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Applied
Soil
Ecology
76 (2014) 68–
77
Contents
lists
available
at
ScienceDirect
Applied
Soil
Ecology
journa
l
h
om
epa
ge:
www.elsevier.com/locate/apsoil
Compatibility
of
Rhizobium
inoculant
and
water
hyacinth
compost
formulations
in
Rosecoco
bean
and
consequences
on
Aphis
fabae
and
Colletotrichum
lindemuthianum
infestations
Victoria
Naluyangea,∗,
Dennis
M.W.
Ochienoa,
John
M.
Maingib,
Omwoyo
Omborib,
Dative
Mukaminegac,
Alice
Amodingd,
Martins
Odendoe,
Sheila
A.
Okothf,
William
A.
Shivogaa,
John
V.O.
Muomaa
aDepartment
of
Biological
Sciences,
Masinde
Muliro
University
of
Science
and
Technology
(MMUST),
P.O.
Box
190-50100,
Kakamega,
Kenya
bDepartment
of
Plant
and
Microbial
Sciences,
Kenyatta
University,
P.O.
Box
43844-00100,
Nairobi,
Kenya
cFaculty
of
Applied
Sciences,
Kigali
Institute
of
Science
and
Technology
(KIST),
P.O.
Box
3900,
Kigali,
Rwanda
dDepartment
of
Soil
Science,
Makerere
University,
P.O.
Box
7062,
Kampala,
Uganda
eSocio-Economics
and
Statistics
Division,
Kenya
Agricultural
Research
Institute
(KARI),
P.O.
Box
169-50100,
Kakamega,
Kenya
fSchool
of
Biological
Sciences,
University
of
Nairobi,
P.O.
Box
30197-GPO,
Nairobi,
Kenya
a
r
t
i
c
l
e
i
n
f
o
Article
history:
Received
10
September
2013
Received
in
revised
form
16
December
2013
Accepted
18
December
2013
Keywords:
Aphis
fabae
Compost
Lake
Victoria
Nitrogen
Rhizobium
Water
hyacinth
a
b
s
t
r
a
c
t
The
common
bean,
Phaseolus
vulgaris
is
an
important
crop
for
food
security
and
nitrogen
fixation
through
Rhizobium
symbiosis.
Commercial
Rhizobium
inoculants
are
being
promoted
to
fix
nitrogen
and
enhance
bean
production
in
the
Lake
Victoria
basin.
Rhizobium
symbiosis
depends
on
nutrients,
especially
phos-
phorus,
which
is
widely
applied
as
diammonium
phosphate
(DAP)
in
the
Lake
Victoria
basin.
Water
hyacinth,
Eichornia
crassipes
(Mart.)
Solms-Laubach
(Pontederiaceae)
is
being
developed
into
compost,
with
perceived
benefits
of
improving
crop
production
and
limiting
its
disastrous
spread
in
Lake
Victoria.
High
nutrient
content
in
water
hyacinth
compost
can
stimulate
Rhizobium
nodulation
and
nitrogen
fixa-
tion,
consequently
improving
plant
growth
and
pest
resistance.
However,
it
is
not
yet
established
whether
Rhizobium
inoculants
and
water
hyacinth
composts
are
compatible
options
for
plant
growth
promotion
and
pest
suppression
in
beans.
A
field
experiment
with
two
trials
was
conducted
to
assess
the
compat-
ibility
of
commercial
Rhizobium
inoculant,
DAP,
cattle
farmyard
manure
(FYM),
and
four
formulations
of
water
hyacinth
compost
i.e.,
water
hyacinth
only
(H),
with
molasses
(H+Mol),
cattle
manure
culture
(H+CMC)
or
effective
microbes
(H+EM).
Rhizobium
inoculated
plants
had
high
number
of
root
nodules
when
grown
with
H+CMC
and
H+EM.
Plants
were
large
in
size
with
short
development
period
when
grown
with
the
composts,
especially
H+CMC
and
H+EM.
Those
grown
with
H+EM
produced
high
num-
ber
of
flowers.
Rhizobium
inoculated
plants
had
high
anthracnose
incidence
than
non-inoculated
ones
when
grown
with
H+CMC.
Those
grown
with
H+EM
had
low
anthracnose
incidence,
but
was
high
in
FYM.
During
flowering,
Rhizobium
inoculated
plants
had
higher
Aphis
fabae
population
than
non-inoculated
ones
when
grown
in
FYM
or
without
fertilizer.
Those
grown
with
H+EM
had
the
lowest
A.
fabae
popu-
lation.
Yields
in
water
hyacinth
compost
were
improved,
especially
for
H+CMC
in
the
second
trial.
DAP
treated
plants
had
more
flowers
and
pods
having
heavy
seeds,
with
low
anthracnose
and
A.
fabae
infes-
tations;
but
had
low
germination
rates
that
reduced
the
yields.
In
conclusion,
the
commercial
Rhizobium
inoculant
is
predominantly
compatible
with
water
hyacinth
compost
formulations
containing
effective
microbes
and
cattle
manure
culture,
which
could
enhance
tolerance
of
bean
plants
to
aphids
and
possi-
bly
to
anthracnose
disease.
These
two
water
hyacinth
compost
formulations
need
further
investigation
for
their
potential
in
enhancing
food
production
and
alleviating
the
water
hyacinth
problem
in
the
Lake
Victoria
basin.
© 2014 Elsevier B.V. All rights reserved.
∗Corresponding
author
at:
Masinde
Muliro
University
of
Science
and
Technology,
Biological
Sciences,
Kakamega-Webuye
road,
Kakamega,
Kenya.
Tel.:
+254700187001.
E-mail
address:
vicluy@gmail.com
(V.
Naluyange).
1.
Introduction
The
common
bean
Phaseolus
vulgaris
L.
(Fabaceae)
is
a
very
important
crop
for
food
security
and
nutrition
worldwide.
The
crop
is
also
important
due
to
its
symbiotic
nitrogen
fixing
capacity,
which
contributes
to
improvement
of
soil
fertility
(Maingi
et
al.,
2001;
Bala
et
al.,
2011).
However,
bean
production
in
sub-Saharan
0929-1393/$
–
see
front
matter ©
2014 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.apsoil.2013.12.011
Author's personal copy
V.
Naluyange
et
al.
/
Applied
Soil
Ecology
76 (2014) 68–
77 69
Africa
has
been
declining
over
years.
