Transcript Unit 5

Chapter 9
William P. Cunningham
University of Minnesota
Mary Ann Cunningham
Vassar College
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1
Soils are Complex Ecosystems
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Soil is a renewable resource that develops
gradually through the weathering of rocks and the
accumulation of organic material.
The accumulation of topsoil is a very slow process.
Under the best circumstances it accumulates at a
rate of about 1 mm/year.
2
6 Components of Soil
•
Soil is a marvelous, complex substance; an
entire ecosystem that is hidden to most of us.
In general it has 6 components:
 Sand and gravel
 Silt and clay
 Dead organic material
 Soil fauna and flora
 Water
 Air
3
Variation in Soil Composition
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Loam soils are considered best for agriculture
because they are a mixture of sand, silt and clay.
Brazilian tropical soils are deeply weathered red
clays which have little organic material. They hold
few nutrients and water .
The rich, black soils of the Midwestern US are rich
in nutrients and organic material and contain a
mixture of sand, silt and clay to hold moisture well
4
Soil Texture Pyramid
5
Grassland vs. Tropical Rainforest Soils
6
Soil Fauna Determine Fertility
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Soil bacteria, algae and fungi decompose leaf litter
making recycled nutrients available to plants.
A single gram of soil can contain hundreds of soil
bacteria and 20 meters of tiny fungal strands.
Tiny worms and nematodes process organic
material and create air spaces as they burrow.
Larger insects, spiders and mites loosen and
aerate the soil as well.
Micorrhizal symbiosis, an association between
plant roots and certain fungi. The plant feeds the
fungus and the fungus provides water and
inorganic nutrients to the plant enhancing growth. 7
Soil Ecosystems
8
Soils are Layered
•
Soils are stratified into horizontal layers called soil
horizons.
 Horizons taken together make up soil profile.
- O Horizon (Organic layer)
 Leaf litter, most soil organisms and partially
decomposed organisms
- A Horizon (Surface soil)
 Mineral particles mixed with organic
material
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Soil Profiles
-
-
-
E Horizon (washed out)
 Depleted of soluble nutrients
B Horizon (Subsoil)
 Often dense texture from accumulating
nutrients
C Horizon or regolith (Parent Material)
 Weathered rock fragments with little
organic material
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11
Food Comes from the A Horizon
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In the farm belt, the dominant soils are mollisols.
These soils have a thick, organic-rich A-Horizon
which developed when this land was covered by
prairie grasslands.
Alfisols are another soil type important for farming.
These soils developed in deciduous forests and
have a thinner A-Horizon and less organic material.
12
Chapter 14
William P. Cunningham
University of Minnesota
Mary Ann Cunningham
Vassar College
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
15
Environmental Effects of Mining
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Disturbance or removal of land surface
80,000 metric tons of dust
Toxic air pollutants
Chemical and sediment runoff
 When sulfur bearing minerals are exposed to air
and water, they produce sulfuric acid.
Vast quantities of ore must be crushed and washed
to obtain small quantities of metal; enormous
amounts of freshwater are thereby contaminated
with acid, arsenic, heavy metal.
16
Environmental Effects of Mining
•
Open pit or strip mining
creates huge holes in
the earth which fill with
contaminated
groundwater. Surface
material is left in long
ridges called spoil
banks, but because
they do not contain
topsoil, there is often
no vegetation for many
years.
18
Restoration
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Surface Mining Control and Reclamation Act (1977)
requires better restoration of strip-mined lands,
especially if land classed as prime farmland.
 Difficult and expensive
- Complete reclamation often costs more than
$10,000 / hectare.
 50% of U.S. coal is strip mined.
19
Mining
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Mining companies have recently begun to remove
Appalachian coal via mountaintop removal.
•
Ridge tops are removed to access a coal bed. The
material from the ridge top is crushed and dumped
into adjacent river valleys, burying streams.
•
Clean Water Act
20
Processing Ores
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Metals are extracted from ores by heating or
treatment with chemical solvents.
