Food

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Unit 07

• Food Agriculture

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Chapter 11

• Producing Enough Food for the World

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Who cares about food and agriculture?

• Today
• 2 billion people lack reliable access to food
• 800 million people today are chronically
  malnourished
• 300 million of these are children

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Percents indicate the percent of people in each
location that are undernourished.
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Quality of Food Malnourishment

• One in three people has a deficiency of one
  or more vitamins and minerals, especially vitamin
  A, iodine (causes goiter - enlargement of thyroid
  gland), and iron.
• A micronutrient disorder

Figure 13-2
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War and the EnvironmentUndernourishment

• Starving children collecting ants to eat in
  famine-stricken Sudan, Africa which has been
  involved in civil war since 1983.

Figure 13-3
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Kwashiorkor
In the Ga language of Ghana, kwashiorkor means
"the sickness of the child who is displaced from
the breastor the disease of the displaced
child"

• Kwashiorkor is an ailment that results from
  severe protein deficiency. It is mainly seen in
  the tropical and subtropical regions of west and
  central Africa. It commonly occurs when a child
  is weaned onto a diet deficient in protein after
  the birth of another child.
• A macronutrient disorder

The photograph above shows Sudanese children with
severely swollen abdomens, a characteristic
symptom of kwashiorkor
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Daily Intake of Calories Worldwide
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Eating Too MuchOvernutrition

• Overnutrition and lack of exercise can lead to
  reduced life quality, poor health, and premature
  death.
• A 2005 Boston University study found that about
  60 of American adults are overweight and 33 are
  obese (totaling 93).
• Americans spend 42 billion per year trying to
  lose weight.
• 24 billion per year is needed to
• eliminate world hunger.

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Population and Income Growth will Fuel Increased
Food Demand
Increased food demand matrix
High
Year 2020 Demand 75
61
88
147
Projection(75)

• Population growth 45
• Increased meat consumption 30
• Shift to healthy and specialized foods

Caloric shift to meat products
Medium
76 Base Case
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100
Low
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61
88

• In India, the gains
• from the Green
• Revolution are
• getting saturated

Low
Medium
High
Population X income growth
Source IFPRI, FAO
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Food Production

• Food production from croplands, rangelands,
  ocean fisheries, and aquaculture has increased
  dramatically.
• Wheat, rice, and corn provide more than half of
  the worlds consumed calories.
• Fish and shellfish are an important source of
  food for about 1 billion people mostly in Asia
  and in coastal areas of developing countries.

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Industrial Food Production High Input
Monocultures

• About 80 of the worlds food supply is produced
  by industrialized agriculture.
• Uses large amounts of fossil fuel energy, water,
  commercial fertilizers, and pesticides to produce
  monocultures.
• Greenhouses are increasingly being used.
• Plantations are being used in tropics for cash
  crops such as coffee, sugarcane, bananas.

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Locations of the worlds principal types of food
production.
Plantation agriculture
Industrialized agriculture
Intensive traditional ag.
Shifting cultivation
No agriculture
Nomadic herding
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World Land Use
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Crops Rangeland Provides food for grazing and
browsing animals without plowing and
planting Pasture Plowed, planted and
harvested to provide forage for animals
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Geographic Distribution of World Production of a
Few MAJOR Small-grain Crops
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World Small Grain Production
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Aquaculture

• Aquaculture
• The farming of food in aquatic habitats
• Mariculture
• The farming of ocean fish

Vietnamese fishery.
Site of mollusk cultivation in eastern Canada
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Six Ways Agroecosystems Differ from Natural
Ecosystems

1. Try to stop ecological succession and keep the
   agroecosystem in an early successional state
2. Monoculture Large areas planted with a single
   species
3. Crops are planted in neat rows
4. Farming greatly simplifies biological diversity
5. Plowing is unlike any natural soil disturbance
6. Genetic modification of crops.

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Limiting Factors

• Limiting Factor
• The single requirement for growth available in
  the least supply in comparison to the need of an
  organism
• 2 Types of Life-Important Chemicals
• 1. Macronutirents
• 2. Micronutirents
• Synergistic Effects a change in availability of
  one resource affects the response of an organism
  to some other resource

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Increasing the Yield per Acre

• 1. The Green Revolution
• Programs that have led to the development of new
  strains of crops with higher yields, better
  resistance to disease or better ability to grow
  under poor conditions
• 2. Improved Irrigation

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Organic Farming

• 3 Qualities
• It is more like natural ecosystems than
  monocultures
• It minimizes negative environmental impacts
• The food that results from it does not contain
  artificial compounds

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Genetically Modified Food

• Genetically Modified Crops are modified by
  genetic engineers to produce higher crop yields
  and increase resistance to drought, cold, heat,
  toxins, plant pests and disease.