Such
declines
have
been
attributed
to
agronomic
constraints
such
as
inferior
germplasms,
low
soil
fertility,
pests
and
diseases
(Odendo
et
al.,
2011).
Bean
varieties
have
been
succumbing
to
anthracnose
disease
caused
by
Colletotrichum
lindemuthianum
(Beebe,
2012;
Kharinda,
2013),
as
well
as
a
complex
of
viruses
transmitted
by
aphids
(Omunyin
et
al.,
1995;
Beebe,
2012).
Soils
have
been
depleted
of
essential
nutrients
for
bean
production,
particularly
nitrogen
and
phosphorus
(Kimani
et
al.,
2007;
Kimani
and
Tongoona,
2008).
Several
strategies
are
being
developed
and
applied
to
enhance
bean
production.
These
strategies
include
improving
germplasm
in
terms
of
yield
potential
and
pest
resistance.
For
instance,
high
yielding
bean
varieties
that
are
moderately
resistant
to
anthrac-
nose
have
been
produced
in
Kenya
(Wagara
et
al.,
2003;
Kharinda,
2013).
Despite
these
efforts,
abiotic
stresses,
especially
low
soil
fertility
has
been
hindering
the
performance
of
improved
bean
varieties
(Jansa
et
al.,
2011).
Recently,
there
have
been
efforts
to
improve
legume
production
through
the
application
of
symbiotic
microbes
such
as
Rhizobium
species,
which
enhance
bean
produc-
tion
by
fixing
atmospheric
nitrogen
(Samac
and
Graham,
2007).
Some
symbiotic
Rhizobium
species
also
protect
plants
from
pests
and
diseases
through
induced
resistance
(Elbadry
et
al.,
2006;
Dutta
et
al.,
2008).
However,
the
ability
of
Rhizobium
species
to
fix
nitro-
gen
is
limited
by
inadequate
nutrients
in
soil,
especially
phosphorus
(O’Hara
et
al.,
1988;
Graham
and
Vance,
2000).
This
has
necessi-
tated
the
application
of
synthetic
fertilizers
such
as
diammonium
phosphate
(DAP)
and
triple
superphosphate
(TSP)
on
beans.
How-
ever,
there
have
been
reports
of
these
synthetic
fertilizers
being
incompatible
with
Rhizobium
species
through
inhibition
of
legume
nodulation
(Waterer
and
Vessey,
1993).
This
has
necessitated
the
use
of
organic
soil
amendments
that
are
more
compatible
with
Rhizobium
species
(Saini
et
al.,
2004;
Zengeni
et
al.,
2006).
The
overuse
of
synthetic
fertilizers
has
also
been
linked
to
eutrophication
of
water
bodies,
causing
problems
such
as
the
spread
of
water
hyacinth
Eichhornia
crassipes
(Mart.)
Solms-
Laubach
(Pontederiaceae)
in
Lake
Victoria
within
East
Africa
(Lung’ayia
et
al.,
2001;
Cavalli
et
al.,
2009).
To
mitigate
this
prob-
lem
of
fertilizer-induced
eutrophication,
water
hyacinth
is
being
developed
into
compost
for
crop
production,
with
an
anticipated
benefit
of
controlling
the
invasive
weed
in
Lake
Victoria
while
promoting
organic
farming.
Water
hyacinth-derived
composts
are
rich
in
nutrients,
especially
nitrogen
and
phosphorus
(Amoding
et
al.,
1999;
Okalebo
et
al.,
2006;
Gunnarsson
and
Petersen,
2007),
which
influence
root
colonization
by
Rhizobium
species
and
enhance
plant
resistance
to
pathogens
(Zahran,
1999).
Four
water
hyacinth
compost
formulations
have
been
developed
for
potential
use
within
the
Lake
Victoria
basin
namely;
water
hyacinth
compost
only,
water
hyacinth
compost
enhanced
with
effective
microbes
(EM),
water
hyacinth
compost
with
molasses,
and
water
hyacinth
compost
with
cattle
manure
culture
(Naluyange,
2013;
Osoro
et
al.,
2014).
Studies
are
being
conducted
on
the
identification
of
Rhizobium
species
native
to
potential
areas
for
the
application
of
water
hyacinth
compost
within
Lake
Victoria
basin
(Muthini
et
al.,
2014).
However,
we
are
not
aware
of
any
studies
investi-
gating
compatibility
of
Rhizobium
inoculants
and
the
previously
mentioned
water
hyacinth
compost
formulations.
The
objective
of
the
present
study
was
to
establish
whether
commercial
Rhizobium
inoculant
and
water
hyacinth
compost
for-
mulations
are
compatible
in
bean
growth
promotion,
and
whether
they
have
any
consequences
on
infestations
by
aphids
and
the
anthracnose
pathogen
C.
lindemuthianum.
2.
Materials
and
methods
2.1.
Experimental
design
A
field
experiment
was
conducted
at
the
Masinde
Muliro
Uni-
versity
of
Science
and
Technology
(MMUST)
farm
(N
00
17.104’,
E
034◦45.874’;
altitude
1561
m
a.s.l.).
The
land
had
been
fallow
and
colonized
by
the
African
couch
grass
Digitaria
scalarum
(Schweinf.)
Chiov.
(Poaceae)
for
over
5
years.
Soils
in
this
region
have
been
clas-
sified
as
dystro-mollic
Nitisols
(FAO,
1974;
Rota
et
al.,
2006).
The
experiment
was
laid
out
in
a
randomized
block
design
compris-
ing
a
2
×
6
factorial
experiment
with
Rhizobium
inoculum
factor
having
two
levels
(with
or
without
inoculation)
and
fertilizer
fac-
tor
with
six
levels
i.e.,
no
fertilizer
(Non),
diammonium
phosphate
fertilizer
(DAP),
water
hyacinth
compost
only
(H),
water
hyacinth
compost+molasses
(H+Mol),
water
hyacinth
compost+effective
microbes
(H+EM),
and
water
hyacinth
compost+cattle
manure
cul-
ture
(H+CMC).
In
the
first
trial,
water
hyacinth
compost
only
was
not
applied,
while
in
the
second
trial,
cattle
farmyard
manure
(FYM)
prepared
under
the
MMUST
farm
management
replaced
water
hyacinth
compost+molasses.