 Smelting - roasting ore to release metals
- Major source of air pollution
 Heap-Leach Extraction - crushed ore piled in
large heaps and sprayed with a dilute alkaline
cyanide solution which percolates through the
pile to dissolve the gold
- Effluent left behind in ponds can leak into
surface water or groundwater.
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22
Conserving Geologic Resources
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Recycling
 Aluminum must be extracted from bauxite by
electrolysis.
- Recycling waste aluminum consumes onetwentieth the energy of extraction from raw
ore.
 Nearly two-thirds of all aluminum beverage
cans in U.S. are recycled.
 Other metals commonly recycled:
- Platinum, gold, copper, lead, iron, steel
23
Substituting New Materials for Old
•
Reduce metal consumption by using new materials
or new technologies.
 Metal pipes replaced by plastic pipes
 Metal wires replaced by fiber optics
 Steel replaced by polymers, aluminum, ceramics
and new alloys
24
Chronic Hunger and Food Security
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In 1960, 60% of the population of developing
countries was considered chronically
undernourished.
 Today it is less than 14%.
•
Poverty is the greatest threat to food security (Ability
to obtain sufficient food on a daily basis).
25
Hunger Around the World
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Causes of Famines Usually Social & Political
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Famines are characterized by large-scale food
shortages, massive starvation, social disruption, and
economic chaos.
 Mass migrations often occur because productive
capacity has been sacrificed.
 Environmental conditions are an immediate
trigger.
 However, armed conflict and political oppression,
commodity hoarding, price gouging, wars and
poverty are commonly underlying causes.
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Famines
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Aid policies of rich countries often serve to
distribute surplus commodities and produce a
feeling of generosity BUT
 Herding people into feeding camps is typically
counterproductive.
 Many die on the way, others die in epidemics or
from violence, and being away from their land,
they are not there to replant their crops when
weather returns to normal.
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Plumpy Nut
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Overeating is also a Growing Problem
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In the US and other developed countries, highly
processed foods rich in sugar and fat have become
a large part of the diet.
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Harvard Dietary Pyramid
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Vitamins Can Prevent Illness
•
Malnourishment - nutritional imbalance caused by a
lack of specific dietary components or an inability to
absorb or utilize essential nutrients
 3 billion people suffer from vitamin, mineral or
protein deficiency.
 Results in illness, reduced mental capacity,
developmental abnormality, stunted growth,
death
34
Nutritional Problems
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Iron deficiency is the most common dietary
imbalance in the world.
 Leads to anemia, insufficient hemoglobin in
the blood
- Increases risk of death from hemorrhage in
childbirth and affects development
 Red meat, eggs, legumes, and green
vegetables are all good sources of iron.
Lack of iodine leads to goiter as well as stunted
growth and reduced mental capacity.
Lack of vitamin A affects as many as 140 million
children and 350,000 go blind each year.
35
Protein Deficiency Diseases
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Kwashiorkor - occurs mainly in children whose diet
lacks high-quality protein
 Reddish-orange hair, bloated stomach
Marasmus - “To Waste Away” - caused by a diet
low in protein and calories
 Very thin, shriveled
36
37
Key Food Sources

Worldwide, three crops deliver the majority of
the needed nutrients to humanity:
- Wheat, Rice and Corn

In addition, potatoes, barley, oats and rye are
staples in cool, moist climates.
Cassava, sweet potatoes, and other roots and
tubers are staples in warm, wet climates.

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Grain Needed to Produce Various Meats
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Costs and Benefits of Meat Production
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Meat is a concentrated, high-value source of
protein, iron, fats and other nutrients.
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Meat production is a good indicator of wealth as
meat is expensive to produce:
 ie. It takes > 8kg of grain to produce 1kg of beef.
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Meat Production is Energy-Intensive
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It takes at least 16x as much fossil fuel to
produce a kg of meat as it does a kg of grain.
UN Food and Agriculture Organization
experts estimate that livestock produce 20%
of the worlds emissions of greenhouse
gases.
Reducing your meat consumption by 1/5 is
would reduce your energy consumption more
that switching from a standard car to a
hybrid!
