EFFECT OF SELECTED INSECTICIDE ON WHITEFLY (Bemisia tabaci) INFESTING BRINJAL PLANTS


Publisher: Asian Economic and Social Society 
ISSN (P): 2304-1455, ISSN (E): 2224-4433  
Volume 3 No. 4 April 2013. 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Effects of Variety and Fertilizers on Number of 

Grains/Cob of Maize in Asaba Area of Delta State 

 
 

Enujeke E. C. (Department of Agronomy, Delta State 

University, Asaba Campus, Nigeria) 

 

 

 

 

Citation: Enujeke E. C. (2013) “Effects of Variety and Fertilizers on Number of Grains/Cob of 

Maize in Asaba Area of Delta State”, Asian Journal of Agriculture and Rural Development, Vol. 3, 

No. 4, pp. 215-225. 



Effects of Variety and Fertilizer on ... 

215 
 

 
 

 
Author(s) 

 

Enujeke E. C.  
Department of Agronomy, Delta 

State University, Asaba Campus, 
Nigeria 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Effects of Variety and Fertilizers on Number of 

Grains/Cob of Maize in Asaba Area of Delta State 

 
 

Abstract 

 

This study carried out in the Teaching and Research Farm of 

Delta state University, Asaba Campus from March 2008 to 

June, 2010 to evaluate the effects of variety, organic manure 

and inorganic fertilizer on number of grain/cob of maize. The 

experiment was carried out in a Randomized Complete Block 

Design (RCBD) replicated three times in a factorial layout. 

Four different rates of poultry manure, cattle dung and NPK 

20:10:10 fertilizer were applied to three different maize 

varieties sown at 75cm x 15 cm and evaluated for number of 

grains/cob. The result obtained indicated that hybrid variety, 

9022-13, which had 5090, was superior. Also, plants that 

received inorganic fertilizer were outstanding in number of 

grains/cob with values of 441.5 in 2008 and 506.0 in 2009 

followed by the plants received poultry manure (444.0 in 

2008 and 468.0 in 2009). Based on the rates of application of 

manure/inorganic fertilizer, plants that received 450kgha
-1

 of 

NPK 20:10:10 fertilizer were outstanding in numbers of 

grains/cob of maize with values of 532.8 in 2008 and 570.8 in 

2009. The results of interaction showed that variety, manure 

type and rates of application were significantly (p<0.05) 

different. Based on the findings of this study, it is 

recommended that (i) Hybrid variety 9022-13 should be 

grown in Asaba area. (ii) NPK 20: 10:10 mineral fertilizers 

should be applied at the rate of 450kgha
-1

 to enhance maize 

yield. 

 
Keywords: Organic manure, Inorganic fertilizer, Number of grains/cob, Asaba, Delta State 

 

Introduction  

 

Maize (Zea mays L) is one of the major cereal 

crops grown in the humid tropics and Sub-

Saharan Africa. It is a versatile crop and ranks 

third following wheat and rice in world 

production as reported by Food and 

Agriculture Organization (FAO, 2002). Maize 

crop is a key source of food and livelihood for 

millions of people in many countries of the 

world. It is produced extensively in Nigeria, 

where it is consumed roasted, baked, fried, 

pounded or fermented (Agbato, 2003). In 

advanced countries, it is an important source 

of many industrial products such as corn sugar, 

corn oil, corn flour, starch, syrup, brewer’s grit 

and alcohol (Dutt, 2005). Corn oil is used for 

salad, soap-making and lubrication. Maize is a 

major component of livestock feed and it is 

palatable to poultry, cattle and pigs as it 

supplies them energy (Iken et al. 2001). The 

stalk, leaves, grain and immature ears are 

cherished by different species of livestock 

(Dutt, 2005).  

 

In spite of the increasing relevance and high 

demand for maize in Nigeria, yield across the 

country continues to decrease with an average 

of about 1 t/ha which is the lowest African 

yield recorded (Fayenisin, 1993).  

 

The steady decline in maize yield can be 

attributed to:  

1. Rapid reduction in soil fertility 

caused by intensive use of land and  

reduction of fallow period as reported 

by Directorate of Information and 



Asian Journal of Agriculture and Rural Development, 3(4): 215-225 

216 
 

Publications of Agriculture (DIPA, 

2006). 