Each
of
the
resulting
12
treatment
combinations
(plots)
had
25
plants
(n)
in
3
blocks
(i.e.,
N
=
900).
Each
plot
was
in
form
of
a
row
containing
the
25
plants
spaced
at
20
cm,
with
a
distance
of
40
cm
between
the
plots,
without
border
rows.
The
treatment
rows
were
completely
randomized
to
mini-
mize
non-experimental
bias
in
sampling
for
natural
infestations
of
aphids
and
anthracnose
disease
on
bean
plants.
This
experiment
was
conducted
during
the
long
rain
season
between
20th
April
to
30th
July
2012,
and
then
repeated
between
30th
May
and
31st
August
2012.
The
soil
samples
collected
on
14th
April
2012,
and
four
water
hyacinth
manure
formulations
(Table
1)
developed
under
the
VicRes
project
NR-03
2010
were
analyzed
for
their
chemical
char-
acteristics
based
on
Okalebo
et
al.
(2002)
at
the
Department
of
Soil
Science,
University
of
Nairobi.
2.2.
Water
hyacinth
compost
formulations
Four
types
of
water
hyacinth
compost
were
prepared
con-
currently
from
the
same
batch
of
water
hyacinth
material
using
Table
1
Chemical
characteristics
of
the
water
hyacinth
compost
formulations
and
the
soil
from
the
experimental
field.
Parameter
HaH+MolbH+EMcH+CMCdSoil
Organic
carbon
(%)
12.2
5.4
13.5
13.4
2.5
Total
nitrogen
(%)
1.3
0.6
1
1.1
0.26
Total
phosphorus
(ppm)
280
265
270
375
18.9
Potassium
(cmolckg−1)
25
21.2
24.5
21
0.41
Sodium
(cmolckg−1)
2.1
1.8
1.7
1.9
0.1
Calcium
(cmolckg−1) 20.7
37.2
27.5
22.3
2.3
Magnesium
(cmolckg−1)
9.3
9.3
15.3
12
0.8
Zinc
(ppm)
3.0
3
4
2
1.9
Iron
(ppm)
1.3
1.3
1.7
1.9
0.37
pH
8.4
8.4
8.4
8.1
4.2
aWater
hyacinth
compost
only.
bwater
hyacinth
compost
with
molasses.
cwater
hyacinth
compost
with
effective
microbes.
dwater
hyacinth
with
cattle
manure
culture.
Author's personal copy
70 V.
Naluyange
et
al.
/
Applied
Soil
Ecology
76 (2014) 68–
77
aboveground
closed
aerobic
heap
design
in
4
replicates.
Sixteen
heap
stands
measuring
1
×
1
×
1.5
m
(L
×
W
×
H),
made
of
wooden
frame
and
chicken
wire
mesh,
with
a
fitting
polythene
sack
on
the
inner
part
were
constructed.
The
top
part
of
these
heap
stands
was
left
open
for
turning
of
the
compost.
Water
hyacinth
was
harvested
manually,
then
taken
to
the
composting
site
and
sun-
dried
for
seven
days.
It
was
chopped
into
small
pieces
of
about
5
cm
using
a
chaff
cutter
to
increase
the
surface
area
for
decom-
position.
Dried
and
chopped
water
hyacinth
material
(20
kg)
was
put
into
the
heap
stands
to
form
a
layer
∼10
cm
thick.
In
the
preparation
of
water
hyacinth
compost+effective
microbes
(H+EM)
formulation,
this
10
cm
layer
was
sprayed
with
10
L
of
2%
effective
microorganisms
solution
(EMTM),
containing
photosynthetic
bacte-
ria
(Rhodopseudomonas
palustris),
lactic
acid
bacteria
(Lactobacillus
plantarum
and
L.
casei),
yeast
(Saccharomyces
cerevisae),
molasses,
and
water
(EM
Technologies
Ltd,
Embu,
Kenya).
This
process
was
repeated
until
the
heap
reached
1.2
m
high
holding
∼240
kg
of
the
water
hyacinth
material
in
twelve
layers.
A
similar
approach
was
used
in
the
preparation
of
water
hyacinth
compost+molasses
(H+Mol),
except
that
10
L
of
2%
molasses
solution
was
applied.
For
water
hyacinth
compost
only
(H),
10
L
of
water
without
any
other
ingredient
was
applied
after
every
layer.
For
water
hyacinth
compost+cattle
manure
culture
(H+CMC),
a
culture
made
of
5
kg
decomposed
cattle
manure
per
10
L
of
water
was
prepared
as
a
source
of
saprophytic
microbes.
This
cattle
manure
culture
(CMC)
was
applied
after
every
water
hyacinth
layer
was
spread
onto
the
heap
stand,
amounting
to
∼60
kg
of
cattle
manure
per
heap.
The
compost
heaps
were
mixed
every
10
days
using
forked
shov-
els
to
increase
aeration
and
facilitate
uniformity
of
temperature
for
decomposition
within
55
days.
Moisture
content
(60%)
in
the
compost
heaps
was
monitored
using
moisture
meter
(Model
PM-
300,
Shenzhen
Hinet
Electronic
Co.
Ltd,
Guangdong,
China).
The
4
replicate
heaps
for
each
type
of
water
hyacinth
compost
were
then
mixed
thoroughly
into
composite
heaps
for
use.
This
com-
post
is
dark
in
colour
with
particles
of
loamy
texture.
From
each
of
the
composite
heaps,
250
g
samples
were
randomly
picked
for
nutrient
analysis
at
the
Department
of
Soil
Science,
University
of
Nairobi.
2.3.
Seed
inoculation
and
planting
Rosecoco
bean
seeds
(GLP
2)
(Kenya
Seed
Company
Ltd)
were
inoculated
with
Rhizobium
inoculant
powder
(BIOFIX®,
MEA
Ltd,
Kenya)
as
per
the
manufacturer’s
directions.
The
seeds
(250
g)
were
mixed
in
gum
Arabic
solution
(0.5
gum
Arabic/5
mL
of
sterile
luke-
warm
water).
The
gum
Arabic-coated
seeds
(250
g)
were
mixed
with
the
Rhizobium
inoculant
powder
(1
g).
Controls
were
coated
with
the
gum
Arabic
solution
only.
Planting
holes
∼200
cm3volume
(i.e.,
∼5
cm
diameter
and
∼10
cm
deep)
were
dug
using
a
shovel.
