fourth agricultural science week of west and central africa and 11th coraf/wecard general assembly...
TRANSCRIPT
Fourth Agricultural Science Week of West and Central Africa and 11th
CORAF/WECARD General Assembly
Venue : Niamey, Niger
Date: 16 – 20 Juin 2014
Effect of inoculation with exogenous Bradyrhizobium japonicum strains
and phosphorus application on soybean [Glycine max (L.) Merrill] productivity in two agro-ecological
zones of Benin
Theme
OUTLINE
1- Introduction
2-Methods
3-Results
4-Conclusion
1- INTRODUCTION
Agriculture = base of Beninese economy
Main agricultural constraints in sub-Saharan Africa = constant decrease of soil fertility and inadequacy of cropping systems (Saïdou et al., 2012).
Result = continuous decline in crop yields
To improve crop yields, use of chemical fertilizers whose needs became increasingly important (World Bank, 2008).
risks for the environment (pollution of groundwater) in addition to the expensive cost of manures and the obligation to repeat fertilization
1-INTRODUCTION
Alternative: Crop-livestock integration systems
1- INTRODUCTION
But if animals don’t have a quality diet, they couldn’t produce good dejection for soil fertilization.
Legumes residues are the most beneficial
So, interest of the use of dualpurpose legumes like soybean [Glycine max (L.) Merrill] in crop-livestock integration systems
Soybeans, a major source of inexpensive vegetable protein for human and animal consumption (FAO, 2010)
The fixation of soybean as much as 300 kg of N ha – 1 in addition to the release, in the soil, of nearly 80% for the following crop are current estimate (Hungria et al., 2006).
To improve biological nitrogen fixation, inoculation with efficients strains of soils bacteria like rhizobia is very important (Hussain et al., 2011).
INTRODUCTION
General objective:
to assess if exogenous
Bradyrhizobium japonicum strains
can improve soybean productivity in
Benin.
2- OBJECTIVES
Specific objectives:
(i) to study the effect of exogenous Bradyrhizobium
japonicum strains on yield and yield-related parameters
of soybean,
(ii) to determine the main interaction effects of
Bradyrhizobium japonicum strains and phosphorus on
soybean productivity
(iii) to identify the most effective strain to introduce in
crop-livestock integration systems in Benin.
2- OBJECTIVES
3- METHODS
Experimental site: Two Agro-Ecological Zones (AEZ) producers of soybean
3- METHODS
Crop food-producing zone of southern Borgou (Northern Benin: Savè, Glazoué) Climate: soudanian
Annual rainfall: 1100 mm and 1200 mm
Experimental site: Two Agro-Ecological Zones (AEZ) producers of soybean
3- METHODS
Cotton zone of central Benin : Bembérèkè et N’dali
Climate: soudano-guinnean
Annual rainfall: 1000 mm
In both zones, experiments were established in ferruginous degraded soils.
Plant material: One variety of soybeans (TGX
1910-14F)
Microbiological material: Four exogenous
strains of Bradyrhizobium japonicum were used
for inoculums production: FA3, STM3043 and STM3045 obtained from
Laboratory of Mediterranean and tropical symbiosis of Montpellier (France).
USDA110 from Laboratory of soils Microbiology of Nairobi University (Kenya).
These strains were cultivated in Yeast-Mannitol-Broth medium and were fixed in peat.
3- METHODS
Experimental design: in each zone, split plot with
two factors
3- METHODS
T: témoinI1: FA3,I2: STM 3043,I3: STM 3045, I4: USDA 110
Six soybean producers in each zone
Data collection
Soil sampling from fields before sowing for
assessement of Soil texture, pH, total carbon, CEC,
available P, total Nitrogen etc of soil on surface (0-15 cm)
At flowering time (10 weeks after sowing):
nodulation, mycorrhizal colonization, biomass dry weight
and nitrogen content
At harvest (4 months after sowing): straw and grain
yield
3- METHODS
Statistical analysisAll statistical analysis was carried out using SAS
software version 9.2.
