Transcript Document 4664

Food Resources
G. Tyler Miller’s
Living in the Environment
13th Edition
Chapter 13
Key Concepts
 Methods of producing food
 Increasing food production
 Environmental effects of food production
 Increasing sustainability
How Is Food Produced?
Sources of food
Croplands (grain – 76% world’s food)
Rangelands (grazing livestock – 17%)
Oceanic Fisheries (fish – 7%)
Increase in Global Food Production
Since 1950 Due to:
 Increased technology: tractors,
farm machinery, fishing boats, etc.
 Inorganic chemical fertilizers
 Irrigation
 Pesticides
 High yield varieties of corn, rice,
and wheat
 Densely populated feedlots and
pens (cattle, pigs, chickens)
 Aquaculture
But, this increase has led to:
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Environmental degradation
Pollution
Lack of water for irrigation
Overgrazing
Overfishing
Loss of vital ecological services
What plants and animals feed the
world?
 Wheat, rice, and corn provide over half
the calories we consume globally
 Annuals: must be replanted every year
 15 plant and 8 terrestrial animal species
provide over 90% of our food
 2/3 of world’s population survive
primarily on grains
 As incomes rise, people consume more
meat (more grain indirectly)
 Beef, pork, and chicken are main
animal sources of food
Types of Food Production
 Industrialized/High-put Agriculture
 Traditional
Major Types of Agriculture
INDUSTRIALIZED
Plantation agriculture
Practiced primarily in tropical
developing countries
Involves growing cash crops
(bananas, coffee, soybeans,
sugarcane, cocoa, and vegetables)
on large monoculture plantations,
mostly for sale to developed
countries
Major Types of Agriculture
INDUSTRIALIZED
Industrialized (high-input)
Use fossil fuels, water, fertilizer,
pesticides to produce large quantities
of a single crop (monoculture)
Major Types of Agriculture
TRADITIONAL
44% of World’s People practice this
Traditional subsistence:
Uses mostly human labor
Draft animals to produce only
enough crops and livestock for the
family’s survival
Major Types of Agriculture
TRADITIONAL
Traditional intensive
Increased input of human and
draft labor
Increased input of water
Increased input of fertilizer
Enough food to feed family and
Attempt
to
increase
yield
to
produce
make an income
extra for sale
World Food Production
Industrialized agriculture
Plantation agriculture
Shifting cultivation
Nomadic herding
Intensive traditional agriculture
No agriculture
Land
Labor
Capital
Fossil fuel
energy
Industrialized agriculture
in developed countries
Land
Labor
Capital
Fossil fuel energy
Intensive traditional agriculture
in developing countries
An average of 60% of
the people in
developing countries
are involved DIRECTLY
in producing food,
compared with only
8% in developed
countries and 2% in
the United States.
Land
Labor
Capital
Shifting cultivation in tropical
forests in developing countries
Land
Labor
Capital
Nomadic herding in
developing countries
Food Type
Kilocalories of fossil fuel input per kilocalorie of protein output
Feed lot beef
20-78
Pigs
35
22
Broiler chicken
Rangeland Beef
10
Sheep
10
Vegetables
2-4
© 2004 Brooks/Cole – Thomson Learning
Croplands
Ecological Services
• Help maintain water
flow and soil infiltration
Economic Services
• Food crops
• Fiber crops
• Provide partial erosion
protection
• Can build soil organic
matter
• Store atmospheric
carbon
• Provide wildlife habitat
for some species
• Crop genetic
resources
• Jobs
Producing Food by Green-Revolution
Techniques (1950-1970)
 High-input monoculture
 Selectively bred or genetically-engineered
crops
 High inputs of fertilizer
 Extensive use of pesticides
 High inputs of water
 Increased intensity and frequency of
cropping (> yield, several times/season; saves land)
Green Revolutions
First green revolution
Second green revolution
(developed countries)
(developing countries)
Major International agricultural
research centers and seed banks
CHINA
HIGH-YIELD HYBRID
DO NOT POST TO INTERNET
INDONESIA
Semidwarf Rice called IR-8.
