Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
Greenhouse. We would also like to thank Professor
Steve Teh for his profound knowledge and relentless
dedication in assisting us with this study.
Literature Cited
MacKinney, G. 1941. The absorption of light by
chlorophyll solutions. J. Biol. Chem. 140: 315-322.
Milius, S. 2004. Rewriting the nitrogen story:
plant cycles nutrient forward and
backward. Science News 166.1:5(2).
Reed, H., Martiny, J., 2007. Testing the functional
significance of microbial composition in natural
communities. FEMS Microbiology Ecology 62:161-
170.
Vitousek, P., Walker, L., Whiteaker, L., Matson, P.,
1993. Nutrient limitations to plant growth during
primary succession in Hawaii Volcanoes National
Park. Biogeochemistry 23:197-215.
The Effects of Organic Fertilizer vs. Inorganic Fertilizer (Miracle Gro) on Growth of
Tomato Plants
Cynthia Tran and Camille Barlow
Department of Biological Science
Saddleback College
Mission Viejo, CA 92692
The effects of organic and inorganic (chemical) fertilizers were studied on the growth of
tomato plants within a four week period. One group of eight tomato plants were given an
organic fertilizer and the other eight a chemical (Miracle Gro) fertilizer. Plants grown in a
chemical fertilizer had a higher average chlorophyll concentration than plants grown in
organic fertilizer (P= 0.000518, one tail unpaired T·test) 333.75 ± 9.28mg/L. The
chlorophyll concentration in the leaves between both groups suggested that chemical
fertilizers would yield taller, greener, and thus more tomatoes per plant. The height
differences between the two groups were displayed after the second week of growth with
inorganic fertilized tomato plants taller by an average of 5cm. Organic fertilizers have a
slow release of nitrogen compared to chemical fertilizers that have readily available
nitrogen levels. The results indicated that growth in tomato plants are greatly influenced
by the amount of nitrogen available to the plants in their fertilizer.
Introduction
Fertilizer is nutrients added to soil to make it
more fertile. Miracle Grow (chemical fertilizer) will
produce taller, greener leaves, and heavier mass of
tomatoes than Organic Fertilizer. Miracle Grow
contains exact amounts of all three nutrients of
nitrogen, phosphorus, and potassium. The amount of
nitrogen that is readily available and easy to control
results in greater efficiency of plant growth (Heeb et
al., 2005). Organic Fertilizers consisting of cow,
sheep, poultry, and horse manure contain low levels of
each nutrient. They are dependant on microorganisms
in the soil to break down and release the nutrients.
Organic Fertilizers have a slower release of nitrogen
which if needed immediately would not be able to
provide (Chu et al., 2006). Nitrogen is the main
nutrient required the most in tomato plant. The tomato
plants grown in fertilizer with the most abundant
amount of nitrogen will yield heavier masses of
tomatoes (Wang et al., 2001).
Two groups of sixteen tomato plants (eight
with chemical fertilizer/eight with organic fertilizer)
were placed outside receiving equal amounts of water
and sunlight for growth monitoring. Averages of
chlorophyll concentration, height of growth and
number of blossoms were collected during a four week
period. A hypothesis that the chemical fertilizer will
produce taller and greener tomato plants over the
tomato plants given organic fertilizer.
Material and Methods
64
Saddleback Journal of Biology
Spring 2008