• Please read the board and get out something to write with!

Hungry to learn?

“The way we eat has changed more in the past 50 years than

in the past 10,000 years.”

•Uniformity of product• Control by very few companies• Industrial food processes•Monoculture• Processing

It produces a lot of food, but is this sustainable?

(Something that can go on and on because it doesn’t use up resources faster than they are created.)

Big changes

Remember the lesson of the Inca!

Monoculture

Monoculture

Polyculture

Polyculture

Polyculture

Benefits: Easy to manage Provides uniformity Can be grown by few

people as long as they have large machines

Lack of diversity = potential loss of crop to disease/pest

Need for pesticides Need for inorganic

fertilizer because crop takes particular nutrient from soil

Loss of biodiversity from field edges/cover crops

What are the tradeoffs of monoculture?

Pests and diseases generally are plant-specific.

• Examples –

• Boll weevil attacks cotton plants

• Rust fungus attacks corn

• Yellow rust fungus attacks wheat

• Colorado potato beetle only attacks potatoes

Diversity protects harvests from pests and diseases because they run out of food.

Monocultures are like a banquet!

Pesticides can move through the environment

• Monocultures are often crop dusted by planes.

• If it rains soon after application, pesticide can runoff into local stream.

What happens in a farming community’s watershed?

• Where would the greatest concentrations of pesticide be?

Biomagnification: the accumulation of toxins as they move up the food chain.

Genetic Resistance

• Individual pests can tolerate different amounts of pesticide. Some individuals are stronger than others and they can survive.

The pesticide treadmill

• Pests develop resistance to pesticide

• Farmer must use Increased dosage, application schedule, increased toxicity

• It’s like a treadmill because once a farmer starts, it’s hard to stop using pesticides.

The Tradeoffs!• Advantages • Disadvantages

Why are monocultures unsustainable?