2. Failure to identify and plant high 

yielding varieties most suited or 

adapted to each agro-ecological zone 

(Kim, 1997; Olakojo et al., 1998).  

3. Use of inappropriate plant spacing 

which determines plant population 

and final yield (Zeidan et al., 2006). 

4. Negligence for soil amendment 

materials such as organic manure and 

inorganic fertilizers which improve 

soil condition and enhance crop yield.   

 

Sonetra (2002) suggested that subsistence 

farmers should apply organic manure directly 

to the soil as a natural means of recycling 

nutrients in order to improve soil fertility and 

yield of crops.  Manures and fertilizers are the 

life wire of improved technology contributing 

about 50 to 60% increase in productivity of 

food grains in many parts of the world, 

irrespective of soil and agro-ecological zone 

(DIPA, 2006).  Reijnties et al. (1992) and 

Adepetu (1997) remarked that the downward 

trend in food production should prompt 

farmers to amend the soil with different 

materials in order to enhance growth and yield 

of crops.  Several organic materials such as 

cattle dung, poultry dropping, pig dung and 

refuse compost have been recommended to 

subsistence farmers in West Africa as soil 

amendments for increasing crop yield (Sobulo 

and Babalola, 1992; Ismail et al., 1990; 

Olayinka, 1996 and Olayinka et al., 1998). 

  

Municipal wastes were reported to have 

reduced soil temperature, increased soil water, 

nutrient status and the yield of maize in 

temperate soils (Movahedi et al., 2000).  Cattle 

dung has been reported to contain 0.3 – 0.4 % 

N, 0.1 – 0.2 % P and 0.1 – 0.3 % K (Subedi 

and Gurung, 1991).  According to Adekunle et 

al. (2005) cattle dung applied at the rate of 10 

t/ha to cowpea resulted to increased plant 

height, leaf area, pod number, pod weight as 

well as improved soil structure in a mixed 

farming system.  Stefan (2003) indicated that 

fresh poultry dropping contain 70% water, 

1.4% N, 1.1% P2O5 and 0.5% K2O while dried 

poultry manure contains 13% water, 3.6% N, 

3.5% P2O5 and 1.6% K2O.  Ayodele (1993) 

reported that inorganic fertilizers are known to 

influence the quantity and yield of maize.  

Iken and Anusa (2004) recommended an 

optimum plant population of 53,333 plants/ha 

for maximum yield of maize.  Their report 

indicated that this is obtainable using a spacing 

of 75cm x 25cm at 1 plant per stand or 75cm x 

50cm at 2 plants per stand.  Azam et al. (2007) 

reported that spacing of 75cm x 35cm resulted 

in increased grain yield of maize while 75cm x 

15cm gave maximum cob weight.  Similar 

report by Allessi and Power (2004) revealed 

that maize cob weight decreased with 

increased plant population. 

 

At present, there are no recommended 

standards taking into consideration the 

different combinations of such cultural 

practices as varietal selection, rates of 

appropriate organic manure and mineral 

fertilizer which interplay to influence yield and 

optimal performance of maize in Asaba area of 

Delta State. Against this background, the 

broad objective of this study, therefore, was to: 

identify variety of maize most suited or 

adapted to Asaba area and the appropriate 

fertilizer types and rates for the variety. 

 

The specific objectives were to: 

 (i) identify the best variety for Asaba 

area. 

(ii) determine the effects of NPK 

(20:10:10) mineral fertilizer, poultry 

manure, cow dung on number of 

grains/cobs maize. 

 

Materials and Methods 

 

Site Description 

The study was carried out in the Teaching and 

Research Farm of Delta State University, 

Asaba Campus from March to December 2008 

and repeated between March and December, 

2009.  Asaba is located at latitude 06
o
14’N and 

longitude 06
o
49’N of the equator. It lies in the 

tropical rainforest zone dominated by 

mangrove, fresh water, swamps, humid forests 

and secondary vegetation (NEST, 1991). Its 

climate is influenced by the movement of the 

Inter-Tropical Discontinuity (ITD). The IDT is 

made up of two wind systems namely the 

moisture-laden South-West monsoon from the 

Atlantic Ocean and the dry cold North-East 

trade wind from the Sahara desert.  The South-

West Trade wind most significantly 

determines the climate condition of Asaba area 

of Delta State.  Asaba is characterized by 

raining season between April and October, 



Effects of Variety and Fertilizer on ... 

