ENVIRONMENTAL SCIENCE 13e
CHAPTER 10:
Food, Soil, and Pest
Management
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
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
Fig. 10-1, p. 206
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
Uses antibiotics and growth hormones
to produce meat and meat products
Fig. 10-1, p. 206
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
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.
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
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
Supplement 3, Fig. 11, p. S12
Fig. 10-2, p. 208
Fig. 10-3, p. 209
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
10-2 How Is Food Produced?
• Concept 10-2 We have used highinput industrialized agriculture and
lower-input traditional methods to
greatly increase supplies of food.
Where We Get Food (1)
• Major sources:
– Croplands
– Rangelands, pastures, and feedlots
– Fisheries and aquaculture
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
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
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
Industrialized Agriculture (2)
• Plantation agriculture primarily in
tropics
– Bananas
– Sugarcane
– Coffee
– Vegetables
– Exported primarily to developed
countries
Traditional Agriculture
• 2.7 billion people in developing
countries
• Traditional subsistence agriculture
• Traditional intensive agriculture
• Monoculture
• Polyculture
Science Focus: Soil is the Base
of Life on Land (1)
• Soil composed of
– Eroded rock
– Mineral nutrients
– Decaying organic matter
– Water
– Air
– Organisms
Science Focus: Soil is the Base
of Life on Land (2)
• Soil is a key component of earth’s
natural capital
• Soil profile
– O Horizon
– A horizon
– B horizon
– C horizon
Fig. 10-A, p. 211
Moss and
lichen
Rock
fragments
Organic
debris
Grasses and
small shrubs
Oak
tree
Honey
fungus
Fern
Millipede
Earthworm
Wood
sorrel
O horizon
Leaf litter
A horizon
Topsoil
Mole
Bacteria
B horizon
Subsoil
Fungus
C horizon
Parent
material
Mite
Nematode
Root system
Red earth mite
Beetle larva
Fig. 10-A, p. 211
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
Fig. 10-4, p. 212
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
Case Study: Brazil – The World’s
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
Production of New Crop
Varieties
• Traditional
– Crossbreeding
– Artificial selection
– Slow process
• Genetic engineering
– Genetic engineering
• >75% of U.S. supermarket food
genetically engineered
Fig. 10-5, p. 214
Fig. 10-5, p. 214
Fig. 10-5, p. 214
Phase 1
Gene Transfer Preparations
A. tumefaciens
Plant cell
Extract DNA
Extract
plasmid
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
Foreign DNA
Host DNA
Nucleus
Transgenic
plant cell
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
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
Fish and Shellfish Production
Have Increased Dramatically
• Aquaculture – 46% of fish/shellfish
production in 2006
– Ponds
– Underwater cages
– China produces 70% of world’s farmed
fish
Fig. 10-6, p. 214
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.
Fig. 10-7, p. 215
Natural Capital Degradation
Food Production
Biodiversity Loss
Loss and degradation
of grasslands, forests,
and wetlands
Fish kills from
pesticide runoff
Killing wild predators
to protect livestock
Loss of genetic
diversity of wild crop
strains replaced by
monoculture strains
Soil
Water
Air Pollution
Human Health
Nitrates in drinking
water (blue baby)
Erosion
Water waste
Loss of fertility
Aquifer depletion
Greenhouse gas
emissions (CO2) from
fossil fuel use
Salinization
Increased runoff,
sediment pollution,
and flooding from
cleared land
Greenhouse gas
emissions (N2O) from
use of inorganic
fertilizers
Pollution from
pesticides and
fertilizers
Greenhouse gas
emissions of methane
(CH4) by cattle
(mostly belching)
Waterlogging
Desertification
Algal blooms and fish
kills in lakes and rivers Other air pollutants
from fossil fuel use
caused by runoff of
and pesticide sprays
fertilizers and
agricultural wastes
Pesticide residues in
drinking water, food,
and air
Contamination of
drinking and
swimming water
from livestock
wastes
Bacterial
contamination of
meat
Fig. 10-7, p. 215
Soil Erosion
•
•
•
•
•
•
Flowing water
Wind
Soil fertility declines
Water pollution occurs
Some natural
Much due to human activity
Fig. 10-8, p. 216
Fig. 10-9, p. 216
Serious concern
Some concern
Stable or
nonvegetative
Stepped Art
Fig. 10-9, p. 216
Drought and Human Activities
• Desertification
• Combination of prolonged draught
and human activities
• 70% of world’s drylands used for
agriculture
• Will be exacerbated by climate
change
Fig. 10-10, p. 217
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
Fig. 10-11, p. 217
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
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
Controversies over Genetically
Engineered Foods
•
•
•
•
Potential long-term effects on humans
Ecological effects
Genes cross with wild plants
Patents on GMF varieties
Fig. 10-12, p. 219
Trade-Offs
Genetically Modified Crops and Foods
Projected
Advantages
Projected
Disadvantages
Need less fertilizer
Need less water
Irreversible and
unpredictable genetic and
ecological effects
More resistant to insects,
disease, frost, and drought
Harmful toxins in food
from possible plant cell
mutations
Grow faster
New allergens in food
Can grow in slightly salty
soils
Lower nutrition
May need less pesticides
Increase in
pesticide-resistant insects,
herbicide-resistant weeds,
and plant diseases
Tolerate higher levels of
herbicides
Higher yields
Can harm beneficial
insects
Less spoilage
Lower genetic diversity
Fig. 10-12, p. 219
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
Industrial Meat Production
Consequences
•
•
•
•
•
Uses large amounts of fossil fuels
Wastes can pollute water
Overgrazing
Soil compaction
Methane release: greenhouse gas
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
Fig. 10-13, p. 220
Trade-Offs
Aquaculture
Advantages
Disadvantages
High efficiency
Needs large inputs of land,
feed, and water
High yield in small volume
of water
Can reduce overharvesting
of fisheries
Large waste output
Can destroy mangrove
forests and estuaries
Low fuel use
Uses grain, fish meal,
and fish oil to feed some
species
High profits
Dense populations
vulnerable to disease
Fig. 10-13, p. 220
10-4 How Can We Protect Crops
from 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).
