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Food and Agriculture
1
“This…is the world that has been pulled over your eyes to blind you from the truth.“
- Morpheus, the Matrix (1999)
Written by James DaurayTextbooks used as reference:
Living in the Environment by Miller Environmental Science by Cunningham & Cunningham
More teaching resources and lectures available here: www.docstoc.com/profile/jamesdauray
Last updated December 21, 2010
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Environmental Science LecturesFood and Agriculture
Producing enough food has become a greater challenge as the human population reaches 7 billion.
Food energy is measured in calories.Undernutrition occurs when someone does not
eat enough calories.Adults need on average 1000 calories per day to
simply survive.Average of 2100 calories needed for a normal,
healthy life.
3
Feeding the World
4
Types of Nutrients
Chronic Hunger and Food SecurityAbout 925 million people are considered
chronically undernourished or malnourished.Most of these are in developing countries.This is about 13% of the world’s population.Theoretically, there should be enough food to supply
about 3000 kcal/day to everyone.
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NUTRITION AND FOOD SUPPLIES
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Inadequate Nutrition Risk
Source: Miller Environmental Science, 13th Edition
Undernutrition – Insufficient caloric intake.Malnutrition - Nutritional imbalance caused by
lack of specific dietary components.Overnutrition – A daily intake of calories that is
too high, leading to obesity.The most common dietary problem in wealthy
countries.Up to 64% of all adult Americans are overweight.
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Types of Malnutrition
Overnutrition
Iron deficiency is the most common dietary imbalance in the world.Leads to anemia – insufficient oxygen
transported to the brain, muscles, and organs due to low red blood cell count.Symptoms include fatigue, dizziness, headacheIncreases risk of death in childbirth
Good sources of iron: Red meat, eggs, beans, and some green vegetables (spinach, broccoli)
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Malnutrition Examples
Iodine deficiency is another very common type of malnutrition, especially in rural developing areas. Iodine is required for
production of thyroid hormones, which control the body’s rate of metabolism.
Chronic lack of iodine can slow all parts of normal development, including body size and brain function.
Lack of iodine can also cause a goiter, or a swollen thyroid gland.
Good sources of iodine: seafood and plant crops from iodine rich soils.
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Malnutrition Examples
Source: Miller Environmental Science, 13th Edition
A famine is when large-scale undernourishment occurs in a population.Most of the population is eating less than the
daily minimum calories needed (1000 calories)Drought causes more than half of famines.
Other significant causes: war and bad governance.Ex: North Korea was reluctant to request foreign
assistance after severe flooding in the 1990s.
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Famines
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Australia Drought of 2006-2009
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Australia Drought of 2006-2009
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Australia Drought of 2006-2009
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Australia Drought of 2006-2009
Aid from rich countries often can help alleviate famines in the short term.Drawbacks to foreign assistance:
Population must crowd together in “food camps” to receive supplies.Lack of sanitationQuick spread of diseases
Foreign aid tends to be short-lived as people’s attention moves elsewhere.Ex: Indonesian tsunami of 2004, Hurricane Katrina of
2005, Haiti earthquake of 2009, Pakistan floods of 2010
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Famines and Foreign Aid
An estimated 90% of the world’s food calories come from 14 species of plants.
Three of those crops deliver a majority of world’s nutrients: wheat, corn, and rice.Main nutrient component of these foods is
carbohydrates.The major food staples are all plants.
Cheaper and easier to produce.Why? Remember the energy pyramid?
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MAJOR FOOD SOURCES
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Ecological Energy Pyramid
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World Food Production
Meat and dairy products are all high in protein, iron, and come from animals.As incomes rise in developing countries, food
choices shift towards higher-quality and more expensive foods.60% of production occurs in lesser developed
countries.
Meat requires a high amount of grain to produce.15 pounds of grain to produce 1 pound of meat.
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Meat and Dairy
Seafood is the biggest protein source in many island and coastal countries.Annual catches of
ocean fish rose by 4% annually between 1950-1988.
Many areas of ocean are now so overharvested that large-scale fishing is unsustainable.
