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ENVIRONMENTAL SCIENCE

ENVIRONMENTAL SCIENCE. CHAPTER 10: Food, Soil, and Pest Management. Core Case Study: Is Organic Agriculture the Answer?. Organic agriculture as a component of sustainable agriculture Certified organic farming: 1. Less than 1% of total world croplands 2. 0.1% of U.S. cropland is organic

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ENVIRONMENTAL SCIENCE

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  1. ENVIRONMENTALSCIENCE CHAPTER 10:Food, Soil, and Pest Management

  2. Core Case Study: Is Organic Agriculture the Answer? • Organic agriculture as a component of sustainable agriculture • Certified organic farming: 1. Less than 1% of total world croplands 2. 0.1% of U.S. cropland is organic 3. 6-18% of croplands are organic in many European countries

  3. Core Case Study: Is Organic Agriculture the Answer? • Many environmental advantages over conventional farming • Requires more human labor • Organic food costs 10-75% more than conventionally grown food • Cheaper than conventionally grown food when environmental costs are included

  4. 10-1 What Is Food Security and Why Is It So Difficult to Attain? • Concept to Learn in Sect. 10-1A:Many of the poor have health problems from not getting enough food, while many people in affluent countries suffer health problems from eating too much. • Concept to Learn in Sect. 10-1B: The greatest obstacles to providing enough food for everyone are poverty, political upheaval, corruption, war, and the harmful environmental effects of food production.

  5. Poor Lack Sufficient Food • Currently, there is enough food for all 1. yet in developing countries 1/6 do not get enough to eat • Poverty – root cause of Food insecurity: 1. Chronic hunger 2. Poor nutrition • Food security: having enough food to meet an individuals nutritional needs.

  6. Nutrition • Its not just about having food: its about having nutritious food. • Macronutrientsand micronutrients • Chronic undernutrition (hunger) 1. not getting enough 2. if prolonged, can lead to malnutrition

  7. Malnutrition • Malnutrition 1. Cause: Low-protein, high-carbohydrate diet 2. Result: Physical and mental health problems • Affects: 6 million children die each year a. Mostly in developing nations 4. Ultimate cause: Vitamin and mineral deficiencies

  8. Overnutrition • Too many calories, too little exercise, or both • Has a similar overall health outlook as undernourished • 1.6 billion people eat too much • 66% of American adults overweight, 34% considered to be obese. Leads to: 1. Heart disease and stroke 2. Type II diabetes and some cancers

  9. 10-2 How Is Food Produced? • Concept to Learn in Sect.10-2: We have used high-input industrialized agriculture and lower-input traditional methods to greatly increase supplies of food.

  10. Where We Get Food • Major sources: • Croplands • Rangelands, pastures, and feedlots • Fisheries and aquaculture

  11. Where We Get Food • Since 1960 tremendous increase in food supply • Better farm machinery • High-tech fishing fleets • Irrigation • Pesticides and fertilizers • High-yield varieties

  12. Only a Few Species Feed the World • Food specialization in small number of crops makes us vulnerable • 14 plant species provide 90% of world food calories • 47% of world food calories comes from rice, wheat, and corn

  13. Industrialized Agriculture • High-input agriculture – monocultures • Large amounts of: • Heavy equipment • Financial capital • Fossil fuels • Water • Commercial inorganic fertilizers • Pesticides • Much food produced for global consumption

  14. Industrialized Agriculture • Plantation agriculture primarily in tropics • Bananas • Sugarcane • Coffee • Vegetables • Exported primarily to developed countries

  15. Traditional Agriculture • 2.7 billion people in developing countries • Traditional subsistence agriculture • Traditional intensive agriculture • Monoculture • Polyculture

  16. Science Focus: Soil is the Base of Life on Land • Soil composed of • Eroded rock • Mineral nutrients • Decaying organic matter (humus) • Water • Air • Organisms

  17. Science Focus: Soil is the Base of Life on Land • Soil is a key component of earth’s natural capital • Soil profile: (soil layers) • O Horizon: leaf litter • A horizon: topsoil • B horizon: subsoil • C horizon: parent materials (usually bedrock) Soil acts like a sponge, storing & releasing water.

