To know a plant, grow a plant!
Activity Title: Soil Carbon Cycling.
Standards: Wisconsin’s Model Academic Standards
B.12.1, B.12.2, B.12.3, E.12.1, E.12.2, E.12.4, E.9-12.1
A.8.1, A.8.2, A.8.3, A.8.4, B.8.6, C.8.1, C.8.2, C.8.3, C.8.4, C.8.6, E.8.1, E.8.3, F.8.9, H.8.1, H.8.2, H.8.3
Overview of Activity: students will investigate the role of soil in carbon sequestration and atmospheric carbon dioxide levels. With an initial investigation of the basic nature of soil, they will proceed to explore the process of converting carbon from an inorganic to an organic form and back. They will then conclude with observations and sampling of carbon dioxide emissions from soil under variable conditions. In the process they will consider the role of soil in carbon cycling, the value of ecosystem processes like decomposition, and the impact of human activity particularly in agriculture.
Levels: Middle school to early high school
Subjects: Earth Science, Agriculture, Environmental Studies
Total Time Frame: 5-7 days (each being a 50 minute time period)
Learning Outcomes: Students will…
- discover how much soil there is for us to use on our planet.
- investigate what can be found in a soil core.
- diagram the path of a carbon atom from the air to the soil and back again.
- evaluate the amount of carbon leaving the soil back into the atmosphere.
- evaluate their knowledge of the carbon cycle through various assessments.
- Identify and explain the biological and chemical processes that affect the conversion of organic carbon in the soil into atmospheric carbon dioxide
- Describe the role that plants play in the carbon cycle
- Develop hypotheses for how carbon could be more effectively sequestered in the soil and defend or reject their hypotheses based on collected evidence
Assumption of Prior Knowledge: prior to the start of this unit, it will be assumed that students will...
- Be aware of climate change
- Know that soil is both partly alive (organic) and not alive (inorganic)
- Know that plants take in carbon dioxide as a part of photosynthesis
- Be able to identify roles that soils serve for human needs, particularly in agriculture
• Hand out Pretest (found elsewhere with this plan).
• Do “Earth as an Apple” demonstration to demonstrate the importance of our soil.
2 websites found: www.alabamaaitc.org/fall00/earth.html (you do the work).
www.farmland.org/images/flash/apple.swf (power point presentation).
• End lesson with students writing on an exit card their level of understanding of the presentation (1=Not a clue; 2=I think I got it; 3=I got it!) Also, they should write on the card what they would like to know about carbon-soil sequestration.
• Students will study a core sample of soil. They will make a list of the items found in the sample: i.e. rocks, roots, bugs, etc.
• The students will write a report on their findings in the soil.
• The students will again do their exit cards.
• The students will hand in their reports.
• The students will do the “Hallway Carbon Cycle” Activity.
I have 15 students this year. As a result, I will have 8 carbon, and 7 oxygen cards. One end of the hall will be the atmosphere, the middle of the hall will be the leaf, and the other end of the hall will be the root system. In the air I will have a carbon and an oxygen card (atom) paired together. At the leaf they will separate, oxygen going back into the air, carbon down to the roots. I would also have the carbon leaving the root system when it gets disturbed (as in plowing the field) and joining back up with an oxygen atom in the atmosphere. We would go through several cycles of this.
• As a review, the students would draw the path of a carbon atom as it travels from air to leaf to root and back again.
• The students would also do the exit cards.
• The students will hand in their drawings.
• The students will begin measuring the amount of carbon being released by the soil by using the CO2 meters. They will need:
• A five gallon bucket, cut in half.
• A hole cut near the top the diameter of the meter.
• An instrument to read the meter.
The students will place the bucket on the ground and let the meter sit over night.
The next day, the students will read the meter to see how much carbon was given off by the soil.
If there is time, the students could take more readings on different soil types, coverings (bark, mulch, or some such item placed over the soil), and if the soil has just been tilled, or if it is packed down. This would require more than the two days listed above.
• Back in the classroom, the students will discuss their findings. We will talk about global warming and the role carbon plays in it. We will use our findings to see if we can control at least a little bit the amount of carbon going into the atmosphere with our farming methods. We will also talk about no-till practices on fields and deep-till practices and see if we can come up with what is the best way to keep carbon in the ground.
• The students will use their exit cards one last time before the test tomorrow and review for the test tomorrow.
• The students will take the post-test, which is the same as the pretest.
Apple (Earth as an Apple Demo)
Soil Core Sample
Cards with the letters “C”(arbon), “H”(ydrogen), and “O”(xygen)
(amount of cards determined by number of students)
5-gallon buckets (cut in half) with a hole the diameter of the meter used to read the
amount of carbon being released from the soil