Food, Soil, and Pest
Management
Chapter 10
Section 10-1
WHAT IS FOOD SECURITY
AND WHY IS IT DIFFICULT TO
ATTAIN?
Many people suffer from chronic
health and malnutrition
• Food security means having daily access to
enough nutritious food to live an active and
healthy life.
• One of every six people in less-developed
countries is not getting enough to eat, facing
food insecurity—living with chronic hunger and
poor nutrition, which threatens their ability to
lead healthy and productive lives.
– The root cause of food insecurity is poverty.
– Other obstacles to food security are political
upheaval, war, corruption, and bad weather, including
prolonged drought, flooding, and heat waves.
Many people suffer from chronic
health and malnutrition
• To maintain good health and resist disease,
individuals need fairly large amounts of
macronutrients, such as carbohydrates, proteins and
fats, and smaller amounts of micronutrients—vitamins
and minerals.
• People who cannot grow or buy enough food to meet
their basic energy needs suffer from chronic
undernutrition, or hunger.
• Many suffer from chronic malnutrition—a deficiency of
protein and other key nutrients, which weakens them,
makes them more vulnerable to disease, and hinders
the normal development of children.
Starving children collecting ants
in Sudan, Africa
Many people do not get enough
vitamins and minerals
• Chronic lack of iodine can
cause stunted growth, mental
retardation, and goiter.
• Almost one-third of the world’s
people do not get enough
iodine in their food and water.
• According to the FAO and the
WHO, eliminating this serious
health problem would cost the
equivalent of only 2–3 cents
per year for every person in
the world.
Many people have health
problems from eating too much
• Overnutrition occurs when food energy intake exceeds
energy use, causing excess body fat.
• Face similar health problems as those under: lower life
expectancy, greater susceptibility to disease and illness,
and lower productivity and life quality.
• Globally about 925 million people have health problems
because they do not get enough to eat, and about 1.1
billion people face health problems from eating too much.
• About 68% of American adults are overweight and half of
those people are obese.
• Obesity plays a role in four of the top ten causes of death
in the United States—heart disease, stroke, Type 2
diabetes, and some forms of cancer.
Section 10-2
HOW IS FOOD PRODUCED?
Food production has increased
dramatically
• About 10,000 years ago, humans began to shift
from hunting for and gathering their food to
growing it and raising animals for food and labor.
• Today, three systems supply most of our food.
– Croplands produce mostly grains.
– Rangelands, pastures, and feedlots produce meat.
– Fisheries and aquaculture provide us with seafood.
• About 66% of the world’s people survive
primarily by eating rice, wheat, and corn.
– Only a few species of mammals and fish provide most
of the world’s meat and seafood.
Food production has increased
dramatically
• Since 1960, there has been an increase in
global food production from all three of the
major food production systems because of
technological advances.
– Tractors, farm machinery and high-tech
fishing equipment.
– Irrigation.
– Inorganic chemical fertilizers, pesticides, highyield grain varieties, and industrialized
production of livestock and fish.
Industrialized crop production relies
on high-input monocultures
• Agriculture used to grow crops can be divided
roughly into two types:
– Industrialized agriculture, or high-input agriculture,
uses heavy equipment and large amounts of financial
capital, fossil fuel, water, commercial inorganic
fertilizers, and pesticides to produce single crops, or
monocultures.
• Major goal of industrialized agriculture is to increase yield,
the amount of food produced per unit of land.
• Used on about 25% of the world’s cropland, mostly in moredeveloped countries, and produces about 80% of the world’s
food.
Industrialized crop production relies
on high-input monocultures
– Plantation agriculture is a form of industrialized
agriculture used primarily in tropical lessdeveloped countries.
• Grows cash crops such as bananas, soybeans,
sugarcane, coffee, palm oil, and vegetables.
• Crops are grown on large monoculture plantations,
mostly for export to more-developed countries.
– Modern industrialized agriculture violates the
three principles of sustainability by relying
heavily on fossil fuels, reducing natural and crop
biodiversity, and neglecting the conservation
and recycling of nutrients in topsoil.
Oil palm plantation – once
covered with tropical rain forest
Traditional agriculture often
relies on low-input polycultures
• Traditional agriculture provides about 20% of the
world’s food crops on about 75% of its cultivated
land, mostly in less-developed countries.
• There are two main types of traditional agriculture.
– Traditional subsistence agriculture supplements energy
from the sun with the labor of humans and draft animals
to produce enough crops for a farm family’s survival, with
little left over to sell or store as a reserve for hard times.
– In traditional intensive agriculture, farmers increase their
inputs of human and draft-animal labor, animal manure
for fertilizer, and water to obtain higher crop yields, some
of which can be sold for income.
A closer look at industrialized
crop production
• Farmers can produce more food by increasing
their land or their yields per acre.