Nature’s Pest Control
• Polycultures – pests controlled by
natural enemies
• Monocultures and land clearing
– Loss of natural enemies
– Require pesticides
Fig. 10-14, p. 221
Increasing Pesticide Use
•
•
•
•
•
Up 50-fold since 1950
Broad-spectrum agents
Selective agents
Persistence
Biomagnification – some pesticides
magnified in food chains and webs
Fig. 10-15, p. 222
Trade-Offs
Conventional Chemical Pesticides
Advantages
Disadvantages
Save lives
Promote genetic
resistance
Increase food
supplies
Kill natural pest enemies
Profitable
Pollute the environment
Work fast
Can harm wildlife and
people
Safe if used
properly
Are expensive for farmers
Fig. 10-15, p. 222
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
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
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
Fig. 10-16, p. 224
Individuals Matter: Rachel
Carson
• Biologist
• DDT effects on birds
• 1962: Silent Spring makes connection
between pesticides and threats to
species and ecosystems
Fig. 10-B, p. 223
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
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
Fig. 10-18, p. 226
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
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.
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
don’t get subsidies
– Some analysts call for ending all subsidies
Reducing Childhood Deaths
• $5–$10 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
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.
Reduce Soil Erosion (1)
•
•
•
•
•
Terracing
Contour plowing
Strip cropping
Alley cropping
Windbreaks
Reduce Soil Erosion (2)
•
•
•
•
•
Shelterbelts
Conservation-tillage farming
No-till farming
Minimum-tillage farming
Retire erosion hotspots
Fig. 10-19, p. 229
Fig. 10-19, p. 229
Fig. 10-19, p. 229
Fig. 10-19, p. 229
(a) Terracing
(c) Alley cropping
(b) Contour planting and strip cropping
(d) Windbreaks
Stepped Art
Fig. 10-19, p. 229
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
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
Restoring Soil Fertility
• Organic fertilizers
– Animal manure
– Green manure
– Compost
• Crop rotation uses legumes to restore
nutrients
• Inorganic fertilizers – pollution
problems
Fig. 10-20, p. 230
Solutions
Soil Salinization
Prevention
Reduce irrigation
Cleanup
Flush soil (expensive
and wastes water)
Stop growing crops for
2–5 years
Switch to salt-tolerant
crops (such as barley,
cotton, and sugar beet)
Install underground
drainage systems
(expensive)
Fig. 10-20, p. 230
Fig. 10-21, p. 231
Sustainable Meat Production
• Shift to eating herbivorous fish or
poultry
• Eat less meat
• Vegetarian
Fig. 10-22, p. 231
7
Beef cattle
Pigs
Chicken
Fish (catfish
or carp)
4
2.2
2
Fig. 10-22, p. 231
Fig. 10-23, p. 232
Solutions
Sustainable Organic Agriculture
More
Less
High-yield
polyculture
Soil erosion
Aquifer depletion
Organic fertilizers
Biological pest
control
Overgrazing
Overfishing
Integrated pest
management
Efficient irrigation
Perennial crops
Crop rotation
Water-efficient
crops
Soil conservation
Subsidies for
sustainable farming
and fishing
Loss of biodiversity
Food waste
Subsidies for
unsustainable
farming and
fishing
Soil salinization
Population growth
Poverty
Fig. 10-23, p. 232
Shift to More Sustainable
Agriculture
•
•
•
•
Organic farming
Perennial crops
Polyculture
Renewable energy, not fossil fuels
Six Strategies for Sustainable
Agriculture
1. Increase research on sustainable
agriculture
2. Set up demonstration projects
3. International fund to help poor farmers
4. Establish training programs
5. Subsidies only for sustainable agriculture
6. Education program for consumers
Fig. 10-24, p. 233
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
Fig. 10-25, p. 234
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
Fig. 10-B, p. 233
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.
Three Big Ideas from This
Chapter - #2
Modern industrialized agriculture ha a
greater harmful impact on the
environment than any other human
activity.
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.
Animation: Land Use
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Animation: Soil Profile
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Animation: Resources Depletion
and Degradation
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Animation: Acid Deposition
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Animation: Transferring Genes
into Plants
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Animation: Effects of
Deforestation
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Animation: Ocean Provinces
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Animation: Pesticide Examples
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Video: The Problem with Pork
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Video: Food Allergy Increase
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Video: Fat Man Walking
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Video: Desertification in China
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