The
composts
and
FYM
were
applied
using
containers
of
150
mL
volumes
per
hole
as
per
the
respective
treatments
and
mixed
with
soil.
For
the
DAP
treat-
ments,
one
leveled
teaspoon
was
mixed
with
soil
in
the
planting
hole.
One
bean
seed
was
sown
in
every
planting
hole
at
a
depth
of
∼2
cm.
2.4.
Plant
growth,
root
nodulation,
and
yields
The
emergence
date
of
every
seedling
was
recorded
indepen-
dently,
and
used
to
determine
the
duration
for
germination.
The
number
of
seedlings
that
germinated
out
of
the
total
number
of
seeds
that
were
planted
was
used
to
determine
the
germination
percentage.
The
germination
rate
recorded
was
for
seedlings
that
emerged
within
20
days
from
the
planting
date.
The
date
for
formation
of
the
first
trifoliate
leaf
was
recorded
and
used
to
calculate
the
duration
in
days
from
the
date
of
planting.
When
the
first
trifoliate
leaves
were
fully
formed
in
∼80%
of
the
seedlings,
plant
height
(stem
base
to
petiole),
length
of
the
middle
leaf
(base
to
apex)
and
its
width
(widest
part)
were
recorded.
The
date
when
the
first
flower
of
every
plant
appeared
was
recorded
and
used
to
calculate
the
duration
for
flowering
in
days
from
the
date
of
planting.
The
number
of
flowers
on
each
plant
was
recorded
every
three
days
for
a
period
of
three
weeks.
Ten
days
from
the
onset
of
flowering,
5
bean
plants
were
randomly
selected
from
each
treatment
per
block
for
the
estimation
of
number
of
root
nodules
associated
with
Rhizobium
colonization.
The
bean
plants
were
dug
out
from
the
soil
into
plastic
bags,
and
the
number
of
root
nodules
per
plant
was
recorded
using
a
tally
counter
in
the
laboratory.
The
date
when
the
first
bean
pod
per
plant
formed
was
recorded
and
used
to
calculate
the
duration
for
pod
formation
in
days
from
the
date
of
planting.
The
date
of
ripening
of
the
first
pod
per
plant
was
recorded
and
used
to
calculate
the
duration
to
maturity
in
days
from
the
date
of
planting.
Plants
were
harvested
indepen-
dently
and
the
number
of
harvested
pods
per
plant
recorded.
The
harvested
pods
from
every
plant
were
packed
in
separate
paper
packets
and
sun
dried
for
a
period
of
five
days.
From
every
paper
packet,
three
pods
were
randomly
selected
and
the
number
of
seeds
in
each
of
the
pod
recorded.
The
weight
of
all
seeds
per
packet
was
recorded
as
seed
weight
per
plant,
which
was
used
to
estimate
yield
per
unit
area
(ton
ha−1)
using
the
formula:-Yield
per
unit
area
=
yײ
(x×n)ˇWhereby:y
=
seed
weight
per
plant
in
grams;
x
=
space
occupied
by
one
plant
(0.08
m2);
n
=
number
of
plants
per
treat-
ment;
˛
=
10−6(converts
weight
in
grams
to
tonnes);
and
ˇ
=
10−4
(converts
area
in
m2to
hectares)
2.5.
Aphid
and
anthracnose
incidences
Aphid
infestations
on
bean
plants
were
recorded
at
the
veg-
etative
and
flowering
stage
of
bean
plants.
Three
screw-capped
containers
each
containing
10
mL
of
70%
ethanol
were
placed
on
every
treatment
row
of
25
plants.
Aphids
from
every
8
plants
per
row
were
collected
into
each
container
using
a
camel
hair
brush
from
leaves
and
stems.
The
collected
aphids
were
identified
under
a
dissection
microscope
(Model
Z45E,
Leica
Inc.,
USA)
at
×
10
magnifications
using
the
features
described
in
Martin
(1983)
and
Holman
(1998),
and
their
absolute
counts
recorded
using
a
tally
counter.
At
the
vegetative
stage,
the
bean
plants
were
also
scored
for
anthracnose
disease
incidence
i.e.,
the
proportion
of
plants
hav-
ing
anthracnose
symptoms,
characterized
by
dark
brown
to
black
lesions
on
leaves
(Hagedorn
and
Inglis,
1986;
Buruchara
et
al.,
2010).
2.6.
Statistical
analysis
Statistical
analysis
was
conducted
using
SAS
9.1
software
(SAS
Institute
Inc.)
at
p
<
0.05
confidence
level.
Descriptive
statistics
such
as
means
were
generated
using
proc
means,
while
frequencies
(per-
centages)
were
generated
using
proc
freq.
Data
on
plant
growth
was
checked
for
normality
using
proc
univariate;
while
proc
tran-
sreg
was
used
to
find
appropriate
Box–Cox
power
transformations
for
normalization
of
data.
Proc
glm
was
used
for
analyses
of
vari-
ance
(ANOVA)
among
the
treatments;
and
means
were
separated
using
LS-means
when
the
effects
of
treatments
were
significant.
Data
on
aphid
populations
and
root
nodule
counts
were
analyzed
using
proc
genmod
(2test;
Poisson)
and
the
means
separated
using
proc
multtest
with
bonferroni
adjustment.
Anthracnose
dis-
ease
incidences
and
germination
percentages
were
analyzed
by
proc
genmond
(2test;
binomial)
and
percentages
compared
using
proc
multtest.
Author's personal copy
V.
Naluyange
et
al.
/
Applied
Soil
Ecology
76 (2014) 68–
77 71
3.
Results
3.1.
Germination
percentage
and
number
of
root
nodules
Seeds
grown
with
DAP
had
significantly
lower
germination
per-
centage
than
the
water
hyacinth
compost
formulations
and
the
controls
in
both
trials
(p
<
0.0001)
(Fig.
1a
and
b).
Germination
per-
centage
was
not
different
between
Rhizobium
inoculated
plants
and
the
respective
controls
(Fig.
1a
and
b).
There
was
significant
difference
in
the
number
of
root
nodules
between
the
twelve
treatments
(p
<
0.0001)
(Fig.
2).
Number
of
root
nodules
was
significantly
higher
in
Rhizobium
inoculated
plants
than
in
the
non-inoculated
ones
when
grown
with
water
hyacinth
compost
containing
cattle
manure
culture
(H+CMC)
and
water
hyacinth
compost
containing
effective
microbes
(H+EM).