41
Agricultural Innovations in Meat Production
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Confined Animal Feeding Operations (CAFO)
Such operations are common in the US, Europe
and China.
New breeds of livestock have also been developed
which produce meat rapidly with shorter turnaround times.
Heavy use of antibiotics allows producers to limit
the spread of disease among animals being raised
in such high densities.
42
Seafood
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Seafood is an important protein source.
Huge boats sweep large portions of the ocean and
kill birds, turtles, and other species as “by-catch”.
Aquaculture (growing aquatic species in pens) is
providing an increasing share of the world’s
seafood.
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Seafood
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Aquaculture supplies food, but it
 uses wild populations to stock and feed captive
populations
 destroys mangrove forests and wetlands used as
nurseries for all marine species
 allows the spread of disease
 releases large quantities of feces, antibiotics and
other pollutants
Polyculture of mixed species of herbivores or filter
feeders can help.
44
Increased Risks of Meat Production
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Converting land to soy and corn production
for animal feed increases soil erosion.
Bacteria-laden manure can escape from feed
lots into the environment causing damage.
Increased use of antibiotics leads to more
antibiotic resistant pathogens.
45
Farming: Conventional and
Sustainable Practices
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Distribution of US Cropland
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Agriculture ISSUES With Soil
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Water Moves Soil in Various Ways
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A farm can lose up to 20 metric tons of
soil/hectare/year from one of these processes:
 Sheet Erosion - thin layer of surface removed
 Rill Erosion - small rivulets of running water
gather together and cut small channels
 Gully Erosion - rills enlarge to form bigger
channels too large to be removed by normal
tillage
 Streambank Erosion - washing away of soil from
banks of streams and rivers
50
Wind Moves Soil Also
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Wind can equal or exceed water as an erosive
force, especially in a dry climate and on flat land.
Desertification - conversion of productive land to
desert
 Intensive farming practices responsible for
erosion:
- Row crops leave soil exposed.
- Weed free-fields
- Removal of windbreaks
- No crop-rotation or resting periods for fields
- Continued monoculture cropping can increase
soil loss tenfold.
51
Desertification
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Farming is Energy Intensive
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

Fossil fuel use began with the advent of tractors
in the 1920’s and increased after WWII with the
use of natural gas to produce synthetic fertilizers.
In the decades that followed, increased reliance
on mechanization has increased the reliance on
fossil fuels
Today, the U.S. food system consumes 16% of
total energy use.
- Most foods require more energy to produce,
process, and transport than we get from
eating them. Eating locally grown foods has
less environmental impact.
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SOIL Conservation
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Food Production can be Sustainable
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There is growing interest in alternative
agriculture that can reduce the use of
energy, antibiotics and other environmental
costs associated with modern agriculture.
Fruits, vegetables, meat, dairy and eggs can
all be produced in more sustainable ways.
Rotational grazing of cattle on grass instead
of feeding them grain and the use of organic
farming techniques can be more
environmentally sustainable.
58
Rotational Grazing
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Food Production Policies
•
Farm subsidies in many countries are protected by
powerful political and economic interests.
 Agricultural subsidies encourage surpluses and
allow American farmers to sell products
overseas at prices below production costs.
 This can distort global markets and cripple
production in developing countries.
60
Soil Conservation

Managing Topography
- Contour Plowing - plowing across slope to
slow flow of water
- Strip Farming - planting different crops in
alternating strips along land contours
- Terracing - shaping land to create level
shelves of earth to hold water and soil
- Plant perennial species.
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Contour Plowing
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Terracing
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Ground Cover Protects Soil
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Methods of Providing Ground Cover
 Annual row crops cause highest rates of erosion
because they leave soil bare for much of the
year.
- Leave crop residue after harvest.
- Plant cover crops such as clover after harvest.
- Interplant two different crops in the same field.
Harvest one; the other is left to hold the soil.
Double harvests are an advantage as well.