Nearly half of seafood harvested is now farmed.
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Seafood
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Food Consumption Differences
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Food Consumptions Differences
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World Food Consumption
Much of the food produced in the developed world is the result of industrialized agriculture.Dependent on the use of heavy equipment, fuel,
fertilizers, pesticides, and irrigation.Most food is grown as a monoculture, or single-
crop farming.
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Industrialized Agriculture
Total food production has increased steadily in the last 50 years, in spite of a decrease in the actual number of farms.
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The Green Revolution
The green revolution marked three major changes in farming and food production:
1. Usage of monocultures of highly-bred or genetically modified species.
2. Increased input of irrigation, fertilizer, herbicides, and pesticides.
3. Produce more than one type of crop each year on a plot of land.
The net effect of the Green revolution and the industrial food system has been to keep food prices artificially low.Americans only spend 10% of their household income on
food.
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The Green Revolution
Agriculture accounts for largest single share of global water use.Most irrigation systems are inefficient.Only about 20% of water withdrawn for irrigation
reaches the plant roots.Where does the rest go?
Two main types of irrigation systems:Overhead sprinkler systemsUnderground drip systems
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Agricultural Water Usage
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Overhead Sprinkler Irrigation
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Underground Drip Irrigation
Lack of three nutrients can slow plant growth: nitrogen, phosphorous, and potassium.Adding these nutrients via fertilizer usually
stimulates growth and increases crop yields.1950 - Average of 7kg/acre used2000 - Average of 25kg/acre used
Adding fertilizer and manure is replenishes soil nutrients depleted from previous years.
Problems with fertilizer?Can runoff into water sources and cause aquatic
plants (algae) populations to expand rapidlyManure can cause bacterial contamination
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Fertilizer
Industrialized farming is energy-intensive.Energy use in agriculture has risen for two
reasons:Increase in use of machinesSpraying of chemical pesticide and fertilizers
In the U.S., the food system consumes 16% of total energy use.Most foods require more energy to produce, process,
and transport than we yield from them.
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Energy
Biological pests are any organisms that reduce crop yields.Examples: Insects, birds, rodents
Pesticides are chemicals that are used to kill or repel biological pests.Half of current crop yields might be lost in the
absence of pesticides.Residue from synthetic pesticides often
remains on the skin of some fruit.Organic foods, by definition, do not use
synthetic pesticides and herbicides.
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Pest Control
The single biggest individual benefit of buying organic is the avoidance of pesticide residues. Not all produce has the same amount of residue.
The “Dirty Dozen” – most contaminated produce Celery (64 different pesticides have been detected) Peaches Strawberries Applies Blueberries Nectarines Bell peppers Spinach Kale Cherries Potatoes Grapes (up to 34 different pesticides detected)
Source: www.thedailygreen.com (list updated yearly)34
To Buy or Not Buy Organic?
The “Clean Fifteen” – least contaminated produce Onions Avacados Sweet Corn Pineapple Mango Asparagus Sweet peas Kiwi Cabbage Eggplant Papaya Watermelon Broccoli Tomato (look for greenhouse grown) Sweet potatoes
Source: www.thedailygreen.com (list updated yearly)35
To Buy or Not Buy Organic?
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How is Meat Produced?
Factory Farming and LivestockThe industrialization of agriculture applies to
the raising of livestock, both for meat and dairy.The traditional method of raising animals in
open pasture is now largely a relic of the past, replaced by highly-mechanized large-scale operations.
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Dairy cows are special breeds chosen for high milk production.
About half of the U.S. dairy cows are raised in confined indoor pens.
As with other mammals, cows only produce milk for about 10 months after giving birth.Must be continuously impregnated to continue
milk production.Female calves are kept within the herdMale calves are usually sent to veal crates.
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Dairy Production
The advantage of raising dairy cattle indoors is that all aspects of their growth, feeding, and behavior can be monitored and controlled.Cows leave their pens twice a day to be milked
mechanically.
39
Dairy Production
The disadvantage is the rapid spread of disease due to the crowding and high amounts of waste manure.