217 
 

with annual mean-rainfall of 1500mm and 

2000mm maximum. The distribution is 

bimodal with peak in July and September, 

coupled with a period of low precipitation in 

August. Mean temperature is 23.8
o
C with 

37.3
o
C as maximum. Relative humidity is 

77.2%, the mean monthly soil temperature at 

100m depth is 20.3
 o

C, while sunshine stands 

at 4.8 bars (Meteorological Office, Asaba, 

2003).  

 

Pre-planting Soil Analysis 

Representative surface soils (0-20cm) were 

sampled with a tubular sampling auger. These 

soil samples were air-dried at room 

temperature for 5 days and crushed to pass 

through a 2mm mesh sieve. Sub-samples from 

the bulked soil sample were further grounded 

to pieces to pass through 100mm-mesh sieve 

for the determination of organic matter.  The 

rest samples were then analyzed to determine 

the physical and chemical properties of the 

soil. The analysis was done at Delta State 

University, Asaba campus. 

 

Analytical Procedure 
 

Physical Properties 

  

Particle Size Distribution: Particle size 

distribution was analyzed using the Bouyoucos 

hydrometer method in which 0.5 N Sodium 

hexameta-phosphate was used as dispersant 

(Landor, 1991). 

Bulk Density: The bulk density (Bd) was 

determined by Core-method. 

Particle Density: This was determined by 

pycometer or specific gravity   bottle method 

as described by Bowles (1992). 

 

Chemical Properties 

  

Soil pH: This was determined in soil: water 

suspension (1:1) using glass electrode pH-

meter as described by Mclean (1982). 

Organic Carbon: This was determined using 

the wet oxidation method of Walkley and 

Black (Walkley and Black, 1945). 

Total Nitrogen: This was determined using 

the modified K. Jeldah distillation method as 

described by Landor (1991). 

Exchangeable Cations (EC) and Effective 

Cation Exchange Capacity (ECEC): 

Exchangeable cations were determined by 

extracting the cations with IN ammonium 

acetate (IN, NHOAC) as displacing solution, 

buffered at pH7 as described by Brady and 

Weils (1999). The extract was then determined 

electrochemically using atomic absorption 

spectrophometry. The effective cation 

exchange capacity (ECEC) was calculated  as 

the sum of exchangeable bases (Ca, Mg, K and 

Na) and exchangeable A1 and H expressed in 

cmo1/kg
-1

 of soil. 

Exchangeable  Acidity: This was  determined 

by titration  method as described by Juo 

(1981). The exchangeable H
+
 and A1

++
 were 

then expressed in cmo/kg
-1

 of soil 

 

Aim of the Experiment  
The experiment was aimed at testing the 

response of three selected maize varieties to 

different rates of organic manure and inorganic 

fertilizer (NPK 20:10:10) 

 

Experimental Design  

The study was carried out in Randomized 

Complete Block Design (RCBD), replicated 

three times in a factorial layout. The factors 

were three sources of nutrients:- poultry 

manure (PM), cattle dung (CD), inorganic 

fertilizer (NPK 20:10:10). The different rates 

of PM were 0, 10, 20, 30t/ha, CD were 0, 10, 

20, 30t/ha and NPK 20:10:10 were 0, 150, 

300, 450kg/ha. 

 

Agronomic Practices  
Among the agronomic practices carried out 

were land preparation/plot layout, planting, 

application of treatments, weeding. 

 

Land Preparation and Plot Layouts 
The land was ploughed and harrowed using 

tractor. Three blocks (or replicates) consisting 

of 36 blocks each were layout, each block will 

measure 2.6m x 2.25m and was separated from 

one another with a  space of 0.5m. Alley 

pathways of 1m separated one block from 

another, and the total number of plots laid out 

in the entire experiment was108. 