Number
of
root
nodules
was
significantly
lower
in
Rhizobium
inoculated
plants
than
in
the
non-inoculated
ones
when
grown
with
water
hyacinth
compost
only
(H)
and
cattle
farmyard
manure
(FYM);
but
not
different
in
DAP
and
controls
(Fig.
2).
Roots
of
Rhizobium
inoculated
plants
grown
with
water
hyacinth
compost
containing
cattle
manure
culture
(H+CMC)
and
water
hyacinth
Fig.
1.
Germination
percentage
of
Rosecoco
bean
seeds
as
affected
by
commercial
Rhizobium
inoculant
and
soil
fertility
amendments
in
the
first
trial
(A)
and
second
trial
(B).
Without
fertilizer
(Non),
diammonium
phosphate
fertilizer
(DAP),
cattle
farmyard
manure
(FYM),
water
hyacinth
compost
only
(H),
water
hyacinth
com-
post+molasses
(H+Mol),
water
hyacinth
compost+cattle
manure
culture
(H+CMC)
and
water
hyacinth
compost+effective
microbes
(H+EM).
Numbers
on
top
of
bars
represent
sample
sizes.
Bars
with
the
same
letter(s)
are
not
significantly
different
(2test,
p
>
0.05).
Fig.
2.
Number
of
root
nodules
in
Rosecoco
bean
plants
as
affected
by
commercial
Rhizobium
inoculant
and
soil
fertility
amendments
in
the
second
trial.
Without
fertil-
izer
(Non),
diammonium
phosphate
fertilizer
(DAP),
cattle
farmyard
manure
(FYM),
water
hyacinth
compost
only
(H),
water
hyacinth
compost+cattle
manure
culture
(H+CMC)
and
water
hyacinth
compost+effective
microbes
(H+EM).
Bars
with
the
same
letter(s)
are
not
significantly
different
(2test,
p
>
0.05).
compost
containing
effective
microbes
(H+EM)
had
significantly
higher
nodule
counts
than
in
the
other
four
fertility
treatments
(Fig.
2).
In
the
non-inoculated
plants,
those
grown
with
water
hyacinth
compost
only
(H)
and
FYM
had
highest
nodule
counts,
followed
by
water
hyacinth
compost
containing
cattle
manure
culture
(H+CMC)
and
water
hyacinth
compost
containing
effective
microbes
(H+EM),
but
lowest
in
DAP
and
the
controls
(Fig.
2).
3.2.
Developmental
period
Plants
grown
with
DAP
had
the
longest
developmental
period,
as
exhibited
in
number
of
days
to
emergence
through
to
the
ripening
of
pods
in
both
trials
(p
<
0.05)
(Tables
2a
and
2b).
Those
that
were
grown
with
water
hyacinth
compost
containing
effective
microbes
(H+EM)
had
the
shortest
developmental
period,
which
was
evident
at
emergence
and
numerically
reflected
through
to
the
ripening
of
pods
in
the
first
trial
(Table
2a).
In
the
second
trial,
plants
grown
with
the
three
water
hyacinth
compost
formulations
took
a
short
period
to
germinate,
which
persisted
to
the
ripening
of
pods
in
the
water
hyacinth
compost
with
cattle
manure
culture
(H+CMC)
(Table
2b).
Plants
from
Rhizobium
inoculated
seeds
took
a
shorter
period
for
emergence,
formation
of
first
trifoliate
leaf
and
pods
than
the
non-inoculated
ones
in
the
second
trial
(Table
2b).
3.3.
Plant
size,
flower
counts,
and
yields
Plants
grown
with
water
hyacinth
compost
containing
effec-
tive
microbes
(H+EM)
had
larger
size
in
terms
of
height
and
leaf
length
compared
to
those
grown
without
fertilizer
in
the
first
trial
(Table
3a).
In
the
second
trial,
plants
grown
with
the
three
for-
mulations
of
water
hyacinth
compost
and
farmyard
manure
(FYM)
were
larger
than
those
grown
with
DAP
and
without
fertilizer
in
terms
of
height
and
leaf
size
(Table
3b).
However,
unlike
in
the
first
trial,
those
grown
with
water
hyacinth
compost
containing
effec-
tive
microbes
(H+EM)
were
smaller
than
the
ones
receiving
water
hyacinth
compost
only
(H)
and
water
hyacinth
compost
containing
cattle
manure
culture
(H+CMC)
in
the
second
trial
(Table
3b).
In
the
first
trial,
plants
grown
with
water
hyacinth
compost
con-
taining
effective
microbes
(H+EM)
and
DAP
produced
more
flowers
than
the
other
treatments
(Table
3a).
In
the
second
trial,
plants
grown
with
the
three
formulations
of
water
hyacinth
compost
and
Author's personal copy
72 V.
Naluyange
et
al.
/
Applied
Soil
Ecology
76 (2014) 68–
77
Table
2a
Developmental
periods
of
Rosecoco
bean
plants
as
influenced
by
Rhizobium
inoculant
and
water
hyacinth
compost
formulations
during
the
first
trial.
Source
of
variation
df
Emergence
First
trifoliate
Flowering
Pod
formation
Pod
ripening
F
values
Rhizobium
(R)
1
0.21
0.47
0.06
0.38
0.16
Fertilizer
(F)
4
9.57***
7.21***
5.23***
4.41**
4.52***
R
×
F
4
0.63
4.07**
1.88
1.18
0.36
Means
(first
row
are
overall
means
for
respective
parameters)
Days
Days
Days
Days
Days
7.3
15.0
36.0
42.9
70.0
Inoculum
Control
7.2
14.9
36.0
42.9
69.9
Rhizobium
7.3
15.0
35.9
42.9
69.9
Fertilizer
Non
7.4
b 15.3
35.3
b
42.3
c
69.9
b
DAP
8.4
a
15.5
38.2
a
44.8a
71.9
a
H+Mol
7.4
b
15.0
36.8
a
43.3
b
70.1
b
H+CMC
7.1
bc 14.8
35.7
b
43.4
b
69.7
b
H+EM
6.9
c
14.7
35.8
b
42.4
bc
69.7
b
Control
Non
7.3
14.9
bc
35.0
42.3
69.9
DAP
8.2
15.4
ab
38.0
44.0
72.0
H+CMC
7.2
14.9
bc
36.0
43.7
69.7
H+Mol
7.4
15.0
bc
36.3
42.9
70.1
H+EM
6.9
14.7
c 36.4
42.6
69.9
Rhizobium
Non
7.5
15.6
a
35.5
42.4
69.9
DAP
8.6
15.5
ab
38.4
45.7
71.7
H+CMC
7.0
14.6
c
35.2
42.8
69.9
H+Mol
7.4
15.0
bc 37.2
43.6
70.2
H+EM
6.9
14.6
c
35.1
42.2
69.5
Without
fertilizer
(Non),
diammonium
phosphate
fertilizer
(DAP),
water
hyacinth
compost+molasses
(H+Mol),
water
hyacinth
compost+cattle
manure
culture
(H+CMC)
and
water
hyacinth
compost+effective
microbes
(H+EM).