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Chapter 12

• Effects of Agriculture on the Environment

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Many environmental problems result from
agriculture

• Desertification
• Degradation of water aquifers
• Salinization
• Accumulation of toxic metals and organic
  compounds
• Loss of biodiversity

• Soil erosion
• Sediment transport and deposition downstream
• On-site pollution from fertilizers and pesticides
• Deforestation

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PROTECTING FOOD RESOURCES PEST MANAGEMENT

• Organisms found in nature (such as spiders)
  control populations of most pest species as part
  of the earths free ecological services.

Figure 13-27
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PROTECTING FOOD RESOURCES PEST MANAGEMENT

• We use chemicals to repel or kill pest organisms
  as plants have done for millions of years.
• Chemists have developed hundreds of chemicals
  (pesticides) that can kill or repel pests.
• Pesticides vary in their persistence.
• Each year gt 250,000 people in the U.S. become ill
  from household pesticides.

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PROTECTING FOOD RESOURCES PEST MANAGEMENT

• Advantages and disadvantages of conventional
  chemical pesticides.

Figure 13-28
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Individuals Matter Rachel Carson

• Wrote Silent Spring which introduced the U.S. to
  the dangers of the pesticide DDT and related
  compounds to the environment.

Figure 13-A
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The ideal Pesticide and the Nightmare Insect Pest

• The ideal pest-killing chemical has these
  qualities
• Kill only target pest.
• Not cause genetic resistance in the target
  organism.
• Disappear or break down into harmless chemicals
  after doing its job.
• Be more cost-effective than doing nothing.

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Superpests

• Superpests are resistant to pesticides.
• Superpests like the silver whitefly (left)
  challenge farmers as they cause gt 200 million
  per year in U.S. crop losses.

Figure 13-29
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Pesticide Protection Laws in the U.S.

• Government regulation has banned a number of
  harmful pesticides but some scientists call for
  strengthening pesticide laws.
• The Environmental Protection Agency (EPA), the
  Department of Agriculture (USDA), and the Food
  and Drug Administration (FDA) regulate the sales
  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.

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Other Ways to Control Pests

• Genetic engineering can be used to develop pest
  and disease resistant crop strains.

Both tomato plants were exposed to
destructive caterpillars. The genetically altered
plant (right) shows little damage.
Figure 13-32
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Case Study
Integrated Pest Management A Component of
Sustainable Agriculture

• An ecological approach to pest control uses a mix
  of cultivation and biological methods, and small
  amounts of selected chemical pesticides as a last
  resort.
• Integrated Pest Management (IPM)

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Case Study Integrated
Pest Management A Component of Sustainable
Agriculture

• Many scientists urge the USDA to use three
  strategies to promote IPM in the U.S.
• Add a 2 sales tax on pesticides.
• Establish federally supported IPM demonstration
  project for farmers.
• Train USDA personnel and county farm agents in
  IPM.
• The pesticide industry opposes such measures.

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Biological Pest Control
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Integrated Pest Management

• Control of agricultural pests using several
  methods together, including biological and
  chemical agents
• Goals
• To minimize the use of artificial chemicals
• To prevent or slow the buildup of resistance by
  pests to chemical pesticides

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What Can You Do?
Reducing Exposure to Pesticides
Grow some of your food using organic methods.
Buy organic food.
Wash and scrub all fresh fruits, vegetables,
and wild foods you pick.
Eat less or no meat.
Trim the fat from meat.
Fig. 13-30, p. 299
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Soil

• Soil Formation Soil is formed slowly as rock
  (the parent material) erodes into tiny pieces
  near the Earth's surface. Organic matter decays
  and mixes with inorganic material (rock
  particles, minerals and water) to form soil.
• Soil Horizons (layers) Soil is made up of
  distinct horizontal layers these layers are
  called horizons. They range from rich, organic
  upper layers (humus and topsoil) to underlying
  rocky layers ( subsoil, regolith and bedrock).

