Food, Soil, and Pest Management

Chapter 12

Core Case Study: Grains of Hope or an Illusion? Vitamin A deficiency in some developing

countries leads to• Blindness• Death

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

and more iron Is this the answer for malnutrition in these

countries?

Challenge of increased food production

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

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 poorproblems from chronic lack of food and poor nutrition, while many people in developed countries have health problems from eating toocountries have health problems from eating too much food.

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

d tiproduction.

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

Food securityy• Daily access to nutritious food to sustain

active healthy lifeactive healthy life

F d i it Food insecurity• Root cause: poverty

Many People Suffer from Chronic Hunger and Malnutrition (1)( )

Macronutrients• Carbohydrates• Proteins• Fats

Micronutrients• Vitamins• Minerals

Key Nutrients for a Healthy Human Lifey y

Many People Suffer from Chronic Hunger and Malnutrition (3)( )

Chronic undernutrition, hungerg Chronic malnutrition

Marasmas-caused by a severe nutritionalMarasmas caused by a severe nutritional deficiency in general. A wasted appearanceappearanceKwasiorkor-the result of a lack of protein in the diet.in the diet.Thin limbs but distended bellies

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

Children with Kwasiorkor

Many People Do No Get Enough Vitamins and Minerals

Most common vitamin and mineral deficiencies in people i d l i t iin developing countries

Iron deficiency causes anemia lack of hemoglobin in Iron- deficiency causes anemia, lack of hemoglobin in RBC which carries O2

Vitamin A- need for eyesight and normal development

Iodine-need for properly functioning thyroid gland, significant neurological problems in developing children

Golden rice

Woman with Goiter in Bangladeshg

Many People Suffer from Chronic Hunger and Malnutrition (4)( )

What progress is being made? p g g• FAO (UN Food and Agriculture

Organization) estimates numbers ofOrganization) estimates numbers of malnourished or undernourished people fell from 918 million in 1970 to 862fell from 918 million in 1970 to 862 million in 2006

• Corn for fuel instead of food may• Corn for fuel instead of food may increase to numbers to 1.2 billion by 20252025

• 6 million children/yr die

10 Facts on Nutrition by the WHOy

http://www.who.int/features/factfiles/nutrition/en/index.html

Acute Food Shortages Can Lead to Famines

Famine• Usually caused by crop failures from

• Drought• Drought• Flooding• War• Other catastrophic events

Many People Have Health Problems from Eating Too Muchg

Overnutrition• 1.6 billion face health problems while

1 billion do not have enough to eat1 billion do not have enough to eat Similar health problems to those who

are underfedare underfed• Lower life expectancy • Greater susceptibility to disease and

illness• Lower productivity and life quality

Overnutrition

1 in 4 overweight BMI> 25g 1 in 20 obese BMI>30

66% f A i d lt 66% of American adults are overweight 33% are obese 50 billion dollars/year to lose weight 50 billion dollars/year to lose weight

while 24 billion would end under and malnutrition globally

Primary Food sourcesy

SOIL: A RENEWABLE RESOURCE

Soil - A complex mixture of weathered pminerals, partially decomposed organic materials, and a host of living organisms.• At least 15,000 different soil types in the

US.• Vary due to influences of parent

material, time, topography, climate, and p g p yorganisms.

• Can be replenished and renewed.p

Soil Composition

Particle size affects soil characteristics.• Spaces between sand particles give

sandy soil good drainage and allowsandy soil good drainage and allow aeration.• Easily dries out• Easily dries out.

• Tight packing of small particles in silty or cla soils makes them less permeable toclay soils makes them less permeable to air and water• Holds water

Soil Composition

Soil Composition

30% silt, 40% sand, 30% clay10% silt, 40% sand, 50% clay

ClayCl80% silt, 10% sand, 10% clay Clay loam

SiltSilt

Soil Compositionp

Activity of organisms living in the soil help f ili d il h ( di icreate structure, fertility, and tilth (conditions

suitable for cultivation).H I l bl id f ti ll• Humus - Insoluble residue from partially decomposed plants and animals.• Most significant factor in soil structure• Most significant factor in soil structure.

• ½ teaspoon of soil contains hundreds of millions of bacteria fungi algaemillions of bacteria, fungi, algae, roundworms, segmented worms, and tiny insects.

