--- Biological Nitrogen Fixation and Sustai ...
---
Biological
Nitrogen Fixation and Sustai
Edited by K. Mulongoy,
M. Cueye and D.S.C. Spen
0 1992 IITA
A Wiley-Sayce
C o - P u b l i c a t i o n
3.3
‘?-
Measuring nitrogen fixed by groundnut varieties in
Senegal using 15N tecfnniciues
A. BADIANE NIANE and F. GUEYE
l
- S
l
UMMARY
A field experiment was carried out at Nioro
Experiment Station in southern-central
Senegal in order
to measure groundnut productivity and
A comparative study of three groundnut varieties,
(20 and 100 kg N/ha) applied in the
% ‘“N excess. re-
spcctively. The results showed that
nitrogen fixation in a11 three varieties.
and maintain soi1 fertility has become necessary in Sencgal,
the cost of fertilizers is prohibitive, and tl::ls
agricultural productivity. Groundnut is widely
The objective of this study
and investigate their response to inoculation un
MATERIA&S
AND METHODS
The study was conducted at Nioro Agricultura
Experiment Station in southem-central Senegal (15”47’N,
13”43’E), which has an annual rainfall of 700 f 00 mm. The soi1 is an Alfisol with a sandy texture; the pH is
almost neutral (6.5) and the organic matter
nt very low (sec Table 1 ovel-le$).
277
278
NITROCEN FIXATION BY CROUNDNUT VARIETIES
I
Table 1
Some physicochemical properties of thk soi1 at the experimental site, Senegal
Soi1 horizons (cm)
-
Soi1 parameter
8.20
- - - - - - - - - ._._
pH water
6.1
6.23
Ph KCI
5.1
5.45
Clay (%)
8.0
9.00
Silt (%)
4.0
4.50
Sand (20-50 p) (%)
17.1
17.20
Sand (50-200 p) (%)
46.5
43.70
Sand (200-2000 pj&(%)
24.4
25.30
Organic C (Y&)
a
7.1
6.76
Total N (%)
0.6
0.66
:IN
10.4
10.24
rota1 P,O, (%)
0.3
0.32
,dvailable P,O, (ppm)
26.2
24.32
lixchangeabie cations (meq/lOO g)
C a
2.19
Mg
0.40.
Na
0.02.
K
0.15
!
The groundnut varieties used were 55.437 (
-30 (V,) and 73-33 (V,). V, is widely grown in the
groundnut basin of Senegal, while V, is well adapte
e Nioro ecological zone. A non-nodulating groundnut
*.
variety from the International Crops Research Inst
Semi-Arid Tropics (ICRISAT) was used as the
control trop. The inoculant used was Bradyrhizo
1000, obtained from the Nitrogen Fixation by
Tropical Agricultural Legumes (NiFTAL) Project
waii, USA; the inoculant was an aqueous suspension
containing 108cells. The seeds were soaked for 30 mi
es in the liquid just before being sown. Two N fertilizer
rates were applied (20 and 100 kg N/ha) in the fonn
ammonium sulphate with 5 and 1 atom % 15N excess,
respectively. A split-plot randomized block design
sed, with inoculation as the main plot, the N fertilizer
rate as a subplot and the groundnut varieties as a
plot. There were five replications.
Each ‘“N subplot
ccvered an area of 3 m2, with an inter-row spacin
cm and 15 cm within rows.
The above-ground portions of a11 plants were h
d 95 days after planting; below-ground parts were not
3
cansidered in this study. The samples were oven-dr
t 70°C. Percentage N was determined on a Kjeldahl
digest and the N isotopes ratio analysis was perfom
n a VG-Isogas mass spectrometer in the Seibersdorf
La.boratory of the International Atomic Energy Ag
Mnny nodules were observed on the uninoculated pl
and most of them were pinkish in colour, suggesting
that they were fïxing nitrogen efficiently. There w
significant differences between uninoculated and
NITROCEN FIXATION BY GROUNDNUT VARIETIES
2 7 9
Table 2
Effects of inoculation with Brad hLzobium strain TA1 1000 and two nitrogen application rates
on yield components (t/ha) of tt! :e groundnut varieties
---.. - - -c
Factor effect
Pods
strüw
_I_--~
A--
Inoculation effect:
without TAC 1000
3.06 bd
4.36 b
with TAL 1000
2.49 a
4.‘15
c v (%)
13
1 17
Y-
Ferti I irer effect:
with 20 kg N/ha
2.74 a
4.07 a
with 100 kg N/ha
2.80 a
4.38 b
c v (%)
8
1 0
Varietal effect:
Variety 55-437 (V,)
2.65 a
4.08 a
Variety 73-30 (V,)
2.55 a
4 . 0 5 a
Variety 73-33 (V,)
3.11 b
5 . 6 4 b
c v (%)
8
1 1
.~.__--.-_-- - - - - . ~.- -- -...