To prevent this, antibiotics are commonly administered to the cattle.Nearly half of all antibiotics used in the U.S. are
used in farm animals.Farms may also inject their cattle with Bovine
Growth Hormone (BGH) to increase milk production.
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Dairy Production
There are significant consequences to the use of additive hormones and antibiotics in cattle feed.
Overuse of antibiotics is increases the risk of bacteria evolving resistance to the antibiotic. When this occurs, the antibiotic becomes unusable.
The use of BGH has multiple effects:The overall health of the cows is affected:
Increased likeliness of mastitis (infection of the udders)Increased rate of lamenessReduced fertility
There are also effects on the milk itself:Increased growth hormone in the milkIncreased pus in the milk, causing it to go sour more
quickly 41
Antibiotics and Hormones
Penicillin is ineffective 25% of the time for strep throat; amoxicillin is ineffective 18% of the time. Source: University of Rochester Study
42
Antibiotic Resistance
Calves are kept in small crates that minimize the amount of movement they are able to make.
Their diet is intentionally iron-deficient. This keeps their flesh pale
44
Veal Calves
Layer Hens – Egg ProductionThe majority of hens (~95%) that supply eggs are
raised in battery cages.These are small cages with slanted floors to drain waste.Hens are confined within small cages their entire life.USDA recommendations for cage size:
Cages are usually 16 inches wide and contain 4 hens.
The highly restricted movement of the hens leads to unusually aggressive behaviors.Beaks are cut or seared off to prevent fighting. 46
Layer Chickens – Egg ProductionChicks that are hatched are sorted by gender;
females are kept; the males are killed and discarded.
The layer hens are subject to near constant light to encourage greater egg production.
Fatigue and mineral depletion are common .Egg production begins to decline when the hens
reach about 12 months.At this point they are slaughtered and used in
processed foods (soup, flavoring, pet foods, etc)The use of antibiotics and growth hormones is
illegal in all poultry.
47
Broiler hens are chickens bred and raised specifically for meat.They have much larger thighs and breasts than
normal; making them very heavy and often unable to stand or walk normally.
Broiler chickens are raised in pens instead of cages to prevent bruising.Beaks and toes are removed to prevent fighting.
The chickens reach their slaughter weight in about 2 months.
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Broiler Hens
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Broiler Pens
Pigs are very sensitive animals, prone to sunburn and heat stress.
As a result, they are primarily raised indoors in temperature-controlled “hatch pens”.
Tails are usually cut off at birth to prevent biting – a common issue in overcrowded pens.
51
Pigs
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Pig Batch Pens
Cattle / PigsThe animals are knocked unconscious either by
electric shock or with a bolt gun.They are hung upside down by their hind legs.The carotid artery and jugular veins are cut, killing
the animal by bloodloss.Poultry
The animals are hung by their feet on a conveyor belt.They are passed through electrified salt water to stun
them unconscious, then their throats are cut.The carcasses are then moved into a vat of boiling
water, which makes feather removal easier.Kosher/Halal
Animals are not stunned before slaughter. 54
Slaughter
55
Slaughter
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Food Additives
BeefThe leftover fat, connective tissue, and organ
pieces from slaughter is liquefied, mixed with ammonia (to reduce bacteria), and combined with ground beef.
Carbon monoxide may also be added to meat packaging to preserve the red color as long as possible.
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Extra Ingredients
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Factory Farming: Slaughter
Source: The Animals Film, 1981
The factory farming process makes food much cheaper than conventional methods.
One big downside is an increase in the number of food recalls.
2010 Recalls228 million eggs ( Salmonella )
2009 RecallsNestle Toll House cookie dough ( E.coli )Pistachios ( Salmonella )Products containing peanut butter / paste ( Salmonella
)2008 Recalls
Beef recall ( cattle were not inspected properly )Maple Leaf brand deli meats ( listeriosis ) 60
The Hidden Costs
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“The Meatrix”
Produced by Free Range Studios2003,2006
Cage FreeChickens are not kept
within cages, but may still be high-density indoor pens.
