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
10-1 What Is Food Security and
Why Is It So Difficult to Attain?
• 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.
• 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
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?
• We have used high-input
industrialized agriculture and lowerinput 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
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
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
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
10-3 What Environmental Problems
Arise from Food Production?
• 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.
Soil Erosion
• Flowing water
• Wind
• Soil fertility
declines
• Water pollution
occurs
• Some natural
• Much due to
human activity
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
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
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
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
10-4 How Can We Protect Crops
from Pests More Sustainably?
• 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
Increasing Pesticide Use
•
•
•
•
•
Up 50-fold since 1950
Broad-spectrum agents
Selective agents
Persistence
Biomagnification – some pesticides
magnified in food chains and webs
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
Pesticide Use
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
Individuals Matter: Rachel
Carson
• Biologist
• DDT effects on birds
• 1962: Silent Spring
makes connection
between pesticides and
threats to species and
ecosystems
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
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?
• 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?
• 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
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
Sustainable Meat Production
• Shift to eating herbivorous fish or
poultry
• Eat less meat
• Vegetarian
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
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
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.