For the past ½ year we have gone over the basic concepts of

environmental science

For the rest of the time we look how those concepts have been

applied (or not)

Sustainable living for humans

What main tasks do humans need to accomplish in order to live sustainably on the Earth?

Tasks Zone(s) of the Earth effected

Food, Soil, and Pest Management

Chapter 12

May have additional readings in other chapters

Poverty and Lack of Food

Not surprisingly, people who are poor do not the mains to obtain enough food for a nutritionally diet

Not enough protein and essential vitiamins, including vitamin A

Core Case Study: Grains of Hope or an Illusion?

Vitamin A deficiency in some developing countries (140 million children)

leads to• Blindness (250,00 to 500,000 under 6)• Susceptible to common childhood infecticous

disease

1999: Porrykus and Beyer• Genetically engineered rice with beta-carotene and

more iron

Worked out agreements with poor farmers to try new strain for free

Is this the answer for malnutrition in these countries?

Challenge of increased food production

Golden Rice: Genetically Engineered Strain of Rice Containing Beta-Carotene

Goals

Reduce poverty

Grow and distribute more food than ever

Reduce environmental harm caused by the impact of such food production

12-1 What Is Food Security and Why Is It Difficult to Attain?

Concept 12-1A Many of the poor suffer health problems from chronic lack of food and poor nutrition, while many people in developed countries have health problems from eating too much food.

Concept 12-1B The greatest obstacles to providing enough food for everyone are poverty, political upheaval, corruption, war, and the harmful environmental effects of food production.

Many of the Poor Have Health Problems Because They Do Not Get Enough to Eat

Food security: each person in a given area has daily access to enough nutritious food to have an active and healthy life

Food insecurity• Root cause: poverty

• Since 1990, India has produced enough grain to feed entire population, but 1/5th of population are malnourished (can not afford to buy or grow food)

• Reasons why?

Problems to obtaining food security

Land, climate variation Political upheaval Corruption War Harmful environmental effects of food production

Many People Suffer from Chronic Hunger and Malnutrition (1)

Macronutrients• Carbohydrates (provide short term energy)• Found in Wheat, rice, corn

• Proteins (help build and repair tissue)• Found in animals and some plants)

• Fats (lipids) (help build membranes, hormones)• Found in animal fats, nuts, oils

Woman with Goiter in Bangladesh

Micronutrients• Vitamins, minerals like• Iron: anemia 1 in 5 people, fatigue• Vitamin A: rice vs pills• Iodine: proper functioning of thyroid gland,

produces hormones and controls metabolism• Found in seafood, iodine rich soils• Lack results in stunted growth, goiter, retardation,

brain damage

Calcium, vitamin C, E are also important

Many People Suffer from Chronic Hunger and Malnutrition (2)

Chronic undernutrition, hunger• Can not meet basic needs • Mental retardation, stunted growth, falling

infectious diseases, unlike developed world

Chronic malnutrition:• Can only live on low protein, high carbohydrate

consisting of just grains

What progress in being made? • Such population fell from 1970-2006 by 50 million

War and the Environment: Starving Children in Famine-Stricken Sudan, Africa

Acute Food Shortages Can Lead to Famines

Famine• A severe shortage of food, accompanied by mass

starvation, social disruption, death

• Usually caused by crop failures from• Drought• Flooding• War• Other catastrophic events

Many People Have Health Problems from Eating Too Much

Overnutrition

Similar health problems to those who are underfed• Lower life expectancy • Greater susceptibility to disease and illness• Lower productivity and life quality

We live in a world

Where

1 billion have health problems from eating too little

1.6 billion have health problems from eating too much

In US

In 2005: • study suggests that 66% of Americans are

overweight, 33% are obese

• 50 billion dollars a year is spent by people trying to lose weight (twice as much as is needed to end under nutrition and malnourishment in the world)

Exit Questions for 12-1

1. What is the difference between food security and food insecurity?

2. Describe the effects of diet deficiencies of vitamin A, iron and iodine.

3. What steps/actions would you take to solve the over-nutrition problem in the US?

4. What actions would you take to reduce chronic hunger and malnutrition?A. In the US

B. In the world

12-2 How Is Food Produced?

