Text Book Page # 186 - 197

1. Text Book Page # 186 - 197

2. Soil Formation Soil – The loose, weathered material on Earth’s surface in which plants can grow. How is soil formed? Soil is formed as rock is broken down by weathering and mixes with other materials on the surface. Bedrock – The solid layer of rock beneath the soil. It gradually weathers into soil whenever it is exposed.

3. Soil Composition and Texture Soil is a mixture of rock particles, minerals, decayed organic material, air, and water. • Humus – Dark colored the decayed organic material in soil; helps create spaces in soil for air and water; rich in elements that plants need • Loam – soil made up of about equal parts of clay, sand, and silt; ideal for most plants

4. Soil Particle Size

6. Soil Horizons Soil horizon – layer of soil that differs in color and texture from layers above or below it. Topsoil – Mixture of humus, clay and other minerals that forms the crumbly, topmost layer of soil; the A horizon Subsoil – The layers of soil beneath the topsoil that contains mostly clay and other minerals; the B horizon

7. Soil 1. Soil is a combination of _____________ and _________________. 2. ____________ = decayed plant and animal material found in soil. Soil that contains 20-30% humus is considered a rich soil for plant growth. Weathered rock Organic matter Humus 3. Soil development

8. 4. Soil layers- The soil profile Topsoil A Horizon ___________ or ___________ = the top layer of soil that contains more humus than the layers below. Sub soil B Horizon ___________ or ___________ = consists of clays and dissolved minerals that have been washed down from above. Contains less humus. C Horizon ___________ = consists of weathered rock fragments, usually from the parent rock below. Bedrock ___________ = the layer of rock beneath the soil. Frequently the parent rock of the soil above.

9. Georgia’s soil is Southern Forest soil – form in wet and warm climate; low in humus.

10. Living Organisms in soil

12. Forming Humus Litter – The loose layer of dead plant leaves and stems on the surface of soil. Decomposers – Soil organisms that breaks down the remains of dead plants and organisms and digest them.

13. Importance of Living organisms in Soil • Some soil organisms, like earthworms, mix the soil and make spaces in it for air and water. • Other soil organisms make humus, which makes soil fertile.

15. Soil Conservation • Soil is one of Earth’s most valuable resources because everything that lives on the land depends directly or indirectly on soil. • Fertile soil is valuable because there is a limited supply. • Less than 1/8th of the land on Earth has soils well suited for farming.

16. Soil Damage and Loss • Soil can become exhausted, or lose its fertility. • Soil can also become lost to erosion by water and wind. • Water erosion can occur wherever soil is not protected by plant cover. • Wind erosion caused the Great Dust Bowl!! Sod – The thick mass of tough roots at the surface of soil keep the soil in place and hold onto moisture.

17. The Dust Bowl – Loss of Topsoil • In the 1930s plowing removed the grass form the Great Plains and exposed the soil. In times of drought, the topsoil quickly dried out, turned to dust, and blew away. • This event helped people appreciate the value of soil. • Check It Out!!

18. Soil Lost To The Seas!!

19. How to help in Soil Conservation? • Soil Conservation is the management of soil to prevent its destruction. • Three ways that soil can be conserved include contour plowing, conservation plowing, and crop rotation.

20. Contour Plowing • Contour plowing is the practice of plowing fields along the contours of a slope. • This helps slow the runoff of excess rainfall and prevents it from washing the soil away.

21. Conservation Plowing • Conservation Plowing disturbs the soil and its plant cover as little as possible. • Dead weeds and stalks of the previous year’s crop are left in the ground to help return soil nutrients.

22. Farmers plants different crops each year Different type of crops absorb different types of nutrients from soil

23. Why Soil Conservation is important? http://education-portal.com/academy/lesson/soil-conservation-fighting-soil-erosion-with-sustainable-soil-use.html#lesson

24. REGENTS REVIEW • In which type of climate does chemical weathering usually occur most rapidly? • 1. hot and dry • 2. hot and wet • 3. cold and dry • 4. cold and wet 2

25. 4 2.Which change in the climate of a location would most likely cause the greatest increase in chemical weathering of local bedrock? 1.lower temperature in winter 2.lower humidity in winter 3.higher atmospheric pressure in summer 4.greater precipitation in summer

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28. 5. Landscapes will undergo the most chemical weathering if the climate is 1.cool and dry 2.cool and wet 3.warm and dry 4.warm and wet 4

29. 6. Which activity demonstrates chemical weathering? 1.freezing of water in the cracks of a sandstone sidewalk 2.abrasion of a streambed by tumbling rocks 3.grinding of talc into a powder 4.dissolving of limestone by acid rain 4

30. 7. Which process is best illustrated by the diagram? • cementation • erosion • metamorphism • weathering 4

31. 8. As a result of the changes in temperature and amount of carbon dioxide, what probably happened to Earth's overall rate of chemical weathering during this time? 1.The rate of chemical weathering decreased. 2. The rate of chemical weathering increases. 3. The rate of chemical weathering remained the same 2

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33. Why Soil Conservation is important? http://education-portal.com/academy/lesson/soil-conservation-fighting-soil-erosion-with-sustainable-soil-use.html#lesson