 

Planting  
Maize seeds were sown on the plots at the rate 

of 1 seed per hole at a depth of 2-3cm, using 

75cm x 15cm spacing as indicated by the first 

experiment. 

 

Procurement and Application of Organic 

Manure and NPK 20:10:10 Fertilizer 
 



Asian Journal of Agriculture and Rural Development, 3(4): 215-225 

218 
 

Well-decomposed cattle dung was collected 

from cattle pen area, while poultry droppings 

were obtained from the battery cage system of 

poultry management of Delta State University, 

Asaba Campus. This organic manure was 

analyzed to determine their nutrient contents. 

NPK 20:10:10 fertilizer was obtained from 

Delta Agricultural Procurement Agency 

(DAPA), Ibusa.These amendment materials 

were incorporated into the plots according to 

the treatment as suggested by Olanikan (2006). 

 

Weeding: Weeding was done three times 

using hoe. 

 

Data Collection: Fourteen middle stands were 

used as sample population for data collection. 

Data collected was number of grains/cob of 

maize. This was done by direct counting after 

harvesting and shelling at the end of the 

sixteenth week from sowing. 

 

Analysis of Soil Sample: Soil samples were 

collected from each experimental plot and 

analyzed for their content of N P and K. 

 

Statistical Analysis: Data collected were 

subjected to analysis of variance (ANOVA) 

and means were separated with Duncan 

Multiple Range Test (DMRT) according to 

Wahua (1999). 

 

Results 
 

Soil Physico-chemical Properties of the 

Experimental Site:  

The pre-physico-chemical properties of the 

experimental site are shown in Table 1. The 

result showed predominantly sand at the 

surface and this tends to decrease with depth 

of profile. Texturally, the soil of the 

experimental site is classified as sandy loam. 

The soil is acidic with pH of 6.2 in H2O and 

5.6 in CaCl. The organic matter content and 

total nitrogen were low with values of 1.22 

gkg
-1

 and 0.113 gkg
-1

. The available P was 

high with value of 26.5 mgkg
-1

. The 

exchangeable cations (Ca, Mg, Na and K) 

were equally low in status with values of 

2.6cmolkg
-1

 for Ca
2+

 and 0.9 cmolkg
-1

 for 

Mg
2+

. The value obtained for Na
+
 was 0.57 

cmolkg
-1

, which was moderate while that for 

K
+
 was 0.08cmolkg

-1
, which was low. The 

CEC was 4.15, while ECEC was 5.6cmolkg
-1

, 

which were generally low. The exchangeable 

acidity was only trace for Al
3+

 and 

characteristically low for H
+
 with a value of 

1.4 cmolkg
-1

. 

 

Nutrient Content (%) of Organic Manure 

Used in the study 

The nutrient content of organic manure 

(poultry manure and cattle dung) used in the 

study is shown in Table 31.  The values of N, 

P and K in poultry manure were significantly 

(P<0.05) higher than their values in cattle 

dung.  With respect to N, poultry manure had 

1.6% against cattle dung which was 0.4%.  

Also, poultry manure had 0.6% P while cattle 

dung had 0.2% P.  The values for K were 0.8% 

in poultry manure, while it was 0.3% in cattle 

dung.

 

 

Table 1: Physico-chemical Properties of Experimental Site 

Soil Property Value Interpretation 

Particle Size Distribution (%) 

Coarse sand  38  

Fine sand  41  

Silt 9  

Clay 12  

Texture   Sandy loam 

Ph 
H2O 6.2 Acidic 

CaCl 5.6 Acidic 

Organic  Carbon gkg
-1

 0.71  

Organic Matter gkg
-1

 1.22 Very low 

Total  Nitrogen gkg
-1

 0.113 Low 

Available  P (ppm) 26.5  

Exchangeable bases (cmol/kg
-1

) 

 Na
+
 0.57 Moderate 



Effects of Variety and Fertilizer on ... 

