Chemical Properties of Soil, Yield and
N, P, K Uptake by Okra as affected by Commercially produced
Organic Based Fertilizers
By
OLOWOKERE, F. A., AJUFO,
C. A. AND OJOWA, F. D.

Sources of commercial production of organic based fertilizers were reported to be few in Nigeria some years ago (Adeoye, 2005). With improved awareness in organic agriculture by the efforts of the following organic bodies:

* Organic agriculture Network (NOAN),
* Government Agencies like Ladoke Akintola
University (Mustapha et. al., 2011)
* Organic Agriculture Project in Tertiary
Institutions in Nigeria (OAPTIN),
* West African Network of Organic
Agriculture Research and Training
(WANOART), organic agriculture is gradually gaining acceptance and it is being practiced on a large scale level.

This then necessitates the production of organic based fertilizers. Many organic fertilizer producing companies are therefore springing up. Commercial production of organic based fertilizers becomes relevant for the following reasons:
* The time required for the preparation of the fertilizers could be used for other activities on the farm.

* Some of the organic based fertilizers are produced to be crop specific.
* Materials with additional properties could be included in the fertilizers.
It is therefore necessary to compare the fertilizers produced by different companies to ascertain their efficiencies.

The experiment was carried out at the screen house of the College of
Plant Science and Crop
Production, Federal University of
Agriculture, Abeokuta (Long. 3°
37´ N and Lat. 7° 68´ E).

Names of Organic based fertilizers used for the experiment:
1. Neem organo compound fertilizer produced by
National Research Institute for Chemical
Technology, Zaria.
2. Sunshine organo-mineral fetilizer produced by the Ondo State Government.
3. Providence organic fertilizer produced by Olaku
Industries Nigeria limited, Abeokuta, Ogun State
4. Gateway Organic fertilizers produced by the
Ogun State Government

MATERIALS AND METHODS CONT’D
Rate of fertilizers Used: 10 t/ha
Weight of soil used: 12 kg/pot
Number of replications: 4
Experimental Design: CRD
Test Crop : Okra (Abelmoschus esculentus)
Variety: NHAE 47-4

MATERIALS AND METHODS CONT’D
DATA COLLECTION: The following parameters were observed weekly between 3 and 6 weeks after planting:
Plant Height: This was done with the aid of a meter rule
Number of Leaves: By physical counting
Yield was measured by harvesting okra fruits at three days interval, these were weighed with a balance.

MATERIALS AND METHODS CONT’D
PLANT SAMPLING: Okra plant samples were cut at soil level at full bloom, oven dried at
65°C to constant weighed and milled for analysis.
SOIL SAMPLING: Pre- planting soil sampling was done before fertilizer application while soil samples were collected from each experimental plot at the end of the experiment, these were air dried, ground and sieved with 2 and 0.5 mm sieves.

MATERIALS AND METHODS CONT’D
PLANT ANALYSIS: Nitrogen, phosphorus and potassium in the plant samples were determined by Kjeldahl, vanadomolybdate (Juo, 1982) and flame photometry respectively. Uptake was determined by multiplying the concentrations of the above nutrients with the dry weights of okra plants.

MATERIALS AND METHODS CONT’D
FERTILIZER ANALYSIS: The fertilizers used for the experiment were analyzed for N, P and K using the above methods, pH was determined by Glass electrode method while organic carbon was by
Walkley Black method.
SOIL ANALYSIS: Particle size analysis was done by hydrometer method (Udo and Ogunwale, 1986), nitrogen by Kjeldahl method (Bremner, 1996), organic carbon by Walkley Black method (Nelson and Sommers, 1989), Phosphorus by Bray 1 method (Bray and Kurtz, 1945). Calcium and
Magnessium were determined by flame photometry.

MATERIALS AND METHODS CONT’D
STATISTICAL ANALYSIS: Data obtained was subjected to the Analysis of Variance, means were separated by Duncan’s
Multiple Range Test at 5 % probability level.

