Chapter 11—Feeding the World
CORE CASE STUDY: A Farm Where Animals Do Most of the Work
I.
Human nutritional requirements are not always satisfied
 Humans survived by hunting and gathering until 10,000 years ago when agriculture
began
 ~24,000 people starve to death every day—8.8 million per year
a. Nutritional Requirements
 Undernutrition is chronic hunger, not consuming enough calories to be healthy
o On average, a person needs 2200 kcal a day to provide the energy to
perform daily functions
o Energy deficits can lower immunity for all and brain development for
children
 Malnutrition is the lack of the proper balance of proteins, carbohydrates,
vitamins, and minerals
o WHO reports 3 billion people are malnourished globally
 Food security is the condition in which people have access (economic, social, or
physical availability) to sufficient, safe, and nutritious food that meets their
dietary needs for an active and healthy life
 Food insecurity is the condition in which people do not have adequate food
access
 Famine is a condition in which food insecurity is so extreme that large numbers
of deaths occur in a given area over a relatively short period
o Usually the result of crop failures due to drought, can have social &
political causes as well
 Anemia, iron deficiency, is the most widespread nutritional deficiency in the
world
 A quarter of a million children go blind every year from vitamin A deficiency
 Overnutrition is the ingestion of too many calories and improper foods, causing
people to be overweight or obese
o Puts people at risk for type 2 diabetes, hypertension, heart disease, and
stroke
 Grains make up the largest component of the human diet (60%)
 Meat, the 2nd largest component, mainly comes from livestock and poultry
o As incomes increase, people tend to add more meat to their diet
b. Reasons for Undernutrition and Malnutrition
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II.
Poverty: unequal food distribution rather than scarcity
Political & economic factors: refugees, lack of food = political unrest, poor resort
to crime or violence to feed their families, rising food prices
Diverting large amounts of agricultural resources to feed livestock & poultry
o ~40% corn & soybeans grown to feed livestock in US
Global grain production: amount of land under cultivation, weather &
precipitation, global prices, land productivity
o Per capita grain production has been level since 1980
The Green Revolution and industrial farming methods have transformed
agriculture
 ~10,000 years ago people began to domesticate plants & animals and cultivate the soil
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 “the single most harmful human action that has taken place”
 Industrial agriculture (agribusiness) applies the techniques of the Industrial Revolution to
the production of food
b. The Energy Subsidy in Agriculture
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The amount of solar energy, fossil fuel energy, and human energy input per calorie
of food is called the energy subsidy
Ex. If it takes 20 kg of grain fed to a cow to produce 1 kg of beef, that beef has an
energy subsidy of 20.
 Energy input per calorie of food obtained is greater for modern agricultural
practices than for traditional agriculture. (fossil fuels used to produce
fertilizers, pesticides, operate machinery, pump water, harvest, transport)
The shift from small farms & human labor to large industrial operations with more
machinery is known as the Green Revolution.
o Food production increased dramatically
o Relied on new strains of wheat that produced higher yields & were disease
resistant
ii. Mechanization
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It is economically advantageous to replace humans and animals with
machines on farms
 Fossil fuels are abundant & cheap, labor wages are relatively
high
Large farms have better economies of scale because their huge output
makes cost of production cheap
Monoculture farms are more efficient
iii. Irrigation
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Waterlogging occurs when soil remains under water for prolonged
periods
 Impairs root growth because roots can’t get oxygen
Salinization occurs when the small amounts of salts in irrigation water
become highly concentrated on the soil surface through evaporation
 Salts can reach toxic levels and impede plant growth
iv. Fertilizers
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Contain primarily N, P, and K
Organic fertilizers are composed of organic matter from plants (crop
waste) and animals (manure)
Synthetic (inorganic) fertilizers are produced commercially
 Pros: Easier to apply, can target poor soil or a certain plant,
easily absorbed by plants
 Cons: Manufacturing uses fossil fuels, more likely to runoff into
waterways & aquifers, do not add organic matter to the soil
v. Monocropping
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Monocropping is the practice of planting only a single species or variety
Dominant agricultural practice in the US
Pros: Greatly improved productivity & efficiency
Cons: increased wind erosion (loss of nutrients & productivity), more
vulnerable to pests, removes habitat for pest predators
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vi. Pesticides
 Pesticides are substances that kill or control organisms that people
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consider pests
 US accounts for 1/3 of global pesticide use
Insecticides target species of insects and other invertebrates
Herbicides target plant species that compete with crops
Broad-spectrum pesticides kill a wide variety of different pests
Selective pesticides kill a narrow range of organisms
Persistent pesticides remain in the environment for a long time
 Ex. DDT is fat-soluble and accumulates in fatty tissues
 Whenever an organism containing DDT is eaten, it is transferred
to the consumer
 Over time, pesticides become concentrated at high trophic
levels in a process known as bioaccumulation
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III.