Producing Food by Traditional Techniques
(Interplanting)
 Intercropping: 2 or more different
crops are grown at the same time
 Polyvarietal cultivation: several varieties of
the same crop are planted at the same time
 Agroforestry (alley cropping): crops
and trees are planted together
 Polyculture: a complex form of intercropping
in which many different plants maturing at
different times are planted together
ADVANTAGES of POLYCULTURE
 Less need for fertilizer
 Less need for water (root systems are at
different depths)
 Protection from wind and water erosion
(soil covered year-round)
 Less need for insecticides (natural
predators thrive)
 Less need for herbicides (weeds have
trouble competing)
 Insurance in case of bad weather
because of diversity of crops produced
On average, low-input
polyculture, with 4 or 5
different crop species,
produces higher yields
per hectare of land than
high-input monoculture.
Nutrition
Undernutrition: lack of food to
meet basic needs (getting 100-400 fewer calories
per day than needed)
Malnutrition: deficiency of nutrients
in diet (deficiency of protein and other key nutrients)
Overnutrition: too many calories
lead to overweight
MARASMUS: “to waste away”
 Occurs when a diet is both low in
calories and protein
 Usually occurs in young children
KWASHIORKOR: “displaced child”
 Severe protein deficiency
 Usually occurs in children 1 – 3
years of age
Undernutrition and Malnutrition
 About 1 in 6 people in developing
countries is chronically undernourished
or malnourished
 Each year at least 10 million people,
half of them children under 5, die
prematurely from:
 Undernutrition
 Malnutrition
 Increased susceptibility to normally
nonfatal diseases
 Infectious diseases from contaminated
drinking water
Poverty
Decreased
energy
Decreased
resistance
to disease
Malnutrition
Decreased
ability
to learn
Decreased
ability
to work
Feedback loop
High death
rate for
children
Shortened
life
expectancy
Micronutrient Deficiencies
 The most widespread micronutrient deficiencies
include Vitamin A, Iron and Iodine.
 Vitamin A - plays essential roles in vision, growth,
and development; the development and
maintenance of healthy skin, hair, and mucous
membranes; immune functions; and reproduction
(found in foods like sweet potato, carrot, mango,
broccoli, spinach)
 Iron – is an essential component of hemoglobin
which transports oxygen throughout the body and
is important in many metabolic reactions (found in
foods like chick peas, boiled spinach, dried apricots
and figs)
 Iodine – plays an essential role in hormone
development in the human body. If you don't have
enough iodine in your diet, it can lead to an
enlarged thyroid gland (goitre) or other iodine
deficiency disorders (found in seafood, iodized salt
and some vegetables)
Overnutrition
 Food energy intake exceeds energy
use and causes body fat (obesity)
 About 1 out of every 7 adults in
developed countries is obese
 In the U.S. about 1 out of every 5
adults is obese
Environmental Effects of Food Production
Biodiversity loss
Soil
Air pollution
Water
Human health
Biodiversity Loss
Loss and degradation of habitat from
clearing grasslands and forests and
draining wetland
Fish kills from pesticide runoff
Killing of wild predators to protect
livestock
Loss of genetic diversity from
replacing thousands of wild crop
strains with a few monoculture strains
Soil
Erosion
Loss of fertility
Salinization
Waterlogging
Desertification
Air Pollution
Water
Greenhouse gas emissions from fossil
Fuel issue
Aquifer depletion
Other air pollutants from fossil fuel use
Increased runoff and
flooding from land cleared
to grow crops
Pollution from pesticide sprays
Sediment pollution from
erosion
Fish kills from pesticide
runoff
Surface and groundwater