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Humus

• The main contributor to the fertility of the
  soil. It originates from decomposing material.
• Found on the SURFACE of the soil
• So for examples one reason why grasslands are
  considered the bread baskets of the world is
  because of their great fertility due in large
  part to the natural humus which accumulates
  because grasses form a large amount of organic
  matter that decomposes.
• Tropical rainforests, however, DO NOT have a
  large amount of humus because the decomposition
  rate there is so fast the nutrients are almost
  immediately reabsorbed by plants. This is why the
  tropical rainforest does not yield fertile soil
  when it is cut down.
• Some forests do have humus, however, deciduous
  forests accumulate humus because of the
  decomposition of plants and animals. Temperate
  rainforests also contain humus because needles
  and leaves will decompose.
• Importance nutrients (fertility), holds water,
  improves soil aeration, prevents erosion,
  improves habitats for soil living organisms,
  improves soil structure, allows roots to grow
  more easily.

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O Horizon - The top, organic layer of soil, made
up mostly of leaf litter and humus (decomposed
organic matter).A Horizon - The layer called
topsoil it is found below the O horizon and
above the E horizon. Seeds germinate and plant
roots grow in this dark-colored layer. It is made
up of humus (decomposed organic matter) mixed
with mineral particles.E Horizon - This
eluviation (leaching) layer is light in color
this layer is beneath the A Horizon and above the
B Horizon. It is made up mostly of sand and silt,
having lost most of its minerals and clay as
water drips through the soil (in the process of
eluviation).B Horizon - Also called the subsoil
- this layer is beneath the E Horizon and above
the C Horizon. It contains clay and mineral
deposits (like iron, aluminum oxides, and calcium
carbonate) that it receives from layers above it
when mineralized water drips from the soil
above.C Horizon - Also called regolith the
layer beneath the B Horizon and above the R
Horizon. It consists of slightly broken-up
bedrock. Plant roots do not penetrate into this
layer very little organic material is found in
this layer.R Horizon - The unweathered rock
(bedrock) layer that is beneath all the other
layers.
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Testing Soil

• Chemical
• pH
• salinity
• organic content (measuring humus)
• Testing for major elements such as N, P, K, S or
  trace elements such as Co, B, Ca, Mg etc.
• Physical
• Soil Texture
• Porosity how much water the soul can old due to
  the amount of air/space available
• Moisture content

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Global Outlook Soil Erosion

• Soil is eroding faster than it is forming on more
  than one-third of the worlds cropland.

Figure 13-10
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Where Eroded Soil Goes Sediments Also Cause
Environmental Problems

• Ways to slow erosion
• Making Soil Sustainable
• Contour Plowing
• No-Till Agriculture
• Combination of farming practices that include not
  plowing the land and using herbicides to keep
  down weeds.

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Desertification of arid and semi-arid lands
Very severe
Moderate
Severe
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Case Study Soil Erosion in the U.S.
Some Hopeful Signs

• Soil erodes faster than it forms on most U.S.
  cropland, but since 1985, has been cut by about
  40.
• 1985 Food Security Act (Farm Act) farmers
  receive a subsidy for taking highly erodible land
  out of production and replanting it with soil
  saving plants for 10-15 years.

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Desertification

• Desertification is the deterioration of land in
  arid, semi- arid and dry sub humid areas due to
  changes in climate and human activities
• Can be caused by
• Poor farming practices
• Conversion of marginal grazing lands to croplands

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Desertification Degrading Drylands

• About one-third of the worlds land has lost
  some of its productivity because of drought and
  human activities that reduce or degrade topsoil.

Figure 13-12
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Carrying Capacity of US Pasture Rangelands

• Bad farming practices have lead to an increase in
  desertification in the US.
• Climate suggests that 1/3 of the earth should be
  deserts, however now deserts cover nearly 50 of
  the planet because of human action!

Average number of cows per square kilometer
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Salinization and Waterlogging

• Repeated irrigation can reduce crop yields by
  causing salt buildup in the soil and waterlogging
  of crop plants.

Figure 13-13
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Solutions
Soil Salinization
Cleanup
Prevention
Reduce irrigation
Flush soil (expensive and wastes water)
Stop growing crops for 25 years
Switch to salt-tolerant crops (such as barley,
cotton, sugarbeet)
Install underground drainage systems (expensive)
Fig. 13-15, p. 281
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Salinization and Waterlogging of Soils A
Downside of Irrigation

• Example of high evaporation, poor drainage, and
  severe salinization.
• White alkaline salts have displaced cops.

Figure 13-14
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SUSTAINABLE AGRICULTURE THROUGH SOIL CONSERVATION

• Modern farm machinery can plant crops without
  disturbing soil (no-till and minimum tillage.
• Conservation-tillage farming
• Increases crop yield.
• Raises soil carbon content.
• Lowers water use.
• Lowers pesticides.
• Uses less tractor fuel.