Science Focus: Soil Is the Base of Life on LandSoil Formation: Soil is formed slowly as rock (the parent

material) erodes into tiny pieces near the Earth's surface. ) y pOrganic matter decays and mixes with inorganic material (rock particles, minerals and water) to form soil. La ers (hori ons) of mat re soils Layers (horizons) of mature soils• O horizon: organic matter /leaf litter• A horizon: topsoilA horizon: topsoil• E horizon: eluviation (leaching occurs)• B horizon: subsoil• C horizon: parent material, slightly broken up• R horizon: unweathered bedrock

Soil erosion: human activities accelerated

Wood sorrelOak tree EarthwormEarthworm

Grasses and small shrubs

Organic debris builds up

FernHoney fungus

Moss and lichen

MoleRock fragments

Millipede

g and lichenO horizon Leaf litter

A horizon TopsoilTopsoil

B horizon Subsoil

BedrockImmature soil

Young soilC horizon

Parent material

Mitematerial Nematode

Root systemRed earth

Fig. 12-A, p. 281

Red earth mite Bacteria

FungusMature soil

14-2 How Are the Earth’s Rocks Recycled?y

Concept 14-2 The three major types of rocks found in the earth’s crust—sedimentary, igneous, and metamorphic—are recycled very slowly by the process of erosion melting andslowly by the process of erosion, melting, and metamorphism.

There Are Three Major Types of Rocks (1)j yp ( )

Earth’s crustC d f i l d k• Composed of minerals and rocks

• Minerals-element or inorganic compound that naturally occurs as a solid in the earth’s crust with an regular

t lli t tcrystalline structure• Rocks-solid combination of one or more minerals

Three broad classes of rocks, based on formation1.Sedimentary- made of sediments

• SandstoneSh l• Shale

• Dolomite• LimestoneLimestone• Lignite• Bituminous coal

There Are Three Major Types of Rocks (2)j yp ( )

2. Igneous- made from fire, liquid rock below earth’s s rface cools and hardensearth’s surface cools and hardens• Granite• Lava rockLava rock

3. Metamorphic-made from preexisting rock that is subjected to high temperatures and pressure• Anthracite• Anthracite• Slate• Marble

The Earth’s Rocks Are Recycled Very Slowlyy y

Rock cycle

Slowest of the earth’s cyclic processesy

Weathering: Biological, Chemical, and Physical Processesy

ErosionTransportation

Weathering

Deposition

Igneous rock Granite, pumice, basalt

Sedimentary rock Sandstone, limestonelimestone

Heat, pressure

C liCooling

Heat, pressure, stress

Magma (molten rock)

Melting

Fig. 14-13, p. 354

Metamorphic rock Slate, marble, gneiss, quartzite

Soil Composition By Texture (touch)p y ( )

http://www.soils.umn.edu/academics/classes/soil2125/doc/6ch2txt.htm

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 d t diti l th d t tl iand traditional methods to greatly increase

supplies of meat, fish, and shellfish.

Food Production Has Increased Dramaticallyy

Three systems produce most of our food• Croplands: 77% using 11% of land• Rangelands, pastures, and feedlots: 16% using

29% of land• Fisheries and Aquaculture: 7%

f Importance of wheat, rice, and corn • 47% ALL calories 42% ALL protein consumed

2/3 l i h h i• 2/3 people survive on one these three grains • 50,000 edible crops, 14 provide 90% calories

T d i i l b l f d d ti Tremendous increase in global food production

Industrialized Crop Production Relies on High-Input Monoculturesg p

Industrialized agriculture, high-input agricultureagriculture• Goal is to steadily increase crop yield• Mostly monocultures• Mostly monocultures• Large dependence of fossil fuels, and commercial

fertilizers and pesticidesfertilizers and pesticides• Plantation agriculture: cash crops• Profitable monoculture crops grown in tropical

developing nations• Increased use of greenhouses to raise crops

U d i id l d lik S i• Used in arid lands like Spain• Increased use of hydroponics

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

Traditional Agriculture Often Relies on Low-Input Polyculturesp y

Traditional subsistence agriculture• Human and draft animal labor

Traditional intensive agriculture• Sell crops for income

Polyculture• Benefits over monoculture• Increase sustainability, less fertilizer & pesticides• Slash-and-burn agriculture• Traditional subsistence agriculture in S Am &

Africa

What is Organically Grown Food?g y

Organic refers to methods of farming and i f d W d d tprocessing foods. Weeds and pests are

controlled without using many traditional ti id d f tili Th t " i "pesticides and fertilizers. The term "organic"

applies to both animal and plant foods.

What is Organically Grown Food?g y

The US Department of Agriculture (USDA) sets, defines and regulates the use and meaning ofdefines and regulates the use and meaning of "Organic" on food labels. These standards prohibit the used of:p

Most synthetic fertilizers and pesticides Sewer sludge fertilizers Genetic engineering Growth hormones Irradiation Antibiotics Artificial ingredients

What is Organically Grown Food?g y

What Foods Are Covered by the April 2001 Standard?

