ENVIRONMENTAL SCIENCE

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ENVIRONMENTAL SCIENCE
13e
CHAPTER 10Food, Soil, and Pest Management
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Core Case Study Is Organic Agriculture the
Answer? (1)

• Organic agriculture as a component of sustainable
  agriculture
• Certified organic farming
• Less than 1 of world cropland
• 0.1 of U.S. cropland
• 6-18 in many European countries

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Core Case Study Is Organic Agriculture the
Answer? (2)

• Many environmental advantages over conventional
  farming
• Requires more human labor
• Organic food costs 10-75 more than
  conventionally grown food
• Cheaper than conventionally grown food when
  environmental costs are included

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Fig. 10-1, p. 206
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Industrialized Agriculture
Uses synthetic inorganic fertilizers and sewage
sludge to supply plant nutrients Makes use of
synthetic chemical pesticides
Uses conventional and genetically modified
seeds Depends on nonrenewable fossil
fuels (mostly oil and natural gas)
Produces significant air and water pollution and
greenhouse gases Is globally export-oriented Use
s antibiotics and growth hormones to produce meat
and meat products
Fig. 10-1, p. 206
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Organic Agriculture
Emphasizes prevention of soil erosion and the use
of organic fertilizers such as animal manure and
compost, but no sewage sludge to help replace
lost plant nutrients
Employs crop rotation and biological pest control
Uses no genetically modified seeds
Makes greater use of renewable energy such as
solar and wind power for generating electricity
Produces less air and water pollution and
greenhouse gases
Is regionally and locally oriented
Uses no antibiotics or growth hormones to produce
meat and meat products
Fig. 10-1, p. 206
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10-1 What Is Food Security and Why Is It So
Difficult to Attain?

• Concept 10-1A Many of the poor have health
  problems from not getting enough food, while many
  people in affluent countries suffer health
  problems from eating too much.
• Concept 10-1B The greatest obstacles to
  providing enough food for everyone are poverty,
  political upheaval, corruption, war, and the
  harmful environmental effects of food production.

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Poor Lack Sufficient Food

• Enough food for all but in developing countries
  1/6 do not get enough to eat
• Poverty Food insecurity
• Chronic hunger
• Poor nutrition
• Food security

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Nutrition

• Macronutrients and micronutrients
• Chronic undernutrition
• Malnutrition
• Low-protein, high-carbohydrate diet
• Physical and mental health problems
• 6 million children die each year
• Vitamin and mineral deficiencies

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Supplement 3, Fig. 11, p. S12
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Fig. 10-2, p. 208
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Fig. 10-3, p. 209
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Overnutrition

• Too many calories, too little exercise, or both
• Similar overall health outlook as undernourished
• 1.6 billion people eat too much
• 66 of American adults overweight, 34 obese
• Heart disease and stroke
• Type II diabetes and some cancers

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10-2 How Is Food Produced?

• Concept 10-2 We have used high-input
  industrialized agriculture and lower-input
  traditional methods to greatly increase supplies
  of food.

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Where We Get Food (1)

• Major sources
• Croplands
• Rangelands, pastures, and feedlots
• Fisheries and aquaculture

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Where We Get Food (2)

• Since 1960 tremendous increase in food supply
• Better farm machinery
• High-tech fishing fleets
• Irrigation
• Pesticides and fertilizers
• High-yield varieties

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Only a Few Species Feed the World

• Food specialization in small number of crops
  makes us vulnerable
• 14 plant species provide 90 of world food
  calories
• 47 of world food calories comes from rice,
  wheat, and corn

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Industrialized Agriculture (1)

• High-input agriculture monocultures
• Large amounts of
• Heavy equipment
• Financial capital
• Fossil fuels
• Water
• Commercial inorganic fertilizers
• Pesticides
• Much food produced for global consumption

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Industrialized Agriculture (2)

• Plantation agriculture primarily in tropics
• Bananas
• Sugarcane
• Coffee
• Vegetables
• Exported primarily to developed countries

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Traditional Agriculture

• 2.7 billion people in developing countries
• Traditional subsistence agriculture
• Traditional intensive agriculture
• Monoculture
• Polyculture

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Science Focus Soil is the Base of Life on Land
(1)

• Soil composed of
• Eroded rock
• Mineral nutrients
• Decaying organic matter
• Water
• Air
• Organisms

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Science Focus Soil is the Base of Life on Land
(2)

• Soil is a key component of earths natural
  capital
• Soil profile
• O Horizon
• A horizon
• B horizon
• C horizon

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Oak tree
Fern
Moss and lichen
Organic debris
Millipede
Honey fungus
Earthworm
Rock fragments
Grasses and small shrubs
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
Nematode
Root system
Red earth mite
Beetle larva
Fig. 10-A, p. 211
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Green Revolution

• Three-step green revolution
• Selectively bred monocultures
• High yields through high inputs fertilizer,
  pesticides, and water
• Multiple cropping
• Second green revolution fast-growing dwarf
  varieties of wheat and rice
• 1950-1996 world grain production tripled

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Fig. 10-4, p. 212
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Case Study Industrialized Food Production in the
U.S.

