Biology IA Proposal
Topic
Nitrogen is a crucial nutrient in the growth of plants – and although approximately 74%
of Earth’s atmosphere consists of nitrogen, this form of nitrogen cannot be used by
plants (Hill, Drozd and Postgate, 1972, pp. 541-558). Plants access nitrogen either from
soil deposits or through a symbiotic relationship with nitrogen-fixing bacteria (Hill,
Drozd and Postgate, 1972, pp. 541-558). From this research, a further research question
can be generated.
Research question
What is the effect of growing Trifolium (clover) in soil with added nitrogen-fixing
bacteria Rhizobia and soil with the bacteria Fankia, in a nitrogen rich fertilizer, with a
nitrogen low fertilizer and in pure soil as measured by the biomass (in grams) after 30
days of growth?
This research question will investigate the most effective method of increasing nitrogen
yield in plants – either by increasing levels of nitrogen in the soil (by using a rich
fertilizer or no fertilizer) or by inoculation of nitrogen-fixing bacteria (either Rhizobia
or Frankia). This is a crucial topic of investigation in today’s day and age where
population and food demands are continuously increasing (Pimental, Huang, Cordova
and Pimental, 1997, pp. 9-14). In order to continue producing enough crop yield to feed
the exponentially increasing world population a more effective, cost efficient and
environmentally friendly method of increasing plant growth rates must be implemented
(Pimental, Huang, Cordova and Pimental, 1997, pp. 9-14).
Hypothesis
H0: There will be no statistically significant difference in the biomass of seedlings grown
with fertilizer or nitrogen fixing bacterium and any difference will be due to chance.
H1: There will be a statistically significant difference in the biomass of seedlings grown
with fertilizer or nitrogen fixing bacterium.
Variables
Independent variable The soil the seedlings were sown in –
either pure, with added Rhizobia,
Frankia, a nitrogen rich fertilizer or a
nitrogen low fertilizer.
Dependent variable The biomass (in grams) of the seedlings
after 60 days of growth.