1. Food, Soil, and Pest Management Chapter 10

2. How Is Food Produced and How Might Food Production Change?  Producing enough food to feed the rapidly growing human population will require growing food in a mix of monocultures and polycultures and decreasing the enormous environmental impact of industrialized agriculture.

3. Physical Tests  Moisture  Texture (sand, silt, or clay)

4. Chemical Tests  N, P, & K (elements)  pH  Organic makeup

5. Where We Get Food  Major sources croplands, rangelands, and fisheries  Since 1960 tremendous increase in food supply Better farm machinery High-tech fishing fleets Irrigation Pesticides

6. Few Species Feed the World  Food specialization in small number of crops makes us vulnerable  2/3 of world live mostly on grains  Rising incomes – more meat  Fish and shellfish important food source in Asia and coasts of developing countries

7. Industrialized Agriculture  High-input agriculture – monocultures  Plantation agriculture primarily in tropics Cash crops Greenhouses  Livestock production – feedlots

8. Case Study: Industrialized Food Production in the U.S.  Industrialized farming agribusiness  Income spent on food – 2% by U.S. consumers vs. 70% by world’s poor  Subsidized through taxes  High health costs from harmful environmental effects  Possible through cheap energy – 17% of commercial energy  Net energy loss

9. Commercial Energy Use by Agriculture

10. Traditional Agriculture  Traditional subsistence agriculture Slash-and-burn agriculture  Traditional intensive agriculture  Monocultures  Polycultures

11. How Serious Are Soil Erosion and Degradation and How Can They Be Reduced?  We can reduce soil erosion and degradation by using proven agricultural techniques and restoring depleted soil nutrients.

12. Loss of Topsoil  15–20 cm of topsoil prevents mass starvation  Centuries to replenish 2.5 cm of topsoil  Soil erosion Erosion faster than formation – soil a nonrenewable resource Soil fertility declines Water pollution occurs Natural and due to human activity

13. Types of Erosion http://www.montereyinstitute.org /courses/AP%20Environmental %20Science/course%20files/mu ltimedia/lesson54/lessonp.html? showTopic=1

14. Severe Gully Erosion in Bolivia Fig. 10-5, p. 205

15. Global Soil Erosion Fig. 10-6, p. 205

16. Approaches to Reducing Soil Erosion  Planting crops without disturbing soil  Soil conservation programs  Subsidies for taking erodible land out of production

17. Global Desertification Fig. 10-7, p. 206

18. Desertification and Human Factors  Desertification: degradation of land in any dryland. It is caused by a variety of factors, such as climate change and human activities. Desertification is a significant global ecological and environmental problem.  Cannot prevent natural causes of drought but can limit human impact  Restore land

19. Causes and Consequences of Desertification Fig. 10-8, p. 206

20. Effects of Irrigation  Leaves behind salts in topsoil  Salinization  Remedies expensive and complex  Waterlogging Attempts to leach salts deeper but raises water table Growing worse

21. Salinization and Waterlogging

22. Fig. 10-9, p. 207 Less permeable clay layer Salinization 1. Irrigation water contains small amounts of dissolved salts. 2. Evaporation and transpiration leave salts behind. 3. Salt builds up in soil. Waterlogging 1. Precipitation and irrigation water percolate downward. 2. Water table rises. Transpiration Evaporation Waterlogging

23. Severe Salinization Fig. 10-10, p. 207

24. Solutions: Soil Salinization Fig. 10-11, p. 208

25. Soil Conservation*  Keep soil covered with vegetation  Conservation-tillage farming  Terracing  Contour farming  Strip cropping  Alley cropping (agroforestry)  Windbreaks  Think long-term

26. Soil Conservation Methods

27. Fig. 10-12, p. 209 (c) Alley cropping (a) Terracing (b) Contour planting and strip cropping (d) Windbreaks

28. Restoring Soil Fertility  Organic fertilizers (compost)  Crop rotation uses legumes to restore nutrients  Inorganic fertilizers (Miracle Gro) – pollution problems “elemental” – NPK value

29. Green Revolution  Three-step green revolution Selectively bred monocultures High yields through high inputs – fertilizer, pesticides, and water Multiple cropping  Second green revolution – fast-growing dwarf varieties of wheat and rice  Past 50 years – world grain production tripled

30. World Production of Grain Fig. 10-13, p. 211

31. Limits to Expanding Green Revolutions  High-inputs too expensive for subsistence farmers  Multicropping has limits  Water not available for increasing population  Irrigated land per capita dropping  Significant expansion of cropland unlikely for economic and ecological reasons

32. Possible solutions  Urban Agriculture Urban gardens (e.g. China) Raising animals in urban areas  Waste less food 70% lost through spoilage, inefficient production, and plate waste  Crop residue as livestock food or biofuels

33. Agriculture’s Environmental Impact  Environmental degradation  Loss of agrobiodiversity  Human-engineered monocultures

34. Major Harmful Environmental Effects of Food Production Fig. 10-14, p. 212

35. Production of New Crop Varieties  Traditional Crossbreeding Artificial selection Slow process  Gene revolution Genetic engineering  >66% of supermarket food genetically engineered

36. Controversies over Genetically Engineered Foods (GMF)  Concerns Potential long-term effects on humans Ecological effects Genes cross with wild plants Patents on GMF varieties  In U.S., industry and USDA oppose labeling

37. Trade-offs: Genetically Modified Foods Fig. 10-15, p. 213

38. Are There Limits to Providing More Meat and Seafood?  Rangeland overgrazing and the harmful environmental impacts of industrial livestock production may limit meat production.  We can harvest fish more sustainably to prevent overfishing and use improved types of aquaculture.