Fruits, Vegetables, Mushrooms, and Grains Dairy products and Eggs Livestock feed Meats and Poultry Fish and seafood Honey

A Closer Look at Industrialized Crop Production

Green Revolution: increase crop yields• Monocultures of high-yield key crops

• E.g., rice, wheat, and cornU l t f f tili ti id d t• Use large amounts of fertilizers, pesticides, and water

• Multiple cropping- growing multiple crops per year

Second Green Revolution• Fast growing dwarf varieties bred for tropical climatesg g p

World grain has tripled in production between 1950-1996

2,000

on

tons

)

1,500

1,000prod

uctio

of m

etric

1,000

Gra

in

(mill

ions

o

500

(

0

1960 1970 1980 1990 2000 20101960 1970 1980 1990 2000 2010Year

Total World Grain Production

Fig. 12-5a, p. 282

400400

350

ctio

n on

)

300

ain

prod

upe

r per

so

250

capi

ta g

railo

gram

s

200

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200

150

1960 1970 1980 1990 2000 2010Year

World Grain Production per Capita

Fig. 12-5b, p. 282

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

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)p ( )

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

D ht• Drought• Salty or acidic soil

Advanced tissue culture techniques

Phase 1 Gene Transfer Preparations

A. tumefaciensPlant cell

Extract plasmidExtract DNA l idExtract DNA

Foreign gene if interest

plasmidForeign gene integrated into plasmid DNA.

A b t i t k l idPhase 2 Make Transgenic Cell

Agrobacterium takes up plasmidA. tumefaciens (agrobacterium)

Enzymes integrate plasmid i t h t ll DNAinto host cell DNA.

Host cell Host DNAForeign DNA

Nucleus Transgenic plant cellPhase 3 G G ti llGrow Genetically Engineered Plant Cell division of

transgenic cells

Cultured cells divide and grow into plantlets (otherwise teleological)

Fig. 12-6, p. 283

Transgenic plants with desired trait

TRADE-OFFSGenetically Modified Crops and Foods

Projected Ad t

Projected Di d tAdvantages DisadvantagesIrreversible and unpredictable genetic and ecological effects

Need less fertilizer

Need less waterecological effects

More resistant to insects, disease, frost, and drought

Harmful toxins in food from possible plant cell mutations

Grow faster N ll i f dGrow faster New allergens in foodCan grow in slightly salty soils Lower nutrition

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

pesticidesTolerate higher levels of herbicides

Can harm beneficial i t

Fig. 12-16, p. 291

Higher yields insectsLess spoilage Lower genetic

diversity

Case Study: Industrialized Food Production in the United States

Agribusiness• Corporate conglomerates• 1/5 Gross National product

Prod ces 17% orld’s grain ith 0 3% ork force• Produces 17% world’s grain with 0.3% work force Annual sales

• US consumers spend 2% income on food vs 11%• US consumers spend 2% income on food vs 11% in 1948

• The poorest 1.2 billion spend about 70% income on food

F d d ti ffi i t l t Food production: very efficient lower costs

Meat Production and Consumption Have Grown Steadilyy

Animals for meat raised in• Pastures• Feedlots-CAFOs confined animal feeding

operations Meat production increased fourfold between

1961 d 20071961 and 2007• Average meat consumption per person has

doubleddoubled Demand is expected to go higher

Industrialized Meat Production

Fish and Shellfish Production Have Increased Dramaticallyy

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

species

Polyaquaculture• Integrate growing crops and animals, with raising

h t l kt t f d h bi fi h I llphytoplankton to feed herbivorous fish In small bodies of water

World Fish Catch, Including Both Wild Catch and Aquacultureq

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 pollutiondesertification, water and air pollution, greenhouse gas emissions, and degradation and destruction of biodiversityand destruction of biodiversity.

Producing Food Has Major Environmental Impactsp

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

NATURAL CAPITAL DEGRADATION

Food Production

Biodiversity Loss Soil Water Air Pollution Human HealthLoss 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

Increased runoff G hand wetlands Pesticide residues in drinking water, food, and airFish 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 Contamination of Desertification Pollution from Greenhouse gasKilling wild predators to protect livestock 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

Algal blooms and fish kills in lakes and rivers caused by BacterialOther air pollutants

Fig. 12-9, p. 286

strains replaced by monoculture strains

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 Boliviay p

Natural Capital Degradation: Global Soil Erosion

Drought and Human Activities Are Degrading Drylandsg g y

Desertification • Moderate• Severe• Very severe

Effect of global warming on desertification

Severe Desertification

Natural Capital Degradation: Desertification of Arid and Semiarid Lands

Excessive Irrigation Has Serious Consequencesq

Irrigation problems • Salinization• Waterlogging

Natural Capital Degradation: Severe Salinization on Heavily Irrigated Landy g

There May Be Limits to Expanding the Green Revolutions

Can we expand the green revolution by• Irrigating more cropland?• Improving the efficiency of irrigation?

