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Food

Food . Chapter 10, Environmental Science. J. Stewart-Presenter. Case Study: Bug cuisine . Food is expensive Modern agriculture hurts the environment So...find new crops or...bugs! Bugs: cheap and easy to get--1500 edible insects, like Mopani Bugs also provide 58-78% protein by weight

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Food

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  1. Food Chapter 10, Environmental Science J. Stewart-Presenter

  2. Case Study: Bug cuisine • Food is expensive • Modern agriculture hurts the environment • So...find new crops or...bugs! • Bugs: cheap and easy to get--1500 edible insects, like Mopani • Bugs also provide 58-78% protein by weight • But, agricultural companies resist change that could hurt profits • And...would you eat them?

  3. Key concepts • Food production: 77% croplands, 16% rangelands, 7% fisheries (3/4 of commercial fisheries fished beyond or at biological limit/sustainable yield) • Soil and Fertilizers (erosion faster than formation) • Nutrition and Food (1/6 under- or malnourished, 1/4 overweight) • Pests and Pesticides • Sustainable agriculture What is a farm? Is it this? Or this?

  4. Food production: Successes Agriculture began about 10,000 yrs ago. Now: • 77% food from croplands: BIG 3--corn, rice, wheat=half of all human calories, • 16% from rangelands, • 7% from fisheries: most important for about 1 billion humans. Huge advances in technology: production TRIPLED from 1950-85--is it enough?

  5. Food Production: Issues "Agriculture has a greater harmful environmental impact than any human activity!" (p.219) - Pollutes air, water, and affects human health - Leads to soil loss and impacts biogeochemical cycles (CHNOPS) - Reduces biodiversity - 30% of world's cropland degraded--17% seriously

  6. Food production: Industrial/High-input Ag. • 80% of present ag. • INPUTS: fuel, fertilizer, pesticides • 10 units of energy for 1 energy unit of food (p. 211) • INCLUDES: Plantation ag. (cash crops like coffee), Feedlots (cows) • Agribusiness in USA: -75% of US ag. production is by large companies -0.3% of world's ag. workforce, yet 17% of world's production -Food to table = 17% of US commercial energy -More food since 1950, fewer workers

  7. Food production: Green Revolution • Monocultures • 1st Revolution-High short-term yields through fertilizer, pesticide inputs (1950s-1970s) • Multiple cropping each year • 2nd Revolution-Developmentof special varieties--since late 1960's (Next: GMO's since late 1990's) • Costs: depends on fertile soil, clean water, 8% of world's oil, and other inputs

  8. Food prod: Traditional 20% is traditional (done by about 40% of world's people). Includes: -subsistence: human labor, animal power -intensive: small farms with increased inputs Methods focus on increased diversity: -interplanting, polyculture, alley cropping (forestry), etc. ...These methods have been shown to be more sustainable and produce higher long-term yields than industrial monocultures. 1 unit of energy input for 10 units of food(p. 211)

  9. Soil: Erosion • Caused by water and wind and increased with reduced plant cover, overgrazing, vehicle use • Topsoil is potentially renewable--on 38% of world's cropland it is not renewed • In USA loss 16x > formation, but slowing

  10. Soil: Desertification, Salinization, Waterlogging Desertification: drylands lose productivity by 10% or more (only severe cases actually become desert). A problem in 70% of drylands. Salinization: Irrigation (1/5 of cropland, 40% of food) results in concentration of salts through evaporation. Can kill plants. Problem on 1/5 of irrigated cropland. Waterlogging: Over-irrigating raises water table with saline water. Problem on 1/10 of irrigated cropland.

  11. Soil: Conservation Soil conservation is key component of sustainable agriculture. How: Conservation tillage: keep soil undisturbed, covered with vegetation Terracing, contour farming, strip cropping: control water run off Windbreaks: reduce wind erosion

  12. Soil and Fertilizers • Fertilizers used to restore lost plant nutrients--esp. N-P-K. • Organic: From plant and animal sources such as manures, compost. Provide nutrients AND structure (humus). • Crop rotation: Added diversity minimizes loss of single nutrient. • Inorganic: Provide nutrients, but NO structure. Runoff is pollutant.

  13. Nutrition: Problems • Enough food is produced :) • Distribution inequal: 1/6 of world underfed :( • Undernutrition=not enough food. Malnourished=not enough nutrients, esp. protein. • Problem: poverty. • Undernutrition problem growing in LDC's. Also lack of micronutrients: vitamin A, iron, and iodine.