219 
 

 K
+
 0.08 Very low 

 Ca
2+

 2.60 Low 

 Mg
2+

 0.90 Low 

Cation Exchange Capacity  4.15  

Exchangeable acidity (cmol/kg
-1

) 

 Al
3+

 Trace  

 H
+
 1.4  

Effective cation Exchangeable 

capacity  (Cmol/kg
-1

) 
5.6  

 

Table 2: Nutrient (%) of Organic Manure used ion the Study 

 Nutrient  Content (%) 

Parameter N P K 

PM 1.6a 0.6a 0.8a 

CD 0.4b 0.2b 0.3b 

Legend:   PM = Poultry Manure, CD = Cattle Dung, N = Nitrogen,  

P = Phosphorus 

 

Effect of Variety, Organic Manure and 

Inorganic Fertilizer on Number of 

Grains/Cob of Maize 

The response of number of grains/cob of 

maize to variety, organic manure and 

inorganic fertilizer is shown in Table 3. There 

were significant differences in the number of 

grains/cob of maize. With respect to varietal 

performance in 2008, hybrid variety 9022-13 

had the highest number of grains/cob (526.6), 

followed by open-pollinated variety BR9922-

DMRSRF2 (474.0) Agbor local variety had the 

lowest number of grains/cob (340.0). The 

order of highest number of grains/cob with 

respect to the varieties sown was 9022-13 > 

BR9922-DMRSRF2 > Agbor local. This was 

also the trend in 2009. Plants that received 

inorganic fertilizer NPK 20:10:10 had the 

highest number of grains/cob (506.0) followed 

by plants that received poultry manure (468.0). 

Plants that received cattle dung had the lowest 

number of grains/cob. The order of 

superio0rity in the number of grains/cob based 

on source of nutrient was inorganic fertilizer 

NPK 20:10:10 > Poultry manure > cattle dung. 

Plants that received higher rates of fertilizer or 

manure had higher number of grains/cob than 

plants that received lower rates. The order of 

highest number of grains/cob based on rate of 

manure in tons/hectare was 30 > 20 > 10 > 0 

while that of fertilizer in kg/ha was 450 > 300 

> 150 > 0. Similar results were also obtained 

in 2009. The result of interaction (Table 4) 

showed that variety, manure type, rate, variety 

* rate were significantly (P<0.05) different and 

affected changes in number of grains/cob of 

maize in 2008 and 2009, while type * rate 

were not significantly (P>0.05) different and 

could not have affected changes in number of 

grains/cob of maize in both years of 

evaluation.

  

 

 

 

 

 

 

 

 

 

 

 



Asian Journal of Agriculture and Rural Development, 3(4): 215-225 

220 
 

Table 3: Effects of Variety, Organic Manure and Inorganic Fertilizer on Number of Grains 

per Cob of Maize in 2008 and 2009 

 No. of grains/cob 

 2008 2009 Mean 

Variety    

9022 – 13 509.0a 526.6a 517.8a 

BR9922-DMRSF2 410.0b 474.0b 242.0b 

Agbor Local 343.3c 430.0c 386.6c 

Nutrient Source    

PM 440.0a 468.0b 454.0a 

CD 380.7b 458.0b 419.3b 

IF 441.5a 506.0a 473.7a 

Rates of application  

(tons or kg/ha) 
   

0 332.6g 394.0d 363.3e 

                      10 382.6f 423.0c 407.3d 

                      20 434.6d 482.0b 458.3c 

                      30 494.8b 542.0a 518.4b 

                      150 409.1e 496.6b 402.8d 

                      300 473.3c 558.0a 515.6b 

                      450 532.8a 570.8a 551.8a 
Means with the same letter(s) under the same column are not significantly different 

 (P  0.05) using Duncan Multiple Range test (DMRT). 

 

 

Table 4:  Effects of Variety, Manure and Inorganic Fertilizer on Number of Grains per Cob of Maize 

in 2008 and 2009 

Variety  Nutrient 

Source 
Rate 

No. of 

Grain/cob 

No. of 

Grain/cob 

9022-13 PM 0 408.0 416.0 

  10 476.0 509.3 

  2   0 544.0 554.6 

  30 612.0 662.6 

  Mean  535.6 

 CD 0 384.0 396.0 

  10 448.0 466.0 

  20 512.0 528.0 

  30 569.3 588.0 

  Mean  494.5 

 IF 0 432.0 412.0 

  150 504.0 492.6 

  300 576.0 642.3 

  450 642.6 651.6 

  Mean  549.6 

BR9922-

DMRSRF2 
PM 0 336.0 400.0 

  10 392.0 416.0 

  20 448.0 484.0 

  30 504.0 528.0 

  Mean  457.0 

 CD 0 288.0 404.6 

  10 336.0 418.6 

  20 384.0 465.3 

manure 
(tha-1) 

   IF 
(kgha-1) 



Effects of Variety and Fertilizer on ... 

