Response of Cowpea (Vigna unguiculata (L.) Walp) to Phosphorus and Inoculation in Sudan Savanna

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International Journal of Applied Research and Technology 38
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Response of Cowpea (Vigna unguiculata (L.) Walp) to
Phosphorus and Inoculation in Sudan Savanna, Nigeria.
Galadanchi, N. I., Mohammed, I. B., Yahaya, S. U. and Zakari, S. A.
Bayero University, Kano State, Nigeria.
Available online: June 30, 2016.
To cite this article:
Galadanchi, N. I., Mohammed, I. B., Yahaya, S. U. and Zakari, S. A. (2016). Response of Cowpea (Vigna unguiculata (L.)
Walp) to Phosphorus and Inoculation in Sudan Savanna, Nigeria. International Journal of Applied Research and
Technology. 5(6): 38 – 43.
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International Journal of Applied Research and Technology 39
International Journal of Applied Research and Technology
Esxon Publishers
Vol. 5, No. 6, June 2016. 38 – 43.
Response of Cowpea (Vigna unguiculata (L.) Walp) to Phosphorus and
Inoculation in Sudan Savanna, Nigeria.
Galadanchi, N. I., Mohammed, I. B., Yahaya, S. U. and Zakari, S. A.
Bayero University, Kano State, Nigeria.
(Received: 07 June 2016 / Accepted: 12 June 2016 / Published: 30 June 2016).
Abstract
This study was conducted at Bayero University, Kano, Teaching and Research Farm (11059 N; 8025 E; 466m above
sea level) and Agricultural Research Station Farm, Minjibir (12010’N, 8039’E; 402m above sea level) to study the growth
response of cowpea to phosphorus and rhizobium inoculation. Treatments consisted of two levels of rhizobium (inoculated
and un-inoculated), three levels of phosphorus (0, 20, 40 kg P2O5 ha-1) and three cowpea varieties (IT93K-452-1, IT97K-
573-1-1 and IT98K-499-35). These were laid out in Split-split plot design and replicated three times. Results of the study
indicated significant effect of variety in most of the characters measured. Significantly (p˂ 0.05) taller plants with higher
number of branches, leaf area index, number of nodules, effective nodules, and grain were observed from IT99K-573-1-1
than all other varieties. Similarly, the plant height, leaf area index, and the grain yield were significantly influenced by
application of phosphorus with 40 kg P2O5 treated plants recording greatest effect. Inoculation of cowpea with rhizobium
MC92 strain, also recorded significant effect on the measured characters and grain yield. Hence, inoculation with rhizobium
MC92 along with 40kgP2O5 ha-1 could enhance performance of cowpea particularly with an adaptable variety.
Keywords: Cowpea, Growth, Grain Yield, Inoculation, Sudan Savanna, Nigeria.
For corresponding author:
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Subject: 0616-0215.
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International Journal of Applied Research and Technology 40
Introduction
Subsistence farmers in the semi-arid and sub humid region of Africa are the major producers and consumers of
cowpea. These farmers not only grow cowpea for the dry seed but also for human consumption, fodder for animal as well as
vegetable material (Ferry, 2002). About two third of the world production is from Africa, cultivated on at least 12.5 million
hectares, with an annual production of over three (3) million tons (Quin, 1997). Phosphorus is a major mineral nutrient
required by plants. It influences nodule development through its basic functions as an energy source (Bekere et al., 2012).
However, the element is generally deficient in savanna soils thus limiting biological nitrogen fixation (Kumaga and Ofori,
2004). It is also essential for seed production and formation of healthy and sound root system which is essential for the uptake
of nutrients from the soil (Das et al., 2008).
Nitrogen fixation is one of the ways through which soil fertility can be improved (Mclaughlin et al., 1990). On the
other hand, rhizobium inoculation is a significant technology employed for the manipulation of rhizobia in improving crop
productivity and soil fertility. This can lead to establishment of large rhizobia in the rhizosphere, as well as improved
nodulation and nitrogen fixation even under adverse soil conditions (Peoples et al., 1995). The combination of rhizobia
inoculation and phosphorus supplementation in legume production was reported to improve production (Ndakidemi et al.,
2006). Despite these advantages, information on the response of cowpea to inoculation with MC92 strain of rhizobia in the
sudan savanna agro-ecology is not sufficient. This research was conceived with the intent of studying the growth response
of cowpea varieties to phosphorus and rhizobium inoculation in the study area.
Materials and Methods
The trials were conducted at Bayero University, Kano Teaching and Research Farm (11059 N; 8025 E; 466m above
sea level) and Agricultural Research Station Farm, Minjibir (12010’ N, 8039’ E; 402m above sea level) in 2014 wet season.