C lti ating more land? Marginal land?• Cultivating more land? Marginal land?• Using GMOs?• Multicropping?Multicropping?

Industrialized Food Production Requires Huge Inputs of Energyg p gy

Industrialized food production and consumption have a large net energy loss

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

4% 2% 6% 5%

Crops Livestock Food processing Food distribution and preparationFood production p pFood production

Fig. 12-15, p. 290

Food and Biofuel Production Systems Have Caused Major Biodiversity Losses j y

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

TRADE OFFSTRADE-OFFSAnimal Feedlots

Ad t Di d tAdvantages DisadvantagesIncreased meat production

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

Greenhouse gas (CO2 and CH4) Less land use ( 2 4)emissions

Reduced overgrazing Concentration of animal wastes that can pollute waterReduced soil

erosion

Protection of

Use of antibiotics can increase

ti i t

Fig. 12-17, p. 292

Protection of biodiversity

genetic resistance to microbes in humans

TRADE OFFSTRADE-OFFSAquaculture

Advantages DisadvantagesNeeds 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 fi h ifisheries Uses grain to feed

some speciesLow fuel use

Fig. 12-18, p. 293

High profitsDense populations vulnerable to disease

12-4 How Can We Protect Crops from Pests More Sustainably?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 chemicaland small amounts of selected chemical pesticides as a last resort (integrated pest management)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)p ( )

Pesticides • Insecticides• Herbicides• Fungicides• Fungicides• Rodenticides

Herbivores, often insects, overcome plant defenses through natural selection: coevolution

http://www.encyclomedia.com/video-farming pesticides.htmlfarming_pesticides.html

http://www.healthline.com/hlvideo/pesticide-safety

We Use Pesticides to Try to Control Pest Populations (2)p ( ) First-generation pesticides

• Borrowed from nature

Second-generation pesticides• Paul Muller: DDT- dichlorodiphenyltrichloroethane• Benefits versus harm

Broad-spectrum agents• Broad toxicity• Broad toxicity

PersistencePersistence• Length of time remaining in environment

Individuals Matter: Rachel Carson

Biologist

Silent Spring

Potential threats of uncontrolled use of pesticides

Rachel Carson, Biologist, g

Modern Synthetic Pesticides Have Several Advantagesg

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 effectiveeffective

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

i t t ti id b t iresistance to pesticides by pest organisms

Expensive for farmersp

Some insecticides kill natural predators and

parasites that help control the pest population

Pollution in the environmentPollution in the environment

Some harm wildlife

Some are human health hazards

Modern Synthetic Pesticides Have Several Disadvantages (2)g ( )

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

i i ti idincrease in pesticide use• High environmental, health, and social costs with

useuse• Use alternative pest management practices

Pesticide industry refutes these findings 2 6 million tons used in US yearly 2.6 million tons used in US yearly

TRADE-OFFS

Conventional Chemical Pesticides

Advantages DisadvantagesSave lives Promote genetic

resistanceIncrease food

li Kill t l tsupplies Kill natural pest enemies

Profitable Pollute the environmentenvironmentCan harm wildlife and people

Work fast

Safe if used l A i f

Fig. 12-20, p. 295

properly Are expensive for farmers

Science Focus: Glyphosate-Resistant Crop Weed Management System: A Dilemmag y

Best-selling herbicide (Roundup) Monsanto• glyphosphate• glyphosphate

Advantages Advantages• Can kill weeds easily among GR crops• Breaks down in soil• Does not leach into water table

Disadvantages• Resistant weeds (GR)• Reliance on this herbicide

What Can You Do? Reducing Exposure to Pesticides

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

3 U.S. federal agencies regulate and assess h lth i k f t ti idhealth risks of current pesticides• EPA • USDA• USDA• FDA

Effects of active and inactive pesticideEffects of active and inactive pesticide ingredients are poorly documented

Circle of poison, boomerang effect- return of banned pesticides on imported foods or through the windthe wind

There Are Alternatives to Using Pesticides (1)( )

Fool the pest

Provide homes for pest enemies

Implant genetic resistancep g

Bring in natural enemiesBring 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 Damageg g g

Natural Capital: Biological Pest Controlp g

Integrated Pest Management Is a Component of Sustainable Agriculturep g

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

chemical tools to reduce crop damage to an i ll t l bl l leconomically tolerable level

• Very successful programs in Indonesia where they banned 57 or of 66 pesticides used on ricethey banned 57 or of 66 pesticides used on rice and phased out pesticide subsidies-pesticide use dropped 65% and yield increased 15%

Disadvantages• Pesticide industry fighting change in subsidies• Depends on expert knowledge

12-5 How Can We Improve Food Security? y

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 wasteand cutting food waste.

