Chapter 12
FOOD, SOIL, AND PEST MANAGEMENT
HOW CAN WE PROTECT CROPS FROM PESTS
MORE SUSTAINABLY?

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 – interferes with human welfare
 Natural enemies—predators, parasites, disease
organisms—control pests

 In
natural ecosystems
 In many polyculture
 agroecosystems
WE USE PESTICIDES TO TRY TO CONTROL
PEST POPULATIONS

Pesticides
 Insecticides
– insects killers
 Herbicides – weed killers
 Fungicides – fungus killers
 Rodenticides – rat and mouse killers

Herbivores overcome plant defenses through
natural selection: coevolution
WE USE PESTICIDES TO TRY TO CONTROL
PEST POPULATIONS
First-generation pesticides-natural chemicals from
plants
 Second-generation pesticides

Paul Muller: DDT Nobel Prize 1948
 Benefits versus harm

Broad-spectrum agents – toxic to many pests and
non-pest species. Chlorinated hydrocarbons: DDT,
organophosphates : malathion, parathion
 Selective or narrow spectrum agents  Persistence – length of time they remain deadly in
the environment for years, biologically magnified in
food webs

INDIVIDUALS MATTER: RACHEL CARSON
Biologist : DDT use
was increasing to
control mosquitoes
 Silent Spring - 1962
 Potential threats of
uncontrolled use of
pesticides
 Gave impetus to the
US environmental
movement

MODERN SYNTHETIC PESTICIDES HAVE
SEVERAL ADVANTAGES

Save human lives prevented deaths from malaria,
typhus and bubonic plague : at least 7 million people

Increases food supplies and profits for farmers
protect 55% of the world’s food supply. Profit $1:$4

Work quickly, long shelf life, easily shipped and
applied

Health risks are very low relative to their benefits

New pest control methods: safer and more effective
MODERN SYNTHETIC PESTICIDES HAVE
SEVERAL DISADVANTAGES

Accelerate the development of genetic resistance, 5
to 10 years, sooner in the tropics

Financial treadmill

Kill natural predators and parasites that help control

Only 0.1-2% of the pesticide applied by aerial or
ground spraying reaches the target pest. Rest
pollutes air, water, harm wild life, affect human
health
MODERN SYNTHETIC PESTICIDES HAVE
SEVERAL DISADVANTAGES



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, $5-10 in damages for every $1 spent
 Use alternative pest management practices could
halve the use of chemical pesticides on 40 major
US crops
Pesticide industry refutes these findings
Campbell soup tomatoes in Mexico, Rice in Indonesia,
Sweden
GLYPHOSATE-RESISTANT CROP WEED
MANAGEMENT SYSTEM: A DILEMMA

Best-selling herbicide (Roundup), Monsanto

Advantages – does not harm living things, degrades
into harmless substances within weeks

Disadvantages - resistant weeds , expensive to develop
other pesticides
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 – residues of
banned chemicals exported to other countries may
come back on food, winds carry persistent
pesticides such as DDT

INTERNATIONAL TREATIES
1998 – 50 countries developed treaty that
requires exporting countries to have consent
from importing countries for exports of 22
pesticides , 5 industrial chemicals
 2000 – 100 countries signed to phase out 12
of the most hazardous persistent organic
pollutants (POP’s), 9 of them hydrocarbons
(DDT)
 United States has not signed this agreement








Fool the pest : rotate
crops, adjust plant
times
Provide homes for
pest enemies
Implant genetic
resistance : GMO’s
Bring in natural
enemies : natural
predators
Use insect perfumes
Hormones
Scald them
ALTERNATIVES TO USING
PESTICIDES
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
 expert
knowledge
USE GOVERNMENT POLICIES TO IMPROVE FOOD
PRODUCTION AND SECURITY
Control prices – keep artificially low
 Provide subsidies – price supports, tax breaks,
subsidies for 31% of global farm income

 Developed
: $280 billion /year
 Substitute traditional subsidies with ones that
promote sustainable farming practices
 Subsidies to fishing – promotes destructive fishing
practices

Let the marketplace decide
USE GOVERNMENT POLICIES TO IMPROVE FOOD
PRODUCTION AND SECURITY

United Nations Children’s Fund (UNICEF)
suggests these measures. Can be done at an
average annual cost of $5-10 / child
 Immunizing
children against childhood diseases
 Encourage breast-feeding
 Prevent dehydration in infants and children
 Prevent blindness – Vitamin A capsule (75c/child)
 Provide family planning services
 Increase education for women
HOW CAN WE PRODUCE FOOD MORE
SUSTAINABLY?

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.
HOW CAN WE PRODUCE FOOD MORE
SUSTAINABLY?

Producing enough food to feed the rapidly
growing human population will require growing
crops in a mix of monocultures and poly
cultures and decreasing the enormous
environmental impacts of industrialized food
production.

Soil conservation,
some methods






Terracing
Contour planting
Strip cropping
with cover crop
Alley cropping,
agroforestry
Windbreaks or
shelterbeds
Conservationtillage farming
No-till
 Minimum tillage


Identify erosion
hotspots
REDUCE SOIL EROSION
SOLUTIONS: MIXTURE OF MONOCULTURE CROPS
PLANTED IN STRIPS ON A FARM
RESTORE SOIL FERTILITY


Organic fertilizer
 Animal manure – dung , urine
 Green manure – freshly cut, growing green vegetation
 Compost microorganisms to break down organic waste
Commercial inorganic fertilizer active ingredients
 Nitrogen
 Phosphorous
 Potassium
Crop Rotation
REDUCE SOIL SALINIZATION AND
DESERTIFICATION

Soil salinization



Prevention
Clean-up
Desertification,
reduce




Population growth
Overgrazing
Deforestation
Destructive forms of
planting, irrigation,
and mining
Reduce irrigation
Switch to salttolerant crops (such
as barley, cotton, and
sugar beet
Flush soil
(expensive and
wastes water
Stop growing
crops for 2–5
years
Install
underground
drainage
systems
(expensive)
SHIFT TO MORE SUSTAINABLE AGRICULTURE

Paul Mader and David Dubois
 22-year
study
 Compared organic and conventional farming

Benefits of organic farming
 little
or no use of synthetic pesticides, fertilizers or
genetically engineered seeds, fields free for 3 years
 livestock raised without genetic engineering
SOLUTIONS
Organic Farming
Improves soil fertility
Reduces soil erosion
Retains more water
in soil during
drought years
Uses about 30% less
energy per unit of yield
Lowers CO2 emissions
Reduces water pollution
by recycling livestock
wastes
Eliminates pollution
from pesticides
Increases biodiversity
above and below ground
Benefits wildlife such
as birds and bats
Fig. 12-32, p. 308
SCIENTISTS ARE STUDYING BENEFITS AND
COSTS OF ORGANIC FARMING

Effect of different fertilizers on nitrate leaching
in apple trees
 calcium
nitrate and alfalfa residues, composted
chicken manure, integrated approach (combined)

Less nitrate leached into the soil after organic
fertilizers were used – 4.4 to 5.6 times less
COMPARISON OF THE ROOTS BETWEEN AN ANNUAL
PLANT AND A PERENNIAL PLANT
Annual Wheat
Crop Plant
Roots of a tall grass
prairie plant
Better at using
water and nutrients
BUY LOCALLY GROWN FOOD ……………………
Supports local economies
 Does not have to be transported far – reduces
greenhouse gas emissions, 5 to 17 times less
 Reduces environmental impact on food
production – grow organic food or buy organic
food grown locally
 Community-supported agriculture (CSA)