Both locations fall in the sudan savanna agro-ecology of Nigeria. These are characterized by two seasons, a wet season (May
to September) and dry season (October to April). Mean annual rainfall and temperature in the locations is about 800mm and
310C, respectively (Nnoli et al., 2006). Soils of the experimental sites were collected at 0 – 15cm soil depths prior to sowing.
These were bulked and analyzed for physico-chemical properties as described by Black (1965). The land was subsequently
ploughed, harrowed and made into ridges. Cowpea were sown at 20 x 75cm spacing. Rhizobium Inoculants containing MC92
strain was used to treat cowpea seeds along with 30ml slurry sticker (30g gum Arabic + 10g inoculants). This is to ensure
adhesion of the inoculants to the cowpea seeds. Single super phosphate (SSP) was basally applied to plots as per treatment
during sowing. Weed infestation was minimized by hand hoeing at 10, 20 and 50 days after emergence. Insect pests were
also controlled using cyperdiforce (cypermethrin 30gl-1 + dimethoate 24gl -1) at the rate of 1liter ha-1.
The treatments consisted of two levels of rhizobium (inoculated and un-inoculated), three levels of phosphorus (0,
20, 40 kg P2O5 ha-1) and three cowpea varieties (IT93K-452-1, IT97K-573-1-1 and IT98K-499-35). Cowpea varieties were
assigned to the main plots, while phosphorus levels were assigned to sub-plots. Inoculation was also assigned to the sub-sub
plot. These were laid out in Split-split plot design and replicated three times. Data were collected on plant height by
measuring the heights of 3 randomly tagged plants from each plot and their means recorded at 6, 9 and 12 weeks after sowing.
The number of branches per plant and leaf area index were also recorded from the same tagged plant. Three plants from the
border row were up-rooted for the determination of number of nodules per plant while the nodules were dissected
longitudinally to determine the effective nodules. The effective nodules were pink while the in-effective nodules were
whitish. The grain yield was also extrapolated from the weights of the harvested net plots. These were subjected to Analysis
of variance using Genstat software 17th edition. Significant treatment means were compared at 5% level of probability using
Duncan Multiple Range Test (Duncan, 1955).
Results and Discussion
Plant height was significantly (p˂ 0.05) influenced by variety in both locations (Table 2). Results of the study
showed that IT99K-573-1-1 produced taller plants than all other varieties. Similarly, leaf area index (LAI), number of
branches per plant, number of nodules, effective nodules and grain yield were significantly influenced by variety in this trial
(Tables 3 and 4). IT99K-573-1-1 consistently out-performed IT97K-499-35 and IT93K-452-1 in all the locations. This could
be explained by the genotypic variability. IT99K-573-1-1 is a spreading type which ultimately bear more branches with more
leaf surfaces. This finding corroborates with that of Nirmal et al (2001) who emphasize on the significance of genotype in
the performance of cowpea. Acquah (2007) also reported similar observation on the role of genotype on cowpea particularly
when augmented with improved practices.
Plant height was significantly (p˂ 0.05) influenced by rhizobium inoculation in this trial (Table 2). Results showed
an increased height with the inoculated plants. This could be due to the role of rhizobium in increasing soil nitrogen. Similar
observation was reported by Bambara and Ndakedemi (2010) for significant response of legumes to rhizobium inoculation.
Number of branches and leaf area index were however not significantly influenced by rhizobium inoculation in both locations
of this trial. This is in contrast with the findings of Srivasta and Verma (1982) who reported an increase in number of branches
with cowpea inoculated with rhizobium. On the other hand, number of nodules and effective nodules were significantly
influenced by inoculation (Table 4). Results showed that the inoculated plants produced better than those that were not
inoculated. This is an indication of effective symbiosis between the host plant and micro-symbionts as reported by Van-wyk
(2003). The grain yield was only significant at Minjibir which is a result of differences in the fertility status of the two
locations. Soils from Bayero University, Farm has higher organic matter, organic carbon and available phosphorus and hence
the effect of inoculation is not well pronounced (Table 1).

International Journal of Applied Research and Technology 41
Plant height was not significantly influenced by phosphorus at both locations. This could be ascribed to its low
mobility in the soil. This contradicts the finding of Magani and Kuchinda (2009) who reported that plant height in cowpea
increases with every increase in P. This result also buttress that plant height in cowpea could best be decided by genotype as
observed by Nirmal et al. (2001). Plants with significantly higher number of branches and leaf area index were observed
from 20 and 40 kg P2O5 treatments only in Minjibir (Table 3). Feller (1995) also reported significant effect of applied P in
soils that is limiting. The soils in BUK has higher P (15.55mg kg-1) than Minjibir (7.95mg kg-1). Similarly, number of
nodules and effective nodules in cowpea increases with every increase in applied P, in which 40kg P2O5 treated plants
produced greater number of nodules only in Minjibir, while the highest number of effective nodules were also recorded from
40kg P2O5 treatment in both locations. This could be due to low P in Minjibir. Similar result was reported by Okeleye and
Okelana (1997) who observed a significant increase in nodulation and grain yield in cowpea with applied P. The grain yield
was also significantly influenced by application of P only in Minjibir (Table 4). Results showed an increase in grain yield
with every increase in P up to 40kg P2O5 in Minjibir, while in BUK all the treatments were statistically at par. This could
also be tied to higher P in soils from BUK. This also corroborates with the report of Feller (1995).
