Mini-dissertation submitted in partial compliance with the requirements of
the Master’s Degree in Technology: Homoeopathy, Durban University of Technology, 2012. / Lettuce is a cool season crop and requires an optimum growing temperature of
18°C. Lettuce is popular in summer as a salad ingredient but supply cannot always
keep up with demand due to high spoilage rates, because of bolting and tip-burn as
a result of heat stress while growing (Maboko &Du Plooy 2007). Heat stress reduces
oxygen availability. This study sought to demonstrate that administration of
homoeopathic Ozonum to hydroponic nutrient solution in a nutrient film technique
design improves the growth ability and quality of lettuce during the summer season
by increasing or improving its ability to absorb oxygen.
The research was conducted at the Agricultural Research Council – Vegetable and
Ornamental Plant Institute (ARC-VOPI) facility at Roodeplaat (near Pretoria), South
Africa. The trial was conducted in a 40% shade net structure in the summer months
of February to April 2012.
Purpose
The general aim was to measure the effect of homoeopathic Ozonum 6CH, Ozonum
15CH and Ozonum 30CH compared to a placebo control (96% alcohol only) on the
growth and yield of leafy lettuce, Lollo Bionda Lobi cultivar grown in a closed
hydroponic system in South African summer climatic conditions.
Objectives:
Determine the increase in growth and yield of leafy lettuce as affected by
Ozonum concentration in terms of: (i) leaf fresh mass; (ii) leaf dry mass; (iii)
number of leaves; (iv) leaf area; (v) chlorophyll content; (vi) root fresh mass;
(vii) root dry mass;
Determine the impact of heat stress in terms of bolting and tip-burn;
Determine the differences in specific plant leaf mineral content between the
experimental groups and control group; and,
Determine the differences between dissolved oxygen (DO) concentrations in
the nutrient solution of the verum group and control group.
Methodology
This was a placebo controlled randomized plant experiment. A total of 384 plants
were laid out in a randomized complete block design with 4 treatments (Ozonum
6CH, Ozonum 15CH Ozonum 30CH and a control) and replicated 4 times. The total
number of plants per plot was 24 and the middle 8 plants were selected as data
plants while other plants were regarded as border plants. Thus, data was gathered
from 96 plants per treatment in total.
Leafy lettuce seeds of cultivar Lollo Bionda Lobi, were sown in polystyrene trays.
The seedlings were transplanted 28 days after sowing into a gravel-film technique
hydroponic system. Ozonum and the placebo was added to the nutrient solution on
the first day and every 6 days thereafter, at the same time as the nutrient solution
was changed. Various daily measurements were recorded. Plants were harvested 27
days after transplanting when final measurements of nutrient content and growth
were made.
Data Analysis
Data was collected over time as repeated measurements; the time factor was
included as a sub-plot factor in the analysis of variance (ANOVA). All data items
collected were subjected to an appropriate analysis of variance using the GenStat
statistical system (VSN International, 2011). The residuals were examined for
deviations from normality and outliers causing skewness were removed. Fisher’s
protected t-LSD (Least Significant Difference) was calculated to compare treatment
means of significant effects (Snedecor & Cochran, 1980).
Results
The results for (i) lettuce yield criteria, (ii) DO concentration, (iii) leaf chlorophyll
content and (iv) specific mineral content of lettuce leaves (Appendix B) indicate that
there was no significant difference between Ozonum treatments and the control.
The incidence of bolting was not observed in lettuce plants among the treatment or
control groups.
Results showed a reduced tendency in tip-burn percentage for treatment Ozonum
30CH although not significantly different to Ozonum 15CH or the control.
Conclusion
The conclusion derived from this study is that homoeopathic Ozonum was not
effective at improving dissolved oxygen levels in the nutrient solution, or in
stimulating growth in lettuce under South African summer climatic conditions
(February to April). Further research is needed to explore the effect Ozonum 30CH
may have on tip-burn.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:dut/oai:localhost:10321/941 |
| Date | 13 November 2013 |
| Creators | De Pontes, Anthony |
| Contributors | Steele, Richard, Maboko, Martin |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 189 p |
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