Concept 12-2A We have sharply increased crop production using a mix of industrialized and traditional agriculture.

Concept 12-2B We have used industrialized and traditional methods to greatly increase supplies of meat, fish, and shellfish.

Food Production Has Increased Dramatically

Three systems produce most of our food• Croplands: 77%• Rangelands, pastures, and feedlots: 16%• Ocean fisheries, Aquaculture: 7%

What you eat

Food systems depend on a small number o f plant and animal species

14 of 50,000 plant species eaten by humans supply 90% of world% calories

# types of grain, wheat, rice, corn provide 47% of calories/ 42% of protein

2/3rds of world’s people survive primarily on these grains

Why- what are the problems

Why do humans specialize in their food crops?

Why would specialization put people in a vulnerable position?

Answer

Crops can fail because• Disease• Environmental degradation• Climate change

Ex: how would the loss of bees effect crops?

Ex: Banana wilt: Panama disease is now found in all banana-producing regions except islands in the South Pacific, the Mediterranean, Melanesia, and Somalia

Tremendous increase in global food production

Why?• Technological advances• Tractors, farm machinery• High tech fishing equipment• Inorganic chemical fertilizers• Irrigation• Pesticides• High yield grain varieties• Factory like stockyards, fish ponds

Increasing reliance on fairly small number of crops

Industrialized Crop Production Relies on High-Input Monocultures

Industrialized agriculture, high-input agriculture• Heavy machinery, large amounts of cash, water,

fuel, fertilizers, pesticides

• Focus on producing large amounts of a single crop (monoculture) Why?

• Goal is to steadily increase crop yield• Plantation agriculture: cash crops

Use of Greenhouses

Increased use of greenhouses to raise crops

Why?

What would be advantages of using greenhouses instead of fields?

Answer

Makes arid lands productive (see coast of spain in pictures on following slides)

On small scale, greenhouses are water efficient, water is recycled

• Hydroponics (using no soils, just water)• 1/5th to 1/10th as much water compared to

conventional farming uses

• Problems, Uses a lot of electricity,

Satellite Images of Greenhouse Land Used in the Production of Food Crops

Problems with intense monocultures?

Water, Energy needs Environmental degradation (fertilizers,

pesticides, topsoil erosion) Weather Disease Others?

Traditional Agriculture Often Relies on Low-Input Polycultures

Practiced by 2.7 billion people, 1/5th crops on ¾ th cultivated land

Two types: Traditional subsistence agriculture:• Relies on human labor, draft animals• Meant to satisfy family needs

Traditional intensive agriculture• Adds more labor, water, fertilizers• Hopes to have extra to sell

Polyculture

Polyculture• Growing several crops in the same space• Reduces chance of losing all of crop• Keeps soil covered (erosion)• Crops mature at different times • Raised beds• Legumes among the corn• Crop-eating insects, and weeds have a harder

time to survive

• Study suggest that low input-poly produces more food than high input-mono

Slash and burn method

• Slash-and-burn agriculture• On small scale, it is sustainable• Ashes provide nutrients• Grow crops(up to 20 types) until soil is depleted of

nutrients• Ground is allow to lie fallow (tress, medicinal

crops)• Able to grow crops again in 10-30 years

Science Focus: Soil Is the Base of Life on Land

Soil composition: • mixture of eroded rock, mineral nutrients,

decaying organic matter, water, air, and a host of living organisms

Soil formation• Bedrock is slowly broken down into fragments by • Physical (freezing, thawing of water)• Chemical (acids created in air or groundwater

runnoff • biological processes (creatures in search of

nutrients (roots)

Layers and age of soil

Immature, young and mature soil

Layers (horizons) of mature soils• O horizon: leaf litter• A horizon: topsoil• Roots of most plants are concentrated in these top

2 layers. Teem with bacteria, worms, insects• Humus- porous mixture, partially decomposed

bodies of plants, clay, sand- nutrients• B horizon: subsoil (mostly inorganic broken down

rock)• C horizon: parent material, often bedrock

Soil Formation and Generalized Soil Profile

Questions about soil

Which is the most valuable horizon?, Why?

Is it renewable?