- Mulch
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Reduced Tillage Leaves Crop Residue
•
Reduced Tillage
 Minimum Till - reducing number of times soil is
disturbed
 Conserv-Till - uses a disc called a coulter to
open a furrow just wide enough for seed
 No-Till - drilling holes in ground for seed
•
Often farmers using conservation tillage depend
relatively heavily on pesticides, which is a
disadvantage.
65
Low Input Sustainable Agriculture
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Small scale, low input agriculture
No synthetic chemicals
Raising cows on pasture grass rather than grain
No antibiotics
Typically produces smaller yield, but production
costs are lower and prices are higher so net gain
is higher
Preserves rural culture better than factory farms
66
Policies can Protect the Land
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The US has an effective Conservation Reserve
Program that pays farmers to take highly erodible
land out of production.
This program prevents the loss of 450 million tons
of topsoil as well as protecting 270,000 km of
streams and storing 48 million tons of carbon every
year.
Modifying government subsidies to encourage
farmers to produce fruits and vegetables for local
consumption rather than grains could provide a
“whole farm” safety net.
67
Green Revolution
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Green Revolution Produced Increased Yields
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technological advances?
modification of a few well-known species.
 Corn yields jumped from 25 bushels per acre to
130 per acre in last century.
- Most of this was gain accomplished through
conventional plant breeding
Green Revolution started over 50 years ago with
the production of tropical, semi-dwarf, wheat and
rice strains which are now grown in developing
countries around the world.
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The Green Revolution and New Crops
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Most of the world’s
food comes from only
16 species.
New crops possible
 Winged bean
 Tricale, a hybrid
between wheat and
rye
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Semi-Dwarf Wheat
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Shortcomings of the Green Revolution
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Green revolution plants are “high responders”
Poor farmers
Pesticide usage
Destruction of soil
Biodiversity
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GMOs
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Genetic Engineering Produces New Crops
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Genetic engineering - DNA splicing. Produces
genetically modified organisms (GMOs) with new
traits.
- Can produce crops with pest-resistance and
wider tolerance levels to frost, drought, low
nutrient soils, salty soils, etc.
- Can improve protein or vitamin content of crop
- Can incorporate oral vaccines into foods such
as bananas for use in developing nations
- Animals can be modified to grow faster or
produce pharmaceuticals in their milk.
74
Gene Transfer Techniques
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Concerns Regarding GMO’s
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Opponents worry that
 GMOs might produce superweeds resistant to
pesticides.
 Native biodiversity may be reduced.
 Novel toxins might be created.
 Technology may only be available to the rich,
making family farms uncompetitive and driving
poor nations further into poverty.
You are already eating GMO’s: 60% of processed
food in the U.S. now contains GMO’s.
76
Pest Resistance and Weed Control

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A gene from the bacterium Bacillus thuringiensis
(Bt) makes toxins that are lethal to butterflies and
beetles. These genes have been transferred
into corn, potatoes and cotton. Reduces
pesticide use and increases yield.
Concern has arisen over several points.
- Spread of genes into wild populations leading
to resistance in pests
- Effect on nontarget species
77
Transgenic Crops
•
Genetically modified organisms are also called
transgenic organisms.
•
Transgenic crops can be engineered to tolerate
high levels of pesticides.
 Roundup Ready and Liberty Link are two of the
most popular. Crops can grow in the presence
of the pesticides (called Roundup and Liberty)
while weeds within the field are killed.
78
Is Genetic Engineering Safe?
•
Environmental and consumer groups have
campaigned against transgenic organisms.
 “Frankenfoods”
 European nations have bans on GMOs.
•
U.S. Food and Drug Administration declined to
require labeling of foods containing GMOs.
 New varieties are “substantially equivalent” to
related traditionally-bred varieties.
79
Is Genetic Engineering Safe?
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GMOs tested so far do not survive well in the wild
and are no more invasive than unmodified plants.
Worry that genetically modified animals will escape
captivity and outcompete their wild relatives.
(Salmon with added growth hormone gene grow 7X
faster than their wild counterparts.)
We should err on the side of safety.
Will GMOs help feed the world or lead to more
economic disparity?
