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Sustainable Agriculture Techniques for Food Security and Nutrition

Explore industrialized vs. organic agriculture, food security issues, importance of healthy diet, and global health impacts. Learn about chronic hunger, obesity, soil health, and traditional farming practices.

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Sustainable Agriculture Techniques for Food Security and Nutrition

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  1. Industrialized Agriculture • Uses : • synthetic inorganic fertilizers and sewage sludge to supply nutrients • synthetic chemical pesticides • conventional and genetically modified seeds • antibiotics and growth hormones to produce meat and meat products • fossil fuels (mostly oil and natural gas) in production • Produces significant air and water pollution and greenhouse gases • Is globally export-oriented Fig. 12-1a, p. 277

  2. Organic Agriculture • Uses: • Soil erosion control • organic fertilizers such as animal manure and compost • crop rotation and biological pest control • no genetically modified seeds • no antibiotics or growth hormones to produce meat and meat products • Produces less air and water pollution and greenhouse gases • Is regionally and locally oriented Fig. 12-1b, p. 277

  3. Food Security and Health • Food security • All or most people in a country have daily access to enough nutritious food to lead active and healthy lives • Food insecurity • Chronic hunger and poor nutrition • Root cause: poverty • Political upheaval, war, corruption, bad weather

  4. Keys to a Healthy Diet • Macronutrients • Carbohydrates – wheat, corn, rice • Proteins – animal and plant products • Fats – animal and plant oils, nuts • Micronutrients • Vitamins (A, B, C, D, E) • Minerals (ex. Ca, Fe, K…)

  5. Chronic Hunger and Malnutrition • Chronic undernutrition: hunger due to low caloric intake • Chronic malnutrition: lack of key nutrients in diet • Stunted growth and development • Vulnerable to disease • Est. 800 million under/malnourished worldwide • Famine: severe food shortage • Drought, flooding, war, other catastrophes

  6. World Hunger Figure 15, Supplement 8

  7. Many People Do No Get Enough Vitamins and Minerals • Most often vitamin and mineral deficiencies in people in less-developed countries • Vitamin B1 (thiamine) - Beriberi • Vitamin D, Ca, K - Rickets • Iodine - Goiter • Vitamin C - Scurvy

  8. Many People Have Health Problems from Eating Too Much • Overnutrition • Excess body fat from too many calories and not enough exercise • Similar health problems to those who are underfed • Lower life expectancy • Greater susceptibility to disease and illness • Lower productivity and life quality • Est. 79 million US adults are overweight/obese • Est. $150 billion in health care costs

  9. Many People Have Health Problems from Eating Too Much • Est. 79 million US adults are obese (1/3 of population) • Est. $150 billion in health care costs Obesity Among U.S. Adults, 2013

  10. 12-2 How Is Food Produced? • Concept 12-2 We have used high-input industrialized agriculture and lower-input traditional methods to greatly increase supplies of food.

  11. Maintaining Soil Health • Soil composition • Eroded rock • Mineral nutrients • Decaying organic matter • Water • Air • Microscopic decomposers

  12. Oak tree Fern Moss and lichen Organic debris Millipede Honey fungus Grasses and small shrubs Rock fragments Earthworm Wood sorrel O horizon Leaf litter A horizon Topsoil Mole Bacteria B horizon Subsoil Fungus C horizon Parent material Bedrock Mite Immature soil Young soil Mature soil Root system Red earth mite Beetle larva Nematode Fig. 12-A, p. 284

  13. Maintaining Soil Health • Farming and crops by definition reduce soil health • Crops remove nutrients • Machinery can compress (or erode) soil • Key goal – find ways to maintain soil health

  14. Food Production Has Increased Dramatically • Three systems produce most of our food • Croplands: 77% of our food on 11% world’s land area • Rangelands, pastures, and feedlots: 16% of our food on 29% of world’s land area • Aquaculture: 7% of our food • Key dominant crops: • Corn • Wheat • Soy • Rice • Oil seed plants (canola, sunflower, rapeseed)

  15. Industrialized Crop Production Relies on High-Input Monocultures • Industrialized agriculture: high-input, monoculture/plantation crops • Goal is to steadily increase crop yield • Grow more food per acre (maintain land area used) • Increased use of greenhouses to raise crops