What roles does a tree do in the soil environment?

What happens if you remove the tree?

Fig. 12-A, p. 281

Wood sorrelOak tree Earthworm

Grasses and small shrubs

Organic debris builds up

FernHoney fungus

Moss and lichen

MoleRock fragments

O horizon Leaf litter

A horizon Topsoil

B horizon Subsoil

BedrockImmature soil

Young soilC horizon

Parent material

Mite

Nematode

Root systemRed earth mite Bacteria

FungusMature soil

Millipede

A Closer Look at Industrialized Crop Production

Green Revolution: increase crop yields (50’s-60’s)• Monocultures of high-yield key crops

• E.g., rice, wheat, and corn• Use large amounts of fertilizers, pesticides, and water

• Multiple cropping: multiple crops grown on same land over 1 year

Second Green Revolution: (70’s and 80’s)• dwarf varieties, more food on less land, saves forest,

wetlands, mountain terrains

World grain has tripled in production

Global Outlook: Total Worldwide Grain Production (Wheat, Corn, and Rice)

Fig. 12-5a, p. 282

2,000

1,500

1,000

Gra

in p

rod

uct

ion

(m

illi

on

s o

f m

etri

c to

ns)

500

0

1960 1970 1980 1990 2000 2010

Year

Total World Grain Production

Fig. 12-5b, p. 282

400

350

300

250

Per

cap

ita

gra

in p

rod

uct

ion

(k

ilo

gra

ms

per

per

son

)

200

150

1960 1970 1980 1990 2000 2010

Year

World Grain Production per Capita

Questions

• What grain production per capita mean?

• Why do you think grain production per capita has stopped growing grown less consistently than total grain production?

Case Study: Industrialized Food Production in the United States

Agribusiness: small number of giant multinational corp in control of growing, processing, distribution and sale of food

Annual sales for ag is bigger auto, steel, housing combined. US is bread basket of world

Food production: very efficient

Percent of income spent on food : 2% compared to 40% in developing , 1.2 bill of poorest spend 70%

Costs of agribusiness

High direct market sales Subsidies Environmental damage costs as a result of

agribusiness (runoff of nutrient and pesticides, diseases)

Health and insurance bills related to agriculture

Crossbreeding and Genetic Engineering Can Produce New Crop Varieties (1)

Gene Revolution• Cross-breeding through artificial selection• Slow process

Genetic engineering• Genetic modified organisms (GMOs):

transgenic organisms

Crossbreeding and Genetic Engineering Can Produce New Crop Varieties (2)

Age of Genetic Engineering: developing crops that are resistant to• Heat and cold• Herbicides• Insect pests• Parasites• Viral diseases• Drought• Salty or acidic soil

Advanced tissue culture techniques

Advantages of gene-splicing over cross-breeding

Rate of genetic change Less random Genes from different species can be used

Advanced tissue culture

Genetic Engineering: Steps in Genetically Modifying a Plant

Fig. 12-6, p. 283

Phase 1 Gene Transfer Preparations

A. tumefaciens

Plant cell

Extract plasmidExtract DNA

Foreign gene if interest

plasmidForeign gene integrated into plasmid DNA.

Phase 2 Make Transgenic Cell

Agrobacterium takes up plasmid

A. tumefaciens (agrobacterium)

Enzymes integrate plasmid into host cell DNA.

Host cell Host DNAForeign DNA

Nucleus Transgenic plant cellPhase 3 Grow Genetically Engineered Plant

Cell division of transgenic cells

Cultured cells divide and grow into plantlets (otherwise teleological)

Transgenic plants with desired trait

Meat Production and Consumption Have Grown Steadily

Animals for meat raised in• Pastures• Feedlots• Sheds

Meat production increased fourfold between 1961 and 2007• Chickens, fish, goats instead of pork, beef

Demand is expected to go higher

Industrialized Meat Production

Fish and Shellfish Production Have Increased Dramatically

Aquaculture, blue revolution• World’s fastest-growing type of food production• Dominated by operations that raise herbivorous

species

Polyaquaculture

World Fish Catch, Including Both Wild Catch and Aquaculture

Fig. 12-8a, p. 285

Fig. 12-8a, p. 285

140

120

100

80Wild catch

Cat

ch

(mil

lio

ns

of

met

ric

ton

s)

60

40

20 Aquaculture

0

1950 1960 1970 1980 1990 2000 2010

Year

Total World Fish Catch

Fig. 12-8b, p. 285

25

20

15

10

Per

cap

ita

catc

h

(kil

og

ram

s p

er p

erso

n)

5

0

1950 1960 1970 1980 1990 2000 2010

Year

World Fish Catch per Person

12-3 What Environmental Problems Arise from Food Production?