• Since 1950, about 88% of the increase in global
food production has come from using high-input
industrialized agriculture to increase yields in a
process called the green revolution.
• Three steps of the green revolution:
– First, develop and plant monocultures of selectively
bred or genetically engineered high-yield varieties of
key crops such as rice, wheat, and corn.
A closer look at industrialized
crop production
– Second, produce high yields by using large inputs of
water and synthetic inorganic fertilizers, and
pesticides.
– Third, increase the number of crops grown per year
on a plot of land through multiple cropping.
• The first green revolution used high-input
agriculture to dramatically increase crop yields in
most of the world’s more-developed countries,
especially the United States, between 1950 and
1970.
A closer look at industrialized
crop production
• A second green revolution has been taking
place since 1967. Fast-growing varieties of rice
and wheat, specially bred for tropical and
subtropical climates, have been introduced into
middle-income, less-developed countries such
as India, China, and Brazil.
– Producing more food on less land has helped to
protect some biodiversity by preserving large areas of
forests, grasslands, wetlands, and easily eroded
mountain terrain that might otherwise be used for
farming.
A closer look at industrialized
crop production
• Largely because of the two green revolutions,
world grain production tripled between 1961 and
2009.
• People directly consume about 48% of the
world’s grain production. About 35% is used to
feed livestock and indirectly consumed by
people who eat meat and meat products. The
remaining 17% (mostly corn) is used to make
biofuels such as ethanol for cars and other
vehicles.
Growth in global grain production of wheat,
corn, and rice between 1961-2010
Crossbreeding and genetic engineering
produce varieties of crops and livestock
• Crossbreeding through artificial selection has been
used for centuries by farmers and scientists to
develop genetically improved varieties of crops
and livestock animals.
– Such selective breeding in this first gene revolution has
yielded amazing results; ancient ears of corn were
about the size of your little finger, and wild tomatoes
were once the size of grapes.
– Typically takes 15 years or more to produce a
commercially valuable new crop variety, and it can
combine traits only from genetically similar species.
– Typically, resulting varieties remain useful for only 5–10
years before pests and diseases reduce their efficacy.
Crossbreeding and genetic engineering
produce varieties of crops and livestock
• Modern scientists are creating a second gene
revolution by using genetic engineering to develop
genetically improved strains of crops and livestock.
– Alters an organism’s genetic material through adding,
deleting, or changing segments of its DNA to produce
desirable traits or to eliminate undesirable ones (gene
splicing); resulting organisms are called genetically
modified organisms.
– Developing a new crop variety through gene splicing is
faster selective breeding, usually costs less, and allows
for the insertion of genes from almost any other organism
into crop cells.
Meat production has grown
steadily
• Meat and animal products such as eggs and milk are
good sources of high-quality protein and represent the
world’s second major food-producing system.
• Between 1961 and 2010, world meat production—
mostly beef, pork, and poultry—increased more than
fourfold and average meat consumption per person
more than doubled.
• Global meat production is likely to more than double
again by 2050 as affluence rises and more middleincome people begin consuming more meat and
animal products in rapidly developing countries such
as China and India.
Fish and shellfish production
have increased dramatically
• The world’s third major food-producing
system consists of fisheries and
aquaculture.
• A fishery is a concentration of particular
aquatic species suitable for commercial
harvesting in a given ocean area or inland
body of water.
• Industrial fishing fleets harvest most of the
world’s marine catch of wild fish.
Fish and shellfish production
have increased dramatically
• Fish and shellfish are also produced through
aquaculture—the practice of raising marine
and freshwater fish in freshwater ponds and
rice paddies or in underwater cages in
coastal waters or in deeper ocean waters.
• Some fishery scientists warn that unless we
reduce overfishing and ocean pollution, and
slow projected climate change, most of the
world’s major commercial ocean fisheries
could collapse by 2050.
Global seafood production,
1950-2008
Section 10-3
WHAT ENVIRONMENTAL
PROBLEMS ARISE FROM
INDUSTRIALIZED FOOD
PRODUCTION?
Food production’s harmful
environmental effects
Topsoil erosion is a serious problem
in some parts of the world
Serious concern
Some concern
Stable or nonvegetative
Stepped Art
Fig. 10-11, p. 214
Drought and human activities
are degrading drylands
• Desertification in arid and semiarid parts of the
world threatens livestock and crop contributions to
the world’s food supply.
• Desertification occurs when the productive potential
of topsoil falls by 10% or more because of a
combination of prolonged drought and human
activities that expose topsoil to erosion.
• The FAO’s 2007 report on the Status of the World’s
Forests estimated that some 70% of world’s arid
and semiarid lands used for agriculture are
degraded and threatened by desertification.
Sand dunes threaten to take
over an oasis in West Africa
Variation in desertification in
arid and semiarid lands, 2007
Excessive irrigation has serious
consequences
• Irrigation boosts productivity of farms; roughly 20%
of the world’s cropland that is irrigated produces
about 45% of the world’s food.