  16. Example – Missouri corn crops Acres planted compared (below) compared to yield (right)

  17. Heavy Equipment Used to Harvest Wheat in the United States Fig. 12-4, p. 281

  18. Plantation Agriculture: Oil Palms on Borneo in Malaysia Fig. 12-5, p. 281

  19. Traditional Agriculture Often Relies on Low-Input Polycultures (1) • Traditional subsistence agriculture • Human labor and draft animals for family food • Traditional intensive agriculture (basis of “organic” farming) • Higher yields through use of manure and water

  20. Traditional Agriculture Often Relies on Low-Input Polycultures • Polyculture • Multiple crops grown in same field • Can be grown simultaneously or rotated season to season • Can benefit soil health • Slash-and-burn agriculture • Subsistence agriculture in tropical forests • Clear and burn a small plot • Grow many crops that mature at different times • Once soil is depleted of nutrients, find a new area to slash

  21. A Closer Look at Industrialized Crop Production • Green Revolution: increase crop yields starting in 1960s • Monocultures of high-yield key crops • Rice, wheat, and corn • Large amounts of fertilizers, pesticides, water (& fuel) • Second Green Revolution • Fast growing dwarf varieties of wheat, rice, and other grains • World grain has tripled in production since 1950s

  22. Global Outlook: Total Worldwide Grain Production (Wheat, Corn, and Rice)

  23. Case Study: Industrialized Food Production in the United States • Agribusiness • Average farmer feeds 129 people • Annual sales greater than auto, steel, and housing combined • Food production: very efficient = low costs • Americans spend 10% of income on food • Hidden costs • (taxpayer) subsidies to farmers to grow (or not grow) crops • costs of pollution and environmental degradation

  24. Industrialized Food Production Requires Huge Inputs of Energy • Mostly nonrenewable energy – oil and natural gas • 19% of total fossil fuel energy use in U.S. • Farm machinery • Irrigate crops • Produce pesticides (petrochemicals) • Commercial inorganic fertilizers • Process and transport food • Emissions of CO2, NO2 and other greenhouse gases • U.S. food travels an average of 2,400 kilometers (1,500 miles)

  25. Crossbreeding and Genetic Engineering Produce New Crop/Livestock Varieties (1) • First gene revolution • Cross-breeding through artificial selection • Slow process (decades to centuries) • Seek to promote specific traits to promote high yield • Genetic engineering = second gene revolution • Alter organism’s DNA • Genetic modified organisms (GMOs): transgenic organisms

  26. Crossbreeding and Genetic Engineering Produce New Crop/Livestock Varieties (2) • Age of Genetic Engineering: developing crops that are resistant to • Herbicides • Insect pests • Parasites • Viral diseases • Heat and cold • Drought • Salty or acidic soil Pests Climate Change

  27. GMO Trade-Offs Advantages Disadvantages Unpredictable genetic and ecological effects Need less fertilizer Need less water Harmful toxins and new allergens in food More resistant to insects, disease, frost, and drought No increase in yields Grow faster More pesticide-resistant insects and herbicide-resistant weeds May need less pesticides or tolerate higher levels of herbicides Could disrupt seed market May reduce energy needs Lower genetic diversity Fig. 12-18, p. 294

  28. Meat Production and Consumption Have Grown Steadily • Animals for meat raised in • Pastures and rangelands (“organic meat”) • Feedlots • Increase in cropland dedicated to feeding animals

  29. Industrialized Meat Production Fig. 12-8, p. 287

  30. Meat Production and Consumption Have Grown Steadily • Worldwide meat production increased fourfold between 1961 and 2007 • Demand is expected to go higher as countries become wealthier

  31. Meat Production and Consumption Have Grown Steadily • Meat consumption greatest in wealthiest countries • Growing fastest in developing countries

  32. Industrial Meat Trade-Offs Animal Feedlots Advantages Disadvantages Increased meat production Large inputs of grain, fish meal, water, and fossil fuels Higher profits Greenhouse gas (CO2 and CH4) emissions Less land use Reduced overgrazing Concentration of animal wastes that can pollute water Reduced soil erosion Use of antibiotics can increase genetic resistance to microbes in humans Protection of biodiversity Fig. 12-19, p. 295