39. Meat Production  Past 50 years meat production up five-fold  Half of meat from grazing livestock, other half from feedlots  Environmental impacts One of biggest water consumers and waste producers 33% more energy to produce meat vs. potato 16% of global methane emissions

40. Sustainable Meat Production  Raising cattle on rangelands and pastures eliminates needs for: Grain Growing soybeans or corn Shipping of grain  Shift to eating herbivorous fish or poultry

41. Efficiency of Converting Grain into Animal Protein

42. Fig. 10-16, p. 215 2 Beef cattle Fish (catfish or carp) Chicken Pigs 7 4 2.2

43. Vacuuming Fish and Shellfish from the Seas  Humans consume 3% known fish species  Aquaculture – 1/3 of fish/shellfish production  Fisheries supply 1 billion people, mostly in Asia  Use of technology and huge nets – trawlers  ~30% bycatch – not profitable and pumped back to the ocean

44. Commercial Fishing Methods

45. Fig. 10-17, p. 216 Buoy Trawler fishing Drift-net fishing Purse-seine fishing Long line fishing lines with hooks Sonar Fish farming in cage Spotter airplane Deep sea aquaculture cage Fish caught by gills Float

46. Energy Costs of Global Fisheries  Heavily dependent on fossil fuels  Energy input 12.5 times more than energy output – fishing fleets

47. Total World Fish Catch Fig. 10-18, p. 217

48. Solutions for Overfishing  Oceans recover with careful management  Develop a sea ethic

49. Aquaculture  The blue revolution  Harmful environmental effects Mixing GMO with wild fish Shrimp farmers clear mangroves, causing loss of wild species Toxic contamination

50. Trade-offs: Aquaculture Fig. 10-19, p. 218

51. Solutions: More Sustainable Aquaculture Fig. 10-20, p. 218

52. How Can We Protect Crops from Pests?  We can sharply cut pesticide use without decreasing crop yields by using a mix of cultivation techniques, biological pest controls, and small amounts of selected chemical pesticides as a last resort (integrated pest management).

53. Nature’s Pest Control  Polycultures – pests controlled by natural enemies  Monocultures and land clearing Loss of natural enemies Require pesticides

54. Spiders: Natural Enemy of Pests Fig. 10-21, p. 219

55. Increasing Pesticide Use  Broad-spectrum agents  Selective agents  Persistence  Biomagnification – some pesticides magnified in food chains and webs

56. Trade-offs: Conventional Chemical Pesticides Fig. 10-22, p. 219

57. Advantages of Modern Pesticides +++++  Save human lives  Increase food supplies  Increase profits for farmers  Work fast  Low health risks when used properly  Newer pesticides safer and more effective

58. Disadvantages of Modern Pesticides -----  Pests become genetically resistant  Put farmers on a financial treadmill  Some insecticides kill natural enemies  May pollute environment  Harmful to wildlife  Threaten human health  Use has not reduced U.S. crop losses

59. Science Focus: Ecological Surprises  Dieldrin killed malaria mosquitoes, but also other insects  Poison moved up food chain Lizards and then cats died Rats flourished Operation Cat Drop  Villagers roofs collapsed from caterpillars – natural insect predators eliminated

60. Alternatives to Pesticides  Fool the pest  Provide homes for pest enemies  Implant genetic resistance  Natural enemies  Pheromones to trap pests or attract predators  Hormones to disrupt life cycle  Scalding with hot water  Integrated pest management – combination of approaches

61. What Can You Do? Fig. 10-23, p. 222

62. Genetic Engineering and Biological Control Fig. 10-24, p. 222Fig. 10-25, p. 222

63. How Can We Produce Food More Sustainably?  Sustainable agriculture involves reducing topsoil erosion, eliminating overgrazing and overfishing, irrigating more efficiently, using integrated pest management, providing government subsides for sustainable farming and fishing, and promoting agrobiodiversity.

64. Government Intervention  Governments influence food production Control prices Provide subsidies Let the marketplace decide  Reduce hunger, malnutrition and environmental degradation Slow population growth Sharply reduce poverty Develop sustainable low-input agriculture

65. Solutions: Sustainable Organic Agriculture Fig. 10-26, p. 224

66. Shift to Sustainable Agriculture  Increase research on sustainable agriculture  Set up demonstration projects  Provide subsidies and foreign aid  Establish training programs

67. What Can You Do? Fig. 10-27, p. 225

68. Animation: Land Use PLAY ANIMATION

69. Animation: Soil Profile PLAY ANIMATION

70. Animation: Resources Depletion and Degradation PLAY ANIMATION

71. Animation: Acid Deposition PLAY ANIMATION

72. Animation: Transferring Genes into Plants PLAY ANIMATION

73. Animation: Effects of Deforestation PLAY ANIMATION

74. Animation: Ocean Provinces PLAY ANIMATION

75. Animation: Pesticide Examples PLAY ANIMATION

76. Video: The Problem with Pork PLAY VIDEO

77. Video: Food Allergy Increase PLAY VIDEO

78. Video: Fat Man Walking PLAY VIDEO

79. Video: Desertification in China PLAY VIDEO