• Most irrigation water is a dilute solution of various
salts that are picked up as the water flows over or
through soil and rocks.
• Repeated annual applications of irrigation water in
dry climates lead to the gradual accumulation of
salts in the upper soil layers—a soil degradation
process called salinization that stunts crop growth,
lowers crop yields, and can eventually kill plants
and ruin the land.
Excessive irrigation has serious
consequences
• Severe salinization has reduced yields on at
least 10% of the world’s irrigated cropland, and
almost 25% of irrigated cropland in the United
States, especially in western states
• Irrigation can cause waterlogging, in which water
accumulates underground and gradually raises
the water table; at least one-tenth of the world’s
irrigated land suffers from waterlogging, and the
problem is getting worse.
• Excessive irrigation contributes to depletion of
groundwater and surface water supplies.
Genetically modified crops and foods
have advantages and disadvantages
Food and biofuel production systems have
caused major losses of biodiversity
• Natural biodiversity and some ecological services are
threatened when forests are cleared and grasslands are
plowed up and replaced with croplands used to produce
food or biofuels, such as ethanol.
• There is increasing loss of agrobiodiversity, the world’s
genetic variety of animal and plant species.
• In the United States, about 97% of the food plant
varieties that were available to farmers in the 1940s no
longer exist, except perhaps in small amounts in seed
banks and in the backyards of a few gardeners.
• The world’s genetic “library,” which is critical for
increasing food yields, is rapidly shrinking.
There are limits to expansion of
the green revolution
– Scientists point out that continuing to increase
these inputs eventually produces no additional
increase in crop yields.
– Since 1978, the amount of irrigated land per person
has been declining, due to population growth,
wasteful use of irrigation water, soil salinization,
and depletion of both aquifers and surface water,
and the fact that most of the world’s farmers do not
have enough money to irrigate their crops.
– We can get more crops per drop of irrigation water
by using known methods and technologies to
greatly improve the efficiency of irrigation.
There are limits to expansion of
the green revolution
– Clearing tropical forests and irrigating arid land could
more than double the world’s cropland, but much of this
land has poor soil fertility, steep slopes, or both.
– Cultivating such land usually is expensive, is unlikely to
be sustainable, and reduces biodiversity by degrading
and destroying wildlife habitats
– During this century, fertile croplands in coastal areas are
likely to be flooded by rising sea levels resulting from
projected climate change.
– Food production could drop sharply in some major foodproducing areas because of increased drought and
longer and more intense heat waves, also resulting from
projected climate change.
Animal feedlots and confined animal feeding
operations have advantages and disadvantages
Aquaculture has advantages
and disadvantages
Section 10-4
HOW CAN WE PROTECT
CROPS FROM PESTS MORE
SUSTAINABLY?
Synthetic pesticides:
advantages and disadvantages
You can reduce your exposure
to pesticides
Integrated pest management is a
component of more sustainable agriculture
• Many pest control experts and farmers believe the best
way to control crop pests is a carefully designed
integrated pest management (IPM) program.
• Farmers develop a carefully designed control program
that uses a combination of cultivation, biological, and
chemical tools and techniques.
• The overall aim of IPM is to reduce crop damage to an
economically tolerable level.
• Farmers first use biological methods (natural predators,
parasites, and disease organisms) and cultivation
controls (such as rotating crops, altering planting time,
and using large machines to vacuum up harmful bugs).
Section 10-5
HOW CAN WE IMPROVE FOOD
SECURITY?
Use government policies to improve
food production and security
• Agriculture is a financially risky business
because farmers have a good or bad year
depending on factors over which they
have little control: weather, crop prices,
crop pests and diseases, loan interest
rates, and global markets.
• Governments use two main approaches to
influence food production:
– Control prices.
– Provide subsidies.
Section 10-6
HOW CAN WE PRODUCE
FOOD MORE SUSTAINABLY?
Soil conservation methods
Three types of systems
commonly used to irrigate crops
Center pivot
(efficiency 80% with low-pressure
sprinkler and 90–95% with LEPA
Gravity flow
sprinkler)
(efficiency 60% and 80% with surge valves)
Water usually pumped from
underground and sprayed
Water usually comes from an aqueduct
from mobile boom with
system or a nearby river.
sprinklers.
Drip irrigation
(efficiency 90–95%)
Above- or below-ground
pipes or tubes deliver
water to individual plant
roots.
Fig. 10-24, p. 229
Ways to prevent soil salinization
and ways to clean it up
Practice more sustainable
aquaculture
Produce meat more efficiently
and eat less meat
• Meat production and consumption
account for the largest contribution to
the ecological footprints of most
individuals in affluent nations.
• If everyone in the world today was on the
average U.S. meat-based diet, the current
annual global grain harvest could
sustainably feed only about one-third of
the world’s current population.