One-way analysis of variance (ANOVA) was performed to determine the statistical differences among the different strains of Bradyrhizobium japonicum. When significant differences (p < 0.05) were noticed, a Student-Newman-Keuls test was used to compare the means
3- METHODS
4- RESULTS
4- RESULTS
Characteristic Central Benin Northern Benin
Sand (%) 81.4 76.2
Silt (%) 8.8 11.0
Clay (%) 8.7 12.2
PH (water) 6.4 6.9Total nitrogen (% ) 0.04 0.06
Available P (ppm) 29.8 32.2
Organic carbon (% ) 1.1 1.7
Organic matter (% ) 1.8 2.9
Physico-chemical properties of the soil before the starting of the experiment
4- RESULTS
Effect of Bradyrhizobium japonicum strains and phosphorus supply on soybean productivity
parameters
Inoculation
Phosphorus
Inoculation*phosphorus
Nodule number <0,0001*** <0,0001*** 0,0028**
Mycorrhizal colonization
<0,0001*** <0,0001*** <0,0001***
Biomass dry weight <0,0001*** <0,0001*** 0,0431*
Nitrogen yield <0,0001*** <0,0001*** 0,0314*
Straw yield <0,0001*** 0,0002*** 0,005 **
Grain yield <0,0001*** <0,0001*** 0,02*
4- RESULTS
Nodule number
Control FA3 STM3043STM3045USDA1100
5
10
15
20
25
30
35
40
45
e
cc
cd
b
b
a
b b
Central Benin
0P50P
Nodule
num
ber
(num
ber/
pla
nt)
100%
Contro
lFA
3
STM30
43
STM30
45
USDA11
00
5
10
15
20
25
30
35
d
c cc c
bab
aab
b
Northern Benin
0P50P
Nodule
num
ber
(num
ber/
pla
nt)
52%
Bars followed by a same letter are not significantly different at p < 0.05 according to Student Newman-Keuls test.
4- RESULTS
Mycorrhizal colonization
Contro
lFA
3
STM30
43
STM30
45
USDA11
00
10
20
30
40
50
60
70 a
b c
b bb
c d37 35
Central Benin
0P50P
Mychori
zati
on r
ate
(%
)
62%
Control FA3 STM3043 STM3045USDA1100
10
20
30
40
50
60
70a
b
c
bb
b
c
d
c c
Northern Benin
0P50P
Mychori
zati
on r
ate
(%
)
65%
Bars followed by a same letter are not significantly different at p < 0.05 according to Student Newman-Keuls test.
4- RESULTS
Shoot dry weight
Control FA3 STM3043 STM3045 USDA1100
5
10
15
20
25
c
bb
bbb
aba
a
abCentral Benin
0P50P
Shoot
dry
weig
ht
(g/p
lant)
66%
0
5
10
15
20
25
c
bb
bbb
a a
abab
Northern Benin
0P50P
Shoot
dry
weig
ht
(g/p
lant)
62%
Bars followed by a same letter are not significantly different at p < 0.05 according to Student Newman-Keuls test.
4- RESULTS
Biomass aspect and color
4- RESULTS
Nitrogen yield
Contro
lFA
3
STM30
43
STM30
45
USDA11
00
50
100
150
200
250
c
bb
b b
b
ab
aab ab
Central Benin
0P50P
Nit
rogen y
ield
(m
g/p
lant)
165%
Contro
lFA
3
STM30
43
STM30
45
USDA11
00
50
100
150
200
250
c
b bb b
b
a a
ab ab
Northern Benin
0P50PSeries3
Nit
rogen y
ield
(m
g/p
lant)
131%
Bars followed by a same letter are not significantly different at p < 0.05 according to Student Newman-Keuls test.
4- RESULTS
Straw yield
Contro
lFA
3
STM30
43
STM30
45
USDA11
00
1000
2000
3000
4000
5000
c
bb b b
abab
aa
b
Central Benin
0P50P
Str
aw
yie
ld (
kg/h
a)
0
1000
2000
3000
4000
5000
6000
c
abab ab ab
ab
aa
abab
Northern Benin
0P50P
Str
aw
yie
ld (
kg/h
a)
Bars followed by a same letter are not significantly different at p < 0.05 according to Student Newman-Keuls test.
75%
71%
4- RESULTS
Grain yield
Control FA3 STM3043STM3045USDA1100
500
1000
1500
2000
2500
3000
c
b
b
b b
b
ab
a
ab abCentral Benin
0P50P
Gra
in y
ield
(kg/h
a)
60%
Contro
lFA
3
STM30
43
STM30
45
USDA11
00
500
1000
1500
2000
2500
3000
c
b
bb
b
b
aab ab
ab
Northern Benin
0P50P
Gra
in y
ield
(kg/h
a)
Bars followed by a same letter are not significantly different at p < 0.05 according to Student Newman-Keuls test.
73%
Results obtained showed that inoculation with exogenous Bradyrhizobium japonicum strains and phosphorus supply had improved productivity of soybean in Benin
The best strains were FA3 in Food producing zone of southern Borgou and STM3043 in cotton zone of central Benin
FA3 and STM3043 strains could be used in crop-livestock integration systems for improving soybean productivity and its quality in Benin.
However, phosphorus supplementation could be reduced by a co-inoculation of soybean with Mycorrhizae and Rhizobia.
5- Conclusion
This work was funded by the University of Abomey-Calavi through the project “Programme de Fonds Compétitifs de Recherche ’’
The authors would like to acknowledge the producers and other actors encountered during the study for their valuable and fruitful collaboration.
ACKNOWLEDGMENTS
Thank you for your kind attention