Transcript Increasing World Crop Production

Food Resources
G. Tyler Miller’s
Living in the Environment
13th Edition
Chapter 13
NCSU
Ag. Institute Club
T-Shirt
How Is Food Produced?
• Sources of food provided by:
– cropland (76%)
– rangeland (17%)
– ocean fisheries (7%)
• Primary plants produced
– wheat, corn, rice
• Primary animals consumed
– beef, pork, chicken
DID YOU KNOW …
• THREE annual grains (wheat, rice, corn)
provide more than half the calories people
consume.
• 2/3 of the worlds pop survives on grains as they
cannot afford meat.
DID YOU KNOW …
• Food productivity has increased due to
technological advances BUT env problems
(irrigation, overgrazing, overfishing, pollution,
degradation) may limit future production.
DID YOU KNOW …
• Dependence on foreign food makes us vulnerable.
• Livestock consume over half of grains grown in
developing countries.
Carnivores
Major Types of Food Production
• Monoculture vs. Polyculture – one crop vs.
diversified many crops
Major Types of Agriculture
• Industrialized (high input)
– uses large quantities of fossil fuel energy,
capital $$, water, machinery, irrigation,
commercial fertilizer, and pesticides
– produces huge quantities of single crops or
livestock (monoculture)
– results in high yield crops and increased revenue temporarily
– results in soil degradation and potential pesticide resistance
• Plantation
– growing cash crops on large monoculture
plantations
– Mostly for sale in developed countries.
Major Types of Agriculture
• Livestock Production – densely populated
feedlots fed grain for plumping before
slaughter (CAFO)
Major Types of Agriculture
• Traditional Agriculture
– Traditional subsistence
• uses human labor and draft animals
• produce only enough food for a family’s
survival.
– Traditional intensive
• increased human and draft labor,
fertilizer, and water
• higher yields producing enough food for
their family and to sell for income.
Subsistence Examples
• Nomadic Herding – support livestock on arid
infertile soil
• Shifting Cultivation – short cultivation
periods followed by long periods of fallow
allowing land to revert back to forest
• Slash and Burn – clearing tropical rain
forest, quickly depletes soil nutrients
Various Growing Techniques
• interplanting – many different crops on same
plot
– polyvarietal cultivation – varieties of same crop on
same plot
– intercropping – using two or more crops close
together, discourages pest buildup (tall vs. short,
deep root vs. shallow root)
– alley cropping – planting trees/shrubs and crops
together in rows
– polyculture – differing the maturity rates & harvest
time of various crops
– http://www.hippocampus.org/Earth%20Science;jsessionid=340D0A82A4EBF826FC
EDB7D9051F16FA
Land
Labor
Capital
Fossil fuel
energy
Industrialized agriculture
in developed countries
Land
Labor
Capital
Fossil fuel energy
Intensive traditional agriculture
in developing countries
World Food Production
Industrialized agriculture
Plantation agriculture
Shifting cultivation
Nomadic herding
Intensive traditional agriculture
No agriculture
Challenge to Farmers:
Produce More Food!
1. Farm more land
2. Produce higher yields per unit
area
What about the
Green Revolution?
Refers to dramatically increased
agricultural productivity resulting from
the introduction of new, high-yielding
strains of grain (rice, wheat, and maize)
Ongoing since 1950s
Producing Food by
Green-Revolution Techniques
High-input monoculture
Scientifically bred or geneticallyengineered crops
High inputs of fertilizer
Extensive use of pesticides
High inputs of water
Increased intensity and frequency of
cropping (multiple cropping)
Green Revolutions
19501970
1967today
First green revolution
Second green revolution
(developed countries)
(developing countries)
Major International agricultural
research centers and seed banks
Producing Food by Traditional
Techniques (Low input agrodiversity)
Interplanting - simultaneously growing a
variety of crops on the same plot
1) Polyvarietal cultivation
–
Planting several varieties of the same crop
in a plot
2) Intercropping
–
Two or more different crops are grown at
the same time on a plot
Producing Food by Traditional
Techniques (Low input agrodiversity)
3) Agroforestry (alley cropping)
–
Crops and trees are planted together
4) Polyculture
–
Different plants maturing at various times
are planted together
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Less fertilizer
Protection from wind and water erosion
Little or no insecticides
Insurance against bad weather
Food Production – Good News
Production is increasing!!
Total World Grain Production
Grain production
(millions of tons)
2,000
1,500
1,000
500
0
1950
1960
1970
1980
Year
1990
2000
2010
Food Production – bad news
Population growth outstripped production
Per capita grain production
(kilograms per person)
World Grain Production per Capita
400
350
300
250
200
150
1950
1960
1970
1980
Year
1990
2000
2010
Did you know ….
• 1 in 6 people in developing countries are
undernourished or malnourished
• 1 in 7 adults in developed countries suffer from
overnutrition/obesity
• 61% of Americans are overweight
• 27% of Americans are obese
Human Nutrition
• Macronutrients
– Protein, carbohydrates, and fats
• Micronutrients
– Vitamins A, C, and E
– Minerals (iron, iodine, and calcium)
Undernutrition – consuming insufficient
food to meet one’s minimum daily
energy needs, suffer from stunted growth
and development, more susceptible to disease
Nutrition
Malnutrition – faulty nutrition, caused
by a diet that does not have enough
protein, essential fats, vitamins,
minerals and other nutrients needed
for good health.