  18. Green Revolution: Higher Yield Crops • Green revolution: a 3 step process 1. Selectively bred monocultures 2. High yields through high inputs – inorganic fertilizers, pesticides, and water • Multiple cropping • First green revolution: took place in U.S. • Second green revolution– fast-growing dwarf varieties of wheat and rice (India & China) • 1950-1996: world grain production tripled!

  19. Case Study: Industrialized Food Production in the U.S. • Industrialized farming has become big business (agribusiness) • Increasing number of giant multinational corporations • ~10% U.S. income spent on food • Subsidized through taxes 1. environmental costs associated are absorbed by government 2. food prices are therefore “artificially” low

  20. Case Study: Brazil – The World’s Emerging Food Superpower • Ample sun, water, and arable (farmable)land • EMBRAPA – a government-established agricultural research corporation • Can grow 2-3 crops per year in tropical savanna (in U.S., its 1 per year) • Lack of transportation impeding further growth as food exporter (roads, shipping)

  21. Production of New Crop Varieties • Traditional methods: 1. Crossbreeding • Artificial selection *A Slow process • Genetic engineering 1. has lead to genetically modified organisms • >75% of U.S. supermarket food genetically engineered

  22. Meat Production • Meat and dairy products are good sources of protein • Past ~60 years meat production up five-fold (more chinese eating meat) • Half of meat from grazing livestock, other half from feedlots (confined animal feeding operations)

  23. Fish and Shellfish Production Have Increased Dramatically • Aquaculture – 46% of fish/shellfish production in 2006, where species are raised in: 1. Ponds • Underwater cages *China produces 70% of world’s farmed fish

  24. 10-3 What Environmental Problems Arise from Food Production? • Concept to Learn in Sect 10-3: Future food production may be limited by soil erosion and degradation, desertification, water and air pollution, climate change from greenhouse gas emissions, and loss of biodiversity.

  25. Soil Erosion • Soil Erosion: movement of surface litter & topsoil from one place to another. Causes: 1. Flowing water 2. Wind • Major associated problems: 1. Soil fertility declines 2. Water pollution occurs • Some naturally occurs • Majority is due to human activity

  26. Drought and Human Activities • Desertification: another environmental problem caused by food production 1. occurs when productive potential of soil falls by 10% • Caused by a combination of prolonged draught and human activities • 70% of world’s drylands used for agriculture are threatened to become deserts. • Will be exacerbated by climate change

  27. Effects of Irrigation • Leaves behind salts in topsoil • Salinization: water evaporation that leaves crystallized salt behind • Affects 10% of global croplands • Waterlogging • Attempts to leach (push) salts deeper but raises water table • Affects 10% of global croplands

  28. Limits to Expanding Green Revolutions • High-inputs of inorganic fertilizers & pesticides too expensive for subsistence farmers • Water is just not available in proportion to the increasing population • Irrigated land per capita has been dropping • Significant expansion of cropland (ie: marginal land) unlikely for both economic and ecological reasons

  29. Industrialized Food Production Requires Huge Energy Inputs • Mostly nonrenewable oil, used to: • Run machinery • Irrigation • Produce pesticides • Process foods • Transport foods • In U.S., food travels an average of 1,300 miles from farm to plate

  30. Industrialized Food Production Requires Huge Energy Inputs • 1940: 1 unit of fossil fuel was required to place 2.3 units of food on our table • Today: 10 units of fossil fuel is required to place only 1 unit of food on our table 1. beef: requires 35 units of fossil fuel to place 1 unit of beef on our table 2. fish: require 12.5 units of fossil fuel to place 1 unit of food

  31. Controversies over Genetically Engineered Foods • Potential long-term effects on humans • Ecological effects • Potential genes crosses with wild plants • Patents on GMF varieties

  32. Food and Biofuel Production Lead to Major Losses of Biodiversity • Forests cleared • Grasslands plowed • Loss of agrobiodiversity • Since 1900, lost 75% of genetic diversity of crops • The genetic “library” of food diversity is shrinking!

