International Journal of Horticulture 2015, Vol.5, No.1, 1
-
7
6
2.4 Crop Establishment and Management
The experimental plots were manually cleared and
raised seedbeds prepared. Organic manures (PM,
PGM and CM) at different levels were incorporated
into the soil at 14 days before transplanting, while
phosphate fertilizer (Ogun Rock Phosphate (ORP) and
Single Superphosphate (SSP) was applied at a fixed
rate of 150kg/ha. Great Lake lettuce cultivar was
obtained from Jos, Plateau State, Nigeria and raised in
the nursery. Lettuce seedlings were transplanted four
(4) weeks after sowing at 25cm x 25cm between rows
and plants; thus giving a plant population of 160,000
stands per hectare. Weeding was carried out as at
when due using hand hoe, while foliage insect pest
control was achieved by spraying Cypermethrin at 5
liters/ha mixed in 80 litres of water at 2 weeks interval
up till 14 days before harvesting.
2.5 Data Collection
Five (5) plants were randomly selected and tagged
from each plot for data collection at 40, 60 and 80
days after transplanting (DAT). The data for the
following parameters were collected: plant height,
number of leaves, leave area, marketable yield, shoot
dry matter, and the nutrient composition of fresh
lettuce (leaf tissue analysis). Plant height was
determined with a meter rule at the distance from the
soil level to the terminal bud; number of leaves was
determined by visual counting of the leaves. Leave
area was measured by tracing the margin of the leaf on
a graph paper and the total leaf area/plant was
obtained by counting the leaf number of 1cm squares
(Edje and Osiru, 1988). Shoot dry matter was taken at
80 DAT, by cutting, oven drying and weighing the
entire above ground vegetation. Marketable yield was
determined by weighing harvested lettuce at 50 DAT
with digital weighing balance and the average of their
respective weights were taken for each treatment. This
was extrapolated to evaluate total yield per hectare.
2.6 Mineral Content Analysis of Leaf Tissue
A microwave was used for digestion of lettuce plant
tissue. A sample of 0.5g of each treatment was
weighed and put in the microwave bomb (Microsoft
®
Encarta
®
2003). For Calcium (Ca) and Zinc (Zn)
analysis, 10ml 6M HCL and 10ml 6M HNO
3
were
used for digestion. For iron (Fe) analysis, 10ml 6M
H
2
SO
4
and 10ml 6M HNO
3
were used for digestion.
These acids were added into the bombs containing the
samples and digested in the microwave for 2 minutes.
The samples were cooled to room temperature in a
water bath and filtered into 50ml volumetric flask.
Dilution to the mark was done using deionized water
(Masarirambi et al., 2010, Masarirambi et al., 2012).
Standard solutions of 0.5 ppm, 1.0 ppm and 2.0 ppm
were prepared from a 1000 ppm stock solution of Ca
and Fe using the formula: C
1
V
1
= C
2
V
2
. With a known
concentration (C
2
) and volume (V
2
) required, the
volume of 1000ppm stock solution was calculated and
necessary dilution done to make V
2.
Standards were
run in the atomic absorption spectrophotometer (AAS)
to determine their absorbance (Masarirambi et al.,
2010, Masarirambi et al., 2012).
2.7 Statistical analysis
The data collected were analysed using MSTAT-C
(Niseen, 1989) statistical package. Analysis of
Variance (ANOVA) was undertaken on data collected
so as to determine if there were any significant
differences amongst treatments. Mean separation
where significant differences were detected was done
by Duncan’s Multiple Range Test (DMRT) (Gomez
and Gomez, 1984)
References
Adeoye O.A., and Agboola, A.A., 1985, Critical level of soil plant available
PK, Zn, Mg, Cu and Mn on Maize leaf content in Sedimentary Soils of
Southwestern Nigeria. Fertilizer Research, 6: 60-71
Adepetu J.A., and Corey, R.B., 1977, Change in nitrogen and phosphorus
availability & phosphorus fraction in two soil of Nigeria under
intensive cultivation. Plant and soil 46:309-316
Akanbi W.B., Togun A.O., Adediran J.A., and Ilupeju E.A.O., 2010, Growth,
Dry Matter and Fruit Yields Components of Okra under Organic and
Inorganic Sources of Nutrients. American-Eurasian Journal of
Sustainable Agriculture, 4(1): 1-13
Akande M.O., Oluwatoyinbo, F.I., Kayode, C.O., and Olowookere, F.A.,
2006, Effects of Ogun phosphate rock amended with different levels of
cowdung on the growth and yield of maize okra intercrop relayed with
cowpea. African Journal of Biotechnology 7 (17): 3039-3043
Ayodele O.J., and Olaniyan, F.O., 1982, Egusi-melon agronomy fertilizer
studies. In: Vegetable Programme. NIHORT Annual Report. Pp. 65 - 69
Bray R.H., and Kurtz, L.T., 1965, Determination of total organic and
available forms of phosphorus in soil. Soil Science, 59: 225-624
Bremner N.M., and Mulranag G.S., 1982, Nitrogen total: in methods of soil
analysis. American Society of Agronomy 9: 595-624
Cooke G.W., 1972,
Fertilizer for maximum yield.
Great Britain: Granada
Publishing Limited. pp. 465
Dirk A.T., and Hargarty M., (eds.) 1984, Soil and Plant Analysis. Guide for
Agricultural Laboratory Directors and Technologists in Tropical
Region, pp. 147
Edje T.O., and Osiru D.S.O., 1988, Methods for determining leaf area in
some crop plants, In: Contributions from the first annual meeting of the
collaborative group in cassava-based cropping systems research.
International Institute of Tropical Agriculture (IITA). Ibadan. Nigeria.
pp. 237-245
FMANR 1996., Federal Ministry of Agricultural and Natural Resources,
Soil fertility investigation (In 5 volumes); Fertility ratings. Produced by