RESULTS
Table 1: Particle size distribution and chemical characteristics of pre- planting soil
Property pH
O. M. (%)
Nitrogen 9%)
Phosphorus (mg/kg)
Potassium (cmol/kg)
Ca (cmol/kg)
Mg (cmol/kg)
Particle size
Sand (%)
Clay (%)
Silt (%)
Texture
Value
7.02
0.79
0.13
7.13
0.18
0.16
1.27
77
14
9
Loamy sand

Table 2: Chemical properties of different commercially produced organic based fertilizers
N (%) P (%) K (%) O. C. (%) Fertilizer pH
(H
2
O)
NM 7.07
GT
SH
PR
7.50
9.03
8.41
3.24
2.10
2.13
6.72
3.28
3.41
0.86
1.04
2.73
2.15
0.84
1.41
37.69
53.95
76.74
49.45
SH – Sunshine organo-mineral fertilizer
PR – Providence organic fertilizer
NM – Neem organo compound fertilizer
GT – Gateway organic fertilizer

Table 3: Effect of Different Commercially Produced
Organic Based Fertilizers on okra plant height (cm)
Treatment 3 WAP
Control 12.43
SH
PR
15.45
14.73
NM
GT
14.08
15.82
NS
4 WAP
16.57
20.57
18.43
19.62
21.38
NS
SH – Sunshine organo-mineral fertilizer
PR – Providence organic fertilizer
NM – Neem organo compound fertilizer
GT – Gateway organic fertilizer
NS – Not Significant
WAP – Weeks after planting
5 WAP
24.42
28.67
27.50
25.75
29.38
NS
6 WAP
33.67
39.00
35.40
39.30
40.42
NS

Table 4: Effect of different commercially produced organic based fertilizers on the number of leaves of okra
Treatment
NM
SH
PR
GT
Control
3 WAP
5.17
5.00
4.67
4.17
4.17
NS
4 WAP
5.83ab
6.17a
5.83ab
5.50ab
4.17b
5 WAP
6.67
7.17
7.33
6.17
6.50
NS
6 WAP
7.33
7.83
7.67
8.00
7.00
NS
SH – Sunshine organo-mineral fertilizer
PR – Providence organic fertilizer
NM – Neem organo compound fertilizer
GT – Gateway organic fertilizer
NS – Not Significant
WAP- Weeks after planting

Table 5: N, P and K uptake by okra grown with commercially produced organic based fertilizers
Treatment
GT
SH
NM
PR
Control
N (mg/g)
15.00
28.29
33.50
14.25
14.36
NS
P (mg/g)
2.21
2.50
1.82
0.95
1.75
NS
K mg/g)
26.46ab
27.21ab
40.10a
26.21ab
12.33b
SH – Sunshine organo-mineral fertilizer
PR – Providence organic fertilizer
NM – Neem organo compound fertilizer
GT – Gateway organic fertilizer
NS – Not Significant

25
20
35
30
15
10
5
50
45
40 b a ab ab ab
0
Control NM
Treatment
SH PR GT
Figure 1: Effect of different commercially produced organic based fertilizers on okra yield.

Table 6: Nitrogen, phosphorus and potassium contents of post planting soil as affected by different types of organic based fertilizers.
Treatment
GT
SH
NM
PR
Control
N (%)
0.16a
0.13ab
0.13ab
0.13ab
0.12b
P (mg/kg)
23.86c
47.41a
18.67d
41.30b
14.40e
K (cmol/kg)
0.16d
0.36b
0.43a
0.27c
0.15d
SH – Sunshine organo-mineral fertilizer
PR – Providence organic fertilizer
NM – Neem organo compound fertilizer
GT – Gateway organic fertilizer

Okra could be planted with gateway organic, sunshine organo-mineral, neem organo compound and providence organic fertilizers for improved yield, crop and soil qualities.
However, it is recommended that this experiment has to be conducted on the field before making any conclusion.

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American Society of Agronomy. Madison Wisconsin, pp
901.
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