Transcript Document

Food, Soil, and Pest Management
Chapter 12
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 – means that every person in a
given area has daily access to enough nutritious
food to have an active and healthy life.
 Global food production has stayed ahead of
population growth.
• However :
• One of six people in developing countries cannot grow
or buy the food they need.
 Food insecurity – living with chronic hunger and
poor nutrition.
Key Nutrients for a Healthy Human Life
 We need large amounts of macronutrients
• (protein, carbohydrates, and fats)
 We also need smaller amounts of micronutrients
• (vitamins such as A,C, and E and various minerals)
Many People Suffer from
Chronic Hunger and Malnutrition
 Some people cannot meet their basic energy needs
• Chronic undernutrition or hunger
 Others lack proteins and key nutrient needs
• Chronic malnutrition
 The root cause of hunger and malnutrition is poverty.
• In 2006, 862 million were undernourished worldwide.
• A 2005 estimate says 6 million children die annually
from undernutrition or nonfatal diseases made worse
by their poor diet.
Many People Do No Get
Enough Vitamins and Minerals
 One in three people has a deficiency of one or
more vitamins and minerals, especially:
• iron – anemia
• vitamin A – blindness
• iodine – goiter or enlarged thyroid gland
 Can lead to deafness
 Famine – a shortage of food in an
area along with mass starvation,
economic and social chaos
• Usually caused by crop failures
from drought, flooding, war, or
other catastrophic events
Many People Have Health Problems
from Eating Too Much
 Overnutrition – excess calories and lack of exercise
can lead to reduced life quality, poor health, and
premature death…same as undernutrition
 A 2005 Boston University study:
• 60% of American adults are overweight
• 33% are obese
 Americans spend $42 billion a year
trying to lose weight.
 Estimates are that $24 billion per year would
eliminate world hunger.
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
 Wheat, rice, and corn provide more than half of
the world’s consumed calories
 Fish and shellfish are an important source of food
for about 1 billion people mostly in Asia
 Of all the biodiversity on the planet, only 14 plant
and 9 animal species make up 90% of the world’s
consumed calories.
Food Production Has Increased Dramatically
 Three systems produce most of our food:
• Grain from croplands: 77%
• Meat from rangelands, pastures, and feedlots: 16%
• Fish from fisheries/Aquaculture: 7%
 Dramatic increase in global food production since 1960.
• Why?
• Technological advances
• More sophisticated farming techniques
• Expanded use of inorganic chemical fertilizers, irrigation,
pesticides, high-yield crops
• Intense farming methods, densely populated feedlots,
breeding/growing pens, aquaculture ponds or ocean cages
Two Types of Agriculture
 Industrial Agriculture (High Input Agriculture)
• A relatively small group of farmers produce large
quantities of a single crop or livestock
• Mostly in developed countries
 Traditional Agriculture (Low Input Agriculture)
• Traditional subsistence agriculture
• Produces enough crops or livestock to feed family
• Traditional intensive agriculture
• Produces enough crops or livestock to feed the
farmer’s family and maybe some to sell
• Mostly in developing countries
Industrialized Crop Production Relies on
High-Input Monocultures
 About 80% of the world’s food supply is produced by
industrialized agriculture.
• Goal is to steadily increase crop yield
• Uses large amounts of fossil fuel energy, water, commercial
fertilizers, and pesticides to produce monocultures.
 Plantation agriculture primarily in tropical developing
countries (bananas, coffee, sugarcane)
• Cash crops – crops intended for sale, not consumption or animals
Traditional Agriculture Often Relies on
Low-Input Polycultures
 Many farmers in developing countries grow a variety
of crops on the same plot of land
• Polyculture: different plants are grown together
 Limited technology, limited equipment, limited impact
on the environment
 Slash-and-burn agriculture – burning underbrush to
provide nutrients to the soil
A Closer Look at Industrialized
Crop Production
 The Green Revolution represents the 88% increase
in food production per unit of area since 1950.
• Monocultures of high-yield key crops
• Selectively breed or genetically engineered crops
• Large inputs of fertilizers, pesticides, water
 The Second Green Revolution involves fast
growing rice/wheat bred for tropical regions.
 Early in the century, one American farmer could
produce food for 2.5 people.
 By 1999, a single farmer could feed over 130 people.
A Closer Look at Industrialized
Crop Production
 Since 1950, high-input agriculture has produced
more crops per unit of land.
• Grain production has tripled during this timeframe
 Why has per Capita grain production gone down
since the early 1980’s?
Crossbreeding and Genetic Engineering Can
Produce New Crop Varieties
 Gene Revolution – increased crop yields, as a
result of mixing organisms’ genes
• Artificial selection has been used for centuries to
develop genetically improved varieties of crops.
• Genetic engineering develops improved strains at
an exponential pace compared to artificial
selection.
• Add beneficial genes
• Delete negative genes
Crossbreeding and Genetic Engineering Can
Produce New Crop Varieties
 Age of Genetic Engineering
• developing crops that are
resistant to:
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Heat and cold
Herbicides
Insect pests
Viral diseases
Drought
Salty or acidic soil
 Controversy has arisen over
the use of genetically modified foods (GMF’s).
• Critics fear that we know too little about the long-term
potential harm to human health and the environment.