221 
 

  30 432.0 526.0 

  Mean  453.6 

 IF 0 360.0 412.0 

  150 420.0 492.6 

  300 480.0 642.3 

  450 540.0 651.6 

  Mean  549.6 

Agbor Local PM 0 312.0 356.6 

  10 364.0 375.3 

  20 416.0 428.0 

  30 468.0 476.6 

  Mean  409.1 

 CD 0 248.0 380.6 

  10 280.0 402.6 

  20 304.0 439.3 

  30 384.0 471.3 

  Mean  423.5 

 IF 0 260.0 376.0 

  150 303.0 474.6 

  300 364.0 480.0 

  450 116.0 500.0 

  Mean  457.7 

Variety    * * 

Manure type   * * 

Rate   * * 

Variety x 

manure type 
  Ns * 

Variety x rate   * * 

Manure type x 

rate 
  Ns Ns 

Variety x 

manure type x 

rate 

  Ns Ns 

Legend: * = significant at 0.05 level of probability, ns = not significant   

 

 

Discussion 
 

Soil Physico-chemical Properties of the 

Experimental Site 

The sandy loam texture of the experimental site 

may be attributed to the Parent Material (PM) 

from which the soil was formed and the climate 

of the area. The soil might be formed from 

sandstone and quartz parent materials. These 

impart sandy texture to the soils. The 

high sand content of the soil could be attributed 

to high content of quartz in the material (Brady 

and Weils, 1999). The weak acid nature of the 

soil of the area may be traced to the marked 

leaching of exchangeable bases resulting from 

the high rainfall associated with the 

environment and the dissociation of strong and 

functional group in the organic matter. This is 

in harmony with the findings of Omokri et al. 

(2007). The low organic matter status of the 

experimental site could be  attributed to the 

rapid decomposition of organic matter due to 

high solar radiation and moisture,this favours 

optimum  microbial activities in the soil, It 

could also be attributed to the annual seasonal 

bush burning which tend to deplete organic 

matter accumulation in the soil (Landor, 199l). 

 

The low level of total nitrogen could be due to 

high temperature. It could also be attributed to 

leaching of’ nitrate by torrential rainfall 

prevalent in the environment (Olatunji et al., 

2007). The high level of’ Phosphorus may be 

attributed to either of these reasons: (i) history of 

land use and cultural practices associated with 

the land use (that is, cropping of crops that do 



Asian Journal of Agriculture and Rural Development, 3(4): 215-225 

222 
 

not take much P nutrient from the soil and the 

application of P organic fertilizers (Nnaji et al., 

2002, Nnaji, 2008). (ii) The parent material from 

which the soil was formed may be rich in P 

minerals (Brady and Weils, 1999). (iii) The soil 

may not be highly acidic as to cause high level of 

fixation (Brady and Weils, 1999, Isirimah et al., 

2003 and Omokri et al., 2007). The low values 

of exchangeable cations may be attributed to the 

leaching of bases from the solum due to high 

rainfall characteristics of the area. The low 

action exchange capacity could be attributed to 

the PM from which the soil was formed, and low 

organic matter (OM) content of the soil. The PM 

from which the soil was formed may be poor in 

basic nutrients. Nnaji et al. (2002) noted that 

soils of the study area were dominated by Fe 

oxide and Kaolinites. These clay minerals are 

low in basic cations (Brady and Weils, 1999). 

The exchangeable acidity was low possibly 

because of the cultural practices associated with 

the land use (that is, previous use of amendments 

to improve soil condition and enhance crop 

yield. The results, generally, are in harmony with 

the findings of Olatunji et al. (2007) and the 

results of soil fertility evaluation in the region. It 

is also consistent with the findings of Nnaji et al. 

(2002), Nnaji, 2008) which reported that the 

history of land use and cultural practices affect 

soil conditions and crop productivity. 