Concept 12-3 Food production in the future may be limited by its serious environmental impacts, including soil erosion and degradation, desertification, water and air pollution, greenhouse gas emissions, and degradation and destruction of biodiversity.

Producing Food Has Major Environmental Impacts

Harmful effects of agriculture on• Biodiversity• Soil• Water• Air• Human health

Major Harmful Environmental Effects on Food Production

Fig. 12-9, p. 286

NATURAL CAPITAL DEGRADATION

Food Production

Biodiversity Loss Soil Water Air Pollution Human Health

Loss and degradation of grasslands, forests, and wetlands

Erosion Water waste Greenhouse gas emissions (CO2) from fossil fuel use

Nitrates in drinking water (blue baby)Loss of fertility Aquifer depletion

Pesticide residues in drinking water, food, and air

Fish kills from pesticide runoff

SalinizationIncreased runoff, sediment pollution, and flooding from cleared land

Greenhouse gas emissions (N2O) from use of inorganic fertilizersWaterlogging

Killing wild predators to protect livestock

Contamination of drinking and swimming water from livestock wastes

Desertification Pollution from pesticides and fertilizers

Greenhouse gas emissions of methane (CH4) by cattle (mostly belching)

Loss of genetic diversity of wild crop strains replaced by monoculture strains

Algal blooms and fish kills in lakes and rivers caused by runoff of fertilizers and agricultural wastes

Bacterial contamination of meat

Other air pollutants from fossil fuel use and pesticide sprays

Topsoil Erosion Is a Serious Problem in Parts of the World

Soil erosion • Natural causes• Human causes

Two major harmful effects of soil erosion• Loss of soil fertility• Water pollution

Natural Capital Degradation: Severe Gully Erosion on Cropland in Bolivia

Natural Capital Degradation: Global Soil Erosion

Fig. 12-11, p. 287

Stepped Art

Stable or nonvegetative

Serious concern

Some concern

Drought and Human Activities Are Degrading Drylands

Desertification: productive potential of land (topsoil) drops because of draought or human activities• Moderate: 10-25% drop in productivity• Severe: 25-50%• Very severe : more than 50% (dunes and gullies)

Effect of global warming on desertification• Prolong drought

Severe Desertification

Natural Capital Degradation: Desertification of Arid and Semiarid Lands

Excessive Irrigation Has Serious Consequences

Irrigation problems • Salinization

• Waterlogging

Natural Capital Degradation: Severe Salinization on Heavily Irrigated Land

There May Be Limits to Expanding the Green Revolutions

Can we expand the green revolution by• Irrigating more cropland?• Improving the efficiency of irrigation?• Cultivating more land? Marginal land?• Using GMOs?• Multicropping?

Industrialized Food Production Requires Huge Inputs of Energy

Industrialized food production and consumption have a large net energy loss

Industrialized Agriculture uses ~17% of All Commercial Energy Used in the U.S.

Fig. 12-15, p. 290

4% 2% 6% 5%

Crops Livestock Food processing Food distribution and preparation

Food production

There Is Controversy over Genetically Engineered Foods

Pros and cons (answers on next pages)

What about chimeraplasty?