Note:
a
Values in the same column followed 1lY the same letter do not differ significantly at p = 0.05 (Duncan).
inoculated plants. The pod and straw yielc iS from the uninoculated plots +ie’re higher than those from the
inoculated plots (sec Table 2). Thus., inocr.k ltion did not improve the performance of the three groundnut
varieties; in the case of V,, it even resulted in a reduction in grain yield (sec Figure 1 owl-le&. The inefficiency
of the inoculation may have been caused by :h e presence of indigenous bradyrhizobia that were more efficient
than the TAL 1000 strain used in this, experin nent.
As shown in Table 2, the higher N applic:a1 iion rate alsc, failed to increase pcld yield. The response of straw
to inoculation and N fertilizer, in terms of t Ot a1 N, was the same as for dry matter (sec Table 3 olle,-leuj). No
varietal difference was observed in terms of le amount of N derivad from the soi1 at the higher N application
rate, but there was a significant difference 1- tween the varieties at the lower rate. Compared to the other two
varieties, V, showed a significant difference I the amount of N derived from thme atmosphere and the fertilizer.
The differences in the amount of N derive
from the soil, fertilizer and atmosphere in the inoculated and
uninoculated varieties at the two N fertilize rates is shown in Figure 2 (ovel-leur).
The high N application rate reduced nitrol n fixation by 35%, except forthe inoculated V, variety (seeTable
4 over-le@ Inhibition of nitrogen fixation 1 ,‘fertilizer has been reported by a number of workers, including
Fried and Broeshart (1975) and Dansa, (198
. The total amount of nitrogen fixed by a11 three varieties ranged
between 20 and 70 kg N/ha.
The finding that nitrogen fixation by indi: nous rhizobia was higher than with the introduced strain justifies
screening more rhizobia, both indigeous a I exotic strains, to identify those that are more efficient in the
experimental conditions described here. ’ le differences between the groundnut varieties also warrant
screening of more varieties to identify the 1 st groundnut/BI-adyl-hizohium
as;sociation.
280
l
NITROCEN FIXATION BY GROUNDNUT VARIETIES
Figure 1
Grain yield of three varieties of groun nut as influenced by inoculation with Bradyrhizobium
strain TAL 1000 and two rates of
2.5 -
T
2.0
1.5
g
-0
-
a,
L= 1.0
W
/-J
55-437
17
73-30
0.5
? 73-33
0
U inoculated
Inoculated
Fertilizer application (kgjha):
20
100
t
:Figure 2
Amount of N derived from soil,
and the atmosphere by three varieties of groundnut as
influenced by inoculation with
obium strain TAL 1000 and two rates of fertilizer N
j-
1 6 C,-
1 4 0.-
1 2 0
i /
r
Ke y
Yà
$&l
Nitrogen
derived from atmosphere
Y
u LSD (0.05) = 5.61
&
2 80
cl Nitrogen derived from fertilizer
g
LSD (0.05) = 2.33
60
40
20
0 -L
noculated
Inoculated
Groundnut variety:
73-30
73-33
55-437
73-30
73-33
Fertilizer application (k@ha):
0 100 20 100
2 0 1 0 0 20 100
20 100
-_
-
NITROGEN FIXATION BY GROUNDNUT VARIETIES
281
Table 3
Shoot N (kgjha) of three grounc
It varieties as influenced by inoculation with Bradyrhizobium
strain TAL 1000 and two rates of
trogen fertilizer application
~_ - - .~_..._ ~~-
-
Variety
~ Fertilizer rates (kg N/ha) ----
accession no.
