Food and Soil Resources
G. Tyler Miller’s
Living in the Environment
14th Edition
Chapter 14
Two Worlds
Soil, a
limited
resource we
depend
upon, but
take for
granted
Chapter 14: Key Concepts
 Methods of producing food
 Increasing food production
 Soil degradation
 Increasing sustainability
Aldo Leopold
There are two spiritual dangers in not
owning a farm. One is the danger of
supposing that breakfast comes from
the grocery store, and the other that
heat from the furnace.
Section 1: How Is Food Produced?
• What systems provide us with food?
• What plants and animals feed the world?
• What are the major types of food production?
How Food Is Produced
Historically:
• Croplands (77%)
• Rangeland (16%)
• Ocean Fisheries (7%)
Since 1950 there has been a
staggering increase in all
production.
Huge technology increase
How Food Is Produced
Technology Changes:
•
•
•
•
•
•
•
•
Farm machinery
Fishing equipment
Fertilizers
Pesticides
Irrigation
GE Foods
Feedlots
Fish farms
Each improvement brings
new challenges
How Food Is Produced
Can we meet the
challenge of feeding 9
billion people by
2050?
• W/O Degradation of
environment
• And reduce poverty
(1 of 5 do not
produce enough food)
How Food Is Produced
• 30,000 possible plant species
people can eat
• Since ag. rev. 10,000 consumed
• Today: 14 plants, 8 terrestrial
animals provide 90% calories
• 3 (wheat, rice and corn) provide
½ world’s calories – all annuals
(potatoes huge also)
• Dramatic reduction in
biodiversity of agriculture
• Most cannot afford meat
How Is Food Produced?
Sources of food
3 Primary plants:
wheat, corn, and rice
4 Primary animals:
fish, beef, pork, and chicken
Major Types of Agriculture
Industrialized agriculture
Plantation
Traditional subsistence agriculture
Traditional intensive agriculture
Major Types of Agriculture
Industrial Agriculture:
• Fossil Fuel Energy
• Heavy Water Use
• Single Crops
(monoculture)
• Commercial fertilizers
• ¼ of all cropland
• Mostly in developed
countries
Industrial agriculture in California
Major Types of Agriculture
Plantation Agriculture:
• Form of industrial
agriculture in tropical
developing countries
• Cash crops: banana,
coffee, sugar cane, cocoa
• Monoculture for sale in
developed countries
• Increasing large livestock
Coffee Plantation
Major Types of Agriculture
Traditional Subsistence
Agriculture:
• Human labor and draft
animals producing food
form family survival
• Nomadic herding
• 42% of world’s people
uses traditional
agriculture
Major Types of Agriculture
Traditional Intensive
Agriculture:
• Increasing human and
animal labor,
fertilizers, water to
get higher yields
• Enough food for
family and to sell
locally
• Agriculture is world’s
leading industry
World Food Production
Fig. 14-2 p. 275
Hunterdon County, New Jersey
Section 2: Producing Food by
Green-Revolution Techniques
 High-input monoculture
 Selectively bred or genetically-engineered
crops
 High inputs of fertilizer
 Extensive use of pesticides
 High inputs of water
 Multiple cropping
Green Revolution in Agriculture
Since the 1950s farmers
having been getting
huge increases in crop
production per unit of
land.
First Step: develop and
plant monocultures of
GM high-yield crops
like corn, rice and
wheat
Cavendish Banana
Green Revolution in Agriculture
Second Step: Use large inputs
of fertilizers, pesticides and
water.
Third Step: Increase number
of crops grown per year on a
plot of land (more crop less
land)
These techniques produce huge
increases in crops BUT need
lots of water, fossil fuels,
machinery, pesticides,
fertilizers
* Uses 8% of world’s oil *
Green Revolution in U.S.
Agribusiness: loss of the family
farm to corporate
farming…Superfarms
• U.S. Ag. More total sales than
auto, steel and housing combined
• 18% of Gross National Income
(1/5 of all U.S. private sector
jobs)
• 0.3% of world’s farmers produce
17% of world’s grain (1/2 of
world’s corn and soybeans)
• Huge increase in efficiency
Green Revolution in U.S.
Developed Countries: People spend
about 40% of income on food
Developing Countries: 70%
Industrial Ag. Needs cheap fossil
fuels…putting food on table
accounts for 17% of energy used
in U.S.