Asterisk
indicates
the
significant
effect,
***p
≤
0.001,
**p
≤
0.01,
*p
≤
0.05.
Means
with
the
same
letter(s)
are
not
significantly
different.
Interactions
are
considered
over
main
effects
wherever
they
are
significant;
no
letters
presented
where
there
is
no
significant
difference.
Table
2b
Developmental
periods
of
Rosecoco
bean
plants
as
influenced
by
Rhizobium
inoculant
and
water
hyacinth
compost
formulations
during
the
second
trial.
Source
of
variation df
Emergence
First
trifoliate
Flowering
Pod
formation
Pod
ripening
F
values
Rhizobium
(R)
1
6.57*
4.02*
2.87
5.21*
1.28
Fertilizer
(F)
4
24.56***
12.86***
7.4***
5.37***
2.77*
R
×
F
4
1.55
1.66
1.93
1.67
0.98
Means
(first
row
are
overall
means
for
respective
parameters)
Days
Days
Days
Days
Days
7.3
15.0
41.0
47.6
74.4
Inoculum
Control
7.4
a
15.1
a
40.9
47.9
a
74.1
Rhizobium
7.2
b
14.9
b
40.9
47.4
b
74.5
Fertilizer
Non
7.4
b
15.1
b
40.8
bc
48.3
b
74.0
bc
DAP
9.7
a
16.6
a
43.8
a
50.4
a
75.8
a
FYM
7.2
bc
14.8
bc
40.6
bc
47.2
bc
74.6
ab
H
7.0
c
14.7
c
40.7
bc
47.2
bc
74.3
abc
H+CMC
6.9
c
14.6
c
40.4
c
46.7
c
73.6
c
H+EM
7.0
c
14.8
bc
41.3
b
47.9
b
74.8
ab
Without
fertilizer
(Non),
diammonium
phosphate
fertilizer
(DAP),
cattle
farmyard
manure
(FYM),
water
hyacinth
compost
only
(H),
water
hyacinth
compost+cattle
manure
culture
(H+CMC)
and
water
hyacinth
compost+effective
microbes
(H+EM).
Asterisk
indicates
the
significant
effect,
***p
≤
0.001,
**p
≤
0.01,
*p
≤
0.05.
Means
with
the
same
letter(s)
are
not
significantly
different.
Interactions
are
considered
over
main
effects
wherever
they
are
significant;
no
letters
presented
where
there
is
no
significant
difference.
FYM
had
more
flowers
than
those
without
fertilizer,
while
the
ones
grown
with
DAP
were
intermediate
(Table
3b).
Plants
grown
with
DAP
produced
the
highest
number
of
pods,
while
those
grown
with
water
hyacinth
compost
containing
cat-
tle
manure
culture
(H+CMC)
had
the
fewest
pods
in
the
first
trial
(Table
3a).
In
the
second
trial,
plants
grown
without
fertilizer
had
fewer
pods
than
the
other
five
fertility
treatments
(Table
3b).
Rhizo-
bium
inoculated
plants
produced
fewer
pods
than
those
without
the
inoculum
in
the
second
trial
(Table
3b);
while
seed
count
per
pod
did
not
vary
between
treatments
in
both
trials
(Tables
3a
and
3b).
Plants
grown
with
DAP
had
the
highest
seed
weight,
while
those
with
water
hyacinth
compost
containing
molasses
(H+Mol)
and
Author's personal copy
V.
Naluyange
et
al.
/
Applied
Soil
Ecology
76 (2014) 68–
77 73
Table
3a
Plant
size,
number
of
flowers
and
yield-related
parameters
of
Rosecoco
bean
plants
as
influenced
by
Rhizobium
inoculant
and
water
hyacinth
compost
formulations
during
the
first
trial.
Source
of
variation df
Plant
size
at
the
first
trifoliate
stage
Flowers
Yield-related
parameters
Leaf
length
Leaf
width
Height
Harvested
pods
Seeds
per
pod
Seed
weight
Yield
per
unit
area
F
values
Rhizobium
(R)1
0.02
1.54
0.4
0.63
1.91
0.69
6.35*
1.63
Fertilizer
(F)
4
2.48*
1.54
3.86**
4.3**
8.45***
1.97
6.8***
18.04***
R
×
F
4
1.41
1.61
1.79
1.12
0.91
0.68
0.89
0.92
Means
(first
row
are
overall
means
for
respective
parameters)
cm
cm
cm
Counts
Counts
Counts
Grams
tons
ha−1
10.1
6.3
6.2
4.9
16.2
4.2
22.5
1.6
Inoculum
Control
14.9
6.3
6.2
4.8
15
4.1
20.4
b
1.5
Rhizobium
15.0
6.3
6.1
4.9
15
4.2
24.6
a
1.7
Fertilizer
Non
10.0
b
6.3
5.9
b
4.8
b
17.0
b
4.1
24.9
b
2.2
a
DAP
10.2
ab
6.8
5.8
b
6.3
a
25.8
a
4.4
32.8
a
0.4
c
H+Mol
9.6
b
6.1
6.1
b
4.6
b
15.3
bc
4.2
18.3
c
1.8
ab
H+CMC
10.1
ab 6.2
6.2
ab
4.4
b
13.4
c
4.0
20.4
c
1.5
b
H+EM
10.7
a
6.5
6.5
a
5.4
a
17.0
b
4.3
23.4
b
2.1
a
Without
fertilizer
(Non),
diammonium
phosphate
fertilizer
(DAP),
water
hyacinth
compost+molasses
(H+Mol),
water
hyacinth
compost+cattle
manure
culture
(H+CMC)
and
water
hyacinth
compost+effective
microbes
(H+EM).
