International Journal of Horticulture 2015, Vol.5, No.1, 1
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7
5
increase
solubility
of
phosphorus.
This
complementary application reduces the dependence of
the farmer on inorganic fertilizer use. It also reduces
the exposure of the soil to the consequences of
inorganic fertilizer application.
2 Materials and Methods
2.1 Experimental Site
The experiment was conducted at two locations in the
rain forest of Nigeria during year 2011/2012 cropping
season. The first experiment was conducted at the
Teaching and Research Farms of Lagos State
Polytechnic, Ikorodu. The geographical location of
Ikorodu is between latitude 5°10' N and longitude 3°
16' and 3°18' E. The soil type has been classified as
Fleventic Eutroctrept (Soil Survey staff), Gleyic
Cambisol (FAO) and Idesan series (Fasina, 1996,
personal communication); while the second trial was
carried out at the Horticultural Unit, Ministry of
Agriculture, Ondo road, Akure; Latitude 7°32' N and
Longitude 5°53' E area of rain forest agro-ecological
zone of Southwestern Nigeria. The soil was classified
as Oxic tropudalf (Adepetu
et al.,
1979), or Luvisol
(FAO). The climate of Akure is essentially humid with
rainfall varying from 2,000 – 5,500mm per annum.
Two distinct seasons exists namely – rainy and dry
seasons. The rainy season started in February and ends
in October. It has a bimodal distribution pattern with
distinct peaks in July and September. Dry spell occurs
between late July and middle of August. Annual air
temperature varies between 27°C - 35°C.
2.2 Pre Soil Analysis
Prior to the commencement and at the end of the
experiment core soil samples were collected at
random from the sites at a depth of 0-15cm. The soil
was air dried, crushed and sieved with a 2mm sieve
mesh. It was then analyzed in a laboratory as follows:
Soil pH was determined elecrometrically in 1:2
suspension of soil 0.1M KCL (Thomas, 1996).
Particle size distribution was determined by the
hydrometer method (Gee and Or, 2002) and total
porosity was calculated from the bulk density as the
fraction of total volume not occupied. Organic carbon
content was determined using Walkey/Black method
procedure (Nelson and Sommers, 1996) and Organic
matter estimated by multiplying with a factor of 1.724.
Total nitrogen content was determined by the
Kjeldahai digestion procedure (Bramner 1996).
Exchangeable bases (Na, K, Ca and Mg) were
determined after leaching with 1 N ammonium acetate
(NH
4
OAC) and were read from the atomic absorption
spectrophotometer while K and Na were read from the
flame photometer (Jackson 1968). Available
phosphorus was determined with the Bray 1 method
(Bray and Kurtz 1965) and exchangeable acidity by
KCL extraction method (Mclean, 1965).
2.3 Experimental Design
The experimental design was Randomised Complete
Block Design (RCBD). The treatment consisted of flat
rate of phosphorus fertilizer application (Rock
phosphate (RP) and Single Super Phosphate (SSP)
(150kg ha
-1
) combined with manure: poultry (pm), pig
(pgm) and cattle (cam) manure each at different levels
(0 t/ha
-1
, 5t/ha
-1
and 10t/ha
-1
) were incorporated into
the soil 2 weeks before planting and at planting
respectively. A control was established. The
combination resulted in 16 treatment combinations viz:
S/n
Treatment
1
0 t/ha
-1
Control
2
8 t/ha
-1
poultry manure + Rock Phosphate
8t PM + RP
3
4 t/ha
-1
poultry manure + Rock Phosphate
4t PM + RP
4
12 t/ha
-1
poultry manure alone
12t PM
5
8 t/ha
-1
pig manure + Rock Phosphate
8t PGM + RP
6
4 t/ha
-1
pig manure + Rock Phosphate
4t PGM + RP
7
12 t/ha
-1
pig manure alone
12t PGM
8
8 t/ha
-1
cattle manure + Rock Phosphate
8t CM + RP
9
4 t/ha
-1
cattle manure + Rock Phosphate
4t CM + RP
10
12 t/ha
-1
cattle manure alone
12t CM
11
8 t/ha
-1
poultry manure + Single Super Phosphate
8t PM + SSP
12
4 t/ha
-1
poultry manure + Single Super Phosphate
4t PM + SSP
13
8 t/ha
-1
pig manure + Single Super Phosphate
8t PGM + SSP
14
4 t/ha
-1
pig manure + Single Super Phosphate
4t PGM + SSP
15
8 t/ha
-1
cattle manure + Single Super Phosphate
8t CM + SSP
16
4 t/ha
-1
cattle manure + Single Super Phosphate
4t CM + SSP
Note: The gross experimental area was 96m
2
and each plot dimension was 1m x 2m and there were 48 plots at each location.