80
Other Things
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Organic Farming
81
Consumers’ Play and Important Role
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Adopting a vegetarian or organic diet can reduce
environmental impact.
An even greater impact can be made by becoming
a locavore, a person who eats locally grown,
seasonal food.
Join a Community Supported Agriculture program
(CSA) in which you make a payment to a local farm
in return for weekly deliveries of food.
82
Chapter 10
William P. Cunningham
University of Minnesota
Mary Ann Cunningham
Vassar College
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
83
Pests and Pesticides
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Biological Pests – organisms such as insects or
fungi that compete with humans to consume
agricultural crops.
Pesticides are chemicals that kill biological pests.
 Biocides kill a wide variety of living organisms
 Herbicides kill plants
 Insecticides kill insects
 Fungicides kill fungi
Synthetically produced pesticides are the most
common method of controlling pests in modern
agricultural production.
84
Pros and Cons of Modern Pesticides
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The era of synthetic organic pesticides began in
1939 with DDT.
DDT was inexpensive, stable, easily applied, highly
effective
By the 1960’s, evidence showed DDT was
concentrating through food chains.
Carnivorous birds such as eagles suffered egg
shell thinning leading to an inability to reproduce.
In 1962, Rachel Carson warned of the dangers and
DDT was banned in the US by the late 1960’s
It is still used in developing countries.
86
Pros and Cons of Modern Pesticides
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Since the development of DDT, many new
synthetic pesticides have been developed.
Like DDT, many of them have proven to have
unintended consequences on non-target species.
The EPA estimates total pesticide use in the U.S.
amounts to about 5.3 billion pounds annually.
 Roughly 80% of all conventional pesticides
applied in the U.S. are used in agriculture or food
storage and shipping.
 Home and Garden use account for about 8% of
US pesticide use annually.
87
Habitable Planet about DDT
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Pesticide Types
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Organophosphates – most abundantly used
synthetic pesticides.
 Roundup-most commonly used
organophosphate herbicide
 Other organophosphates are used as
insecticides and inhibit cholinesterase, an
enzyme necessary for nervous system function.
 Quickly degrade and do not persist.
 Dangerous to workers and can be lethal
90
Pesticide Types
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Chlorinated Hydrocarbons - fast acting and highly
toxic to sensitive organisms
 Atrazine, Paradichlorobenzene (mothballs) and
DDT are examples.
 Persistent and concentrate in food chains
•
Fumigants-small molecules (ie. Carbon
tetrachloride) which are delivered as a gas to
penetrate soil or other materials.
 Used in fungus control on strawberries or to
prevent insect/rodent damage to stored grains.
 Extremely dangerous to workers and restricted
or banned in some areas.
91
Pesticide Types
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Inorganic Pesticides-compounds of toxic elements
such as mercury or arsenic.
 Highly toxic but indestructible and persistent.
 Generally act as nerve toxins.
•
Natural Organic Pesticides-generally extracted from
plants and include such pesticides as nicotine or
pyrethrums.
 Toxic to insects and may prevent wood decay
93
Pesticide Types
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Microbial Agents and Biological Controls- living
organisms or toxins derived from them that are
used in place of pesticides
 Bacteria such as Bacillus thuringiensis kill
beetles.
 Parasitic wasps such as Trichogramma kill
moths.
 Ladybugs are used to control aphids
94
Environmental Effects of Pesticides
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Widespread use of pesticides brings a
number of environmental and health risks.
•
Non-Target Species
 Up to 90% of pesticides never reach intended
target and instead kill beneficial organisms.
 Honey bees are one such example
Pest Resurgence
 Resistant pests survive and repopulate the area
with more resistant pests.
•
95
Persistent Organic Pollutants
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Persistent Organic Pollutants (POP’s) –are
chlorinated hydrocarbons like DDT that are stable,
effective, highly soluble and toxic.
 They can travel far from the point of dispersal.
 Stored in fat and tend to bioaccumulate
- High levels have been detected in predators
at the upper levels of food chains
96
Human Health Problems
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WHO estimates 25 million people suffer acute
pesticide poisoning, and 20,000 die each year.
