Food and Agriculture

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“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.

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Feeding the World

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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.

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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

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Antibiotic Resistance

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Factory Farming: Cattle

Source: The Animals Film, 1981

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

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Veal Calves

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Factory Farming: Veal Calves

Source: The Animals Film, 1981

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.

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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

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Factory Farming: Chickens

Source: The Animals Film, 1981

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.

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Pigs

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Pig Batch Pens

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Factory Farming: Pigs

Source: The Animals Film, 1981

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

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Slaughter

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Food Additives

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Food Additives

The “Smoking Fry” experiment

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 ?