Where does our food come from?

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Where does our food come from?

• Croplands (mostly grain) provide 77 of the
  worlds food
• Rangelands (meat) supply 16
• Oceanic fisheries (fish and shellfish) 7

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How Is Food Produced?

• Sources of food
• Primary plants Wheat, corn, and rice
• Primary animalsfish, beef, pork, and chicken
• 14 plant and 8 animal species provide 90 of the
  global food calories

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Major Types of Agriculture

• Industrialized agriculture
• Large amounts of fossil fuel, water, fertilizer,
  and pesticides to produce monoculture crops or
  livestock animals
• Plantation
• Form of industrialized agriculture single
  ownership
• Traditional subsistence agriculture
• Produce only enough for the family
• Traditional intensive agriculture
• Increase outputs for profit

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Industrialized Agricultural Wastes and Land
Pollution

• Animal Confinement
• Waste runoff
• Overgrazing
• Increases soil erosion
• Sedimentation
• Nutrient application
• Irrigation
• Pesticides

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Waste runoff increases nutrients and pathogens in
streams
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Overgrazing typically strips the land of any
natural protection and leaves the soil very
susceptible to erosion
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Runoff carries sediments, nutrients and
pesticides into streams that damages fish habitat
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Agriculture alters native habitats and reduces
native biodiversity
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Major Types of Agriculture

• Plantation - Form of agriculture that involves
  concentrated ownership of land with the means of
  production in the hands of one family or
  corporation, the use of hired labor, and
  mono-crop production for sale.
• Cash crops mostly for sale in developed countries
• Bananas, coffee, soybeans

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Traditional
Plantation
Industrialized
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World Food Production
Industrialized
Traditional
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Producing Food by Green-Revolution Techniques

• Since 1950, increase in global food production
  has come from increased yields per unit area of
  crop land.

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Producing Food by Green-Revolution Techniques

• Green revolution involves three steps
• High-input monoculture using selectively bred or
  genetically-engineered crops
• High yields using high inputs of fertilizer,
  extensive use of pesticides and high inputs of
  water
• Multiple cropping increase the number of crops
  grown per year on a plot of land.

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Green Revolutions
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Producing Food by Traditional Techniques
Interplanting simultaneously grow several crops
on the same ground. Reduces chance of losing
years crop to pests, bad weather, etc.
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Producing Food by Traditional Techniques

• Types of Interplanting
• Polyvarietal cultivation planting several
  varieties of the same crop
• Intercropping grow two or more different crops
  at the same time (grainnitrogen fixing plant)
• Agroforestry (alley cropping) crops and trees
  are grown together
• Polyculture many different types of plants that
  mature at different times are grown together

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Causes of Soil Erosion

• Wind
• Water
• People farming, logging, construction (or any
  activities that weaken root strength)

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Soil erosion in a wheat field
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Global Soil Erosion
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Soil Degradation on Irrigated Land

• Salinization
• Waterlogging

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Reducing and Cleaning Up Salinization

• Reduce irrigation
• Switch to salt-tolerant crops
• Flush soils
• Not growing crops for 2-5 years
• Install underground drainage

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Saltwater and drainage is a continual problem for
lowland agriculture near Puget Sound.
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Tidegate lets water out, but not back in.
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Solutions Soil Conservation
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Soil Restoration

• Organic fertilizer
• Animal manure
• Green manure fresh cut vegetation
• Compost
• Crop rotation legume crops add nitrogen to soil
• Commercial inorganic fertilizer

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Catching and Raising More Fish

• Fisheries
• Fishing methods
• Overfishing
• Commercial extinction
• Aquiculture
• Fish farming and ranching

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Pesticides Types

• Chemicals that kill undesirable organisms
• Insecticides - insects
• Herbicides - plants
• Fungicides - fungus
• Rodenticides - rodents

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First Generation Pesticides

• Primarily natural substances
• Sulfur, lead, arsenic, mercury
• Plant extracts nicotine, pyrethrum

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Second Generation Pesticides

• Primarily synthetic organic compounds
• Broad-spectrum agents toxic to many species
• Narrow-spectrum agents toxic to few species
• Persistence in the environment

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The Case for Pesticides

• Save human lives spread of disease
• Increase food supplies and lower costs
• Work better and faster than alternatives
• Health risks may be insignificant compared to
  benefits
• Newer pesticides are becoming safer
• New pesticides are used at lower rates

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Characteristics of an Ideal Pesticide

• Affects only target pests
• Harms no other species
• No genetic resistance
• Breaks down quickly in the environment
• Be more cost-effective than doing nothing

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The Case Against Pesticides

• Genetic resistance
• The pesticide treadmill pay more for less
  effect
• Can kill non-target and natural control species
• Can cause an increase in other pest species
• Pesticides do not stay put
• Can harm wildlife
• Potential human health threats

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Bioaccumulation and Biomagnification

• Persistent (non-biodegradable) toxins build up in
  an animal over time bioaccumulation
• Become more concentrated at higher trophic levels
  biomagnification

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Integrated Pest Management

• Ecological system approach
• Reduce pest populations to economic threshold
• Field monitoring of pest populations
• Use of biological agents natural predators,
  parasites, disease
• Chemical pesticides are last resort

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Why is Integrated Pest Management not More Widely
Used?

• Requires expert knowledge
• Slower than conventional pesticides
• Initial costs may be high
• Hindered by pesticide industry

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Solutions Sustainable Agriculture

• Low-input agriculture
• Organic farming
• Profitable
• Increasing funding for research in sustainable
  techniques

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