Transcript Food for the Masses: Modern Agriculture Myth of the Family Farm.

Food for the Masses: Modern Agriculture
Myth of the Family Farm
Intensification of Agriculture
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Myth of the small family farm
Modern agriculture is industrial
need to feed a growing population
Need for ways to grow higher yields of food, fuel,
and fiber from a given amount of land, water, and
labor
• Limits to production: physical and environmental
factors that limit crop growth
• Modern agriculture has extensive environmental
impacts
What is needed to produce food?
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Land
Water
Energy (fuel)
Do other substances increase yield?
– Pesticides, GMOs, herbicides, fertilizer
How Many People Can the Earth Feed?
• Thomas Malthus (1798)
– Human population increases at a geometric
(exponential) rate, while food supplies grow at an
arithmetic rate
– all living creatures increase beyond their available
resources
– Food scarcity would eventually limit population
growth (poverty, disease, war, famine, etc.)
Is Malthus right?
• Agricultural productivity (amount of harvested
biomass) has been enhanced
• world food production has in fact kept up with
rapid population growth. Gains have been
especially dramatic in the past 50 years
Meeting the Needs of a Growing Human
Population
•Rapid growth in demand for ecosystem services
between 1960 and 2000:
– world population doubled from 3 to 6 billion people
– global economy increased more than sixfold
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food production increased 2 ½ times
water use doubled
wood harvests for pulp and paper production tripled
timber production increased by more than half
installed hydropower capacity doubled
Food Production Trends
– Food production has more
than doubled since 1960
– Food production per capita
has grown
– Food price has fallen
But at what cost?
• Serious environmental and human health
costs
– reduced biodiversity
– fragmented natural ecosystems
– diverted or polluted fresh water resources
– altered the nutrient balance of adjacent and
downstream ecosystems
– consumes major amounts of energy and generates
greenhouse gas emissions that contribute to
global climate change
What land is suitable for agriculture?
• In 2000, 37% all Earth’s land used for agriculture.
– 11% used for crops
– Rest used for pastureland (includes cultivated or wild
forage crops for animals and open land used for grazing)
– Estimated ¾ Earth’s land surface is unsuitable for raising
crops without irrigation. Most of the remainder is subject
to some soil, terrain, and/or climate limitations.
– only about 3.5 percent of Earth’s surface is suitable for
agriculture without any physical constraints
Recent Changes in Agric. Land Use
• In regions where productivity is rising faster than demand,
(US, EU, Japan), land is being withdrawn from cultivation.
• These areas rely on agricultural intensification to keep output
high as their farmed lands shrink.
– intensification has serious environmental impacts
• In contrast, land is being converted for agriculture in many
parts of the developing world.
– major cause of deforestation. Clearing forests for
agriculture alters ecosystems that provide important
services such as sequestering carbon or absorbing
floodwaters.
Summary statistics of agriculture in the US at
the beginning and end of the 20th century
Intensification of Corn
• % of land area in each
county that is cropland
(left) and corn harvested
for grain (right).
• Corn harvested for grain
occupied ~23% of US
croplands in 1900 and 17%
in 2002
• Corn was grown
throughout the midwestern
and southeastern US in the
early 1900s, today, these
efforts are primarily
concentrated in the
Midwest.
Conversion to Agriculture leads to land
degradation
Limpopo region, South Africa
Key Inputs for Photosynthesis
CO2 + H2O + sunlight → (CH2O)n + O2
Drought is the biggest limit on agricultural productivity
because plants need an enormous amount of
water.
When plants photosynthesize, they use energy from
sunlight to convert carbon dioxide (CO2) and water
into carbohydrates (plant tissue).
it might appear that plants would need equal amounts
of water and CO2, but the actual ratio is
approximately 400 to 1
Why do plants need so much water?
How Plants Use Water
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98% of a plant's water intake passes up from roots
to leaves and evaporates, exiting the leaf as water
vapor through pores in the leaf surface called
stomata.