Trade-Offs: Genetically Modified Crops and Foods

Fig. 12-16, p. 291

TRADE-OFFSGenetically Modified Crops and Foods

Projected Advantages

Projected DisadvantagesIrreversible and unpredictable genetic and ecological effects

Need less fertilizer

Need less water

More resistant to insects, disease, frost, and drought

Harmful toxins in food from possible plant cell mutations

Grow faster New allergens in foodCan grow in slightly salty soils

Lower nutrition

Increase in pesticide- resistant insects, herbicide- resistant weeds, and plant diseases

May need less pesticides

Tolerate higher levels of herbicides

Higher yieldsCan harm beneficial insects

Less spoilage Lower genetic diversity

Food and Biofuel Production Systems Have Caused Major Biodiversity Losses

Biodiversity threatened when• Forest and grasslands are replaced with

croplands

Agrobiodiversity threatened when• Human-engineered monocultures are used

Importance of seed banks • Newest: underground vault in the Norwegian

Arctic

Industrialized Meat Production Has Harmful Environmental Consequences

Advantages

Disadvantages

Trade-Offs: Animal Feedlots

Fig. 12-17, p. 292

TRADE-OFFSAnimal Feedlots

Advantages Disadvantages

Increased meat production

Large inputs of grain, fish meal, water, and fossil fuelsHigher profits

Greenhouse gas (CO2 and CH4) emissions

Less land use

Reduced overgrazing Concentration of animal wastes that can pollute waterReduced soil

erosion

Protection of biodiversity

Use of antibiotics can increase genetic resistance to microbes in humans

Producing Fish through Aquaculture Can Harm Aquatic Ecosystems

Advantages

Disadvantages

Trade-Offs: Aquaculture

Fig. 12-18, p. 293

TRADE-OFFS

Aquaculture

Advantages Disadvantages

Needs large inputs of land, feed, and water

High efficiency

High yield in small volume of water

Large waste output

Can destroy mangrove forests and estuaries

Can reduce overharvesting of fisheries

Uses grain to feed some speciesLow fuel use

High profitsDense populations vulnerable to disease

Animation: Land use

12-4 How Can We Protect Crops from Pests More Sustainably?

Concept 12-4 We can sharply cut pesticide use without decreasing crop yields by using a mix of cultivation techniques, biological pest controls, and small amounts of selected chemical pesticides as a last resort (integrated pest management).

Nature Controls the Populations of Most Pests

What is a pest?

Natural enemies—predators, parasites, disease organisms—control pests• In natural ecosystems • In many polyculture agroecosystems

What will happen if we kill the pests?

Natural Capital: Spiders are Important Insect Predators

We Use Pesticides to Try to Control Pest Populations (1)

Pesticides • Insecticides• Herbicides• Fungicides• Rodenticides

Herbivores overcome plant defenses through natural selection: coevolution

We Use Pesticides to Try to Control Pest Populations (2)

First-generation pesticides: natural chemicals borrowed from plants (nicotine sulfate from tobacco)

Second-generation pesticides• Synthetic chemical created in labs• Paul Muller: DDT• Benefits versus harm• 100 times more toxic

Broad-spectrum agents

Persistence

Individuals Matter: Rachel Carson

Biologist

Silent Spring

Potential threats of uncontrolled use of pesticides

Rachel Carson, Biologist

Modern Synthetic Pesticides Have Several Advantages

Save human lives

Increases food supplies and profits for farmers

Work quickly

Health risks are very low relative to their benefits

New pest control methods: safer and more effective

Modern Synthetic Pesticides Have Several Disadvantages (1) Accelerate the development of genetic resistance to

pesticides by pest organisms

Expensive for farmers (not all farmers can use them)

Some insecticides kill natural predators and parasites

that help control the pest population

Pollution in the environment

Some harm wildlife (birds, amphibians)

Some are human health hazards

Modern Synthetic Pesticides Have Several Disadvantages (2)

David Pimentel: Pesticide use has not reduced U.S. crop loss to pests• Loss of crops is about 31%, even with 33-fold

increase in pesticide use• High environmental, health, and social costs with

use• Use alternative pest management practices

Pesticide industry refutes these findings

Trade-Offs: Conventional Chemical Pesticides

Fig. 12-20, p. 295

TRADE-OFFS

Conventional Chemical Pesticides

Save lives Promote genetic resistance

Advantages Disadvantages

Increase food supplies Kill natural pest

enemiesProfitable Pollute the

environmentCan harm wildlife and people

Work fast

Safe if used properly Are expensive for

farmers

Science Focus: Glyphosate-Resistant Crop Weed Management System: A Dilemma

Best-selling herbicide (Roundup)

