1. Soil Resources Chapter 7 http://www.youtube.com/watch?v=3HQwYbwmyaY Bill Nye Rocks and Soils

2. What is Soil? Composed of: mineral matter organic matter Modified by: weather water organisms

3. What is Soil? How Soils are Formed From parent material Formation time varies (200 – 1000 years) Depth varies (thin film to 10 ft)

4. What is Soil? Soil Composition Humus

5. What is Soil? Soil Composition Other components: Pore space (wet soil) Pore space (dry soil)

6. What is Soil? Soil Horizons

7. What is Soil? Nutrient Cycling

8. What is Soil? Nutrient Cycling (alternate slide) Organic matter in soil Decomposition Minerals freed and available to plant Plant roots absorb minerals from soil Elements incorporated into organic matter in plants Elements in organic matter in animals

9. Soil Properties and Major Soil Types Soil Properties Affected by Soil Texture

10. Soil Properties and Major Soil Types Soil Acidity pH scale 0 7 14 Most soils (pH = 4-8) Pygmy Forest Death Valley

11. Soil Problems Soil Erosion Caused by water, wind, and ice

12. Soil Problems Nutrient Mineral Depletion

13. Soil Problems Soil Problems in the United States Cultivated soils in southern Iowa, northern Missouri, western and southern Texas, & eastern Tennessee have greatest erosion 25% of agricultural lands lose more topsoil than formed

14. Soil Problems World Soil Problems Mineral depletion in tropical rainforest soils Degradation in the African Sahel

15. Soil Conservation and Regeneration Conservation Tillage

16. Soil Conservation and Regeneration Contour Plowing, Strip Cropping, and Terracing Strip cropping & contour plowing Terracing

17. Soil Conservation and Regeneration Preserving Soil Fertility Organic fertilizers e.g., manure, compost slow release, but nutrient content varies Commercial inorganic fertilizers e.g., typical bagged fertilizer exact nutrient content known, but prone to leaching

18. Soil Conservation and Regeneration Soil Reclamation increasing productivity on eroded land Shelterbelts

19. Soil Video Clip http://www.brainpop.com/science/earthsyste m/soil/preview.weml