheless, the optimal application rate for the growth and
production of onion is not well investigated in Tigray and areas with similar biophysical
setup. Hence, a field experiment was undertaken in
Kilte
–
Awulaelo
district, eastern zone of
Tigr
ay fro
m October 2017 to March
2018 to
study the effect of combined application of
Vermicompost and blended fertilizer on onion bulb production and
selected soil properties
under irrigated soil.
The experiment was laid out in randomized complete block design with
three replications and twelve experimental treatments
(
Vermicompost (VC) at the rate of 4.5,
3 and 1.5 t ha
-
1
each combined with blended fertilizer (NPSZn) at the rate of 75, 50 and 25
kg
ha
-
1
including the same rate of N fertilizers (100 kg ha
-
1
). In addi
tion, full
recommended of
VC (6 t ha
-
1
),
full blanket
recommended
of blended fertilizer (100 kg ha
-
1
) and control
(unfertilized treatment) were used for comparison. Composite Vermicompost and soil samples
were taken before sowing and per plot soil samples
were taken after harvest from a soil depth
of 0
-
30 cm.
B
oth soil and agronomic dada were subjected to statistical analysis using SAS
statistical software (SAS 9.0) and mean separation was done using
least significance
difference
for significantly different treatments means.
Moreover,
partial budget analysis was
done to analyze cost benefit among the treatments.
Soil results revealed that different
integrated nutrient management practices had significant effect on soil chemical prop
erties.
Maximum OC (1.8 mg kg
-
1
), TN (0.2%), Available P (
14.6
mg kg
-
1
) and low C: N ratio (9)
was found
at
VC @ 6 t ha
-
1
.
Conversely, the minimum average soil chemical properties were
observed at the
absolute
control.
The result revealed that the highest
bulb yield (52
t ha
-
1
)
was
obtained from
combined application of
VC @ 4.5 t ha
-
1
+ NPSZn @ 50 kg ha
-
1
with the
advantage of
53.2 %
over the
absolute
control.
The partial
budget
analysis indicated that the
highest net benefit
361,597 (ETB ha
-
1
) was
obtained from VC @ 4.5 t ha
-
1
+ NPSZn @ 50 kg
ha
-
1
with
acceptable marginal rate of return.
It
could,
be
recommended
VC @ 4.5 t ha
-
1
+
NPSZn @ 50 kg ha
-
1
is appropriate
rate for
better onion
bulb
production in the study area
and
for areas with similar biophy
sical setup.
Keywords:
Agronomic data
,
Blended fertilizer
,
Cost benefit analysis,
Onion
bulb
,
Soil chemical propert
ies,
Vermicompost,