 Chronic, or Long-term health effects are difficult
to conclusively document, but effects may
include:
A USDA study shows 73% of conventionally grown
foods in the US contain residue of at least 1
pesticide and some contain more than 1 pesticide.
97
Organic and Sustainable Agriculture
•
Numerous studies have shown organic, sustainable
agriculture is more eco-friendly and leaves soil
healthier than intensive, chemical-based monoculture cropping.
 Organic food must be produced without the use
of hormones, antibiotics, pesticides, synthetic
fertilizers or genetic modification.
 Animals must be raised on organic feed, given
access to the outdoors, given no steroids or
growth hormones and given antibiotics only to
treat disease.
98
Organic and Sustainable Agriculture
•
Critics are disappointed by limited scope of the
definition of organic. They hope to include:
 Growing food in harmony with nature
 Food distribution based on co-ops, farmer’s
markets, and local production
 Food should be simple, wholesome, nutritious.
At present, processed ingredients are allowed in
organic food.
•
Some doubt whether organic growers can produce
enough to feed everyone.
100
Careful Management Can Reduce Pests
•
Behavioral Changes
 Crop Rotation
 Mechanical Cultivation
 Flooding Fields
 Habitat Diversification
 Growing in Pest-Free Zones
 Adjusting Planting Times
 Plant Mixed Polycultures
 Tillage at the Right Time
102
Biological Controls
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Predators or pathogens
Insects that eat weeds
Plants like the neem
tree that make their
own pesticides
Bioengineering
Release of sterile male
insects
Hormones that disrupt
development or attract
insects to traps
103
IPM Uses a Combination of Techniques
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Integrated Pest Management -is a flexible,
ecologically bases strategy that is applied at
specific times against specific pests.
 Some use of pesticides takes place
 Trap crops  Cauliflower in MR. T’s Garden
IPM is being used successfully all over the world.
Cuts pesticide use while maintaining yield.
104
Crop Vacuum Removes Insect Pests
105
Chapter 12
William P. Cunningham
University of Minnesota
Mary Ann Cunningham
Vassar College
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
107
Biodiversity: Preserving Landscapes
108
Boreal and Tropical Forests are Abundant
•
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A Forest is defined as any area where trees cover
more than 10% of the land.
The largest remaining forests on the planet are
found in and cold high latitude areas and humid
equatorial areas.
110
Major Forest Types
112
Forest Destruction in Brazil
114
Rain Forests Burning in Brazil
118
Forest Protection
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About 12% of world’s forests are now protected.
 Africa has the largest protected area (by %)
 Guanacaste National Park in Costa Rica is a
model area for forest guardianship.
 Brazil is a leader in establishing forest reserves
and allows traditional peoples to engage in nondestructive extraction of resources in the forest.
The UN REDD Program- allows less developed
countries get money for protecting their forests by
selling carbon offset credits to more developed
countries who want to offset carbon emissions.
119
Forest Conservation by Region
120
Grasslands
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Occupy about 1/4 of world’s land surface
Frequently converted to cropland, urban areas, or
other human use
More threatened plants in rangelands than in any
other American biome
Can be used sustainably
 Pastoralists herd their animals to adjust to
variations in rainfall and seasonal conditions.
Often overgrazed leading to desertification
125
Overgrazing
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75% of rangelands in the world are degraded; onethird of that is due to overgrazing.
55% of U.S. public lands are in poor or very poor
condition.
Grazing fees charged for use of public lands are
below market value and represent a hidden subsidy
to ranchers.
Ranchers claim that without a viable ranch
economy, western lands would be further
subdivided.
126
New Grazing Methods
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When cattle graze freely, they eat the tender
grasses leaving the tough species to gradually
dominate the landscape.
Rotational grazing confines animals to a small area
for a day or two before shifting them to a new
location.
Some plant communities (e.g. desert Southwest)
cannot tolerate grazing.