Movement of water from the soil to the
atmosphere through the bodies of plants is called
transpiration.
Transpiration has important functions:
1. it carries minerals from the soil to the leaves
2. prevents leaves from overheating
3. most importantly allows uptake of CO2 from the
atmosphere.
Irrigation
Satellite image of
crop circles near
border of Egypt
and Sudan irrigated
from aquifer
• 1/3 global food harvests from irrigated areas (16% of total world
cropland).
• Every year, humans divert about 2,700 cubic kilometers of water (5x
annual flow of the Mississippi River) for crops.
• Allows Egypt to produce agriculture, and greatly expands grain
production in northern China, northwest India, and the western
Great Plains of US
• Impact: depletes normal river flows or contributes to salinization of
agricultural lands
Fertilizer
Seabird manure, a rich
source of nutrients, has
been used as fertilizer for
centuries.
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Plants need N for proteins
Many crop plants quickly deplete N from soils
Other sources of N:
1. manure,
2. naturally occurring N deposits (saltpeter) in mines,
3. guano (seabird droppings) along the coasts of Chile
and Peru and Pacific islands
4. Commercial fertilizer after WWI
History of Synthetic Fertilizer
• 1908 Fritz Haber- Haber-Bosch process (N and H gases combined
to produce ammonia (NH3) then nitrate).
• used in WWI and WWII to make nitric acid for munitions.
• launched the fertilizer industry
• widespread use after WWII, boosted crop productivity
• Impact:
– Requires large amount of energy: high temp, pressure to break
bonds in N gas
– Fertilizer not taken up by plant roots washes into water bodies
and ground water, altering the species composition and
nutrient balance of downstream ecosystems. Can cause dead
zones.
– problem is severe early in the growing season
– Mismanaged livestock manure (discussed in section 6) causes
similar problems
Increasing Yield
• Agricultural ecosystems are unbalanced; inputs ≠
outputs (compare to natural ecosystem)
• Yield = product that can be harvested from an
agricultural system
• increase yields by adding energy & materials,
increasing the efficiency of energy conversion (what
does that mean?) and allocation to the harvested
product (?), or by reducing losses during the growing
process.
• Agricultural yields have risen steadily throughout the
history of human cultivation, but especially through
the 20th century.
• Cereals are the primary source of animal feeds and
non-meat calories for humans worldwide.
Yield
• Productivity = farmers' total output per unit of land
• Huge increase in productivity recently due to intensification
– Land and labor inputs decreased
– irrigation, synthetic fertilizers, pesticides and herbicides, and
mechanization increased
– Scientific advances (higher yielding crop varieties, new strains
easier to harvest, more durable during transport, and longerlasting in storage
– MOST IMPORTANT: increasing the harvest index (the ratio of
harvested (edible) biomass to total biomass).
– "Green Revolution"— 1940s, 30 y transformation of
agriculture in developing regions; distribution of high-yielding
crops, fertilizer, irrigation, and pesticides to subsistence
farmers in Asia and Latin America
Harvest Index Example: Rice
New Efficiencies Lead to New Problems
• Green Revolution helped world food production increase
faster than population growth from 1950 onward.
• However, relied on synthetic fertilizer and irrigation
• new plant varieties were not inherently high-yielding (i.e. not
able to use resources more efficiently than traditional
varieties) and likely would have done worse under "natural"
conditions.