• Industrialized farming agribusiness
• Increasing number of giant multinational
  corporations
• 10 U.S. income spent on food
• Subsidized through taxes

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Case Study Brazil The Worlds Emerging Food
Superpower

• Ample sun, water, and arable land
• EMBRAPA government agricultural research
  corporation
• 2-3 crops per year in tropical savanna
• Lack of transportation impeding further growth as
  food exporter

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Production of New Crop Varieties

• Traditional
• Crossbreeding
• Artificial selection
• Slow process
• Genetic engineering
• Genetic engineering
• gt75 of U.S. supermarket food genetically
  engineered

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Fig. 10-5, p. 214
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Fig. 10-5, p. 214
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Fig. 10-5, p. 214
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Phase 1 Gene Transfer Preparations
A. tumefaciens
Plant cell
Extract plasmid
Extract DNA
plasmid
Foreign gene if interest
Foreign gene integrated into plasmid DNA.
Agrobacterium takes up plasmid
Phase 2 Make Transgenic Cell
A. tumefaciens (agrobacterium)
Enzymes integrate plasmid into host cell DNA.
Host cell
Fig. 10-5, p. 214
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Foreign DNA
Host DNA
Transgenic plant cell
Nucleus
Phase 3 Grow Genetically Engineered Plant
Cell division of transgenic cells
Cultured cells divide and grow into
plantlets (otherwise teleological)
Transgenic plants with desired trait
Fig. 10-5, p. 214
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Meat Production

• Meat and dairy products are good sources of
  protein
• Past 60 years meat production up five-fold
• Half of meat from grazing livestock, other half
  from feedlots

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Fish and Shellfish Production Have Increased
Dramatically

• Aquaculture 46 of fish/shellfish production in
  2006
• Ponds
• Underwater cages
• China produces 70 of worlds farmed fish

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Fig. 10-6, p. 214
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10-3 What Environmental Problems Arise from Food
Production?

• Concept 10-3 Future food production may be
  limited by soil erosion and degradation,
  desertification, water and air pollution, climate
  change from greenhouse gas emissions, and loss of
  biodiversity.

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Natural Capital Degradation
Food Production
Human Health
Biodiversity Loss
Water
Soil
Air Pollution
Loss and degradation of grasslands, forests, and
wetlands
Erosion
Water waste
Greenhouse gas emissions (CO2) from fossil fuel
use
Nitrates in drinking water (blue baby)
Loss of fertility
Aquifer depletion
Pesticide residues in drinking water, food, and
air
Increased runoff, sediment pollution, and
flooding from cleared land
Greenhouse gas emissions (N2O) from use of
inorganic fertilizers
Fish kills from pesticide runoff
Salinization
Waterlogging
Killing wild predators to protect livestock
Contamination of drinking and swimming water from
livestock wastes
Desertification
Pollution from pesticides and fertilizers
Greenhouse gas emissions of methane (CH4) by
cattle (mostly belching)
Loss of genetic diversity of wild crop strains
replaced by monoculture strains
Algal blooms and fish kills in lakes and
rivers caused by runoff of fertilizers
and agricultural wastes
Bacterial contamination of meat
Other air pollutants from fossil fuel use and
pesticide sprays
Fig. 10-7, p. 215
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Soil Erosion

• Flowing water
• Wind
• Soil fertility declines
• Water pollution occurs
• Some natural
• Much due to human activity

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Fig. 10-8, p. 216
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Serious concern
Some concern
Stable or nonvegetative
Stepped Art
Fig. 10-9, p. 216
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Drought and Human Activities

• Desertification
• Combination of prolonged draught and human
  activities
• 70 of worlds drylands used for agriculture
• Will be exacerbated by climate change

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Fig. 10-10, p. 217
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Effects of Irrigation

• Leaves behind salts in topsoil
• Salinization
• Affects 10 of global croplands
• Waterlogging
• Attempts to leach salts deeper but raises water
  table
• Affects 10 of global croplands

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Fig. 10-11, p. 217
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Limits to Expanding Green Revolutions

• High-inputs too expensive for subsistence farmers
• Water not available for increasing population
• Irrigated land per capita dropping
• Significant expansion of cropland unlikely for
  economic and ecological reasons

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Industrialized Food Production Requires Huge
Energy Inputs

• Mostly nonrenewable oil
• Run machinery
• Irrigation
• Produce pesticides
• Process foods
• Transport foods
• In U.S., food travels an average of 1,300 miles
  from farm to plate