Asterisk
indicates
the
significant
effect,
***p
≤
0.001,
**p
≤
0.01,
*p
≤
0.05.
Means
with
the
same
letter(s)
are
not
significantly
different;
those
with
more
than
one
letter
are
intermediate.
Interactions
are
considered
over
main
effects
wherever
they
are
significant;
no
letters
presented
where
there
is
no
significant
difference.
Table
3b
Plant
size,
number
of
flowers
and
yield-related
parameters
of
Rosecoco
bean
plants
as
influenced
by
Rhizobium
inoculant
and
water
hyacinth
compost
formulations
during
the
second
trial.
Source
of
variation df Plant
size
at
the
first
trifoliate
stage
Flowers
Yield-related
parameters
Leaf
length
Leaf
width
Height
Harvested
pods
Seeds
per
pod
Seed
weight
Yield
per
unit
area
F
values
Rhizobium
(R)
1
0.6
0
0.29
1.31
4.53*
1.78
7.56**
3.03
Fertilizer
(F)
5
19.83***
16.57***
4.87***
4.0**
5.11***
1.9
5.36***
5.82***
R
×
F
5
2.04
1.82
1.49
1.29
1.18
1.08
0.99
0.51
Means
(first
row
are
overall
means
for
respective
parameters)
cm
cm
cm
Counts
Counts
Counts
Grams
tons
ha−1
9.1
5.7
4.8
2.5
6.1
2.9
4.0
0.24
Inoculum
Control
15.1
5.7
4.8
2.6
6.7
a
2.9
4.5
a
0.26
Rhizobium
14.9
5.7
4.7
2.4
5.6
b
2.8
3.4
b
0.21
Fertilizer
Non
7.9
d
4.9
c
4.5c
2.0
b
4.5
b
2.8
3.0
d
0.20
b
DAP
7.9
d
5.1
c
4.4
c
2.4
ab
6.4
a
2.6
3.6
cd
0.08
c
FYM
10.0
a
6.3
a
4.8
ab
2.6
a
6.8
a
2.9
4.4
ab
0.32
a
H
9.5
bc
6.0
a
4.9
a
2.4
a
6.2
a
2.8
3.9
bc
0.25
ab
H+CMC
9.8
ab
5.9
a
5.0
a
2.7
a
6.6
a
3.0
4.6
a
0.32
a
H+EM
8.9
c
5.6
b
4.6
bc
2.7
a
6.4
a
2.8
3.9
abc
0.24
ab
Without
fertilizer
(Non),
diammonium
phosphate
fertilizer
(DAP),
cattle
farmyard
manure
(FYM),
water
hyacinth
compost
only
(H),
water
hyacinth
compost+cattle
manure
culture
(H+CMC)
and
water
hyacinth
compost+effective
microbes
(H+EM).
Asterisk
indicates
the
significant
effect,
***p
≤
0.001,
**p
≤
0.01,
*p
≤
0.05.
Means
with
the
same
letter(s)
are
not
significantly
different;
those
with
more
than
one
letter
are
intermediate.
Interactions
are
considered
over
main
effects
wherever
they
are
significant;
no
letters
presented
where
there
is
no
significant
difference.
water
hyacinth
compost
containing
cattle
manure
culture
(H+CMC)
had
the
lowest
seed
weight
in
the
first
trial
(Table
3a).
In
the
second
trial,
those
grown
with
water
hyacinth
compost
containing
cattle
manure
culture
(H+CMC)
had
the
highest
seed
weight,
while
the
ones
grown
with
DAP
and
those
without
fertilizer
had
the
lowest
seed
weight
(Table
3b).
Rhizobium
inoculated
plants
had
heav-
ier
seeds
than
the
controls
in
the
first
trial
(Table
3a);
but
their
seed
weights
were
lower
in
the
second
trial
(Table
3b).
Yield
per
unit
area
in
plants
grown
with
DAP
was
the
lowest
in
both
trials
(Tables
3a
and
3b).
3.4.
Anthracnose
disease
incidences
In
the
first
trial,
there
was
no
significant
difference
in
anthrac-
nose
incidence
between
the
ten
treatment
combinations
(p
>
0.05).
In
the
second
trial,
Rhizobium
inoculated
plants
had
significantly
higher
anthracnose
incidence
than
non-inoculated
ones
when
grown
with
water
hyacinth
compost
containing
cattle
manure
cul-
ture
(H+CMC)
(p
<
0.05),
but
was
not
different
in
the
other
fertility
treatments
(Fig.
3).
Anthracnose
incidence
was
high
in
Rhizobium
inoculated
plants
grown
with
water
hyacinth
compost
containing
Author's personal copy
74 V.
Naluyange
et
al.
/
Applied
Soil
Ecology
76 (2014) 68–
77
Fig.
3.
Anthracnose
incidences
in
Rosecoco
bean
plants
as
affected
by
commercial
Rhizobium
inoculant
and
soil
fertility
amendments
in
the
second
trial.
Without
fertil-
izer
(Non),
diammonium
phosphate
fertilizer
(DAP),
cattle
farmyard
manure
(FYM),
water
hyacinth
compost
only
(H),
water
hyacinth
compost+cattle
manure
culture
(H+CMC)
and
water
hyacinth
compost+effective
microbes
(H+EM).
Numbers
on
top
of
bars
represent
sample
sizes.
Bars
with
the
same
letter(s)
are
not
significantly
different
(2test,
p
>
0.05).
cattle
manure
culture
(H+CMC)
and
FYM
compared
to
the
other
fertility
treatments
(p
<
0.05)
(Fig.
3).
Anthracnose
incidence
in
non-
inoculated
plants
was
not
different
between
the
fertility
treatments
(p
>
0.05)
(Fig.
3).
3.5.
Aphid
density
The
aphids
on
the
bean
plants
were
identified
as
Aphis
fabae
(black
bean
aphid)
based
on
their
dark
colour
(Martin,
1983;
Holman,
1998).
At
the
vegetative
stage,
Rhizobium
inoculated
plants
had
lower
aphid
density
than
non-inoculated
ones
when
grown
with
water
hyacinth
compost
only
(H)
and
DAP;
but
was
higher
when
grown
in
water
hyacinth
compost
containing
cattle
manure
culture
(H+CMC),
and
not
different
in
the
other
fertility
treatments
(Fig.
