1. Soil

2. Soil is…
A combination of weathered rock (sediments), humus (decaying organic matter such as dead plants and animals), air and water

3. In order for soil to form…
Bedrock weathers into sediments

4. And
Organic matter (dead plants and animals) decay to form humus.

5. Sediments and humus mix

6. Quiz your partner
What does soil contain?
How does it form?

7. The Nitrogen Cycle
Healthy soil contains Nitrogen for plants to absorb into their roots.

8. Animals eat plants to get Nitrogen
Nitrogen makes proteins. So when you eat protein you are eating Nitrogen.

9. Protein
Every structure in a living organism is made of protein…your DNA, cells, eyes, everything!
So, organisms need protein and the Nitrogen to live.

10. Quiz your partner Why is Nitrogen important? How do plants get it?
How do animals get it?

11. Nitrogen is now in plants and animals
When the plant or animal dies, this Nitrogen returns to the soil through decomposition.
Manure

12. The air is mostly Nitrogen
Nitrogen in air gets into the soil through Nitrogen Fixing.
Nitrogen Fixing bacteria in roots can change Nitrogen in the air into Nitrogen in the soil.
Lightening can also fix Nitrogen.

13. Quiz your partner
How does get Nitrogen get into the soil (there are four ways)?

14. Nitrogen returns from soil to the air
Bacteria can change the Nitrogen in the soil back into Nitrogen in the air.

15. It is a cycle-draw and put your notes into the cycle

16. Quiz your partner
Describe the entire Nitrogen cycle from the Nitrogen in the air to the soil to the plants, to the animal, back to soil and back to air.