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Controversies over Genetically Engineered Foods

• Potential long-term effects on humans
• Ecological effects
• Genes cross with wild plants
• Patents on GMF varieties

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Trade-Offs
Genetically Modified Crops and Foods
Projected Disadvantages
Projected Advantages
Irreversible and unpredictable genetic
and ecological effects
Need less fertilizer
Need less water
Harmful toxins in food from possible plant cell
mutations
More resistant to insects, disease, frost, and
drought
New allergens in food
Grow faster
Can grow in slightly salty soils
Lower nutrition
Increase in pesticide-resistant
insects, herbicide-resistant weeds, and plant
diseases
May need less pesticides
Tolerate higher levels of herbicides
Can harm beneficial insects
Higher yields
Less spoilage
Lower genetic diversity
Fig. 10-12, p. 219
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Food and Biofuel Production Lead to Major Losses
of Biodiversity

• Forests cleared
• Grasslands plowed
• Loss of agrobiodiversity
• Since 1900, lost 75 of genetic diversity of
  crops
• Losing the genetic library of food diversity

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Industrial Meat Production Consequences

• Uses large amounts of fossil fuels
• Wastes can pollute water
• Overgrazing
• Soil compaction
• Methane release greenhouse gas

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Aquaculture Problems

• Fish meal and fish oil as feed
• Depletes wild fish populations
• Inefficient
• Can concentrate toxins such as PCBs
• Produce large amounts of waste

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Trade-Offs
Aquaculture
Advantages
Disadvantages
High efficiency
Needs large inputs of land, feed, and water
High yield in small volume of water
Large waste output
Can destroy mangrove forests and estuaries
Can reduce overharvesting of fisheries
Uses grain, fish meal, and fish oil to feed some
species
Low fuel use
Dense populations vulnerable to disease
High profits
Fig. 10-13, p. 220
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10-4 How Can We Protect Cropsfrom Pests More
Sustainably?

• Concept 10-4 We can sharply cut pesticide use
  without decreasing crop yields by using a mix of
  cultivation techniques, biological pest controls,
  and small amounts of selected chemical pesticides
  as a last resort (integrated pest management).

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Natures Pest Control

• Polycultures pests controlled by natural
  enemies
• Monocultures and land clearing
• Loss of natural enemies
• Require pesticides

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Fig. 10-14, p. 221
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Increasing Pesticide Use

• Up 50-fold since 1950
• Broad-spectrum agents
• Selective agents
• Persistence
• Biomagnification some pesticides magnified in
  food chains and webs

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Trade-Offs
Conventional Chemical Pesticides
Advantages
Disadvantages
Save lives
Promote genetic resistance
Increase food supplies
Kill natural pest enemies
Pollute the environment
Profitable
Work fast
Can harm wildlife and people
Safe if used properly
Are expensive for farmers
Fig. 10-15, p. 222
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Advantages of Modern Pesticides

• Save human lives
• Increase food supplies
• Increase profits for farmers
• Work fast
• Low health risks when used properly
• Newer pesticides safer and more effective

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Disadvantages of Modern Pesticides

• Pests become genetically resistant
• Some insecticides kill natural enemies
• May pollute environment
• Harmful to wildlife
• Threaten human health
• Use has not reduced U.S. crop losses

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Laws Regulate Pesticides

• Environmental Protection Agency (EPA)
• United States Department of Agriculture (USDA)
• Food and Drug Administration (FDA)
• Congressional legislation
• Laws and agency actions criticized

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Fig. 10-16, p. 224
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Individuals Matter Rachel Carson

• Biologist
• DDT effects on birds
• 1962 Silent Spring makes connection between
  pesticides and threats to species and ecosystems

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Fig. 10-B, p. 223
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Science Focus Ecological Surprises

• Dieldrin killed malaria mosquitoes, but also
  other insects
• Poison moved up food chain
• Lizards and then cats died
• Rats flourished
• Operation Cat Drop
• Villagers roofs collapsed from caterpillars
  natural insect predators eliminated

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Alternatives to Pesticides

• Fool the pest
• Provide homes for pest enemies
• Implant genetic resistance
• Natural enemies
• Pheromones to trap pests or attract predators
• Hormones to disrupt life cycle

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Fig. 10-18, p. 226
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Integrated Pest Management

• Evaluate a crop and its pests as part of
  ecological system
• Design a program with
• Cultivation techniques
• Biological controls
• Chemical tools and techniques
• Can reduce costs and pesticide use without
  lowering crop yields

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10-5 How Can We Improve Food Security?

• Concept 10-5 We can improve food security by
  creating programs to reduce poverty and chronic
  malnutrition, relying more on locally grown food,
  and cutting waste.