Conclusion and Recommendations
Varietal differences recorded significant (p˂ 0.05) effect on growth components and grain yield in cowpea. IT99K-
573-1-1 out-performed IT97K-499-35 and IT93K-452-1 in all the measured characters in this experiment. Similarly, plant
height, number of nodules, effective nodules and grain yield were significantly influenced by rhizobia inoculation in this
trial. Better response were observed from the inoculated plants than those that were not inoculated. There was however
significant effect of phosphorus in these characters only in Minjibir. Results of this finding suggests that adoption of the
rhizobium inoculation technology along with application of 40kg P2O5 ha-1 in soils that are P deficient could enhance cowpea
performance particularly with an adaptable variety.
References
Acquah, G. (2007). Principles of Plant Genetics and Breeding. Blackwell Publishing USA.
Bambara, S. and Patrick A. N. (2010). Effects of Rhizobium innoculation, lime and molybdenum on nitrogen fixation of
nodulated Phaseolus vulgaris L. African Journal of Microbiology Research 4: 682-696.
Bekere, W., Wolde-meskel, E. and Kebed, T. (2012). Growth and nodulation response of soybean (Glycine max L.) to
Bradyrhizobium inoculation and phosphorus levels under controlled condition in South Western Ethiopia. African
Journal of Agricultural Research. 7(30): 4266_4270. Available online at http://www.academicjournals.org/AJAR.
(Accessed on 9/5/12)
Black, C. A. (1965). Methods of Soil Analysis II. Chemical and Microbiological Properties. Madison Wisconsin.American
Society of Agronomy. Pp. 341-350.
Das, A. K., Khaliq, Q.A. and Islam,S. (2008). Effect of Phosphorus fertilizer on the dry matter
accumulation, nodulation and yield in chickpea. Bangladesh Research Publications.
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ASMS process Alexandria, VA. P. 242-428.
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application. International Journal of Agriculture and Biology.
2:324-327.
Magani, I. E. and Kuchinda, C. (2009). Effect of phosphorus fertilizer on growth, yield and crude protein content of cowpea
(Vigna unguiculata [L.] Walp). Nigeria. Journal of Applied Biosciences 23: 1387 – 1393. Available on
www.biosciences.elewa.org.(Accessed on 19/07/2012).
Mclaughlin, M. J, Malik, K. A. Memon, K. S. and Idris, M. (1990). Phosphorus requirements for sustainable agriculture in
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(Phaseolus vulgaris) and soybean (Glycine max) inoculation in northern Tanzania. Australian Journal of
Experimental Agriculture.46:571-577.
Nirmal, R., Kalloo, G. and Kumar, R. (2001).Diet versatility in cowpea (Vigna unguiculata) genotypes. Indian Journal of
Agricultural Sciences.71: 598-601.
Okeleye, K. A. and Okelana, M. A. O. (1997).Effect of phosphorus fertilizer on nodulation, growth, and yield of cowpea
(Vigna unguiculata) varieties. Indian Journal of Agricultural Science.67 (1) 10-12.
Peoples, M. B, Lilley, D. M., Burnett, V. F, Ridley, A. M. and Garden, D. L (1995). Effects of surface application of lime
and superphosphate to acid soils on growth and N2 fixation by subterranean clover in mixed pasture sward. Soil
Biology and Biochemistry 27: 663- 671.
Quin, F. M. (1997). Introduction. In B.B. Singh, D. R. Mohan Raj, K.E. Dashiell and L.E.N. Jackai (eds). Advances in
Cowpea Research. Co Publication IITA and JIRCAS, IITA, Ibadan, Nigeria.Pp. Ix-xv.
Srivastava, S. N. L. and Verma, S. C. (1982). Effect of bacterial and in organic fertilizer on the growth, nodulation and
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International Journal of Applied Research and Technology 42
Tables
Table 1: Physico-chemical properties of soils taken from 0 - 30cm depth at the experimental site before the establishment
of the trials at Minjibir and B.U.K in 2014.