 

Nutrient Content (% dry matter) of Organic 

Manure used in the Study 

The values of N, P and K were higher in poultry 

manure than in cattle dung used in the study 

possibly because poultry manure, especially 

those produced in deep litter or battery cage 

house, have more concentrated nutrient content 

compared with other types of animal manure. 

This is similar to the findings of Sharpley and 

Smith (1995) and Brady and Weils (1999) who 

reported that among the different sources of 

organic manure which have been used in crop 

production, poultry manure was found to be the 

most concentrated in terms of nutrient content. It 

is also in harmony with the findings of Subedi 

and Gerung (1991) and D1PA (2006) who 

reported that poultry manure has higher levels of 

N. P and K than cattle dung. It is also consistent 

with the findings if Ibeawuchi et al. (2007) who 

reported higher levels of N. P and K in plots 

treated with poultry manure than in plots treated 

with other nutrient sources. 

 

Effect of Variety, Organic Manure and 

Inorganic Fertilizer on Number of Grains/cob 

of Maize 

Hybrid variety 9022-13 had higher number of 

grains/cob than open-pollinated variety BR9022-

DMRSRF2 and Agbor local possibly because 

hybrid maize varieties possess outstanding 

quality with respect of high grain yield. This is 

consistent with the findings of Odeleye and 

Odeleye (2001) and Sajjan et al. (2002) who 

reported that fruit production, grain yield and 

other yield components are usually influenced by 

genetic quality of individual variety. It is also in 

consonance with the findings of Olakojo et al. 

(1998) who reported that hybrid maize varieties 

have yield advantage of 25 to 50% over the best 

open-pollinated variety in Nigeria. Plants that 

received poultry manure had higher number of 

grains/cob than plants that received cattle dung 

probably because poultry manure must have 

increased the carbon content, water holding 

capacity, aggregation of soil, and decreased the 

bulk density of the soil. This is similar to the 

findings of Egerszegi (1990) who reported that 

poultry manure increased the carbon content, 

water holding capacity, aggregation of soil and 

decreased bulk density of soil where it was 

applied. Poultry manure could have also 

increased the water soluble and exchangeable 

potassium and magnesium, which enhanced 

yield as reported by Jackson et al. (1999). The 

superiority of plants that received inorganic 

fertilizer over other plants with respect to higher 

number of grain/cob could be attributed to better 

yield enhancement credited to inorganic 

fertilizers over other nutrient sources. This is 

similar to the findings of Ayodele (1993) and 

Giller (2003) who reported that inorganic 

fertilizers influenced crop quality and improved 

yield over 50% than their unfertilized 

counterparts. It is also consistent with the 

findings and report of Akintoye and Olufolaji 

(2005) on Cayene pepper. Higher rates of 

inorganic fertilizers or organic manure produced 

better response with respect to higher number of 

grains/cob possibly because higher rates satisfied 

the crop’s requirement. This is similar to the 

findings of Olarewaju and Isma (1990) and 

Ayodele (1993) who suggested that accurate rate 

and type of fertilizer should be applied using the 

best method at the most appropriate time. 

 

 

 

 



Effects of Variety and Fertilizer on ... 

223 
 

Conclusion and Recommendations 
 

This study was carried out to evaluate the effects 

of variety and fertilizers on number of grains/cob 

of maize in Asaba area of Delta State. It was a 

factorial experiment carried out in a Randomized 

Complete Block Design (RCBD) with three 

replicates. Four different rates of poultry manure, 

cattle dung and inorganic fertilizer NPK 

20:10:10 were applied to three maize varieties 

sown at 75 cm x 15 cm plant spacing. The results 

obtained indicated that hybrid variety 9022-13 

was superior in number of grains/cob of maize 

and that plants which received inorganic 

fertilizer application rate of 450 kgha
-1

 had the 

highest number of grains/cob. Based on the 

findings of the study, it was recommended that 

(i) Hybrid maize variety 9022-13 be grown in the 

study area (ii) farmers who prefer mineral 

fertilizer should apply 450 kgha
-1

 to enhance 

number of grains/cob of maize in Asaba area of 

Delta State. 

 

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