Meat Production and Consumption
Have Grown Steadily
 Meat production increased fourfold from 1961–2007
 Industrialized livestock production:
• Densely populated feedlots are common
• System uses a lot of energy and water and produce
huge amounts of animal waste
Industrialized Meat Production Has Harmful
Environmental Consequences
Fish and Shellfish Production
Have Increased Dramatically
 Aquaculture – raising large numbers of fish and
shellfish in ponds and cages
• world’s fastest growing type of food production.
 Fish farming involves cultivating fish in a controlled
environment and harvesting them in captivity.
Producing Fish Through Aquaculture Can
Harm Aquatic Ecosystems
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
 Modern agriculture has a greater harmful
environmental impact than any human activity.
• Loss of biodiversity as a result of monocultures
• Loss of genetic variability in crops and livestock
• High input of chemicals
• Air, water pollution
• Greater soil erosion
Producing Food Has
Major Environmental Impacts
Topsoil Erosion Is a Serious Problem
in Parts of the World
 Soil erosion is the
movement of soil
components,
especially surface
litter and topsoil, by
wind or water.
 Soil erosion increases through activities such as
farming, logging, construction, overgrazing, and
off-road vehicles.
 Soil erosion lowers soil fertility and can overload
nearby bodies of water with eroded sediment.
Topsoil Erosion Is a Serious Problem
in Parts of the World
 Soil is eroding faster than it
is forming on more than onethird of the world’s cropland.
Excessive Irrigation Has Serious Consequences
 Irrigation problems:
• Salinization – repeated
irrigation can reduce
crop yields by causing
salt buildup in the soil
• Waterlogging
Natural Capital Degradation:
Desertification of Arid and Semiarid Lands
Industrialized Food Production
Requires Huge Inputs of Energy
 Industrialized agriculture uses about 17% of all
commercial energy in the U.S. and food travels an
average 2,400 kilometers from farm to plate.
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).
We Use Pesticides to Try to
Control Pest Populations
 What is a pest?
• Only about 100 species of plants (weeds), animals
(mostly insects), fungi, microbes cause the most damage
 Chemists have developed hundreds of chemicals
(pesticides) that can kill or repel pests.
 Pesticides
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Insecticides
Herbicides
Fungicides
Rodenticides
 2.6 million tons of pesticides (600 different active chemicals)
used annually
We Use Pesticides to Try to
Control Pest Populations
 First-generation pesticides
• Natural chemicals derived from plants
 Second-generation pesticides
• Man-made chemicals from a laboratory
• DDT was the first
 Broad-spectrum agents
• Toxic to many pest and non-pest species
 Narrow-spectrum agents
• Effective against a specific group of species
 Pesticides vary in their persistence
• How long they remain deadly in the environment
We Use Pesticides to Try to
Control Pest Populations
 The ideal pest-killing chemical has these qualities:
• Kill only target pest
• Not cause genetic resistance in the target organism
• Disappear/break down into harmless chemicals after
doing its job
• Be more cost-effective than doing nothing
Modern Synthetic Pesticides Have Several
Advantages/Disadvantages
 Each year > 250,000 people in the U.S. become ill from
household pesticides
Laws and Treaties Can Help to Protect Us
from the Harmful Effects of Pesticides
 The Environmental Protection Agency (EPA), the U.S.
Department of Agriculture (USDA), and the Food and
Drug Administration (FDA) regulate the sale and use of
pesticides under the Federal Insecticide, Fungicide and
Rodenticide Act (FIFRA).
• The EPA has only evaluated the health effects of 10% of
the active ingredients of all pesticides.
• Cite lack of funding for complex and lengthy project
 The Food Quality Protection Act strengthens FIFRA by
reducing the allowable level of chemicals by a factor of 10
for which the health effects are still unknown.
• Precautionary Principle
There are Alternatives to Using Pesticides
 There are cultivation, biological, and ecological
alternatives to conventional chemical pesticides.
• Fool the pest through cultivation practices.
• Biological pest control
• Provide homes for the pest enemies.
• Bring in natural enemies.
• Use pheromones to lure pests into traps.
• Use hormones to disrupt life cycles.
• Implant genetic resistance into plants.
Both tomato plants were exposed to destructive caterpillars.
The genetically altered plant (right) shows little damage.
Integrated Pest Management Is a Component
of Sustainable Agriculture
 Integrated pest management (IPM)
• Crops and pests are evaluated as parts of a larger
ecosystem
• Comprehensive
plan including:
cultivation,
biological controls,
and chemical tools
applied in a
coordinated way
12-6 How Can We Produce Food
More Sustainably?
 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.
 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.
Soil Conservation Methods
 There are many different soil conservation techniques
that can be employed to reduce soil erosion:
Terracing
Contour planting
Soil Conservation Methods
Alley cropping
Strip cropping
Windbreaks
No-till or minimum tillage
Restore Soil Fertility
 Fertilizers can help restore soil nutrients, but runoff of
inorganic fertilizers can cause water pollution.
• Organic fertilizers – From plant and animal materials
• Animal manure
• Green manure – freshly cut vegetation plowed into soil
• Compost – broken-down organic matter
• Commercial inorganic fertilizers
• Made from minerals
• Active ingredients contain nitrogen (N), phosphorous
(P), and potassium (K) and other trace nutrients
Shift to More Sustainable Agriculture
 Three main ways to reduce
hunger and malnutrition and
the harmful effects of
agriculture:
• Slow population growth
• Sharply reduce poverty
• Develop and phase in
systems of more
sustainable, low input
agriculture over the next
few decades