The efficiency of converting
grain into animal protein varies
More sustainable, low-input food production
has a number of major components
Major advantages of organic
farming over conventional
Ways you can eat more
sustainably
Three big ideas
• About 925 million people have health problems
because they do not get enough to eat and 1.1
billion people face health problems from eating
too much.
• Modern industrialized agriculture has a greater
harmful impact on the environment than any
other human activity.
• More sustainable forms of food production will
greatly reduce the harmful environmental
impacts of industrialized food production
systems while likely increasing food security.
End of “Short Version”
• The slides that follow are those taken out
of the “long version” of this same lecture.
You should still read the following slides
for better understanding, but I will not go
over them in class unless you have
specific questions.
Many people do not get enough
vitamins and minerals
• Deficiency of one or more vitamins and minerals,
usually vitamin A, iron, and iodine.
• Some 250,000–500,000 children younger than
age 6 go blind each year from a lack of vitamin A,
and within a year, more than half of them die.
• Lack of iron causes anemia which causes fatigue,
makes infection more likely, and increases a
woman’s chances of dying from hemorrhage in
childbirth.
• 1/5 people in the world suffers from iron
deficiency.
Traditional agriculture often
relies on low-input polycultures
• Many traditional farmers grow several crops
on the same plot simultaneously, a practice
known as polyculture.
– Crop diversity reduces the chance of losing
most or all of the year’s food supply to pests,
bad weather, and other misfortunes.
– Crops mature at different times, provide food
throughout the year, reduce the input of human
labor, and keep the soil covered to reduce
erosion from wind and water.
Traditional agriculture often
relies on low-input polycultures
– Lessens need for fertilizer and water, because
root systems at different depths in the soil
capture nutrients and moisture efficiently.
– Insecticides and herbicides are rarely needed
because multiple habitats are created for
natural predators of crop-eating insects, and
weeds have trouble competing with the
multitude of crop plants.
– On average, such low-input polyculture
produces higher yields than does high-input
monoculture.
A closer look at industrialized
crop production
• In the U.S., industrialized farming has evolved into
agribusiness, as a small number of giant
multinational corporations increasingly control the
growing, processing, distribution, and sale of food in
U.S. and global markets.
• Since 1950 U.S. industrialized agriculture has more
than doubled the yields of key crops such as wheat,
corn, and soybeans without cultivating more land.
• Americans spend only about 13% of their disposable
income on food, compared to the percentages up to
50% that people in China and India and most other
less-developed countries have to pay for food.
A closer look at industrialized
crop production
• In the U.S., industrialized farming has evolved into
agribusiness, as a small number of giant
multinational corporations increasingly control the
growing, processing, distribution, and sale of food in
U.S. and global markets.
• Since 1950 U.S. industrialized agriculture has more
than doubled the yields of key crops such as wheat,
corn, and soybeans without cultivating more land.
• Americans spend only about 13% of their disposable
income on food, compared to the percentages up to
50% that people in China and India and most other
less-developed countries have to pay for food.
Crossbreeding and genetic engineering
produce varieties of crops and livestock
– Currently, at least 70% of the food products on U.S.
supermarket shelves contain some form of genetically
engineered food or ingredients, but no law requires the
labeling of GM products.
– Certified organic food, which is labeled as makes no use
of genetically modified seeds or ingredients.
– Bioengineers plan to develop new GM varieties of crops
that are resistant to heat, cold, herbicides, insect pests,
parasites, viral diseases, drought, and salty or acidic soil.
They also hope to develop crop plants that can grow
faster and survive with little or no irrigation and with less
fertilizer and pesticides.
Meat production has grown
steadily
• About half of the world’s meat comes from livestock
grazing on grass in unfenced rangelands and
enclosed pastures.
• The other half is produced through an industrialized
system in which animals are raised mostly in densely
packed feedlots and concentrated animal feeding
operations (CAFOs), where they are fed grain, fish
meal, or fish oil, which are usually doctored with
growth hormones and antibiotics.
• Feedlots and CAFOs, and the animal wastes and
runoff associated with them, create serious
environmental impacts on the air and water.
Industrialized food production
requires huge inputs of energy
• The industrialization of food production has been
made possible by the availability of energy,
mostly from nonrenewable oil and natural gas.
• Energy is needed to run farm machinery, irrigate
crops, and produce synthetic pesticides and
synthetic inorganic fertilizers, as well as to
process food and transport it long distances
within and between countries.
• As a result, producing, processing, transporting,
and consuming industrialized food result in a
large net energy loss.
Producing food has major
environmental impacts
• Spectacular increases in the world’s food
production since 1950. The bad news is the
harmful environmental effects associated with
such production increases.
• According to many analysts, agriculture has a
greater total harmful environmental impact
than any human activity.
• These environmental effects may limit future
food production and make it unsustainable.