Certified HumaneChickens are uncaged and
“must be able to perform natural behaviors such as nesting”.
Free RangeAnimals are kept outdoors
and allowed to roam.
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Alternative Production MethodsOrganic
No unnatural feeds or feed additives given to animals.
No additives in the final product.
Does not address treatment of animals
Arable Land – Land that is fertile and can be used to grow crops.
Soil - A complex mixture of minerals, decomposing organic materials, and living organisms.
Soil is generated from rock by two processes:Physical weathering – Rock is broken down by wind
and waterChemical weathering – Rock reacts with substances
such as acid or water.The best soils for farming have deep topsoil
layers.Grasslands, deciduous forests. 63
Soil and Farming
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Soil Ecosystems
Much of the arable land on Earth has been lost.Estimates:
3 million hectares of cropland ruined annually via erosion,
4 million transformed into deserts8 million paved or built upon.
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Land Degradation
Stepped Art
Stable or nonvegetative
Serious concern
Some concern
Fig. 10-9, p. 216
Desertification – Dry areas become more desert-like due to human activities.OvergrazingGlobal climate change
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Land Degradation Cont’d
Erosion is any natural process that redistributes soil and minerals across the earth.
Erosion becomes a problem when it occurs too quickly.
Two biggest causes of erosion:WindWater
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Erosion
Sheet Erosion - Thin, uniform layer of soil removed by high winds.
Rill Erosion - Small rivulets of running water gather and cut small channels in the soil.
Gully Erosion - Rills enlarge to form channels too large to be removed by normal tillage.
Streambank Erosion - Washing away of soil from established streambanks.
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Mechanisms of Erosion
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Dust Bowl
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Figure 07.18
Wind can be a strong force of erosion, especially in a dry climate and on flat land.
Wind erosion is worsened by intensive farming practices:
Planting crops in rows, leaving the soil in between exposed.
Having fields completely free of weedsRemoval of windbreaks such as treesNo crop-rotation or resting periodsContinued monocultures
Growing the same crop every year
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Erosion and Farming
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Managing TopographyContour Plowing - Plowing across slope to slow flow
of water.Strip Farming - Planting different crops in alternating
strips along land contours.Terracing - Shaping land to create level shelves of
earth to hold water and soil.
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SUSTAINABLE AGRICULTURE
Fig. 10-19, p. 229
Fig. 10-19, p. 229
Fig. 10-19, p. 229
Fig. 10-19, p. 229
Providing Ground CoverThe most erosion occurs in fields that are bare –
do not have any cover.Ways to avoid bare ground:
Leave crop residue after harvest.Plant different crops each season.Lay down mulch.
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Soil Conservation
Table 07.02
Genetically Modified Organisms (GMO’s)Contain DNA possessing genes borrowed from
unrelated species.Can produce crops with new traits only found in
other species.Opponents fear GMOs are untested and may cause
health effects when eaten, such as allergies60% of all processed foods in North America
contain transgenic products.Corn and soy
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Genetic Engineering
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GMOs Currently on the MarketFood Properties Percent Modified in US
SoybeansResistant to certain
herbicides89%
Corn
Resistant to certain herbicides
Insect resistance - using Bt proteins from a bacterium
Vitamin-enriched corn, with 169x increase in
Vitamin A, 6x the vitamin C and 2x
folate.
60%
Cotton (cottonseed oil) Pest-resistant cotton 83%
Hawaiian papayaVariety is resistant to the
papaya ringspot virus.50%
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GMOs Currently on the MarketFood Properties Percent Modified in US
TomatoesRipening enzyme is
suppressed, lengthening shelf-life.
Taken off the market due to commercial failure.
PotatoesProduces amylopectin instead
of starch.
Industrial productionof amylopectin for glossy
paper coatings and adhesive cement.
Canola Resistance to herbicides, 75%
Sugar caneResistance to certain
pesticides, high sucrose content.
?
Sugar beet Resistance to herbicides ?
Sweet cornProduces its own bioinsecticide
(Bt toxin)?
RiceGenetically modified to contain high amounts of
Vitamin A ?