• highly susceptible to pests and diseases, required heavy use
of pesticides
• new plants were short, more susceptible to competition from
weeds, so farmers also had to use herbicides to raise them
(affects non-target plants)
Pesticides
• Monoculture -planting large holdings of one or a few highyield crop varieties
• Increased efficiency (mechanized cultivation, harvest
• vulnerable to pests and pathogens because nutrient-rich and
no natural protection from genetic diversity
• many pest species spread rapidly in ecosystems where
disturbances (plowing) have eliminated natural predators
• Pesticides are effective but often cause health problems
• organochlorines (DDT, etc)
– cause human health effects (dizziness, seizures, respiratory illness, and
immune system dysfunction);
– reduced Bald Eagle popultions;
– most are now banned in US
• Newer pesticides less toxic (but still toxic) and many pests
become resistant to them
Alternatives to Pesticides and Herbicides
• releasing natural insect predators or
• breeding resistance into crops (some corn seeds
engineered to resist certain pests)
• integrated pest management -farmers consider each
crop and pest problem as a whole and design a
targeted program drawing on multiple control
technologies, including pesticides, natural predators,
and other methods.
– Rice in Indonesia
Example of Integrated Pest Mgt
• 1986, IPM in Indonesia to control
the planthopper (lays eggs inside
rice plant stalks)
• Farmers monitored fields for
planthoppers and their natural
predators, treated outbreaks
using minimal pesticides or
biological controls
• rice production increased by 15%,
while pesticide use fell by 60%
Best/Worst Produce with Pesticides
Dirty Dozen
(buy these organic)
1. Peach
2. Apple
3. Bell Pepper
4. Celery
5. Nectarine
6. Strawberries
7. Cherries
8. Kale
9. Lettuce
10.Grapes (Imported)
11.Carrot
12.Pear
Clean 15 –lowest in pesticides
1. Onion
2. Avocado
3. Sweet Corn
4. Pineapple
5. Mango
6. Asparagus
7. Sweet Peas
8. Kiwi
9. Cabbage
10. Eggplant
11. Papaya
12. Watermelon
13. Broccoli
14. Tomato
15. Sweet Potato
Livestock
• monoculture farmers raise one or a few animal strains bred to
maximize output (hens that lay more eggs, dairy cows that
produce more milk, etc.)
• Technology -antibiotics and hormone treatments, to make
animals grow larger and more quickly
• animals confined indoors instead of letting them range
(cheaper and ‘more efficient’)
• global meat and dairy production predicted to double
between 2000 and 2050
• Major environmental impacts
Problems with Feedlots
• Crowding stresses animals, promotes disease
• Antibiotics to treat and prevent illnesses, promote growth are
identical or similar to antibiotics used in humans,
• promotes drug resistant bacterial strains that can infect humans
through the food chain or via direct exposure
• massive quantities of animal waste:
– One cow can produce >40 lbs manure per day.
– Many store millions of gallons of manure in tanks or lagoons until
it can be used on neighboring fields.
– Risk of leaking or spillover, polluting waterways with excessive
nutrients, antibiotics, hormones
• produce air pollutants that are significant hazards at scales ranging
from local to global
• generates 18% of world greenhouse gas emissions
• accounts for 8% of world water use,
• probably the largest water pollution source
Genetic Improvement
• selective breeding –breeding plants/ animals to select for
desirable traits
– Relies on traits existing in nature
• GMOs (genetically modified organisms)
– More precise modern
– Can use DNA sequences from different species (Ex: ‘Bt
corn’ has a gene from the bacterium Bacillus thuringiensis
that kills insects
– Varieties developed to tolerate herbicides (more than 80%
US soybeans are Round-up Ready).
• USDA has approved 63 genetically engineered crops, including
corn, soybeans, cotton, potatoes, wheat, canola, and papaya
• AKA ‘transgenic’ plants
GMOs
• golden rice, several genes have been added so
that the plant produces betacarotene (vitamin
A) in its grains
• Helps reduce Vit A deficiencies from diets
based on conventional rice
• What’s wrong with traditional approach of a
balanced diet?