Inoculation
20
100
_ _ _ _ ---_--..-_I--.. .-.- -. --
55-437 (V,)
With TAL 1000
67.5 aa
93.7 c
73-30 (V,)
117.3 b
120.8 b
73-33 (V,)
117.2 b
121.3 b
55-437 (V,) -q
Without TAL 1000
91.7c
97.7 c
73-30 (V,)
108.9 bc
112.1 b
73-33 (V,)
153.9 a
159.4 a
cv (Vo)
9
9
-_-
~.-~
Note:
a
Values in the same column followed bl
e same letter do not differ significantly at p = 0.05 (Duncan).
Table 4
Percentage of nitrogen fixed by t
te groundnut varieties as influenced by inoculation with
ikadyrbizobium strain TA1 1000
Id two rates of nitrogen fertilizer application
Variety
-- Fertilizer rates (kg N/ha) ---
accession no.
Inoculation
20
lO0
55-437 (V,)
With TAL 1000
38 aa
28 a
73-30 (V,)
52 b
33 b
73-33 (V,)
50 b
3fb
55-437 (V,)
Without TAL 1000
38 a
26 a
73-30 (V,)
47 b
30 a
73-33 (V,)
46 b
36 b
Note:
a
Values in the same column followed bl
e same letter do not differ significantly at p = 0.05 (Duncan).
Acknowledgements
This study was funded by the Food and Agricult
Organization (FAO)/Intemational,4tomic Energy Agency (IAEA)
African Regional project. 1 wish to thank Dr M
iueye for providing the inoculum, H. Axmann (IAEA Seihersdorf
lahoratory) for conducting the isotopic analysis a
Y. Ndaiye, S. Cissé and S. Faye for managing the field trial.
References
Danso, S.K.S. 1986. Comments on paper “Estim;
n of N, fixation by isotope. Dilution: An appraisal of techniques
involving 15N enrichment and their applicatic
By Chalk, P.M. (1985)‘. Soi1 Biol. IIiochem. 18: 243-44.
Fried, M. and Broeshart, H. 1975. An independe]
neasurement of the amount of nitrogen fixed by a legume trop.
Plant and Soil. 43: 707-I 1.
--
I-
Biological
Nitrogen Fixation and Sustai
Edited by K. Mulongoy,
M. Cueye and D.S.C. Spen
0 1992 IITA
A Wiley-Sayce
C o - P u b l i c a t i o n
3.3
‘?-
Measuring nitrogen fixed by groundnut varieties in
Senegal using 15N tecfnniciues
A. BADIANE NIANE and F. GUEYE
l
- S
l
UMMARY
A field experiment was carried out at Nioro
Experiment Station in southern-central
Senegal in order
to measure groundnut productivity and
A comparative study of three groundnut varieties,
(20 and 100 kg N/ha) applied in the
% ‘“N excess. re-
spcctively. The results showed that
nitrogen fixation in a11 three varieties.
and maintain soi1 fertility has become necessary in Sencgal,
the cost of fertilizers is prohibitive, and tl::ls
agricultural productivity. Groundnut is widely
The objective of this study
and investigate their response to inoculation un
MATERIA&S
AND METHODS
The study was conducted at Nioro Agricultura
Experiment Station in southem-central Senegal (15”47’N,
13”43’E), which has an annual rainfall of 700 f 00 mm. The soi1 is an Alfisol with a sandy texture; the pH is
almost neutral (6.5) and the organic matter
nt very low (sec Table 1 ovel-le$).
277
278
NITROCEN FIXATION BY CROUNDNUT VARIETIES
I
Table 1
Some physicochemical properties of thk soi1 at the experimental site, Senegal
Soi1 horizons (cm)
-
Soi1 parameter
8.20
- - - - - - - - - ._._
pH water
6.1
6.23
Ph KCI
5.1
5.45
Clay (%)
8.0
9.00
Silt (%)
4.0
4.50
Sand (20-50 p) (%)
17.1
17.20
Sand (50-200 p) (%)
46.5
43.70
Sand (200-2000 pj&(%)
24.4
25.30
Organic C (Y&)
a
7.1
6.76
Total N (%)
0.6
0.66
:IN
10.4
10.24
rota1 P,O, (%)
0.3
0.32
,dvailable P,O, (ppm)
26.2
24.32
lixchangeabie cations (meq/lOO g)
C a
2.19
Mg
0.40.