Topsoil erosion is a serious
problem in parts of the world
• Soil erosion is the movement of soil
components, especially surface litter and topsoil
from one place to another by the actions of wind
and water.
• Erosion of topsoil has two major harmful effects.
– Loss of soil fertility through depletion of plant
nutrients in topsoil.
– Water pollution in nearby surface waters, where
eroded topsoil ends up as sediment. This can kill fish
and shellfish and clog irrigation ditches, boat
channels, reservoirs, and lakes.
Topsoil erosion is a serious
problem in parts of the world
• By removing vital plant nutrients from topsoil and
adding excess plant nutrients to aquatic systems,
we degrade the topsoil and pollute the water, and
thus alter the carbon, nitrogen, and phosphorus
cycles.
Agriculture contributes to air pollution
and projected climate change
• Agricultural activities create a lot of air pollution.
• Account for more than 25% of the human-generated
emissions of carbon dioxide, other greenhouse gases.
• Industrialized livestock production alone generates
about 18% of the world’s greenhouse gases; cattle
and dairy cows release the greenhouse gas methane
and methane is generated by liquid animal manure
stored in waste lagoons.
• Nitrous oxide, with about 300 times the warming
capacity of CO2 per molecule, is released in huge
quantities by synthetic inorganic fertilizers as well as
by livestock manure.
There is controversy over
genetically engineered foods
• Controversy has arisen over the use of
genetically modified (GM) food and other
products of genetic engineering.
• Its producers and investors see GM food as a
potentially sustainable way to solve world
hunger problems and improve human health.
• Some critics consider it potentially dangerous
“Frankenfood.”
– Recognize the potential benefits of GM crops.
– Warn that we know too little about the long-term
potential harm to human health and ecosystems from
the widespread use of such crops.
There is controversy over
genetically engineered foods
– Warn that GM organisms released into the
environment may cause some unintended harmful
genetic and ecological effects.
– Genes in plant pollen from GM crops can spread
among nonengineered species. The new strains can
then form hybrids with wild crop varieties, which could
reduce the natural genetic biodiversity of wild strains.
– Most scientists and economists who have evaluated
the genetic engineering of crops believe that its
potential benefits will eventually outweigh its risks.
– Others have serious doubts about the ability of GM
crops to increase food security compared to other
more effective and sustainable alternative solutions.
There are limits to expansion of
the green revolution
• Factors that have limited the current and
future success of the green revolution:
– Without huge inputs of inorganic fertilizer,
pesticides, and water, most green revolution
and genetically engineered crop varieties
produce yields that are no higher (and are
sometimes lower) than those from traditional
strains.
– High inputs cost too much for most
subsistence farmers in less-developed
countries.
Industrialized meat production has
harmful environmental consequences
• Producing meat by using feedlots and other
confined animal production facilities increases
meat production, reduces overgrazing, and
yields higher profits.
• Such systems use large amounts of energy
(mostly fossil fuels) and water and produce huge
amounts of animal waste that sometimes pollute
surface water and groundwater and saturate the
air with their odors and emitting large quantities
of climate-changing greenhouse gases into the
atmosphere.
Industrialized meat production has
harmful environmental consequences
• Meat produced by industrialized agriculture is
artificially cheap – harmful environmental and
health costs are not included in the prices.
• Overgrazing and soil compaction and erosion by
livestock have degraded about 20% of the world’s
grasslands and pastures.
• Rangeland grazing and industrialized livestock
production cause about 55% of all topsoil erosion
and sediment pollution, and 33% of the water
pollution that results from runoff from excessive
inputs of synthetic fertilizers.
Industrialized meat production has
harmful environmental consequences
• The use of fossil fuels energy pollutes the
air and water, and emits greenhouse gases.
• Use of antibiotics is widespread in
industrialized livestock production facilities.
– 70% of all antibiotics used in the United States
are added to animal feed to prevent the spread
of diseases in crowded feedlots and CAFOs
and to make the livestock animals grow faster.
Industrialized meat production has
harmful environmental consequences
– Widespread antibiotic use in livestock is an
important factor in the rise of genetic resistance
among many disease-causing microbes.
• Reduces the effectiveness of some antibiotics used
to treat infectious diseases in humans.
• Promotes the development of new and aggressive
disease organisms that are resistant to all but a very
few antibiotics currently available.
• Animal waste produced by U.S. meat is roughly
130 times that of its human population.
Pesticide use has not reduced
U.S. crop losses to pests
• Synthetic pesticide use has not reduced U.S.
crop losses to pests, mostly because of
genetic resistance and reduction of natural
predators.
• Three conclusions from a study that
evaluated data from more than 300
agricultural scientists and economists:
– Between 1942 and 1997, estimated crop
losses from insects almost doubled from 7%
to 13%, despite a 10-fold increase in the use
of synthetic insecticides.
