This is my Biology Honor's Project for the Honor's Program. This is a written report on the experiment. This experiment took an entire semester where I conducted and came up with my very own project to test the growth rate effects of fertilizer on nitrogen fixated plants.

1. Jenna Kol
Bio 1A
15th May 2019
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The Effects of Fertilizer on Nitrogen – Fixing Plants
A Growth Enhancement Journey
Abstract
Nitrogen-fixating plants have a symbiotic relationship with bacteria. Plants are capable of
fixing nitrogen due to Rhizobia, a bacterium within root system nodules, that produces nitrogen
compounds. Fertilizer contains specific N-P-K ratios that provide essential macronutrients
needed for plant growth that soil sometimes lack. The objective of this experiment was to test the
growth success and effects of fertilizer on nitrogen - fixing plants; specifically, on Lupines
succulentus and Bean Bush. These species were chosen as test subjects because both contain
nitrogen – fixing properties, as well as to have variability of the test subjects within the
experiment. Over the span of two months, specific growth traits were measured in a control
group, plants grown in an environment without fertilizer, and a treatment group, an environment
with fertilizer. I hypothesized that if nitrogen - fixing plants are capable of successfully growing
on their own without the use of nitrogen, then adding fertilizer will cause the plants to have a
greater success of growth traits. In conclusion, my hypothesis was supported throughout the
course of this experiment. The Lupines were counted as inconclusive due to no percent
germination. Bean seeds within the control group doubled the length in (mm) for stem and
largest leaf length compared to the treatment group. To conclude, although nitrogen - fixing
bacteria causes plants to fix nitrogen in a way to prosper their growth, adding fertilizing can also
increase the chances of a higher growth rate.
Introduction
Nitrogen-fixating plants have a symbiotic relationship with bacteria that allows the plant
to fix nitrogen in a way that it supports their growth. Rhizobia is a bacterium within nodules in
the plant’s root system that produces nitrogen compounds. Nitrogen, phosphorus, and potassium
are three of the most important nutrients needed for plants to successfully grow and prosper.
Nitrogen can help cater to the importance for the growth leaves on plants and other growth traits.
Plants rely on soil for these nutrients. Fertilizers contains a specific N-P-K ratio that helps
increase fertility of soil lacking these macronutrients. The two species tested within this
experiment is the Lupines succulentus and Bean Bush Drag on Heirloom Bean Seeds. Lupines
are popular cultivated plants and planted throughout North America as ornamentals. They are
typically grown near beaches in sand where the roots are able to penetrate through. When grown
in dense soil, it typically takes longer duration of time for the Lupines to grow. These species
were tested because both of these species contain nitrogen – fixing properties. Furthermore, to
test the effects of fertilizer on the growth success as well as have variability of the test subjects.
The Bean Bush Dragon is also a popular cultivated crop so it would be interesting to see if
fertilizer could be used to increase an economic agricultural perspective.
The objective of this experiment is to test the growth success and effects of fertilizer on
nitrogen - fixing plants; specifically, on Lupinus succulentus and Bean Bush Dragon’s Tongue
Organic Heirloom Seeds. Two nitrogen - fixing plants were tested for their growth success with
and without fertilizer. If fertilizer is added to nitrogen - fixing plants, specifically lupine and
bean seeds, then there will be a greater success in the growth traits - heavier in mass, lengthier
stems, more production of leaves, coloration, then the nitrogen - fixing plants that are growing
with just soil and no fertilizer. If nitrogen - fixing plants are capable of successfully growing on