Na
0.02.
K
0.15
!
The groundnut varieties used were 55.437 (
-30 (V,) and 73-33 (V,). V, is widely grown in the
groundnut basin of Senegal, while V, is well adapte
e Nioro ecological zone. A non-nodulating groundnut
*.
variety from the International Crops Research Inst
Semi-Arid Tropics (ICRISAT) was used as the
control trop. The inoculant used was Bradyrhizo
1000, obtained from the Nitrogen Fixation by
Tropical Agricultural Legumes (NiFTAL) Project
waii, USA; the inoculant was an aqueous suspension
containing 108cells. The seeds were soaked for 30 mi
es in the liquid just before being sown. Two N fertilizer
rates were applied (20 and 100 kg N/ha) in the fonn
ammonium sulphate with 5 and 1 atom % 15N excess,
respectively. A split-plot randomized block design
sed, with inoculation as the main plot, the N fertilizer
rate as a subplot and the groundnut varieties as a
plot. There were five replications.
Each ‘“N subplot
ccvered an area of 3 m2, with an inter-row spacin
cm and 15 cm within rows.
The above-ground portions of a11 plants were h
d 95 days after planting; below-ground parts were not
3
cansidered in this study. The samples were oven-dr
t 70°C. Percentage N was determined on a Kjeldahl
digest and the N isotopes ratio analysis was perfom
n a VG-Isogas mass spectrometer in the Seibersdorf
La.boratory of the International Atomic Energy Ag
Mnny nodules were observed on the uninoculated pl
and most of them were pinkish in colour, suggesting
that they were fïxing nitrogen efficiently. There w
significant differences between uninoculated and
NITROCEN FIXATION BY GROUNDNUT VARIETIES
2 7 9
Table 2
Effects of inoculation with Brad hLzobium strain TA1 1000 and two nitrogen application rates
on yield components (t/ha) of tt! :e groundnut varieties
---.. - - -c
Factor effect
Pods
strüw
_I_--~
A--
Inoculation effect:
without TAC 1000
3.06 bd
4.36 b
with TAL 1000
2.49 a
4.‘15
c v (%)
13
1 17
Y-
Ferti I irer effect:
with 20 kg N/ha
2.74 a
4.07 a
with 100 kg N/ha
2.80 a
4.38 b
c v (%)
8
1 0
Varietal effect:
Variety 55-437 (V,)
2.65 a
4.08 a
Variety 73-30 (V,)
2.55 a
4 . 0 5 a
Variety 73-33 (V,)
3.11 b
5 . 6 4 b
c v (%)
8
1 1
.~.__--.-_-- - - - - . ~.- -- -...
Note:
a
Values in the same column followed 1lY the same letter do not differ significantly at p = 0.05 (Duncan).
inoculated plants. The pod and straw yielc iS from the uninoculated plots +ie’re higher than those from the
inoculated plots (sec Table 2). Thus., inocr.k ltion did not improve the performance of the three groundnut
varieties; in the case of V,, it even resulted in a reduction in grain yield (sec Figure 1 owl-le&. The inefficiency
of the inoculation may have been caused by :h e presence of indigenous bradyrhizobia that were more efficient
than the TAL 1000 strain used in this, experin nent.
As shown in Table 2, the higher N applic:a1 iion rate alsc, failed to increase pcld yield. The response of straw
to inoculation and N fertilizer, in terms of t Ot a1 N, was the same as for dry matter (sec Table 3 olle,-leuj). No
varietal difference was observed in terms of le amount of N derivad from the soi1 at the higher N application
rate, but there was a significant difference 1- tween the varieties at the lower rate. Compared to the other two
varieties, V, showed a significant difference I the amount of N derived from thme atmosphere and the fertilizer.
The differences in the amount of N derive
from the soil, fertilizer and atmosphere in the inoculated and
uninoculated varieties at the two N fertilize rates is shown in Figure 2 (ovel-leur).
The high N application rate reduced nitrol n fixation by 35%, except forthe inoculated V, variety (seeTable
4 over-le@ Inhibition of nitrogen fixation 1 ,‘fertilizer has been reported by a number of workers, including
Fried and Broeshart (1975) and Dansa, (198
. The total amount of nitrogen fixed by a11 three varieties ranged
between 20 and 70 kg N/ha.