• Marasmus
– Diet low in both calories and protein
• Kwashiorkor
– Severe protein deficiency
Marasmus – “wasting disease”
Kwashiorkor
“displaced child”
What’s the Deal?
Enough food is produced to meet the basic nutritional
needs of every human on the planet. However, it is
NOT DISTRIBUTED EQUALLY due to differences in
soil
climate
political power
economic power
average per capita income (POVERTY)
POVERTY is the problem, not the common misconception
that the globe is not producing enough food!
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
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
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•
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
Traditional
Crossbreeding
Apple
1) Slow process
Offspring
Cross
breeding
Best results
New
offspring
Desired
result
2) Can combine
traits only
from closely
related
species
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
1) Half the time
as
conventional
crossbreeding
2) Cuts costs
3) Allows
insertion of
genes from
almost any
other
organism
Transgenic cell
from Phase 2
Cell division of
transgenic cells
Culture cells
to form plantlets
Transgenic plants
with new traits
Increasing World Crop Production
• Continued Green Revolution
techniques?
– Without fertilizer, water, and pesticides
green revolution varieties are no more
productive than traditional varieties
– Green revolution varieties and their
needed inputs cost too much for
subsistence farming.
– Grain yields are increasing at a much
slower pace.
Increasing World Crop Production
• Continued Green Revolution
techniques?
– Actual gains from green and gene
revolutions may be overstated.
– Crop yield may start dropping for a
number of environmental reasons.
– Increased loss of biodiversity can limit
genetic raw material.
Increasing World Crop Production
• Introducing new foods
– Getting farmers to take risk of
growing new types of food.
– Getting consumers to try new foods.
Increasing World Crop Production
• Working more
land
Cultivated
Grazed
Tropical
forest
Arid land
11%10%
8%
6%
14%
Forests,
arid
lands
51%
“Many analysts believe
that significant
expansion of cropland is
unlikely over the next
few decades.”
Ice, snow, deserts
mountains
Not usable
How about producing more
meat…
• Rangeland is land that is…
– too dry
– too steeply sloped
– too infertile …to grow crops
(40% of ice-free land area)
• Pastures
– managed grasslands or enclosed meadows
How is meat produced?
• Open grazing
– 80% of cattle,
sheep and goats
are raised on
rangeland
•Feedlots
–Account for
40% of the
world’s meat
production
Kilograms of grain needed per kilogram of body weight
Beef cattle
7
Pigs
Chicken
Fish (catfish
or carp)
4
2.2
2
Producing more meat
• Condition of the world’s rangelands
– DECLINING!
• Environmental consequences of meat
production
– See Connections page 299
– Read Spotlight page 300
Catching and Raising More Fish
• Fisheries – concentrations of aquatic
species suitable for commercial
harvesting in a given body of water
• 55% of annual commercial catch
comes from the ocean.
• 33% from aquaculture.
• 12 % from inland freshwater fishing.
Commercial Fishing Methods
Trawler
fishing
Fish farming
in cage
sonar
Spotter airplane
Purse-seine
fishing
trawl
trawl flap
lines
fish school
trawl
bag
Long line fishing
lines with
hooks
Fish caught
by gills
float
Drift-net
fishing
buoy
Potential to harvest more fish
• 1950-1982
+ Fish catch increased 5-fold
+ Per capita seafood catch doubled
• Since 1982
– Little increase in commercial fish
catch
– Per capita commercial fish catch
falling
Potential to harvest more fish
The primary cause of depletion of
fish stocks is too many fishing
boats pursuing too few fish or
OVERFISHING
(Tragedy of the Commons)
• Habitat destruction
• Global warming
Aquaculture
• Fish farming
– Cultivating fish in a controlled
environment.
– Harvesting them when they reach the
desired size.
– Catfish are the leading aquaculture
product in the US
Aquaculture
• Problems
– Raises demand for ocean fish as fish
meal to feed aquaculture species
– Creating vast amounts of animal waste in
coastal areas
– Farming of carnivorous fish increases
over-fishing of smaller marine species.
Future
• Increasing wild catch and aquaculture
will not increase world food supplies
significantly.
• Fish and shellfish supply only 1% of
the energy and 6% of the protein in
the human diet.
Government Agricultural Policy
• Financially risky business
• Forms of assistance.
– Keep food prices artificially low.
– Give farmers subsides to keep them in
business and encourage them to increase
food production.
– Eliminate price controls and subsides and
let farmers and fishers respond to
market demand without government
control.
• Increase aid for the poor
Future limitations to
increased food production
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Lack of water for irrigation
Reduced genetic diversity
Leveling off of yields
Environmental effects which degrade
existing cropland
Solutions: Sustainable Agriculture
1) Slowing population growth
2) Reducing poverty
3) Phasing in systems of sustainable
agriculture (also called organic
farming)
‘Organic’ foods
Plants
• Produced without
synthetic pesticides,
fungicides, and
herbicides
• Cannot include
genetically
engineered foods or
be irradiated
• Cannot be grown on
soils fertilized with
sewage sludge
Animals
• Produced from 100%
organically grown
feed.
• Given access to
outdoor range or
pasture
• Produced without use
of hormones and
antibiotics
Principles of Sustainability
• Most ecosystems use renewable solar
energy as the primary source of
energy.
• Ecosystems replenish nutrients and
dispose of wastes by recycling
chemicals.
Principles of Sustainability
• Biodiversity helps maintain the
sustainability of ecological
functioning of ecosystems and serves
as a source of adaptation to changing
environmental conditions.
• In nature there are always limits to
population growth and resource
consumption.