pollution from pesticides
and fertilizers
Overfertilization of lakes
and slow-moving rivers
from runoff of nitrates and
phosphates from
fertilizers, livestock
wastes, and food
processing wastes
Human Health
Nitrates in drinking water
Pesticide residues in drinking water,
food, and air
Contamination of drinking and
swimming water with disease organisms
from livestock wastes
Bacterial contamination of meat
Increasing World Crop Production
 Crossbreeding and artificial selection
 Genetic engineering (gene splicing)
 Genetically modified organisms (GMOs)
 Continued Green Revolution techniques
 Introducing new foods
 Working more land
Crop
Desired trait
(color)
Cross breeding
Pear
Apple
Offspring
Cross
breeding
Best results
New
offspring
Desired
result
Phase 1
Make Modified Gene
cell
Identify and extract
gene with desired trait
Identify and remove
portion of DNA
with desired trait
gene
DNA
Plasmid
Remove plasmid
from DNA of E. coli
E. coli
DNA
Insert extracted DNA
(step 2) into plasmid
(step3)
Genetically
modified
plasmid
plasmid
Insert modified
plasmid into E. coli
Grow in tissue
culture to
make copies
Phase 2
Make Transgenic Cell
Transfer plasmid
copies to a carrier
agrobacterium
A. tumefaciens
(agrobacterium)
Agrobacterium
inserts foreign
DNA into plant
cell to yield
transgenic cell
Plant cell
Nucleus
Host DNA
Foreign DNA
Transfer plasmid
to surface
microscopic metal
particle
Use gene gun
to inject DNA
into plant cell
Phase 3
Grow Genetically Engineered Plant
Transgenic cell
from Phase 2
Cell division of
transgenic cells
Culture cells
to form plantlets
Transgenic plants
with new traits
Concerns with GMO’s
 “Frankenfood”
 We know far too little
 GMO’s cannot be recalled if they
cause harm
 No mandatory labeling (at this time)
 Crop seeds with “terminator
genes”
Projected
Advantages
Need less fertilizer
Advantages
and
Disadvantages
of Genetically
Modified
Foods
Need less water
More resistant to
insects, plant
disease, frost, and
drought
Faster growth
Can grow in slightly
salty soils
Less spoilage
Better flavor
Less use of conventional pesticides
Tolerate higher
levels of herbicide
use
Projected
Disadvantages
Irreversible and
unpredictable
genetic and ecological effects
Harmful toxins in
food from possible
plant cell mutations
New allergens
in food
Lower nutrition
Increased evolution
of pesticideresistant insects
and plant diseases
Creation of herbicideresistant weeds
Harm beneficial
insects
Lower genetic
diversity
Will People Try New Foods?
 Winged bean-protein rich legume
 Produces its own nitrogen
 Has multiple edible parts
 Microlivestock (INSECTS)-there are
about 1500 edible species; 3 – 4 times
as protein rich as beef, fish, or eggs

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Black ant larvae (Mexico)
Giant waterbugs (Thailand)
Emperor moth caterpillars (South Africa)
Cockroaches (Kalahari desert)
Butterflies (Bali)
Ants (Colombia)
Producing More Meat
 Rangeland
 Pasture
 Efficiency
Kilograms of grain needed per kilogram of body weight
Beef cattle
7
Pigs
Chicken
Fish (catfish
or carp)
4
2.2
2
 Adaptations of rangeland plants
 Range condition and management
 Environmental consequences
Rangeland and Pasture
 Rangeland is land that is too dry,
too steeply sloped, or too infertile
to grow crops (makes up about
40% of ice-free land)
 Pasture is managed grasslands or
enclosed meadows usually planted
with domesticated grasses
Ecology of Rangeland Plants. Rangeland grasses grow from
the bottom up and are renewable as long as the bottom half of
the plant (where photosynthesis takes place) is not eaten.
Ungrazed
Grazed
Metabolic
reserve
Recovery
Metabolic
reserve
intact
Metabolic
reserve
If the metabolic reserve is eaten (like during overgrazing)
the plant is weakened and can die.