We use pesticides to help
control pest populations
• Broad-spectrum agents are toxic to many pests,
but also to beneficial species. Examples are
chlorinated hydrocarbon compounds, such as
DDT, and organophosphate compounds, such as
malathion and parathion.
• Selective, or narrow spectrum, agents are
effective against a narrowly defined group of
organisms. Examples are algaecides for algae and
fungicides for fungi.
We use pesticides to help
control pest populations
• Development of a variety of synthetic pesticides—
chemicals used to kill/control populations of organisms that
we consider undesirable such as insects, weeds, and mice.
• Common types of pesticides include insecticides (insect
killers), herbicides (weed killers), fungicides (fungus
killers), and rodenticides (rat and mouse killers).
• Plants produce chemicals called biopesticides to ward off,
deceive, or poison the insects and herbivores that feed on
them.
• Since 1950, pesticide use has increased more than 50fold, and most of today’s pesticides are 10–100 times more
toxic than those used in the 1950s.
• Use of biopesticides is on the rise.
We use pesticides to help
control pest populations
• In the United States, about 25% of pesticide use is
on houses, gardens, lawns, parks, playing fields,
swimming pools, and golf courses, with the
average lawn receiving ten times more synthetic
pesticides per unit of land area than an equivalent
amount of cropland.
• In 1962, biologist Rachel Carson warned against
relying primarily on synthetic organic chemicals to
kill insects and other species we regard as pests.
Laws and treaties can help to protect us
from the harmful effects of pesticides
• Up to 98% of the potential risk of developing cancer
from pesticide residues on food grown in the U.S.
would be eliminated if EPA standards were as strict
for pre-1972 pesticides as they are for later ones.
• Banned/unregistered pesticides may be manufactured
in one country and exported to other countries.
• In what environmental scientists call a circle of
poison, or the boomerang effect, residues of some
banned or unapproved chemicals used in synthetic
pesticides exported to other countries can return to
the exporting countries on imported food.
Reduce soil erosion
• Soil conservation involves using a variety of
ways to reduce soil erosion and restore soil
fertility, mostly by keeping the soil covered with
vegetation.
• Some of the methods farmers can use to reduce
soil erosion:
– Terracing and contour planting are ways to grow food
on steep slopes without depleting topsoil.
– Strip cropping involves planting alternating strips of a
row crop and another crop that completely covers the
soil, called a cover crop.
Reduce soil erosion
– Alley cropping, or agroforestry involves one or more
crops planted together in strips or alleys between
trees and shrubs, which provide shade.
– Farmers can establish windbreaks, or shelterbelts, of
trees around crop fields to reduce wind erosion.
– Conservation tillage farming by using special tillers
and planting machines that drill seeds directly through
crop residues into the undisturbed soil.
– Retire the estimated one-tenth of the world’s marginal
cropland that is highly erodible and accounts for the
majority of the world’s topsoil erosion.
Reduce soil erosion
• Soil erosion in the United States.
– A third of the country’s original topsoil is gone and
much of the rest is degraded.
– In 1935, the United States passed the Soil Erosion
Act, which established the Soil Conservation Service
(SCS) as part of the USDA.
• Now called the Natural Resources Conservation Service
– Farmers and ranchers were given technical
assistance to set up soil conservation programs.
– U.S. farmers are sharply reducing some of their
topsoil losses through a combination of conservationtillage farming and government-sponsored soil
conservation programs.
Restore soil fertility
• Organic agriculture uses only organic fertilizers
and crop rotation to replenish the nutrients.
• Synthetic inorganic fertilizers are usually inorganic
compounds that contain nitrogen, phosphorus,
and potassium.
– Inorganic fertilizer use has grown more than 900%
since 1950; now about one-fourth of the world’s crops.
– Fertilizer runoff can pollute nearby bodies of water and
coastal estuaries where rivers empty into the sea.
– They do not replace organic matter. To completely
restore nutrients to topsoil, both inorganic and organic
fertilizers should be used.
Produce meat more efficiently
and eat less meat
• More sustainable meat production and
consumption involves shifting from less grainefficient forms of animal protein, (beef,
carnivorous fish), to more grain-efficient
forms (poultry, herbivorous farmed fish).
• Eating less meat by having one meatless day
per week.
• Healthier to eat less meat.
• Replace meat with a balanced vegetarian
diet.
Shift to more sustainable food
production
• Industrialized agriculture produces large
amounts of food at reasonable prices, but
is unsustainable because it:
– Relies heavily on fossil fuels.
– Reduces biodiversity and agrobiodiversity.
– Reduces the recycling of plant nutrients back
to topsoil.
Shift to more sustainable food
production
• More sustainable, low-input agriculture has
a number of major components.
– Organic farming.
• Sharply reduces the harmful environmental effects of
industrialized farming and our exposure to pesticides.