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their own without the use of nitrogen, then by adding fertilizer that contains levels of nitrogen on
nitrogen - fixing plants, will cause the plants to have a greater success of growth traits that are
being measured.
Materials
The two species that were tested are the Bean Bush Dragon Heirloom seeds, and the
Lupines succulentus seeds. Other important materials used: Gold Pure “All Purpose Fertilizer”,
LPC green house, 28 pots, 14 Lupine seeds, 14 bean seeds, soil, DI water, ruler, field notebook,
thermometer, garden gloves, two 150mL beaker, hot plate, 28 stakes, labeling tape.
Methods
First, the seeds must be prepared before planting in soil. Water was boiled on a hot plate
up to 180 F. 14 lupine seeds were placed in beaker of warm water and was left alone until the
next day. 14 bean seeds were placed in room temperature water and was left alone until the next
day. 7 lupine seeds were planted in soil with fertilizer and 7 lupine seeds were planted in soil
without fertilizer. 7 bean seeds were planted in soil with fertilizer and 7 bean seeds were planted
in soil without fertilizer. The control group represented the lupine seeds soil without fertilizer,
and the bean seeds in just soil without fertilizer. The treatment group represented the lupine
seeds grown in soil with fertilizer, and the bean seeds grown in soil with fertilizer. The effects of
fertilizer on nitrogen-fixing plants were measured through growth traits. The growth traits
measured were: length of stem (mm), length of longest leaf (mm), amount of leaves produced
after germination. All in all, there was a total of 28 plants that were observed and recorded every
once a week by its growth traits.
Data

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Graph 1.1: shows that the beans with fertilizer had a higher increase in stem height over time by
almost double the amount than beans planted without fertilizer

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Graph 1.2: displays the bean seeds grown with fertilizer increased at a faster rate than the beans
without the fertilizer. The growth rate is exponential in both groups, however double the amount
within the beans grown with fertilizer in their soil.
Results:
The first signs of germination were on March 11th. In the fertilizer treatment 4 seeds
germinated compared to 3 seeds in the control. Only one lupine seed grew in the control group,
therefore the lupine data was not considered and was counted as inconclusive for the lupine
seeds. According to the graph 1.1, the average stem height of beans, the stem height of the beans
with a fertilizer had a greater increase over time than the beans without the fertilizers. The stem
height over time increased almost as double as much than that of the beans without fertilizers.
Within graph 1.2, the average length of leaf for beans with fertilizer vs without fertilizer, the
beans with fertilizer doubled in leaf length compared to the leaf of the beans grown without
fertilizer. The average amount of leaves produced from beans with fertilizer vs without fertilizer,
was not considered since during half of the experiment, the leaves became flaccid and dead due
to the pesticide added to get rid of the gnats. On April 16th a second trial was produced with
same methods used and species, but the plants did not germinate in time, thus the data was
inconclusive for the second set.
Discussion
Others have shown that symbiotic bacteria play a vital role in the growth productivity in a
community as well as its structure (Marcel et al. 2006). Two nitrogen - fixing plants were tested
for their growth success with and without fertilizer. Fertilizer contains specific N-P-K ratios that
provide essential macronutrients needed for plant growth that soil sometimes lack. The growth
traits being measured were the length and number of leaves produced, and the height of the stem.
From the results you can conclude that there were more bean seeds that germinated in fertilizer
than those who haven’t. All four bean seeds grown in fertilizer had a larger length in stem and
length of largest leaf than those produced in the non-fertilized soil. Since there was greater
success in the growth traits being measured, you can conclude that my hypothesis was somewhat
supported through this experiment. Although nitrogen - fixing bacteria causes plants to fix
nitrogen in a way to prosper their growth, adding fertilizing can also increase the chances of a
higher growth rate. Although the overall experiment successfully supported my hypothesis, there
were many problems that occurred throughout the experiment. Within the fifth week, specifically
the week of April 2nd, numerous amounts of gnats had invaded the plants, and latched onto the
leaves of the plants. Afraid of stunting the plants growth, a pesticide was spread over all the
plants to get rid of the gnats. By the following week, less gnats occurred, however, the plants
became flaccid and the leaves hung lose. The rest of the plants did not germinate so a new set of
Lupines and bean seeds were planted. Only two germinated before the project could be do so the
second set of plants were inconclusive. There was a high risk of planting Lupine seeds, since
they take a longer duration of time to germinate and because there is a set time to this project.
Unfortunately, one Lupine seed germinated, so the results for that species counted as
inconclusive. If this experiment is to be tested again, consider a longer duration of time to
measure the plants as well as a greater amount of variability amongst the plants, since many of
them were unable to germinate from the start. The data can be questionable since the sample is

