International Journal of Horticulture 2015, Vol.5, No.1, 1
-
7
2
variable rates of organic manure and phosphate
fertilizer on yield and proximate nutrient composition
of lettuce (
Lactuca sativa
) in South Western Nigeria.
1 Results and Discussion
1.1 Pre cropping soil analysis
The data on the initial chemical properties of the soils
used for the study are presented in Table 1. Particle
size fraction showed that the soils were sandy clay
loam (Akure) and loamy sand (Ikorodu) in texture and
low in fertility as reflected by the low content of
organic carbon, and total nitrogen. The available
phosphorus (P) and exchangeable bases (Ca, Mg and
K) were seemingly low based on the ratings of
FMANR, (1996) for this agro-ecological zone. The
low fertility status of the soils is a true reflection of
most humid environment that are strongly weathered
with low activity of clay mineralogy and high acidity
due to intense precipitation with its associated erosion
and leaching in the environment. The pH value was
within the pH range 5.50 – 6.50 and is good for good
performance of vegetables (Pureseglove, 1991), most
nutrient elements were below the critical range
(Adeoye and Agboola, 1985). These revealed that
there is need for soil amendment in form of fertilizer
application to improve the growth and yield of lettuce.
Cooke (1972) reported that the major nutrients
required by the crop are Nitrogen (N), Phosphorus (P)
and Potassium (K). Inadequate supply of any of these
nutrients during crop growth would have negative
impact on the reproductive capability, growth and
yield of the plant (Vine, 1953; Solubo, 1972) and
supplementary amount of nutrients can be added to
soil inform of organic or inorganic fertilizer to correct
inadequate supply of nutrients to the crop (Dirk and
Hogarth, 1984).
Table 1 Pre cropping soil analysis
Ikorodu
Akure
pH (1:2 H
2
O)
6.50
5.50
Organic carbon (%)
1.44
1.53
N %
0.31
0.44
Available P (mg/kg)
4.22
3.85
K
(cmol/kg)
0.53
0.36
Na (cmol/kg)
0.33
0.38
C (cmol/kg)
1.08
0.49
Mg (cmol/kg)
0.34
0.65
H (cmol/kg)
0.13
0.11
Particle size
Loamy sand
Sandy clay loam
1.2 Effects of soil amendment on lettuce yield
attributes
Sole application of organic manure and combinations
with phosphorus exerted significant (P<0.05)
influence on yield attributes of lettuce in both
locations. In Ikorodu, 4t PM + RP plot had the lowest
fresh weight of harvested lettuce (0.29kg/plant) and
12t PM recorded the lowest fresh weight in Akure
(0.04kg/plant). Highest fresh weight of 0.83kg/plant
was recorded in plot treated with 8t CM + SSP
combination followed by 0.79kg/plant recorded from
plot treated with 4t CM + SSP combination for Ikorodu
and 0.67kg/plant was recorded in plots treated with 4t
PGM + RP and 12t CM followed by 0.13kg/plant
recorded from 8t PM + RP and 8t PGM + SSP
combinations and 0.11kg/plant from control and 8 t
PGM + RP combination plots respectively (Figure 1).
Figure 1 Fresh weight of harvested lettuce