• Encourages more humane treatment of animals used
for food and is a more economically just system for
farm workers and farmers.
• Requires more human labor than industrial farming.
• Yields can be lower but farmers do not have to pay
for expensive synthetic pesticides, herbicides, and
fertilizers; typically get higher prices for their crops.
Shift to more sustainable food
production
– Organic polyculture.
• A diversity of organic crops is grown on the same
plot.
• Use polyculture to grow perennial crops—crops that
grow back year after year on their own.
• Helps to conserve and replenish topsoil, requires and
wastes less water, and reduces the need for
fertilizers and pesticides.
• Reduces the air and water pollution associated with
conventional industrialized agriculture.
– Shift from using imported fossil fuel to relying
more on solar energy for food production.
Shift to more sustainable food
production
• Five major strategies to help farmers and
consumers make the transition to more
sustainable agriculture:
1. Greatly increase research on more sustainable
organic farming and perennial polyculture, and on
improving human nutrition.
2. Establish education and training programs in more
sustainable agriculture for students, farmers, and
government agricultural officials.
3. Set up an international fund to give farmers in poor
countries access to various types of more sustainable
agriculture.
Shift to more sustainable food
production
4. Replace government subsidies for environmentally
harmful forms of industrialized agriculture with
subsidies that encourage more sustainable
agriculture.
5. Mount a massive program to educate consumers
about the true environmental and health costs of the
food they buy. This would help them understand why
the current system is unsustainable, and it would help
build political support for including the harmful costs of
food production in the market prices of food.
Laws and treaties can help to protect us
from the harmful effects of pesticides
• The wind can also carry persistent pesticides from
one country to another.
• In 1998, more than 50 countries developed an
international treaty that requires exporting
countries to have informed consent from importing
counties for exports of 22 synthetic pesticides and
5 industrial chemicals.
• In 2000, more than 100 countries developed an
international agreement to ban or phase out the
use of 12 especially hazardous persistent organic
pollutants. The U.S. has not signed.
Integrated pest management is a
component of more sustainable agriculture
• They apply small amounts of insecticides—mostly based
on those naturally produced by plants—only when insect
or weed populations reach a threshold where the
potential cost of pest damage to crops outweighs the
cost of applying the pesticide.
• Broad-spectrum, long-lived pesticides are not used, and
different chemicals are used alternately to slow the
development of genetic resistance and to avoid killing
predators of pest species.
• A well-designed IPM program can reduce synthetic
pesticide use and pest control costs by 50–65%, without
reducing crop yields and food quality.
Integrated pest management is a
component of more sustainable agriculture
• IPM can also reduce inputs of fertilizer and
irrigation water, and slow the development of
genetic resistance, because pests are attacked
less often and with lower doses of pesticides.
• Disadvantages of IPM:
– It requires expert knowledge about each pest
situation and takes more time than does using
conventional pesticides.
– Methods developed for a crop in one area might not
apply to areas with even slightly different growing
conditions.
Integrated pest management is a
component of more sustainable agriculture
– Initial costs may be higher, although long-term costs
typically are lower than those of using conventional
pesticides.
– Widespread use of IPM is hindered in the United
States and a number of other countries by
government subsidies for using synthetic chemical
pesticides, as well as by opposition from pesticide
manufacturers, and a shortage of IPM experts.
• The USDA could promote IPM three ways:
– First, add a 2% sales tax on synthetic pesticides and
use the revenue to fund IPM research and education.
Integrated pest management is a
component of more sustainable agriculture
– Second, set up a federally supported IPM
demonstration project on at least one farm in every
county in the United States.
– Third, train USDA field personnel and county farm
agents in IPM so they can help farmers use this
alternative.
– Because these measures would reduce its profits, the
pesticide industry has vigorously, and successfully,
opposed them.
Nature controls the populations
of most pests
• A pest is any species that interferes with
human welfare by competing with us for
food, invading homes, lawns and gardens,
destroying building materials, spreading
disease, invading ecosystems, or simply
being a nuisance.
• Worldwide, only about 100 species of
plants (“weeds”), animals (mostly insects),
fungi, and microbes cause most of the
damage to the crops we grow.
Nature controls the populations
of most pests
• In natural ecosystems and many polyculture
agroecosystems, natural enemies (predators,
parasites, and disease organisms) control the
populations of most potential pest species.
– Spiders kill far more crop-eating insects every year
than humans do by using chemicals.
• When we clear forests and grasslands, plant
monoculture crops, and douse fields with
chemicals that kill pests, we upset many of these
natural population checks and balances that
help to maintain biodiversity.
We use pesticides to help
control pest populations
• Pesticides vary in their persistence, the
length of time they remain deadly in the
environment.
– DDT and related compounds remain in the
environment for years and can be biologically
magnified in food chains and webs.
– Organophosphates are active for days or weeks
and are not biologically magnified but can be
highly toxic to humans.
