Ch 7-8 Part 2

1. Ch 7-8 Part 2 Lessons 5 and 6

2. Lesson 5 Soil Use, Abuse, and Conservation

3. Think About It… Why is soil important?

4. Focus Question… Why is it important to preserve and conserve our soil?

5. Natural Resources: An Overview… • What are natural resources? • the resources that Earth provides • What are renewable resources? • those resources that are possible to use indefinitely without causing a reduction in the available supply • Examples include fresh air, fresh surface water, most groundwater, fertile soil, elements that cycle through Earth, all living things

6. Natural Resources: An Overview… 3. What is sustainable yield? • The replacement of renewable resources at the same rate at which they are consumed Examples include… farm animals, lumber, crops

7. Natural Resources: An Overview… 4. What is a nonrenewable resource? • those resources that exist in a fixed amount and can only be replaced by processes that take thousands or millions of years. • Examples include fossil fuels, gemstones, and elements such as gold, copper, and silver. http://library.thinkquest.org/17531/fossil.html

8. Old Growth Trees – Nonrenewable! http://johnsilvius.cedarville.org/family/annualrings.jpg

9. Soil, Agriculture, and Environmental Issues… How long can it take to form just a few inches of soil? • 1000 years! Each decade, Earth loses about 7 % of our topsoil. http://indianapublicmedia.org/amomentofscience/disappearing-soil/ This field in England was left bare and is prone to erosion.

10. Desertification… Desertification … is when productive land becomes a desert a. is caused by overgrazing and removing vegetation in dry areas b. is a growing problem in North Africa, the Middle East, the western USA, and Australia c. can be prevented by • grazing cattle wisely and… • planting vegetation to anchor soil and retain water • See next slide

11. Desertification in the Sahel… http://oceanworld.tamu.edu/resources/environment-book/Images/water-hole-cattle.jpg

12. Biodiversity Loss… • Biodiversity can be defined as the number and variety of living things. • Ecosystems with a high biodiversity are more stable than those with fewer species. (like rain forests) http://www.srl.caltech.edu/personnel/krubal/rainforest/Edit560s6/www/animals.html

13. Biodiversity Loss… c. Monoculture can be defined as the planting of just one species in a field. i. Basically, one crop take the place of many species. This decreases biodiversity! ii. It is easier for a farmer to grow crops with a monoculture but can lead to crop failure. http://www.bio.davidson.edu/people/kabernd/seminar/2004/Grp4/monoculture.html

14. Pesticides… Pesticides are used to eliminate organisms that destroy crops. They can cause BIG problems. • They can accumulate in the food chain. • They can kill beneficial insect predators. • They can kill decomposers such as worms. • They can be washed into local waterways and pollute the water.

15. Topsoil Loss: Erosion … • Topsoil can take thousands of years to form so it is hard to replace. • Erosion can occur when grasslands or forests are cleared. • Traditional plowing can make topsoil vulnerable to wind or water erosion. • Things in original soil that can’t be replaced are trace minerals, earthworms, N-fixing bacteria, and humus.

16. Topsoil Loss: Erosion… e. Two practices that help conserve topsoil are… • no-till farming • planting a clover cover every few years http://images.sciencedaily.com/2010/05/100511112013.jpg http://www.extension.org/pages/31597/overview-of-vineyard-floor-management

17. Deforestation… • Deforestation is the removal of trees without adequate replanting. • People use wood for firewood, charcoal, paper, and lumber. • Clear-cutting may result in the loss of soil and clog waterways with sediment. • Two ways to prevent this… • selective logging • buffer zones of trees along streambeds.

18. Deforestation: Selective Logging… The impact of selective logging (taking only some trees from a forest) can be seen in this view of the Tīhoi state forest in 1976. Above the logging road 55% of the timber has been removed, below it only 30% has been removed, while further down is an area of unlogged native forest. Between 1975 and 1984, when selective logging was the only type of harvesting permitted in native forests, the Forest Service carried out trials to see if the damage it caused could be reduced. http://www.teara.govt.nz/en/forestry-research/2/2

19. Urbanization… People moving to urban areas can have many impacts on the land... • Natural habitats are lost as forests are cleared and wetlands are filled. • Construction causes the erosion of topsoil. • Development takes land away from agricultural use. • Large volumes of solid waste are produced.

20. Urbanization… • Why do old landfills created pollution problems? • dangerous chemicals can leak out • Bioremediation is the use of organisms to clean up wastes.

21. Properly Designed Landfill… http://your.kingcounty.gov/dnr/kidsweb/images/landfill_diagram.gif

22. Lesson 6 Mass Movements

23. Think About It… What law basically says that “what goes up must come down!”?

24. Focus Question… How is each mass movement caused and how does each affect Earth’s surface?

25. Mass Movements… • What are mass movements? • The downhill movement of loose sediments or weathered rock due to the force of gravity • Where do all mass movements occur? • On slopes! The Grand Tetons in Wyoming http://www.destination360.com/north-america/us/wyoming/rocky-mountains

26. http://geology.about.com/od/naturalhazardsclimate/ig/Landslides/creepdiagram.htmhttp://geology.about.com/od/naturalhazardsclimate/ig/Landslides/creepdiagram.htm Creep… • Creep is… • The slow, steady, downhill flow of loose, weathered material • Creep occurs… • On slopes • Creep changes the landscape by… • causing everything on the slope to tilt http://www.kidsgeo.com/geology-for-kids/0073-creeps.php

27. Mudflows… • A Mudflow is… • …fast-moving mud and water • A Mudflow occurs… • …in volcanic or semi-arid regions • A Mudflow causes people and objects to… • be swept away Mudflow in California http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/mass_movement_weathering/mass_movement_1.html

28. Landslides… Landslide in La Choncita, Ca • A Landslide is… • …a thin block of loose Earth slides on bedrock • A Landslide occurs on slopes that… • …are steep and saturated with water • A Landslide causes… • $2 billion of damage each year in the USA • http://sccounty01.co.santa-cruz.ca.us/oes/landslide%20and%20mudflow.htm http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/mass_movement_weathering/mass_movement_1.html

29. Slumps… • A Slump is… • A mass of Earth material rotates and slides along a curved surface • A Slump occurs… • On moderate to steep slopes with thick soil • A Slump changes the landscape … • by causing crescent-shaped scars on slopes A Slump in Teddy Roosevelt N.P. http://here4now.typepad.com/here4now/2009/08/theodore-roosevelt-national-park-part-ii-north-unit.html

30. Avalanche… • An Avalanche is… • A landslide in snowy mountainous areas • An Avalanche occurs… • On steep slopes with at least a 35 degree angle • An Avalanche causes… • Deaths by suffocation and structures to be buried Avalanche in Teton Co., Wyoming http://www.tetonwyo.org/AgencyTopic.asp?topicID=201704

31. Rock Falls… • A Rock Fall is… • Falling rocks! • A Rock Fall occurs… • In high elevations, steep road cuts, rocky coasts • A Rock Fall causes… • road blocks and sometimes destruction to property • The one on I40 near Asheville took 3 months to clear up! http://www.knoxnews.com/news/2009/oct/26/engineers-ready-assess-damage-i-40-slide-site/ http://www.wbtv.com/global/story.asp?s=11379555