Advantages

Disadvantages

Exposure to pesticides

Effects of pesticides in small amounts on the growth of children

EPA

EPA limitations • Money• Testing and enforcement

Case Study: Ecological Surprises

1955: Dieldrin sprayed to control mosquitoes

Malaria was controlled

Dieldrin didn’t leave the food chain

Domino effect of the spraying

Happy ending

Laws and Treaties Can Help to Protect Us from the Harmful Effects of Pesticides

U.S. federal agencies• EPA• USDA• FDA

Effects of active and inactive pesticide ingredients are poorly documented

Circle of poison, boomerang effect

There Are Alternatives to Using Pesticides (1)

Fool the pest

Provide homes for pest enemies

Implant genetic resistance

Bring in natural enemies

There Are Alternatives to Using Pesticides (2)

Use insect perfumes• E.g., pheromones

Bring in hormones

Scald them with hot water

Solutions: An Example of Genetic Engineering to Reduce Pest Damage

Natural Capital: Biological Pest Control

Integrated Pest Management Is a Component of Sustainable Agriculture

Integrated pest management (IPM) • Coordinate: cultivation, biological controls, and

chemical tools to reduce crop damage to an economically tolerable level

Disadvantages• Success in one ecosystem, biome may not

translate to success in others• Initial higher cost• Requires expert knowledge

Governmental support

Add tax to sale of pesticides Set of demonstration farms in each county Train USDA personnel in IPM practices

What Can You Do? Reducing Exposure to Pesticides

12-5 How Can We Improve Food Security?

Concept 12-5 We can improve food security by creating programs to reduce poverty and chronic malnutrition, relying more on locally grown food, and cutting food waste.

Use Government Policies to Improve Food Production and Security (1)

Control prices (make sure food is affordable)

whose happy, whose not?

Provide subsidies• Keeps farmers in business, increase food

production• 31% of farm income, surplus depress prices

Let the marketplace decide, but help the poor/needy buy food

Change how subsidies are given

Payments used to promote more sustainable farming and aquaculture practices• Organic growing• Polycultures• IPM implementation

Use Government Policies to Improve Food Production and Security (2)

United Nations Children’s Fund (UNICEF) suggests these measures to limit nutrition related childhood deaths

• Immunizing children against childhood diseases• Encourage breast-feeding • Prevent dehydration in infants and children• Provide family planning services• Increase education for women

Why?

Why would limiting health problems in children by an important step toward global food security?

Government organizations and their role in food production

USDA

EPA

Laws and the Environment

There are a number of laws passed by the legislature meant to protect the environment during food production

How would you rate the success of the laws? Compared to Europe? China? Africa?

What limitations exist that hinder success of these laws

Can you think of reasons why anyone would not want these laws enacted or enforced?

12-6 How Can We Produce Food More Sustainably? (1)

Concept 12-6A Sustainable food production will require reducing topsoil erosion, eliminating overgrazing and overfishing, irrigating more efficiently, using integrated pest management, promoting agrobiodiversity, and providing government subsidies for more sustainable farming, fishing, and aquaculture.

12-6 How Can We Produce Food More Sustainably? (2)

Concept 12-6B Producing enough food to feed the rapidly growing human population will require growing crops in a mix of monocultures and polycultures and decreasing the enormous environmental impacts of industrialized food production.

How can we produce more food sustainably?

Soil conservation (protect the topsoil) Restore soil fertility Reduce desertification and salinization Practice more sustainable aquaculture Produce and use meat more efficiently Practice more organic sustainable farming

methods

Reduce Soil Erosion

Soil conservation, some methods• Terracing• Contour planting• Strip cropping with cover crop• Alley cropping, agroforestry• Windbreaks or shelterbeds• Conservation-tillage farming • No-till• Minimum tillage

Identify erosion hotspots, reduce farming there

Soil Conservation Methods

Fig. 12-24a, p. 302

Fig. 12-24a, p. 302(a) Terracing

Fig. 12-24b, p. 302

Fig. 12-24b, p. 302(b) Contour planting and strip cropping

Fig. 12-24c, p. 302

Fig. 12-24c, p. 302(c) Alley cropping

Fig. 12-24d, p. 302

Fig. 12-24d, p. 302(d) Windbreaks

(a) Terracing (b) Contour planting and strip cropping

(c) Alley cropping(d) Windbreaks Fig. 12-24, p. 302

Stepped Art

Solutions: Mixture of Monoculture Crops Planted in Strips on a Farm

Case Study: Soil Erosion in the United States—Learning from the Past

What happened in the Dust Bowl in the 1930s?