Can raise wild species such as bison, which forage
more efficiently and fend off predators, diseases
and pests better than cattle
127
Rotational Grazing
•
Intensive rotational
grazing encloses
livestock in a small
area for a short time
within a movable
electric fence to force
them to eat vegetation
evenly and fertilize the
area evenly.
128
Ecosystem Management
•
Ecosystem management attempts to integrate
sustainable ecological, economic, and social goals
in a unified systems approach.
130
133
Conservation and Economic Development
•
Struggle to save ecosystems cannot be divorced
from struggle to meet human needs.
 Ecotourism - tourism that is ecologically and
socially sustainable
 Native people have valuable ecological
knowledge that can be used in ecosystem
management.
 UNESCO initiated “Man and Biosphere” program
(MAB) calling for the establishment of biosphere
reserves, protected areas divided into zones with
different purposes.
142
A Model Biosphere Reserve
143
Size and Design of Nature Preserves
•
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SLOSS debate - Is it
better to have single
large or several small
reserves?
Edge effects
Corridors of natural
habitat essential
144
How Small Can a Habitat Be?
147
Chapter 22
William P. Cunningham
University of Minnesota
Mary Ann Cunningham
Vassar College
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Urbanization and Sustainable Cities
What is better for saving soil?
Urbanization or Suburbia?
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Urbanization
•
Vast majority of humanity has always lived in rural
areas where they subsisted on natural resources
 Huge urban agglomerations appearing around
world – megalopolis- BoWas, SanFra Diego ?
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Urban Share of Total Population
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Cities Larger Than One Million in 2025
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Government Policies Can Drive Urban Growth

Developing countries often spend majority of
budgets on improving urban areas.
- Major cities gain a monopoly on new jobs,
education, and general opportunity, which
attracts more people.
- Governments manipulate exchange rates and
food prices to benefit the more politically
powerful urban populations.
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Sewage in Jakarta, Indonesia
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Current World Problems
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Housing



At least 1 billion people live in slums
shantytowns
Sometimes people simply occupy land that they
neither own nor rent, creating squatter towns
which can have thousands.
Around 100 million people have no home at all.
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Slum
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Shantytown
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Developed World
•
Urban Sprawl


Cities build out, instead of up
Ex. LA vs. NY
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Growth of Las Vegas, Nevada
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Smart Growth
•
Smart Growth makes efficient and effective use of
land resources and existing infrastructure.
 Minimizes wasted space and money
 Makes land-use planning democratic
 Mixes land uses
 Encourages diversity
 Preserves natural spaces
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New Urbanist Movement
•
•
•
•
•
•
•
•
Recapture small town feel in big city
Organize city into modules of 30,000 to 50,000
people
Determine in advance where development will take
place
Locate everyday services more conveniently
Increase jobs in a community by locating offices
and commercial centers near suburbs
Encourage walking and low-speed vehicles
Promote diversity in housing designs
Create housing “superblocks”
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Green Urbanism
•
Green urbanism redevelops existing cities to be
ecologically sound.
 Focus on in-fill and brownfield development
 Build high density, low-rise, mixed income housing
near city centers
 Provide incentives for alternative transportation
 Encourage ecological building techniques


Greenfield = building on new land/farmland
Brownfield/Brownstone= redevelop existing areas
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Green Urbanism - Smart Cities
•
Smart cities of the future will have minimal
environmental impacts:
 Roof top solar panels and wind turbines will
generate energy.
 Plug-in hybrid cars will serve as a dispersed
electrical storage grid.
 Food will be grown in rooftop gardens.
 Mass transit will move people quickly and
inexpensively.
 Rainwater will be filtered and re-used.
 Recycling of metal and glass will be standard.
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Open Space Design Preserves Landscapes


Conservation Development – (also called cluster
development) preserves at least half of a
subdivision as natural areas, farmland, or other
forms of open space
More for Suburban development
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Designing for Open Space
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Open Space Design
•
•
People want view of
interesting landscape
with wildlife and
walking paths.
By clustering homes, a
conservation
subdivision can have
same number of lots,
but more open space.
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