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SUSTAINABLE AGRICULTURE THROUGH SOIL CONSERVATION

• Terracing, contour planting, strip cropping,
  alley cropping, and windbreaks can reduce soil
  erosion.

Figure 13-16
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SUSTAINABLE AGRICULTURE THROUGH SOIL CONSERVATION

• Fertilizers can help restore soil nutrients, but
  runoff of inorganic fertilizers can cause water
  pollution.
• Organic fertilizers from plant and animal
  (fresh, manure, or compost) materials.
• Commercial inorganic fertilizers Active
  ingredients contain nitrogen, phosphorous, and
  potassium and other trace nutrients.

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THE GREEN REVOLUTION AND ITS ENVIRONMENTAL IMPACT

• Since 1950, high-input agriculture has produced
  more crops per unit of land.
• In 1967, fast growing dwarf varieties of rice and
  wheat were developed for tropics and subtropics.

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THE GREEN REVOLUTION AND ITS ENVIRONMENTAL IMPACT

• Lack of water, high costs for small farmers, and
  physical limits to increasing crop yields hinder
  expansion of the green revolution.
• Since 1978 the amount of irrigated land per
  person has declined due to
• Depletion of underground water supplies.
• Inefficient irrigation methods.
• Salt build-up.
• Cost of irrigating crops.

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THE GREEN REVOLUTION AND ITS ENVIRONMENTAL IMPACT

• Modern agriculture has a greater harmful
  environmental impact than any human activity.
• Loss of a variety of genetically different crop
  and livestock strains might limit raw material
  needed for future green and gene revolutions.
• In the U.S., 97 of the food plant varieties
  available in the 1940 no longer exist in large
  quantities.

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Biodiversity Loss
Soil
Air Pollution
Human Health
Water
Loss and degradation of grasslands, forests, and
wetlands
Erosion
Water waste
Nitrates in drinking water
Greenhouse gas emissions from fossil fuel use
Loss of fertility
Aquifer depletion
Pesticide residues in drinking water, food, and
air
Salinization
Increased runoff and flooding from cleared land
Other air pollutants from fossil fuel use
Waterlogging
Desertification
Fish kills from pesticide runoff
Sediment pollution from erosion
Contamination of drinking and swimming water with
disease organisms from livestock wastes
Greenhouse gas emissions of nitrous oxide from
use of inorganic fertilizers
Fish kills from pesticide runoff
Killing wild predators to protect livestock
Surface and groundwater pollution from pesticides
and fertilizers
Belching of the greenhouse gas methane by cattle
Loss of genetic diversity of wild crop strains
replaced by monoculture strains
Bacterial contamination of meat
Overfertilization of lakes and rivers from runoff
of fertilizers, livestock wastes, and food
processing wastes
Pollution from pesticide sprays
Fig. 13-18, p. 285
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THE GENE REVOLUTION

• To increase crop yields, we can mix the genes of
  similar types of organisms and mix the genes of
  different organisms.
• 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.
• Controversy has arisen over the use of
  genetically modified food (GMF).

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The Terminator Gene

• A genetically modified crop which has a gene to
  cause the plant to become sterile after the first
  year

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Grazing on Rangelands

• Overgrazing occurs when the carrying capacity is
  exceeded. It can cause severe damage to lands
• It is important to properly manage livestock,
  including using appropriate lands for gazing and
  keeping livestock at a sustainable density

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SOLUTIONS 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.

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Solutions
Sustainable Organic Agriculture
More
Less
High-yield polyculture
Soil erosion
Soil salinization
Organic fertilizers
Aquifer depletion
Biological pest control
Overgrazing
Overfishing
Integrated pest management
Loss of biodiversity
Efficient irrigation
Loss of prime cropland
Perennial crops
Food waste
Crop rotation
Subsidies for unsustainable farming and fishing
Water-efficient crops
Soil conservation
Population growth
Subsidies for sustainable farming and fishing
Poverty
Fig. 13-33, p. 302
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Sustainable Agriculture

• Results of 22 year study comparing organic
  and conventional farming.

Figure 13-34
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What Can You Do?
Sustainable Organic Agriculture
Waste less food
Eat less or no meat
Feed pets balanced grain foods instead of meat
Use organic farming to grow some of your food
Buy organic food
Eat locally grown food
Compost food wastes