  33. Industrial Meat Production Consequences • Uses large amounts of fossil fuels • Wastes can pollute water • Overgrazing • Soil compaction • Methane release: greenhouse gas

  34. Aquaculture Problems • Fish meal and fish oil as feed • Depletes wild fish populations • Inefficient: takes 3 kg of wild fish to produce 1 kg of farmed fish • Can concentrate toxins such as PCBs from the ocean floor • Produce large amounts of waste, which makes its way into our water supplies

  35. How Can We Protect Cropsfrom Pests More Sustainably? • Concept to Learn in Sect. 10-4: 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).

  36. Nature’s Pest Control • Pest: Any species that interferes with human welfare (destroying crops, buildings, lawns, ecosystems) 1. Approx 100 species cause most damage. • Polycultures: (systems containing many species) – pests are controlled by natural enemies • Monocultures and land clearing lead to: • Loss of natural enemies • Requirement of pesticides

  37. Increasing Pesticide Use • Up 50-fold since 1950 • Broad-spectrum agents: toxic to many species (including beneficial species) • Selective agents: more specific • Persistence of pesticides varies (how long they will remain/work) • Biomagnification – some pesticides are magnified in food chains and webs (DDT)

  38. Advantages of Modern Pesticides • Save human lives (reduce insect-spread diseases) • Increase food supplies 1. presently, 55% of food is lost to pests • Increase profits for farmers • Work fast • Low health risks when used properly • Newer pesticides safer and more effective 1. Tend to use plant-derived chemicals

  39. Disadvantages of Modern Pesticides • Pests become genetically resistant (in just 5-10 years) • Some insecticides kill natural enemies • May pollute environment 1. are capable of moving to places they should not be. • Harmful to wildlife • Threaten human health (estimated 20-40,000 deaths/year) 1. over 3,300,000 become ill/year

  40. Disadvantages of Modern Pesticides • Use has not reduced U.S. crop losses 1. They are approximately the same since first using them in the 1940s. 2. Despite their use, insect damage to crops has actually increased. • For every dollar spent on pesticides, there is an estimated $5-10 in damages that are caused to the environment!

  41. Laws Regulate Pesticides • Environmental Protection Agency (EPA) • United States Department of Agriculture (USDA) • Food and Drug Administration (FDA) • Congressional legislation • Laws and agency actions criticized, because of lack of enforcement. 1. studies show a potential 98% reduction in related cancers if they did!

  42. 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 (wasps) were eliminated

  43. Alternatives to Pesticides • Fool the pest (crop rotation) • Provide homes for pest enemies • Implant genetic resistance • Natural enemies (bacteria, parasites) • Pheromones to trap pests or attract predators • Hormones to disrupt life cycle

  44. Integrated Pest Management • Evaluate a crop and its pests as part of ecological system • Design a program with: • Cultivation techniques • Biological controls • Chemical tools and techniques • Can reduce costs and pesticide use without lowering crop yields

  45. How Can We Improve Food Security? • Concept to Learn in Sect. 10-5: We can improve food security by creating programs to reduce poverty and chronic malnutrition, relying more on locally grown food, and cutting waste.

  46. Use Government Policies to Improve Food Production and Security • Control food prices • Helps consumers • Hurts farmers • Provide subsidies to farmers • Price supports, tax breaks to encourage food production • Can harm farmers in other countries who don’t get subsidies • Some analysts call for ending all subsidies

  47. Reducing Childhood Deaths • $5–$10 annual per child would prevent half of nutrition-related deaths • Strategies • Immunization • Breast-feeding • Prevent dehydration from diarrhea • Vitamin A • Family planning • Health education for women

  48. How Can We Produce Food More Sustainably? • Concept to learn in sect. 10-6: More sustainable food production involves reducing overgrazing and overfishing, irrigating more efficiently, using integrated pest management, promoting agrobiodiversity, and providing government subsidies only for more sustainable agriculture, fishing, and aquaculture.

  49. Reduce Soil Erosion • Terracing • Contour plowing • Strip cropping • Alley cropping • Windbreaks

  50. Case Study: Soil Erosion in the United States • Dust Bowl in the 1930s • 1935 Soil Erosion Act • Natural Resources Conservation Service • Helps farmers and ranchers conserve soil • One-third topsoil gone • Much of the rest degraded • Farmers paid to leave farmland fallow

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