Fertilizer Survivorship/Growth Effects on Earthworms

Jonathan PizzuttiCentral Catholic High School

Grade 11

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ProblemInorganic fertilizers contain substances that can

potentially harm the ecosystem.Fertilizers may be harming earthworms that naturally

enrich soil.

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Inorganic FertilizerSubstance that increases the ability of soil to support

and maintain plant growth using chemical materials.Faster than organic fertilizer.The cost to produce these inorganic

fertilizers takes up almost 2% of the

world’s energy production.The fertilizer used in this experiment

is Scotts® Turf Builder®.

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Scotts® Turf Builder® IngredientsUreaManganese OxideAmmonium Phosphate, MonobasicPotassium SulfateFerrous SulfateAmmonium SulfateManganese Sulfate AnyhydrousNuisance Dust

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EarthwormsTerrestrial annelid worms that belong to the

Oligochaeta class.Mainly live in soil, but some species live in decaying

plant matter, manure, decaying logs, acidic humus, and the mud in streams.

Eat their way through

earth or organic material

when burrowing.

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Earthworm FertilizationEarthworms pull in organic substances and turn

them into humus that is nutrient and mineral rich.Constantly burrow through soil causing it to mix and

aerate allowing excess water to drain and air to enter and leave.

Have been shown to dramatically increase phosphate, nitrogen, and potash in soil.

Is less expensive than inorganic fertilization.Many farmers and gardeners buy earthworms for

this fertilization.If earthworms process fertilizer enriched soil,

will this exposure compromise their health?6

PurposeTo determine whether or not inorganic fertilizers

have an effect on the survivorship or growth of earthworms.

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HypothesesNull Hypothesis

The inorganic fertilizer will have no significant effect on the survivorship or growth of the earthworms.

Alternate Hypothesis

The inorganic fertilizer will significantly decrease the survivorship of the earthworms.

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Materials

-a measuring cup that measures in mL-a liter of water-a graduated cylinder that measures in mL-latex gloves-a permanent marker

-42 earthworms-a bag of Scotts® Turf Builder®

-a medium bag of regular soil-42 large plastic cups-a scale that measures in grams

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Procedure1) Seven different combinations of soil and fertilizer were made in the amount of 200 grams in seven different plastic cups.2) The mixtures were thoroughly mixed into their designated cups by shaking and by hand.3) Five replicates of each of the cups were made.4) Each worm was individually weighed with the scale.5) The weights of the worms were recorded.6) The worms were added to their designated plastic cups.

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Procedure (continued)7) The worms were covered with a layer of the mixture.8) 10 mL of water was added to each of the cups.9) The worms were left to sit for 24 hours.10) Worms were checked to be living or dead.11) Any dead worms were disposed.12) Each worm was lightly shaken and rubbed to clean off any excess dirt.13) Steps 4-12 were repeated three more times.14) Steps 4-5 were repeated.

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Concentrations

Concen-tration

0%(Control)

0.001% 0.01% 0.1% 1% 10% 20%

Amountof Soil

200 g 199.998g 199.98 g 199.8 g 198 g 180 g 160 g

Amount ofFertilizer

0 g 0.002 g 0.02 g 0.2 g 2 g 20 g 40 g

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ResultsThe earthworms in the mixtures with 1%, 10%, and

20% concentrations of fertilizer all died within the first day.

The earthworms in the control, 0.1%, 0.01%, and 0.001% mixtures survived the entire four day experiment.

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The Effects of Inorganic Fertilizer on Earthworm Growth

Day 0 Day 1 Day 2 Day 3 Day 40%

10%

20%

30%

40%

50%

60%

Control0.100%0.010%0.001%

Per

cent

Gro

wth

of

Wor

ms

X

Y

Day of the Experiment

P-Value0.125048

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HypothesesNull Hypothesis

The inorganic fertilizer will have no significant effect on the survivorship or growth of the earthworms.

-Accepted for the 0.001%, 0.01%, and 0.1% groups.

-Rejected for the 1%, 10%, and 20% groups.

Alternate Hypothesis

The inorganic fertilizer will significantly decrease the survivorship of the earthworms.

-Rejected for the 0.001%, 0.01%, and 0.1% groups.

-Accepted for the 1%, 10%, and 20% groups.15

Limitations:-Amount of time to conduct the experiment.-Amount of worms available to test.-The worms were not necessarily in prime condition.-Some equipment used was not professional.-The environment was not ideal for the earthworms.

Extensions:-Do more trials at smaller concentrations of fertilizer.-Perform behavioral tests on the worms.-Use different brands of fertilizers.-Use individual ingredients of fertilizer.-Use different types of worms and other organisms.

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SourcesBailey, Kenneth. "Fertilizer Homepage." North Carolina Cooperative Extension: Home. 26 Feb. 2002. Web. 28 Jan. 2012. <http://www.ces.ncsu.edu/cumberland/fertpage/inorganic.html>."Biology of Earthworms." Earthworms Info. 19 Aug. 2011. Web. 26 Jan. 2012. <http://earthwormsinfo.com/category/biology-of-earthworms>.Conrad, Jim. "Earthworms." Backyard Nature with Jim Conrad. Web. 10 Dec. 2011. <http://www.backyardnature.net/earthwrm.htm>."Inorganic Fertilizers." Indoor Gardening Guide. Web. 10 Dec. 2011. <http://www.indoor-gardening-guide.com/articles/plant- care/Inorganic-fertilizers.html>.Frankel, Zorba S. "Boosting Earthworm Populations and Fertilizing With Worm Castings." Worm Digest. 11 Sept. 2005. Web. 28 Jan. 2012. <http://www.wormdigest.org/content/view/54/2/>.

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