  14. Nutrition: Solutions -Immunizations -Education (esp. women), Family planning -Breast feeding -Vitamins,Nutrients (i.e. A for blindness, iodine for thyroid/metabolism, iron for blood/anemia) -Prevent dehydration -Reduce overnutrition in MDCs:Over 68% of Americans overweight or obese (National Health and Nutrition Examination Survey (NHANES), 2012)

  15. Food: Increasing Plant Production Human population expected to reach 9 billion by 2050 • 3rd Revolution: Genetic Engineering? Over 2/3 of US supermarket food contains GE crops. • Benefits: Short-term reduction in pesticide, herbicide use, no loss in nutrition. • Drawbacks: Superbugs, superweeds, persistent toxins in food, allergies, corporate ownership of seeds, minimal or no long term yield increases, no long-term reduction in inputs, few long-term studies.

  16. Food: Increasing Plant Production Use more water? Waterexpensive and aquifers (underground water) are being depleted. Use more land? Very little new landleft that is viable for growing crops. What can be done?See the green on upcoming slides.

  17. Food: Meat Meat production is intensive: -Half of world's cropland and water useage, -20x more manure than humans, -22% or more (Sci. Amer., 2009) of greenhouse gases (CH4, CO2), overgrazing, endanger wild species.

  18. Food: Meat • 43% of beef from feedlots with as many as 100,000 cattle! Over 50% of pork, about 75% of poultry is non-pasture, “factory” farmed. • Shift from beef, pork--> to fish, poultry (more grain-efficient) OR grass-fed, free-range cattle.

  19. Food: Fish Fisheries: Aquatic species suitable for commercial harvest About 3/4 of 200 the most valuable fisheries overfished or at limit. Often subsidized by governments.

  20. Food: Fishing Management Careful management would allow 125 of 128 depleted fisheries to recover. Management: -Quotas -Limit boats -No fish during spawning -Restrict use of long lines, drift nets, other harmful methods -Create reserves -Consumerawareness

  21. Food: Fish Farming, Ranching CONS: Large inputs of land, feed, And water needed Produces large and concentrated outputs of waste Destroys mangrove forests Increased grain production needed to feed some species Fish can be killed by pesticide runoff from nearby cropland Dense populations vulnerable to disease PROS Highly efficient High yield in small volume of water Increased yields through cross- breeding and genetic engineering Can reduce over- harvesting Little use of fuel High profits Aquaculture Farming=Controlled environment Ranching=Captive with some release (ie salmon)

  22. Pests and Food Pests damage crops and reduce yield: weeds, herbivorous insects, fungus, microbes. In balanced ecosystems, pests are not usually a major problem. Ecosystem service: Natural enemies (i.e. ladybugs, spiders eat herbivorous insects). In agricultural systems (low diversity), up to 55% of crops can be lost to pests.

  23. Pesticides Insecticides (pesticides) kill animal pests, Herbicides kill plant pests--usually toxic chemicals. But they also... -Accelerate genetic resistance -Kill natural pest enemies -Do NOT reach target pests 98% of time! -Harm wildlife -Threaten human health: cancer, death In 1942, we lost 7% of crops to insect pests. Now we use 33x more pesticides, yet we lose 13%! So why use them? -Can help eradicate disease and save lives -Can increase food supply and profits when used correctly -Work well in short term -New pesticides safer and needed in smaller amounts Rachel Carson’s Silent Spring (1962) raised awareness about DDT and pesticides in general.

  24. Pesticides: Solutions Laws: 57 pesticides banned by the EPA 1972-2004. Poorly enforced. Different outside US. 1996 Food Quality Protection Act. Genetic Engineering?:See previous slides Biological controls: Introduce natural enemies Natural chemicals: Pheromones and hormones can change pest behavior. Physical controls: Water spray or vacuuming. Integrated Pest Management (IPM): 1) Allow for some crop loss, 2) Learn: Biological, physical controls first. 3) Small amount of carefully applied pesticides How? Educate, change farming subsidies practices, tax pesticides to fund IPM

  25. Sustainable Agriculture Mentioned previously: Traditional methods, Soil conservation Reduce resource input, work with nature (BioSPoRN) ALSO... Reduce poverty Slow population growth MORE: • organic fertilizers • pest control • efficient irrigation • perennial crops • crop rotation • soil conservation • subsidies LESS: • soil erosion • soil salinization •  overgrazing • overfishing • food waste • population growth • poverty

  26. Bibliography Miller, Environmental Science,(2006) Fiala, Nathan, How Meat Contributes to Global Warming, Scientific American, http://www.scientificamerican.com/article.cfm?id=the-greenhouse-hamburger(2009) National Health and Nutrition Examination Survey (NHANES) (2012) Carson, Rachel, Silent Spring (1962) THE END

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