  33. Producing Food Has Major Environmental Impacts • Harmful effects of agriculture on • Biodiversity – creating large swaths of monoculures • Soil • Depletion of nutrients • Addition of foreign chemicals • Water • Use in irrigation • Pollution from fertilizers, pesticides • Air • Dust and chemicals • Greenhouse Gases • Human health

  34. Natural Capital Degradation Food Production Biodiversity Loss Soil Water Air Pollution Human Health Loss and degradation of grasslands, forests, and wetlands in cultivated areas Erosion Water waste Emissions of greenhouse gas CO2 from fossil fuel use Nitrates in drinking water (blue baby) Aquifer depletion Loss of fertility Increased runoff, sediment pollution, and flooding from cleared land Pesticide residues in drinking water, food, and air Salinization Emissions of greenhouse gas N2O from use of inorganic fertilizers Waterlogging Fish kills from pesticide runoff Desertification Pollution from pesticides and fertilizers Contamination of drinking and swimming water from livestock wastes Killing wild predators to protect livestock Emissions of greenhouse gas methane (CH4) by cattle (mostly belching) Increased acidity Loss of genetic diversity of wild crop strains replaced by monoculture strains Bacterial contamination of meat Other air pollutants from fossil fuel use and pesticide sprays Fig. 12-10, p. 289

  35. Topsoil Erosion Is a Serious Problem in Parts of the World • Soil erosion • Movement of soil by wind and water • Poor farming techniques increase risk • Two major harmful effects of soil erosion • Loss of soil fertility (removal of topsoil) • Water pollution (sediment in water)

  36. Topsoil Erosion on a Farm in Tennessee Fig. 12-11, p. 289

  37. Natural Capital Degradation: Gully Erosion in Bolivia Fig. 12-12, p. 290

  38. Wind Removes Topsoil in Dry Areas Fig. 12-13, p. 290

  39. Natural Capital Degradation: Global Soil Erosion Fig. 12-14, p. 291

  40. Drought and Human Activities Are Degrading Drylands • Desertification Causes • Overgrazing • Unreplenished farmland or grassland • Drought • Over watering (salinization) • Human agriculture accelerates desertification

  41. Severe Desertification Fig. 12-15, p. 291

  42. Natural Capital Degradation: Desertification of Arid and Semiarid Lands Fig. 12-16, p. 292

  43. Excessive Irrigation Has Serious Consequences • Salinization • Gradual accumulation of salts in the soil from irrigation water • Lowers crop yields and can even kill plants • Affects 10% of world croplands • Waterlogging • Irrigation water gradually raises water table • Can prevent roots from getting oxygen • Affects 10% of world croplands

  44. Natural Capital Degradation: Severe Salinization on Heavily Irrigated Land Fig. 12-17, p. 292

  45. Agriculture and Air Pollution and Projected Climate Change • Dust and chemical sprays • 25% of all human-generated greenhouse gases related to crops and livestock • Livestock contributes 18% of gases: methane in cow belches • Grass-fed better than feedlots

  46. There Are Limits to Expanding the Green Revolution • Industrial farming techniques require large inputs of fertilizer, pesticides, and water • Can we expand/refine the green revolution by • Irrigating more cropland? • Improving the efficiency of irrigation? • Cultivating more land? Marginal land? • Improving pesticide use? • Using GMOs?

  47. Nature Controls the Populations of Most Pests • What is a pest? • Interferes with human welfare • Natural enemies—predators, parasites, disease organisms—control pests • Pesticide use can alter these natural systems

  48. We Use Pesticides to Try to Control Pest Populations (1) • Pesticides • Insecticides • Herbicides • Fungicides • Rodenticides • Pests can overcome plant defenses through natural selection: coevolution

  49. We Use Pesticides to Try to Control Pest Populations (2) • First-generation pesticides • Borrowed from plants • Second-generation pesticides • Lab produced: DDT and others • Broad-spectrum agents: kills everything • Narrow-spectrum agents: kills a specific target pest

  50. Trade-Offs Conventional Chemical Pesticides Advantages Disadvantages Save lives Ex. Anti-Marlaial agents Promote genetic resistance Kill natural pest enemies Increase food supplies Pollute the environment Can harm wildlife and people Work fast Safe if used properly Are expensive for farmers Profitable to farmer Fig. 12-22, p. 299

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