Problems with GMOs
• potential harm to nearby ecosystems and the
possibility that GMO crops or animals will hybridize
with and alter the genetic makeup of wild species
– Ex: genes from high-yield GMO crops could give wild plants
qualities that make them more weedy and invasive
• Human health effects unknown
• Hard to predict
• Food containing GMOs unlabeled (organic food does
not contain GMOs)
Agriculture and Energy
• use energy directly to heat and cool buildings, operate equipment,
pump irrigation water, and transport products
• indirectly uses energy to make fertilizer (natural gas) and pesticides
(petroleum and natural gas).
• Most energy-intensive: Raising livestock on grain
– consumes fossil fuel to make pesticides and fertilizers to grow
feed crops.
– Fattening one steer on corn to market weight can consume the
equivalent of 35 gallons of oil
– inefficient because animals convert only a fraction of the energy
in their feed grain to growth
– 2 kg of grain to produce 1 kg poultry,
– 4 kg grain to make 1 kg pork
– 7 kg grain to produce 1 kg of beef
• Food processing and long-distance shipment consume additional
energy.
Future of Food
• As we produce more food, do we sacrifice
quality?
– Ex: corn-fed livestock
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Higher in saturated fat
Increased incidence of toxic E. coli strain O157:H7
Energy-intensive
Leads to cattle illness
Major environmental impacts
• What can we do to improve the quality of our
individual diets?
10 Simple Tips to make positive changes to your
eating habits and to our food system:
1. Stop drinking sodas and other sweetened beverages.
You can lose 25 lbs in a year by replacing one 20 oz soda a day
with a no calorie beverage (preferably water).
2. Eat at home instead of eating out.
Children consume almost twice as many calories when eating
food prepared outside the home.
3. Support the passage of laws requiring chain restaurants to post
calorie information on menus and menu boards.
Half of the leading chain restaurants provide no nutritional
information to their customers.
4. Tell schools to stop selling sodas, junk food, and sports drinks.
Over the last two decades, rates of obesity have tripled in
children and adolescents aged 6 to 19 years.
5. Meatless Mondays—Go without meat one day a week.
~ 70% of antibiotics used in the US are given to farm animals.
6. Buy organic or sustainable food with little or no pesticides.
According to the EPA, over 1 billion pounds of pesticides are used each
year in the U.S.
7. Protect family farms; visit your local farmer's market.
Farmer's markets allow farmers to keep 80 to 90 cents of each dollar spent
by the consumer.
8. Make a point to know where your food comes from—READ LABELS.
The average meal travels 1500 miles from the farm to your dinner plate.
9. Tell Congress that food safety is important to you.
Each year, contaminated food causes millions of illnesses and thousands of
deaths in the U.S.
10. Demand job protections for farm workers and food processors, ensuring
fair wages and other protections.
Poverty among farm workers is more than twice that of all wage and
salary employees.
What is organic?
• USDA certification standards adopted 2002
• Organic Agriculture -"An ecological production management
system that promotes and enhances biodiversity, biological
cycles and soil biological activity. It is based on management
practices that restore, maintain and enhance ecological
harmony." (USDA)
• Additional cost in buying organic food has decreased, but still
more expensive than conventional food
• Health benefits from eating organic (to humans and
environment) outweigh cost
USDA Organic standards
Organic standards prohibit:
– Genetically modified organisms (GMOs), seeds or
ingredients
– Bio-solids (sewage sludge) and synthetic fertilizers
– Synthetic pesticides, herbicides or fungicides
– Antibiotics or added growth hormones
– Animal by-products in animal feed
Organic practices require:
– Continual monitoring, maintenance and improvement of soil
health
– Crop rotation, mulching and other practices to prevent soil
erosion and enhance soil health
– Specific composting methods for both animal and plant waste
– Outdoor access for livestock
– Pasture for all ruminants
– 100 percent certified organic feed for organic animals
– Inspections of all farm fields, processing facilities and
production and sales records by agents accredited as USDA
Certifiers
– Periodic testing of soil and water used in production
No certification standards for fabrics, health supplements,
beauty products, household cleaners, pet foods, farmed
or wild seafood.