Ungrazed
Overgrazed
Metabolic
reserve
Death
Most of
metabolic
reserve
eaten
Death
Rangeland: Overgrazed (left) and
lightly grazed (right.)
DO NOT POST TO INTERNET
Overgrazed
Riparian Zone
Arizona’s San Pedro River
Recovery
10 Years Later
Undergrazing
 Can reduce the net primary
productivity of grassland vegetation
and grass cover
 More likely in arid areas
Environmental Consequences of
Meat Production
 More than half of world’s cropland is
used to produce livestock feed
 Livestock consume 36% of world’s
grain
 Livestock use more than half the
water drawn from rivers and
aquifers (irrigation)
 Manure runoff leads to water
pollution
 Erosion resulting from grazing
 Cattle produce 16% of methane
(greenhouse gas)
Catching and Raising More Fish
The World’s 3rd major food-producing system
Fisheries – concentrations of particular aquatic
species in a given ocean area
Fishing methods (bycatch – thrown back in)
Sustainable yield
Overfishing (Tragedy of the Commons)
Commercial extinction (over fishing)
Aquaculture
Fish farming and ranching
Spotter airplane
Trawler
fishing
Fish farming
in cage
Purse-seine
fishing
trawl flap
trawl
lines
sonar
fish school
trawl bag
Fish caught
by gills
Drift-net fishing
Long line fishing
lines with
hooks
float buoy
800
80
Abundance
70
600
60
50
400
40
30
200
20
0
1960
1970
1980
Year
1990
2000
Abundance
(kilograms/tow)
Harvest
(thousands of metric tons)
Harvest
Human capture
Fish change form
Salmon
processing
plant
Fish enter rivers
and head for
spawning areas
To hatchery
In the fall spawning salmon
deposit eggs in gravel nests and die
Modified
Life
Cycle
Grow to maturity
in Pacific Ocean
in 1-2 years
Eggs are taken from adult
females and fertilized with
sperm “milked” from males
Fry hatch in the spring...
Normal
Life
Cycle
Eggs and young are
cared for in the hatchery
And grow in the stream
for 1-2 years
Grow to smolt
and enter the ocean...
Fingerlings migrate downstream
Fingerlings
are released into river
Advantages
Highly efficient
High yield in small
volume of water
Increased yields
through
crossbreeding
and genetic
engineering
Disadvantages
Large inputs of
land, feed, and
water needed
Produces large
and concentrated
outputs of waste
Destroys
mangrove forests
Can reduce
overharvesting
of conventional
fisheries
Increased grain
production
needed to feed
some species
Little use of fuel
Fish can be killed
by pesticide runoff
from nearby
cropland
Profit not tired to
price of oil
High profits
Dense populations
vulnerable to
disease
Tanks too
contaminated to
use after about
5 years
AQUACULTURE
Government Agricultural Policy
Artificially low prices – consumers are
happy, but farmers don’t make much money
Subsidies – given to farmers to keep them in
business (comes from taxpayer’s money)
Elimination of price controls – let
farmers respond to market demand without
government interference
Food aid – with any excess food
Solutions: Sustainable Agriculture
Low-input agriculture
Organic farming
More benefits to the poor
Increasing funding for research in
sustainable techniques
Increase
High-yield
polyculture
Decrease
Soil erosion
Soil salinization
Organic fertilizers
Aquifer depletion
Biological pest
control
Integrated pest
management
Irrigation efficiency
Perennial crops
Overgrazing
Overfishing
Loss of
biodiversity
Loss of prime
cropland
Crop rotation
Food waste
Use of more waterefficient crops
Soil conservation
Subsidies for
more sustainable
farming and
fishing
Subsidies for
unsustainable
farming and
fishing
Population growth
Poverty
Components of
More
SUSTAINABLE,
LOW
THROUGHPUT
Agriculture