By Kimberly Flessner
How does the composition of the soil affect its fertility? Students will determine whether the soil’s composition has an effect on how well plants grow.
Materials: Each Group (3 or 4 students)
- 1 2-liter bottle
- 2 supports
- 1 tray
- Some combination of soil, sand, and clay
- 6 bean seeds (or corn)
- grass seeds
- 1 rooted plant such as colius
- masking tape
After a discussion on the differences in soil compositions throughout the state, we would look at how that could affect what types of crops can be grown in the region.
Each group will be given a 2-liter bottle. They are asked to cut a rectangle out of one of the sides of the bottle large enough to plant the seeds/plants in. Holes also need to be poked into the bottom of the bottle for drainage.
Different mixtures of soil will be put into each group’s container.
- 1/2 clay, 1/2 soil
- all soil
- all sand
- 1/3 sand, 1/3 clay, 1/3 soil
- You can make as many different mixtures as there are groups in your class.
Each group then plants three areas of the container with three different seeds/plants. The same amount of water and sunlight is provided for all containers.
Each group should label their container and describe the soil composition? Students will then place the bottle on the supports in a tray to catch the drainage.
Students are asked to individually journal on how the plants and seeds are growing in each of the containers throughout the allotted time frame.
Students could be asked to find out which part of the state has the same soil composition as their set-up. Then do a report on the types of crops raised there, and compare that with their results.
I set this activity up before we discuss it in class, so we have some results to compare to as we look at each soil type.
The supports I use are from another teacher who had some students make them. They are just two boards about four inches by five inches. One with a deep dip and the other with a shallow dip to fit the neck of the 2-liter bottle.
It works best if you can get some plants rooted before this activity so students can see, not only how the soil affects the seeds, but also how it affects an “already established” plant.