1. How Much Soil is There? 75% of earth is covered by water Only 10% of the earth’s land surface is land able to grow crops (=ARABLE LAND) – Why? Desert, polar, mountain areas Limited terrain, fertility, soil quality, amount of water.

3. Soil Formation Physical Weathering – Glaciers, wind, running water break down material into soil over thousands of years. Chemical Weathering – Oxidation, acidification Biological Actions – Decomposers (bacteria, fungi, lichens) break organic matter into minerals

4. Plants need certain minerals… Especially: – Nitrogen – Phosphorus – Potassium These minerals help plants: – Photosynthesize – Make proteins to become strong – Produce seeds, flowers, fruit – Use water efficiently – BUT TOO MUCH OF ANY CAN BE TOXIC!

5. Agriculture is the key development that led to the rise of human civilization.

6. In the beginning… Humans were nomadic. – Hunters and gatherers – What challenges does this lifestyle pose?

9. Agriculture allowed permanent settlements. Started around 7000 B.C. (Fertile Crescent) 5000 B.C. Intense cultivation, irrigation, domestication of animals. Middle Ages: more advanced irrigation; crop rotation. 1492: global exchange of plants and animals 1800s: new tools; ammonium nitrate allows increased crop yields.

11. Green Revolution Mid 1900s Introduced modern farming methods – Scientifically produced seeds, fertilizers and pesticides These technologies increase crop yield but…add to pollution and disrupts ecological balance

12. Farming Then & Now: PLOWING THEN: Mostly done by hand. NOW: Use machines that require minimal human effort.

13. Farming Then & Now: IRRIGATION Then: Farms were by bodies of water and farmers built a contraption to pump water to the surface. Now: Farmers use irrigation by drip system or sprinkler – Not efficient uses of water!

14. Early Irrigation Methods

16. Farming Then & Now: FERTILIZER Then: Burned weeds was added to the soil. Now: Chemical fertilizers were developed; refined waste is used.

17. Farming Then & Now: PEST CONTROL Now: We spray insects with a chemical so it kills the insects but does not harm the plant.

19. Agriculture has a greater harmful effect on air, soil, water and biodiversity resources than any other human activity.

20. 1950 to 1990 – Use of fossil fuels increased 4X – Irrigated areas 2X – Use of chemical fertilizers 10X – Use of pesticides 30X

21. Large use of fossil fuels to power machinery, pump water, manufacture pesticides. – Uses 8% of world’s oil output. An average of about 10 units of nonrenewable, fossil fuel based energy are needed to put 1 unit of food energy on the table.

22. Farming’s Future? Sustainable Agriculture- farming that conserves natural resources and helps keep the land healthy indefinitely. – Reduced water use for irrigation – Organic fertilizers (compost, manure) > chemical fertilizers – Biological/physical methods for pest control > chemical pesticides.

23. Current Issues Land use policies Pesticide use Food safety Animal welfare Genetically modified organisms (GMOs) Bovine growth hormone (BGH)

24. How Much Soil is There? 75% of earth is covered by water Only 10% of the earth’s land surface is land able to grow crops (=ARABLE LAND) – Why? – Desert, polar, mountain areas – Limited terrain, fertility, soil quality, amount of water.

25. Plants need certain minerals… Especially: – Nitrogen – Phosphorus – Potassium These minerals help plants: – Photosynthesize – Make proteins to become strong – Produce seeds, flowers, fruit – Use water efficiently – BUT TOO MUCH OF ANY CAN BE TOXIC!

26. What is Organic Farming? Food grown without the use of synthetic fertilizers, chemical pesticides, and antibiotics. – Cannot be genetically engineered

27. Farming Methods: Preparing the Land No-till cultivation – Machine drills holes in topsoil for seed planting without disturbing the soil overall. Helps to prevent erosion.

28. Farming Methods: Planting Contour farming: plow and plant across the slope > up and down – Prevents erosion from irrigation Strip cropping: wide rows of a crop are alternated with grass. – Prevent wind erosion; helps control pests, reduce mineral depletion. Terracing: build ridges down a hillside like stairs. – Retains water from running downhill

34. While the average dairy cow produced almost 5,300 pounds of milk a year in 1950, today, a typical cow produces more than 18,000 pounds.

35. Bovine Growth Hormone (BGH) About 2/3 of cattle are injected with hormones – To grow faster – To produce more milk Milk have higher incidence of infections and then need more antibiotics!

36. What’s the problem with a antibiotics? Bacteria can become resistant. Antibiotics are given to animals because… http://www.youtube.com/watch?v=enwU5jIX SlU http://www.youtube.com/watch?v=enwU5jIX SlU