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so small. To change this and have the data more reliable, definitely consider a larger sample. In
conclusion, the experiment did support my hypothesis. Growth traits were considerably more
successful in the Bean Seeds with the fertilizer than the two species of plants without the
fertilizer.
Since the sample size was low, an experiment similar to mine was compared to support
my overall results. The Role of Indigenous Nitrogen – Fixing Bacteria in Promoting Plant
Growth on Post Tin Mining Soil, was conducted to test the effects of fertilizer and nutrient
compounds in nitrogen – fixing plants, without their nitrogen – fixing properties. Post Mining
soil has poor nutrient content in soil, and low PH. The environment is unfavorable to plant
growth specifically Sporghum bicolor. In order to conduct this particular experiment, nitrogen –
fixing bacteria was removed from the plant. A greenhouse experiment was conducted which
added different NPK ratios of fertilizer and the plant was grown in eight different soil types. The
results concluded that Azospirillum lipoferum isolated from nutrient carbon exhibited the greatest
growth rate. All in all, this overall experiment just supported the idea that was prioritized within
my experiment is that nutrient compounds, fertilizer and soil type, effect the overall success
growth of the plant. Bacterial communities/rhizospheres rely on soil type, depth, plant type,
number of plants that grow, available nutrients, pH, pesticides, pollution, and soil texture
(Widawati 2018).
Conclusion
My hypothesis was supported throughout the course of this experiment. The Lupines
were counted as inconclusive due to no percent germination. Bean seeds within the control group
doubled the length in (mm) for stem and largest leaf length compared to the treatment group.
Although nitrogen - fixing bacteria causes plants to fix nitrogen in a way to prosper their growth,
adding fertilizing can also increase the chances of a higher growth rate.
Appendix
Figure 1: Experimental Set-Up: first group of Lupines and Bean seeds

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Figure 2: The only set of plants germinated from the first trial
Figure 3: Plants were sprayed with pesticides for removal of gnats by the 5th week
Figure 4: Flaccid leaf, discoloration
Figure 5: Flaccid leaf, discoloration between two plants

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Figure 6: Plants still had gnats despite the use of pesticide spray
Figure 7: Weekly progress (March 20th)

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Figure 8: Bean and lupine seeds that germinated and were observed and recorded for its
growth traits
Work – Cited
Brusamarello-Santos, Liziane Cristina, Gilard, Françoise, Brulé Lenaïg, Quilleré Isabelle,
Gourion Benjamin, Ratet Pascal, Maltempi de Souza, Emanuel Lea, Peter J., Hirel, Bertrand.
2017. Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen
fixing plant-interacting bacteria Herbaspirillum Seropedicae and Azospirillum Brasilense. PLOS
ONE. 12(3): 1-19.
Emer N, Semenov A, Zelenev A, Zinyakova N, Kostina N, Golichenkov M. 2014. Daily
Dynamics of the number and activity of nitrogen-fixing bacteria in fallow and intensely
cultivated soils. Soil Biology. 47(8): 801-808.
Marcel G.A., Van Der Heijden, Roy Bakker, Joost Verwaal, Tanja R. Scheublin, Matthy Rutten,
Richard Van Logtestijn, Christian Staehelin. 2006. Symbiotic bacteria as a determinant of plant
community structure and plant productivity in dune grassland. FEMS Microbiology Ecology.
56(2): 178-187.

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Widawati S, Suliasih. 2018. Role of Indigenous Nitrogen – fixing Bacteria in Promoting Plant
Growth on Post Tin Mining Soil. Makara Journal of Science. 23(1): 28-38.