1.  Soil Components 6 th Grade Science

2. OBJECTIVES  Students will be able to explain how the formation of soil is related to the parent rock type and the environment in which it develops.  Students will understand that good health of humans requires: monitoring the lithosphere, maintaining soil quality, and stewardship.

3. ESSENTIAL QUESTIONS  What is the relationship between rocks, soil, and the environment?  How does soil quality affect humans?  How do humans affect soil quality?

4. Warm-up  Predict in complete sentences: What is soil or “dirt”?  Quietly Review the soil project.

5. What is soil? Including rocks Broken down dead plants animals

6. What is soil?  Soil is a complex mixture of minerals, water, air, organic matter, and countless organisms that are the decaying remains of once-living things. It forms at the surface of land – it is the “skin of the earth.” Soil is capable of supporting plant life and is vital to life on earth. http://www.soils4kids.org/about

7. Soil Horizon  Horizon is a side profile of the layers of soil  Soil is usually divided into 3 main layers, but will also include the layers above and below for a total of 5 layers.

9. Soil Horizons Diagram Dark brown/black Reddish brown (clay) Grayish brown Contains weathered rocks Solid rock

10. O Horizon: Litter  Not really a layer of soil  It’s on top of the first layer of soil  Contains grass, plants, and animals

11. A Horizon: Topsoil  1 st layer of soil  Darkest layer of soil (dark brown or black)  Contains humus, plant roots, small animals, water, and nutrients for plant growth  The darker the soil, the more nutrients it contains

12. B Horizon: Subsoil  2 nd layer of soil  Lighter in color (reddish brown)  Fewer nutrients and water  Limited plant growth

13. C Horizon: Parent Material  3 rd layer of soil  Lightest in color (gray)  No nutrients, animals, or plant growth  Contains weathered rock and sediment

14. R Horizon: Bedrock  Below the last layer of soil  Solid Rock  Has not been weathered or broken down yet  No soil in this layer http://science.unctv.org/content/soil-science- down-and-gritty-dirt http://science.unctv.org/content/soil-science- down-and-gritty-dirt silly soil conservation song

15. What are the characteristics of soil? - Texture-what the soil feels like -Particle Size (see picture) -pH-acidity in the soil -Water retention-how well it holds water -Viability-nutrients in the soil (nitrogen, phosphorus, etc).