4a).
Among
the
Rhizobium
inoculated
plants,
those
grown
with
water
hyacinth
compost
containing
cattle
manure
culture
(H+CMC)
had
significantly
high
aphid
density;
while
water
hyacinth
compost
containing
effective
microbes
(H+EM)
had
significantly
low
aphid
counts
among
the
non-inoculated
plants
(Fig.
4a).
At
the
flowering
stage,
Rhizobium
inoculated
plants
had
signifi-
cantly
higher
aphid
density
than
non-inoculated
ones
when
grown
with
DAP,
FYM
or
without
fertilizer
(p
<
0.05)
(Fig.
4b).
Among
the
Rhizobium
inoculated
plants,
aphid
density
was
highest
in
those
grown
with
FYM
and
without
fertilizer,
followed
by
water
hyacinth
compost
containing
cattle
manure
culture
(H+CMC),
but
lowest
in
plants
grown
with
DAP,
water
hyacinth
compost
only
(H)
and
water
hyacinth
compost
containing
effective
microbes
(H+EM)
(Fig.
4b).
In
the
non-inoculated
plants,
aphid
density
was
significantly
high
in
plants
without
fertilizer
but
low
in
those
grown
with
DAP
and
water
hyacinth
compost
containing
effective
microbes
(H+EM)
(Fig.
4b).
4.
Discussion
The
production
of
beans
in
sub-Saharan
has
been
declining
partly
due
to
low
soil
fertility.
This
has
lead
to
the
develop-
ment
of
commercial
Rhizobium
inoculants
for
nitrogen
fixation
(Mugendi
et
al.,
2011).
Composts
such
as
those
produced
from
water
hyacinth
are
also
being
developed
to
enhance
crop
pro-
duction
(Woomer
et
al.,
2000;
Gunnarsson
and
Petersen,
2007).
Compatibility
between
such
technologies
in
beans
would
be
a
sus-
tainable
factor
in
food
production.
Fig.
4.
Density
of
Aphis
fabae
on
Rosecoco
bean
plants
as
affected
by
commer-
cial
Rhizobium
inoculant
and
soil
fertility
amendments
during
the
vegetative
stage
(A)
and
the
flowering
stage
(B).
Without
fertilizer
(Non),
diammonium
phosphate
fertilizer
(DAP),
cattle
farmyard
manure
(FYM),
water
hyacinth
compost
only
(H),
water
hyacinth
compost+cattle
manure
culture
(H+CMC)
and
water
hyacinth
com-
post+effective
microbes
(H+EM).
Bars
with
the
same
letter(s)
are
not
significantly
different
(2test,
p
>
0.05).
Rosecoco
bean
seeds
treated
with
water
hyacinth
com-
post+effective
microbes
took
a
short
period
for
germination
in
the
first
trial;
this
also
occurred
in
all
the
three
formulations
of
water
hyacinth
compost
in
the
second
trial,
especially
when
compared
to
DAP.
Furthermore,
hyacinth
composts
exhibited
better
percentage
germination
than
those
with
DAP.
Low
seed
germination
has
been
reported
in
chickpea
grown
with
phosphate
fertilizer
(TSP),
and
was
attributed
to
phytotoxicity
and
high
osmotic
pressure
that
con-
strains
water
uptake
by
seeds
(Zhang
and
Rengel,
2002;
Kabir
et
al.,
2010).
However,
the
water
hyacinth
composts
seemed
to
have
no
significant
effect
on
percentage
seed
germination
when
compared
to
plants
without
fertilizer.
The
contribution
of
Rhizobium
inoculant
to
seed
germination
in
time
and
percentage
was
not
evident.
Other
strains
of
Rhizobium
such
as
Bradyrhizobium
japonicum
have
been
reported
to
enhance
bean
seed
germination
through
production
of
Nod
factors
and
phytohormones
(Prithiviraj
et
al.,
2003;
Cassan
et
al.,
2009).
Rhizobium
nodulation
was
very
poor
in
bean
plants
grown
with-
out
fertilizers.
This
is
because
symbiosis
between
legumes
and
Rhizobium
requires
nutrients
especially
phosphorus
for
successful
nodulation
(Vance
et
al.,
2002).
The
addition
of
DAP
did
not
improve
Author's personal copy
V.
Naluyange
et
al.
/
Applied
Soil
Ecology
76 (2014) 68–
77 75
root
nodulation.
Although
poor
nodulation
may
be
linked
to
toxi-
city
of
DAP
on
Rhizobium
(Maheshwari
et
al.,
2010),
this
cannot
be
fully
supported
by
data
in
the
present
study,
since
nodule
counts
in
plants
without
fertilizer
were
similar
to
those
with
DAP.
The
composts
and
cattle
farmyard
manure
enhanced
Rhizobium
nodula-
tion
in
a
differential
manner.
Water
hyacinth
compost
only
and
the
farmyard
manure
appeared
to
favour
nodulation
by
natural
Rhizo-
bium
populations,
because
there
were
more
nodules
in
plants
that
had
not
been
inoculated.
It
has
been
suggested
that
native
Rhizo-
bium
strains
are
better
adapted
for
symbiosis
within
their
area
of
origin
than
introduced
commercial
ones
(Lopez-Garcia
et
al.,
2002;
Martinez-Romero,
2003;
Dean
et
al.,
2009).
However,
the
adaptabil-
ity
of
such
strains
is
likely
to
be
altered
by
soil
amendments
(Zahran,
1999;
Andrade
et
al.,
2002).
This
is
because
nodulation
of
the
com-
mercial
Rhizobium
inoculant
was
better
in
plants
grown
with
water
hyacinth
compost
enhanced
with
cattle
manure
culture
(H+CMC)
or
effective
microbes
(H+EM).
Therefore,
based
on
nodulation,
these
two
types
of
water
hyacinth
compost
can
be
considered
compatible
with
the
commercial
Rhizobium
inoculant.
Plants
treated
with
composts
including
those
from
water
hyacinth
(Tarkalson
et
al.,
1998;
Widjajanto
et
al.,
2001,
2002;
Lata
and
Veenapani,
2011),
and
those
inoculated
with
Rhizobium
are
expected
to
be
large
in
size
(Carter
et
al.,
1994;
Karaca
and
Uyanoz,
2012).
This
seemed
to
be
the
case
in
the
present
study,
as
bean
plants