The finding that nitrogen fixation by indi: nous rhizobia was higher than with the introduced strain justifies
screening more rhizobia, both indigeous a I exotic strains, to identify those that are more efficient in the
experimental conditions described here. ’ le differences between the groundnut varieties also warrant
screening of more varieties to identify the 1 st groundnut/BI-adyl-hizohium
as;sociation.
280
l
NITROCEN FIXATION BY GROUNDNUT VARIETIES
Figure 1
Grain yield of three varieties of groun nut as influenced by inoculation with Bradyrhizobium
strain TAL 1000 and two rates of
2.5 -
T
2.0
1.5
g
-0
-
a,
L= 1.0
W
/-J
55-437
17
73-30
0.5
? 73-33
0
U inoculated
Inoculated
Fertilizer application (kgjha):
20
100
t
:Figure 2
Amount of N derived from soil,
and the atmosphere by three varieties of groundnut as
influenced by inoculation with
obium strain TAL 1000 and two rates of fertilizer N
j-
1 6 C,-
1 4 0.-
1 2 0
i /
r
Ke y
Yà
$&l
Nitrogen
derived from atmosphere
Y
u LSD (0.05) = 5.61
&
2 80
cl Nitrogen derived from fertilizer
g
LSD (0.05) = 2.33
60
40
20
0 -L
noculated
Inoculated
Groundnut variety:
73-30
73-33
55-437
73-30
73-33
Fertilizer application (k@ha):
0 100 20 100
2 0 1 0 0 20 100
20 100
-_
-
NITROGEN FIXATION BY GROUNDNUT VARIETIES
281
Table 3
Shoot N (kgjha) of three grounc
It varieties as influenced by inoculation with Bradyrhizobium
strain TAL 1000 and two rates of
trogen fertilizer application
~_ - - .~_..._ ~~-
-
Variety
~ Fertilizer rates (kg N/ha) ----
accession no.
Inoculation
20
100
_ _ _ _ ---_--..-_I--.. .-.- -. --
55-437 (V,)
With TAL 1000
67.5 aa
93.7 c
73-30 (V,)
117.3 b
120.8 b
73-33 (V,)
117.2 b
121.3 b
55-437 (V,) -q
Without TAL 1000
91.7c
97.7 c
73-30 (V,)
108.9 bc
112.1 b
73-33 (V,)
153.9 a
159.4 a
cv (Vo)
9
9
-_-
~.-~
Note:
a
Values in the same column followed bl
e same letter do not differ significantly at p = 0.05 (Duncan).
Table 4
Percentage of nitrogen fixed by t
te groundnut varieties as influenced by inoculation with
ikadyrbizobium strain TA1 1000
Id two rates of nitrogen fertilizer application
Variety
-- Fertilizer rates (kg N/ha) ---
accession no.
Inoculation
20
lO0
55-437 (V,)
With TAL 1000
38 aa
28 a
73-30 (V,)
52 b
33 b
73-33 (V,)
50 b
3fb
55-437 (V,)
Without TAL 1000
38 a
26 a
73-30 (V,)
47 b
30 a
73-33 (V,)
46 b
36 b
Note:
a
Values in the same column followed bl
e same letter do not differ significantly at p = 0.05 (Duncan).
Acknowledgements
This study was funded by the Food and Agricult
Organization (FAO)/Intemational,4tomic Energy Agency (IAEA)
African Regional project. 1 wish to thank Dr M
iueye for providing the inoculum, H. Axmann (IAEA Seihersdorf
lahoratory) for conducting the isotopic analysis a
Y. Ndaiye, S. Cissé and S. Faye for managing the field trial.
References
Danso, S.K.S. 1986. Comments on paper “Estim;
n of N, fixation by isotope. Dilution: An appraisal of techniques
involving 15N enrichment and their applicatic
By Chalk, P.M. (1985)‘. Soi1 Biol. IIiochem. 18: 243-44.
Fried, M. and Broeshart, H. 1975. An independe]
neasurement of the amount of nitrogen fixed by a legume trop.
Plant and Soil. 43: 707-I 1.
--
I-