Energy used to grow, store, process,
package, transport, refrigerate,
cook
10 units of energy for 1 unit of food
energy in your stomach
Green Revolutions
First green revolution
Second green revolution
(developed countries)
(developing countries)
Major International agricultural
research centers and seed banks
Fig. 14-4 p. 277
Producing Food by Traditional
Techniques
Interplanting
Polyvarietal cultivation
Intercropping
Agroforestry (alley cropping)
Polyculture
Look up terms on page 278
Showing where energy is used in food
production in U.S. Food travels avg. of 1,500
miles from farm to fork in U.S.
New Jersey Peach Farm: What are the
advantages and disadvantages of eating locally grown food?
Section 3: Soil Erosion
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•
•
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What causes soil erosion?
How serious of a problem is it?
Good news and bad news from the U.S.
What is desertification?
How do salts degrade the soil?
Causes of Soil Erosion
Wind
Water #1
People
Why
care
about
soil
erosion?
Impacts of Soil Erosion
• Loss of soil fertility
• Sediment runoff causes
problems in surface water
(pollution, clog ditches,
boat channels, reservoirs)
• #1 source of U.S. water
pollution
• Renewable only on LONG
timeframes (200-1,000yrs.
for 1 inch)
Soil Erosion
On Ag. land in U.S. today, soil is eroding 16 times
faster than it is created
Global Soil Erosion
Areas of serious concern
Areas of some concern
Stable or nonvegetative areas
Fig. 14-7 p. 280
Soil Erosion in the US
Dust Bowl – 1930s: Fig. 14-5 p. 281
Reductions in erosion since 1987
1985 Food Security Act
Huge Erosion Problems During “Dust Bowl” era
Causes of Desertification
Overgrazing
Deforestation
Erosion
Salinization
Soil Compaction
Natural Climate Change
Refer to Fig. 14-10 p. 283
World Desertification
Fig. 14-9 p. 282
Desertification: causes and
consequences.
•Occurring on 1/3 of world’s land
Salinization
1. Irrigation water
contains small
amounts of
dissolved salts
2. Evaporation
and
transpiration
leave salts
behind
3. Salt builds up
on soil
Reducing and Cleaning Up
Salinization
Reduce irrigation
Switch to salt-tolerant crops
Flush soils
Not growing crops for 2-5 years
Install underground drainage
Refer to Fig. 14-12 p. 283
Soil Degradation on Irrigated Land
Salinization
Evaporation
Evaporation
Transpiration
 Waterlogging
1. Precipitation and
irrigation water
percolate
downward
2. Water table rises
3. Bad for roots
Waterlogging
Less permeable
clay layer
Fig. 14-11 p. 283
Section 4: Soil Conservation
• What is soil conservation and how does it
work?
• What are some methods for reducing soil
erosion?
• Inorganic versus organic fertilizers
Soil Conservation
Involves many ways of reducing soil erosion and
restoring fertility to soil.
Conventional Tillage
Farmers plow the land and
then break up and
smoothes soil to make a
planting surface
• Leaves soil vulnerable to
erosion
• Midwest tillage often
down in fall (winter bare)
Conservation Tillage
Disturbing the soil as little
as possible while planting
crop
• Not tilling over winter
• Planting without
disturbing soil
• Special equipment
“inject” soil with seed,
fertilizer etc.
• In 2003 45% of U.S.
farms
Solutions: Soil Conservation
Conventional-tillage
Conservation tillage
Terracing
Refer to Fig. 14-14 p. 285
Contour farming
Strip and alley cropping
Windbreaks
Land Classification
Terracing
Used on
steep
slopes
Reduces
erosion
and water
loss
Contour
planting
Planting crops
in rows across
the slope
Strip
Cropping
Cover Crops: can be planted
right after harvest to hold onto
soil during winter
Alternating
crops from
row crops and
crops that
completely
cover surface
Alley Cropping: several cops planted together in rows
(alleys) Increases shade (less water) Provide windbreaks
Windbreaks
Soil Restoration
Organic fertilizer
Animal manure
Compost
Crop rotation
Commercial inorganic fertilizer
Organic Fertilizer
Has decreased in the U.S.
due in part because
most farmers no longer
raise livestock and it
costs too much to
transport
• Poop Factory and
Phillies Soil
• Inorganic fertilizers
have taken off
Inorganic Fertilizers
Nitrogen, Phosphorous,
Potassium
• Grown in usage worldwide
• Credited with increasing
crop yields (1/4 of world
crops)
• W/o could only feed 2-3
billion people
• Many problems associated
(see next slide)
The amount of energy needed to produce a single
hamburger is enough to power a small car 20 miles