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Published byMerry Osborne Modified over 9 years ago
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“The way we eat has changed more in the past 50 years than in the past 10,000 years.”
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Remember the lesson of the Inca!
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Monoculture
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Polyculture
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Corn, wheat, soy and rice…60% of human food supply. What 3 crops provide most of the world’s food?
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Subsidy or Subsidize assistance paid to a business or economic sector Most subsidies are made by the government to producers or distributors to prevent the decline of that industry Crops subsidized in the U.S.: Corn, rice, wheat, milk, soybeans, sugar, tobacco, cotton
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Corn Cheap corn = lots of corn! Broken down in lab into lots of chemicals used in food. Subsidies make the unhealthy food cheap.
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Reason #3 to protect biodiversity: Agricultural Of 80,000 known edible plants on the planet, we depend on 20 species to provide 90% of global food supply. Corn, rice, soy and wheat are 60% alone!
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Pests and diseases generally are plant- specific. Examples – Boll weevil attacks cotton plants Rust fungus attacks corn Yellow rust fungus attacks wheat
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Conventional agriculture relies heavily on petroleum
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Weighing in at 1,250 pounds (567 kilograms), Marina Wilson's champion steer Grandview Rebel is ready for auction at a county fair in Maryland. Raising this steer has taken an agricultural investment equal to 283 gallons (1,071 liters) of oil, represented here by the red drums. That includes everything from fertilizers on cornfields to the diesel that runs machinery on the farm. Overall, it takes three-quarters of a gallon of oil to produce a pound of beef
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Pesticides – “To use or not to use?”
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Pesticides to know 1 st generation – derived from plants/minerals found in nature – Sulfur (used on wine grapes) – Arsenic (rodenticide) – Rotenone modern insecticide from tropical legume – pyrethrum (insecticide derived from chrysanthemums) 2 nd generation – created in labs, not found in nature – Atrazine (insecticide used on more US corn crops) – Glyphosate (Roundup) – DDT dichlorodiphenyltrichloroethane
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DDT – the first of the second generation WW II Pacific theater - 1939 Persistent contact insecticide applied in farms and cities 1960’s – decline in Bald Eagles – unable to deposit Ca + in egg shells
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Bioaccumulation leads to biomagnification (storing fat soluble chemicals in fat cells of body) (concentration of toxins up the food chain)
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Rachel Carson Silent Spring 1962 Controversy – makers of DDT not happy with her work, tried to prevent publication of the book. Died of breast cancer 1964 Led to banning of DDT use in US in 1972
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DDT still used in Africa to combat malaria Banned for agricultural use, but used to save human lives Trade offs! US is #1 maker of DDT in the world still (we just don’t use it on our land!)
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Genetic resistance
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Pests develop resistance to pesticide through genetic resistance Increased dosage, application schedule, increased toxicity required to keep killing pests The pesticide treadmill
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Be target specific Harm no other species Disappear or break down after doing its job Not cause genetic resistance Be more cost effective than doing nothing Ideally, a pesticide would...
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