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

Control prices

Provide subsidies

Let the marketplace decidep

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

United Nations Children’s Fund (UNICEF) t thsuggests these measures

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

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

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

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

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 enormousand polycultures and decreasing the enormous environmental impacts of industrialized food productionproduction.

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

Fig. 12-24a, p. 302

Fig. 12-24b, p. 302

Fig. 12-24c, p. 302

Fig. 12-24d, p. 302

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

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

What happened in the Dust Bowl in the 1930s?

Migrations to the East, West, and Midwest

1935: Soil Erosion ActSCS S il C ti S i id d• SCS, Soil Conservation Service, provided education to farmers and ranchers on soil conservation (now called the Natural Resources (Conservation Service)

M il ti d d More soil conservation needed

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

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

Restore Soil Fertilityy

Organic fertilizer• Animal manure• Green manure• Compost

Commercial inorganic fertilizer active ingredients • Nitrogen• Phosphorous

( )• Potassium (also called Potash)

Reduce Soil Salinization and Desertification

Soil salinization- accumulation of soluble salts f di i d l i i il t thof sodium, magnesium and calcium in soil to the

extent that soil fertility is severely reduced. • Prevention- adequate and focused irrigationPrevention adequate and focused irrigation• Clean-up- flush soils with water-allow fields to

remain fallow Desertification, reduce

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

mining

SOLUTIONSSoil Salinization

Prevention CleanupFlush soil (expensiveFlush soil (expensive and wastes water)

Reduce irrigation

Stop growing crops for 2–5 years

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

Install underground drainage systems ( i )

Fig. 12-28, p. 305

sugar beet) (expensive)

Practice More Sustainable Aquacultureq

Open-ocean aquaculture• Choose herbivorous fish

Polyaquaculture• Raising a sustainable food chain of organisms

significantly reducing waste

Solutions: More Sustainable Aquacultureq

Produce Meat More Efficiently and Humanelyy

Shift to more grain-efficient forms of protein

Shift to farmed herbivorous fish

Develop meat substitutes; eat less meatp ;

Whole Food Markets: more humane treatment ofWhole Food Markets: more humane treatment of animals

Efficiency of Converting Grain into Animal Protein

Shift to More Sustainable Agriculture (1)g ( )

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

Benefits of organic farming

Shift to More Sustainable Agriculture (2)g ( )

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• Subsidies and foreign aid• Training programs; college curricula

SOLUTIONSSustainable Organic Agriculture

More LessHigh-yield Soil erosionHigh yield polycultureOrganic fertilizers

Aquifer depletion

Biological pest Overgrazingg pcontrol OverfishingIntegrated pest management Loss of

biodiversityEfficient F d tEfficient irrigationPerennial crops Subsidies for

unsustainable farming and fishing

Food waste

Crop rotationWater efficient fishingWater-efficient crops Soil salinizationSoil conservationSubsidies for

Population growth

Fig. 12-31, p. 307

Subsidies for sustainable farming and fishing

growth

Poverty

SOLUTIONSOrganic Farming

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

Uses about 30% less energy per unit of yieldLowers CO emissionsLowers CO2 emissionsReduces water pollution by recycling livestock wastesEliminates pollution from pesticidesIncreases biodiversity above and below ground

Fig. 12-32, p. 308

above and below groundBenefits wildlife such as birds and bats

Science Focus: Scientists Are Studying Benefits and Costs of Organic Farmingg g

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 Cropsp

Polycultures of perennial crops

Wes Jackson: natural systems agriculture y gbenefits• 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 Foody y

Supports local economies

Reduces environmental impact on food production• Why?

Community-supported agriculture• http://www.localharvest.org/csa/

What Can You Do? Sustainable Organic Agricultureg g

In Class Writingg

What are the three most important pactions you would take to reduce chronic hunger and malnutritionchronic hunger and malnutrition

A) In the United States?and

B) In the world?B) In the world?