Pesticide use has not reduced
U.S. crop losses to pests
– The estimated environmental, health, and
social costs of pesticide use in the United
States are $5–10 in damages for every dollar
spent on pesticides.
– Alternative pest management practices could
cut the use of synthetic pesticides by half on
40 major U.S. crops without reducing crop
yields
• The pesticide industry disputes these
findings.
CASE STUDY: Ecological Surprises:
The Law of Unintended Consequences
• In the 1950s, dieldrin (a DDT relative) was used
to eliminate malaria in North Borneo. This
started an unexpected chain of negative effects.
• Small insect-eating lizards that lived in the
houses died after eating dieldrin-contaminated
insects. Cats died after feeding on the lizards.
Rats flourished and villagers became threatened
by plague carried by rat fleas.
• The WHO successfully parachuted healthy cats
onto the island to help control the rats.
CASE STUDY: Ecological Surprises:
The Law of Unintended Consequences
• The villagers’ roofs fell in. The dieldrin had killed
wasps and other insects that fed on a type of
caterpillar that was not affected by the
insecticide. The caterpillar population exploded,
and ate the leaves used to thatch roofs.
• Ultimately, both malaria and the unexpected
effects of the spraying program were brought
under control.
Laws and treaties can help to protect us
from the harmful effects of pesticides
• In the U.S., three federal agencies, the EPA, the
USDA, and the FDA regulate the sale and use of
pesticides under the Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA), first
passed in 1947 and amended in 1972.
• Under FIFRA, the EPA was supposed to assess
the health risks of the active ingredients in
synthetic pesticide products already in use.
– After more than 30 years, less than 10% of the active
ingredients in pesticide products have been tested for
chronic health effects, due to lack of funding.
Laws and treaties can help to protect us
from the harmful effects of pesticides
• In 1996, Congress passed the Food Quality
Protection Act, due to growing scientific evidence
and citizen pressure concerning the effects of
small amounts of pesticides on children.
– Act requires the EPA to reduce the allowed levels of
pesticide residues in food by a factor of 10 when there
is inadequate information on the potentially harmful
effects on children.
• Between 1972 and 2010, the EPA used FIFRA to
ban or severely restrict the use of 64 active
pesticide ingredients, including DDT and most
other chlorinated hydrocarbon insecticides.
There are alternatives to
synthetic pesticides
• Many scientists believe we should greatly
increase the use of biological, ecological,
and other alternative methods for
controlling pests and diseases that affect
crops and human health. Here are some
of these alternatives:
– Fool the pest. A variety of cultivation practices
can be used to fake out pests.
– Provide homes for pest enemies.
– Implant genetic resistance.
There are alternatives to
synthetic pesticides
– Bring in natural enemies. Use biological
control by importing natural predators,
parasites, and disease-causing bacteria and
viruses.
– Use insect perfumes.
– Bring in the hormones.
– Reduce use of synthetic herbicides to control
weeds.
Use government policies to improve
food production and security
• To improve food security, some analysts
urge governments to establish special
programs focused on saving children from
the harmful health effects of poverty.
– Immunizing more children against childhood
diseases.
– Preventing dehydration from diarrhea by giving
infants a mixture of sugar and salt in water.
– Preventing blindness by giving children an
inexpensive vitamin A capsule twice a year.
Restore soil fertility
• Topsoil conservation is the best way to maintain
soil fertility, with restoring some of the lost plant
nutrients being the next option.
• Organic fertilizer from plant and animal materials.
– Animal manure: the waste of cattle, horses, poultry, and
other farm animals adding organic nitrogen, stimulating
the growth of beneficial soil bacteria and fungi.
– Green manure: consists of freshly cut or growing green
vegetation that is plowed into the topsoil to increase the
organic matter and humus available to the next crop.
– Compost is produced when microorganisms in soil
break down organic matter in the presence of oxygen.
Reduce soil salinization and
desertification
• One way to prevent and deal with soil salinization
is to reduce the amount of water that is put onto
crop fields through use of modern efficient
irrigation.
– Drip, or trickle irrigation, also called microirrigation, is
the most efficient way to deliver small amounts of
freshwater to crops precisely.
– These systems drastically reduce freshwater waste
because 90–95% of the water input reaches the crops.
– By using less freshwater, they also reduce the amount
of harmful salt that irrigation water leaves in the soil.
Reduce soil salinization and
desertification
• Reducing desertification is not easy because we can’t
control the timing and location of prolonged droughts
caused by changes in weather patterns.
• We can reduce population growth, overgrazing,
deforestation, and destructive forms of planting,
irrigation, and mining, which have left much land
vulnerable to soil erosion and thus desertification.
• Work to decrease the human contribution to
projected climate change, which is expected to
increase severe and prolonged droughts in larger
areas of the world during this century.
• Restoration via planting trees.