The purpose of this experiment was to determine the effect of soil moisture on the growth of beans. In addition, I determined the effect of earthworms in the soil on bean growth.
I became interested in this idea when my family’s corn did not grow very well in our garden in Colorado almost every year.
The information gained from this experiment can be used to help farmers living in areas of low rainfall, to learn how to keep their plants alive.
HYPOTHESIS My first hypothesis is that the bean plants with the earthworms will grow taller. My second hypothesis is the group with the 100 mL of water will grow higher.
I base my hypotheses on information collected from textbooks, the Internet, and some CD-ROM’s.
Back to top
EXPERIMENT DESIGN The constants in this study were:
- amount of soil in each pot
- size of the earthworms
- how many seeds are planted in each pot
- the type of pot
- size of the pot
- how much water is used in each pot every time
- the amount of light
- the depth the seeds are planted
- the amount of compost
- number of worms
- soil compactness
The manipulated variables are the amount of water and whether earthworms were in the soil added to each pot.
The responding variable was the growth of the bean plants.
To measure the responding variable I held the plant outstretched in the pot and measured the plant in centimeters.
Back to top
||Whole lima beans
|| Tap water
||"Schlutz Plant Food"
|| Bucket that can hold 1,000 mL
|| Measuring cup
Back to top
1. Place 220 g of potting soil in each of the six pots.
2. Label the first three pots as follows: Dry with worms, Wet with worms, and
ì Wettest with worms.
3. Label the others as follows: Dry, Wet, and Wettest.
4. Place four earthworms in the Dry with worms pot, four earthworms in Moist with worms, and four worms in Wet with worms.
5. Then poke three two centimeter, in length, width , and depth, holes in a triangle , in the middle of the container , with either your finger or pencil in all six pots.
6. Drop one lima bean in the holes in the pots.
7. Cover the seeds with the soil dug out from the holes.
8.Pat the soil down with your hand three times.
9.Get a bucket that holds 1,000 mL.( This is what you’ll use when watering the plants.)
10. Pour about1,000 mL into the bucket.
11. Add 7 drops of Schlutz Plant Food.
12. Water the Dry pots with 50 mL .
13. Water the Moist pots with 100 mL
14. Water the Very Wet pots with 150 mL.
After seeds are planted:
15. Water the plants the exact same amount of water, you did the first time you watered the plants, every day.
16. Make notes of how much the controlled plants grew, and how much the plants with the earthworms grew, right after you watered the plants.
17. After at least three sprouts are up, start rotating the pots one quarter turn.
Back to top
RESULTS The original purpose of this experiment was to find out if earthworms added to the soil would make the bean plants grow higher and stronger.
The results of the experiment were that the average height of the plants of the "Moist"(100 mL) groups was greater than any of the other groups. The groups with the least amount of growth were the “Very Wet” groups.
According to the data collected from my experiment, the worms must have helped because the plants in “Dry with worms” (50 mL) grew rather high even though it had a lack of water. The other groups with worms also grew higher even if the pots had too much water or just the right amount of water in the pot.
Back to top
CONCLUSION My hypothesis was that the bean plants would grow higher with more earthworms added to the soil.
The results indicate that this hypothesis should be accepted, because the plants in the pots with worms seemed to grow stronger and better.
Because of the results of this experiment, I wonder if the season, even if they were inside a house, would affect how the plants grew.
If I were to conduct this project again I would have written more detailed notes to give the reader a better picture in his/her mind. I also would have taken more pictures of the root systems after we took them out of the pot. The last difference I would make would be to make sure that the plants all got the equal amount of light.
Back to top
Beans and earthworms are two important living things in the world. Beans give people and animals food, while earthworms help people grow stronger and healthier crops, like corn and tomatoes.
Beans are small and oval-shaped and can be grown almost anywhere. While underground in the soil or dirt, the beans start soaking up water. As they do, the beans get fatter and fatter, until they burst open and a green sprout comes out that will soon become the root that the other smaller, hair-like, roots come out of. As the sprout comes out of the ground, the bean comes out, too. After a few days, the bean opens up, and leaves come out. Then, they just keep growing up and the leaves get larger. Beans are important food sources in the world. They can be used in soups, tacos, and other dishes.
Earthworms are large, segmented worms that burrow down into the ground and belong to the group of hermaphrodites. After the soil that the earthworm eats, passes through the worm’s intestines some of the soil’s nutrients become a lot more available to the plants growing nearby. Also, after the soil passes through the worm’s intestines, the soil becomes more stable because of the nutrients. Both female and male worms may produce young. The sex organs of earthworms are located near the front of the worms in different places. During reproducing, earthworms meet in different directions with their undersides pushed against one another. A tube of mucus that is hidden in the citellum, the large ringlike part you often see on worms, stick the earthworms together. The citellum then attaches itself to the parts containing the spermathecae. After a few days, the citellum makes a hard ring of material, which slips forward and collects eggs and sperm as it moves over the openings. After the ring comes off the worm, the ends seal up. The cocoon may carry 20 eggs, which hatch after about 12 weeks. Although some species of the earthworm like to eat dead plants, dead herbage, dead leaves, or animal dung, other species prefer to feed on fungi and microorganisms.
Water is the most important and most used resource in the world. It is made up of oxygen, phosphorus, and nitrogen. Water is used to refresh humans, animals, and plants. Because of so much use, water is rapidly disappearing. Salt water cannot be used for human drinking water because of it’s harsh and bitter taste.
Soil is the granular matter that pretty much forms the top layer of a lot of land on the planet Earth. Plants everywhere need soil to grow. The soil stabilizes the plants and gives them nutrients. Sometimes, if the soil is too dry, the plants in it cannot grow. If the soil is too wet, the plant’s seeds rot and do not grow at all either.
Air is a combination of gases including nitrogen, oxygen, argon, water vapor, carbon dioxide, neon, helium, krypton, hydrogen, xenon, and ozone. It is used by humans, animals, and plants. Without oxygen, everyone and everything, on Earth would die.
As you can see, beans, earthworms, water, soil, and air are all important in people's, animal's and plant's lives. All of them help feed people, beans provide food, earthworms help grow food, water helps irrigate plants, soil gives the plants nutrients and stabilizes the roots of the plant, and air helps plants complete photosynthesis.
Back to top
Fraser, Trish. “The Earthworm Hole: The Industrious Earthworm.” (Online) Available
http://www.crop.crinz/curresea/soilwormint.html., November 17,1999
“Basic Red Worm Information.” (Online) Available http://www.mcps.k12.md.us/schools/georgianforestes/worminfo.html., November 17, 1999
Olsen, Gayle. “Science/Nature for Kids.” (Online) Available http://kidscience.about.com/kidsteens/kidscience/library/weekly/aao33097.html., November 17, 1999
The Animal World, Chicago: World Book, Inc., 1997. Pp. 16 and 39
The Plant World, Chicago: World Book, Inc., 1997. Pp. 84-87
Back to top
Top of page
Menu of 1999-2000 Science Projects
Back to the Selah Homepage