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Use Government Policies to Improve Food
Production and Security

• Control food prices
• Helps consumers
• Hurts farmers
• Provide subsidies to farmers
• Price supports, tax breaks to encourage food
  production
• Can harm farmers in other countries who dont get
  subsidies
• Some analysts call for ending all subsidies

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Reducing Childhood Deaths

• 510 annual per child would prevent half of
  nutrition-related deaths
• Strategies
• Immunization
• Breast-feeding
• Prevent dehydration from diarrhea
• Vitamin A
• Family planning
• Health education for women

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10-6 How Can We Produce Food More Sustainably?

• Concept 10-6 More sustainable food production
  involves reducing overgrazing and overfishing,
  irrigating more efficiently, using integrated
  pest management, promoting agrobiodiversity, and
  providing government subsidies only for more
  sustainable agriculture, fishing, and
  aquaculture.

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Reduce Soil Erosion (1)

• Terracing
• Contour plowing
• Strip cropping
• Alley cropping
• Windbreaks

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Reduce Soil Erosion (2)

• Shelterbelts
• Conservation-tillage farming
• No-till farming
• Minimum-tillage farming
• Retire erosion hotspots

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Stepped Art
Fig. 10-19, p. 229
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Fig. 10-19, p. 229
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Fig. 10-19, p. 229
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Fig. 10-19, p. 229
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Fig. 10-19, p. 229
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Government Intervention

• Governments influence food production
• Control prices
• Provide subsidies
• Let the marketplace decide
• Reduce hunger, malnutrition, and environmental
  degradation
• Slow population growth
• Sharply reduce poverty
• Develop sustainable low-input agriculture

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Case Study Soil Erosion in the United States

• Dust Bowl in the 1930s
• 1935 Soil Erosion Act
• Natural Resources Conservation Service
• Helps farmers and ranchers conserve soil
• One-third topsoil gone
• Much of the rest degraded
• Farmers paid to leave farmland fallow

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Restoring Soil Fertility

• Organic fertilizers
• Animal manure
• Green manure
• Compost
• Crop rotation uses legumes to restore nutrients
• Inorganic fertilizers pollution problems

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Solutions
Soil Salinization
Prevention
Cleanup
Flush soil (expensive and wastes water)
Reduce irrigation
Stop growing crops for 25 years
Switch to salt-tolerant crops (such as barley,
cotton, and sugar beet)
Install underground drainage systems (expensive)
Fig. 10-20, p. 230
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Fig. 10-21, p. 231
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Sustainable Meat Production

• Shift to eating herbivorous fish or poultry
• Eat less meat
• Vegetarian

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7
Beef cattle
Pigs
4
2.2
Chicken
Fish (catfish or carp)
2
Fig. 10-22, p. 231
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Solutions
Sustainable Organic Agriculture
More
Less
High-yield polyculture
Soil erosion
Aquifer depletion
Organic fertilizers
Overgrazing
Biological pest control
Overfishing
Integrated pest management
Loss of biodiversity
Efficient irrigation
Food waste
Perennial crops
Subsidies for unsustainable farming and fishing
Crop rotation
Water-efficient crops
Soil salinization
Soil conservation
Population growth
Subsidies for sustainable farming and fishing
Poverty
Fig. 10-23, p. 232
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Shift to More Sustainable Agriculture

• Organic farming
• Perennial crops
• Polyculture
• Renewable energy, not fossil fuels

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Six Strategies for Sustainable Agriculture

• Increase research on sustainable agriculture
• Set up demonstration projects
• International fund to help poor farmers
• Establish training programs
• Subsidies only for sustainable agriculture
• Education program for consumers

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Solutions
Organic Farming
Improves soil fertility
Reduces soil erosion
Retains more water in soil during drought years
Uses about 30 less energy per unit of yield
Lowers CO2 emissions
Reduces water pollution by recycling livestock
wastes
Eliminates pollution from pesticides
Increases biodiversity above and below ground
Benefits wildlife such as birds and bats
Fig. 10-24, p. 233
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Fig. 10-25, p. 234
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Science Focus The Land Institute and Perennial
Culture

• Polycultures of perennial crops
• Live for years without replanting
• Better adapted to soil and climate conditions
• Less soil erosion and water pollution
• Increases sustainability

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Fig. 10-B, p. 233
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Three Big Ideas from This Chapter - 1

• About 925 million people have health problems
  because they do not get enough to eat and 1.6
  billion people face health problems from eating
  too much.

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Three Big Ideas from This Chapter - 2

• Modern industrialized agriculture ha a greater
  harmful impact on the environment than any other
  human activity.

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Three Big Ideas from This Chapter - 3

• More sustainable forms of food production will
  greatly reduce the harmful environmental impacts
  of current systems while increasing food security
  and national security for all countries.