Soil Characteristics
B.U.K
Minjibir
Particle Size
Sand (%)
89
86
Silt (%)
4.2
7.0
Clay (%)
6.0
7.0
Textural class
Sandy loam
Sandy loam
Chemical Composition
pH in water
6.1
6.8
Organic carbon (%)
0.490
0.470
Total nitrogen (%)
0.08
0.06
Available phosphorus (mg/kg)
15.55
7.95
Exchangeable bases (Cmol/kg)
Ca
0.30
2.25
Mg
4.12
0.833
K
0.61
0.334
Na
0.31
0.178
CEC
4.330
4.866
Table 2: Plant height of cowpea as influenced by variety, inoculation and phosphorus at B.U.K and Minjibir.
Treatment
B.U.K Minjibir
Weeks After Sowing
6 9 12 6 9 12
Variety (V)
IT99K – 573-1-1
106.2a
122.3a
188.2a
68.51a
88.06a
108.6a
IT97K – 499 – 35
35.2c
46.3c
54.7c
24.05c
39.17c
44.4c
IT93K – 452 – 1
77.0b
82.5b
121.9b
31.06b
50.10b
51.9b
SE+
3.01
2.56
8.10
3.71
3.21
3.10
Inoculation (I)
Inoculated
75.2a
86.4a
128.1a
41.7a
60.5a
69.5a
Un-inoculated
69.7b
80.1b
113.4b
40.68b
57.71b
67.4b
SE+
2.31
2.48
4.79
1.50
1.51
1.81
Phosphorus
0
74.4
86.6
121.1
40.7
59.6
67.0
20
69.9
80.1
121.6
40.3
57.1
67.0
40
74.0
84.4
122.1
42.4
60.5
70.9
SE+
2.81
3.01
5.86
1.81
2.21
2.20
Interaction
ns
ns
ns
Ns
ns
ns
V*P
ns
ns
ns
Ns
ns
ns
V*I
ns
ns
ns
Ns
ns
ns
P*I
ns
ns
ns
Ns
ns
ns
V*P*I
ns
ns
ns
Ns
ns
ns
Means followed by the letter within a column are statistically similar at 5% level of probability using DMRT.

International Journal of Applied Research and Technology 43
Table 3: Number of branches per plant and leaf area index of cowpea as influenced by variety, inoculation and phosphorus
at BUK and Minjibir.
Number of Branches Leaf Area Index
Treatment
B.U.K
Minjibir
B.U.K
Minjibir
Variety (V)
IT99K – 573-1-1
6.70a
6.00a
4.20a
3.80a
IT97K – 499 – 35
4.60b
4.60b
3.40b
3.10b
IT93K – 452 – 1
5.10b
4.70b
3.30b
3.20b
SE +
0.461
0.211
0.153
0.071
Inoculation (I)
Inoculated
5.40
5.00
3.70
3.40
Un-inoculated
5.60
5.10
3.60
3.30
SE +
0.251
0.111
0.142
0.081
Phosphorus (P)
0
5.30
4.80b
3.70
3.20b
20
5.60
5.30a
3.80
3.40ab
40
5.60
5.00ab
3.40
3.50a
SE +
0.312
0.212
0.222
0.081
Interaction
V*P
ns
ns
ns
ns
V*I
ns
ns
ns
ns
P*I
ns
ns
ns
ns
V*P*I
ns
ns
ns
ns
Means followed by the letter(s) within a column are statistically similar at 5% level of probability using DMRT.
Table 4: Number of nodules, effective nodules and grain yield of cowpea as influenced by variety, inoculation and
phosphorus at BUK and Minjibir.
Number of Nodules Effective Nodules Grain Yield (kg/ha)
Treatment
B.U.K
Minjibir
B.U.K
Minjibir
B.U.K
Minjibir
Variety (V)
IT99K – 573-1-1
72.3ab
66.3a
66.7a
80.6a
1033a
806a
IT97K – 499 – 35
58.9b
60.6a
63.2ab
61.3b
746b
682b
IT93K – 452 – 1
77.6a
64.4a
47.8b
59.3b
635b
605b
SE +
9.31
6.41
8.20
20.00
63.8
57.3
Inoculation (I)
Inoculated
74.2a
65.3a
66.9a
73.4a
781
764a
Un-inoculated
65.0b
62.3b
51.6b
60.7b
828
631b
SE +
7.26
2.21
7.01
16.41
55.2
17.8
Phosphorus
0
67.0
58.1b
51.9b
53.1b
845
572c
20
68.6
61.1b
60.6a
55.6b
833
692b
40
73.2
72.1a
65.3a
92.6a
836
828a
SE +
8.89
2.81
8.51
20.11
43.1
33.0
Interaction
V*P
ns
ns
ns
ns
ns
ns
V*I
ns
ns
ns
ns
ns
ns
P*I
ns
ns
ns
ns
ns
ns
V*P*I
ns
ns
ns
ns
ns
ns
Means followed by the letter(s) within a column are statistically similar at 5% level of probability using DMRT.