Migrations to the East, West, and Midwest

1935: Soil Erosion Act

More soil conservation needed

Natural Capital Degradation: Dust Storm, Driven by Wind Blowing across Eroded Soil

Natural Capital Degradation: The Dust Bowl of the Great Plains, U.S.

Restore Soil Fertility

Organic fertilizer• Animal manure• Green manure• Compost

Commercial inorganic fertilizer active ingredients • Nitrogen• Phosphorous• Potassium

Reduce Soil Salinization and Desertification

Soil salinization• Prevention• Clean-up

Desertification, reduce• Population growth• Overgrazing• Deforestation• Destructive forms of planting, irrigation, and

mining

Solutions: Soil Salinization

Fig. 12-28, p. 305

SOLUTIONSSoil Salinization

Prevention Cleanup

Flush soil (expensive and wastes water)

Reduce irrigation

Stop growing crops for 2–5 years

Switch to salt-tolerant crops (such as barley, cotton, and sugar beet)

Install underground drainage systems (expensive)

Practice More Sustainable Aquaculture

Open-ocean aquaculture• Choose herbivorous fish

Polyculture

Solutions: More Sustainable Aquaculture

Produce Meat More Efficiently and Humanely

Shift to more grain-efficient forms of protein

Shift to farmed herbivorous fish

Develop meat substitutes; eat less meat

Whole Food Markets: more humane treatment of animals

Efficiency of Converting Grain into Animal Protein

Fig. 12-30, p. 306

Beef cattle 7

Pigs 4

Chicken 2.2

Fish (catfish or carp) 2

Shift to More Sustainable Agriculture (1)

Paul Mader and David Dubois • 22-year study• Compared organic and conventional farming

Benefits of organic farming

Shift to More Sustainable Agriculture (2)

Strategies for more sustainable agriculture• Research on organic agriculture with human

nutrition in mind• Show farmers how organic agricultural systems

work• Subsidies and foreign aid• Training programs; college curricula

Solutions: Sustainable Organic Agriculture

Fig. 12-31, p. 307

SOLUTIONS

Sustainable Organic Agriculture

More LessHigh-yield polyculture

Soil erosion

Organic fertilizers

Aquifer depletion

Biological pest control

Overgrazing

OverfishingIntegrated pest management

Loss of biodiversity

Efficient irrigation

Perennial crops Subsidies for unsustainable farming and fishing

Food waste

Crop rotationWater-efficient crops

Soil salinizationSoil conservationSubsidies for sustainable farming and fishing

Population growth

Poverty

Solutions: Organic Farming

Fig. 12-32, p. 308

SOLUTIONS

Organic Farming

Improves soil fertilityReduces soil erosionRetains more water in soil during drought years

Uses about 30% less energy per unit of yield

Lowers CO2 emissionsReduces water pollution by recycling livestock wastes

Eliminates pollution from pesticidesIncreases biodiversity above and below ground

Benefits wildlife such as birds and bats

Science Focus: Scientists Are Studying Benefits and Costs of Organic Farming

Effect of different fertilizers on nitrate leaching in apple trees

Less nitrate leached into the soil after organic fertilizers were used

Significance?

Science Focus: Sustainable Polycultures of Perennial Crops

Polycultures of perennial crops

Wes Jackson: natural systems agriculture benefits• No need to plow soil and replant each year• Reduces soil erosion and water pollution• Deeper roots – less irrigation needed• Less fertilizer and pesticides needed

Comparison of the Roots between an Annual Plant and a Perennial Plant

Buy Locally Grown Food

Supports local economies

Reduces environmental impact on food production

Community-supported agriculture

What Can You Do? Sustainable Organic Agriculture