Nonpersistent pesticides break down relatively rapidly (weeksmonths)
 Ex. Roundup has fewer long term effects, but has to be
applied more often
 Pest populations are large, have big gene pools, and evolve
rapidly
 Pests that survive application of a pesticide are resistant
 With each generation the resistant fraction of the
population increases
 The positive feedback loop of pesticide development, followed by
pest resistance, followed by new pesticide development is called
the pesticide treadmill
Genetic engineering is revolutionizing agriculture
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Artificial selection of plants and animals was the first genetic modification done by
humans thousands of years ago
b. The Benefits of Genetic Engineering
i. Increased Crop Yield and Quality
 GE can create strains of organisms that are resistant to pests or harsh
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environmental conditions or high salinity.
Plants are being engineered to produce essential nutrients like vitamin
A, pharmaceuticals, and other compounds more cheaply.
Animals are being engineered to also produce pharmaceuticals, mature
more quickly or grow larger.
ii. Potential Changes in Pesticide Use
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Genetic engineering for resistance to pests could reduce the need for
pesticides.
Bacillus thuringiensis is a natural soil bacterium that produces toxin that
kills larvae.
 The Bt gene that codes for production of this toxin has been
inserted into crop plants.
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The “Roundup Ready” gene gives plants resistance to the herbicide.
 Farmers can spray Roundup on their fields without harming
their crops.
 Widely used in corn, soybeans, and cotton.
iii. Increased Profits
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The reduced amount of pesticides used with GM crops reduces
expenses.
GM crops produce higher yields, increasing revenues.
Could lead to higher incomes for farmers, lower food prices, or both.
c. Concerns about Genetically Modified Organisms
 The US uses more GM crops every year.
 Many countries (especially European) ban GMOs over safety concerns.
ii. Safety for Human Consumption
 GMOs could possibly cause allergic reactions but there is little evidence
to support this claim.
Horizontal transfer of GM genes to gut bacteria.
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iii. Effects on Biodiversity
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Newly added genes may transfer to wild plants
 Alter or eliminate natural plant varieties
 Buffer zones around GM crops attempt to stop this
Use of GM seeds = loss of biodiversity in crop plants
iv. Regulation of Genetically Modified Organisms
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IV.
There are no labeling regulations in the US for GMOs
 This might suggest something is “wrong” to consumers
 GMO materials are almost ubiquitous in the US agricultural
system
Alternatives to industrial farming methods are gaining more attention
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Conventional agriculture is industrial agriculture
Small-scale farming (traditional agriculture) is common in the developing world
 Human labor is less expensive than machinery & fossil fuels
a. Shifting Agriculture and Nomadic Grazing
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Shifting agriculture involves clearing land and using it for only a few years until the
soil is depleted of nutrients
 Common in tropical countries
 Slash-and-burn is the traditional technique (releases CO2)
Land may be used to frequently to allow proper recovery
 Soil productivity decreases rapidly
 Land only suitable for grazing
Desertification is the process of topsoil being eroded away coupled with salinization
from irrigation leaving land unproductive
 Occurring most rapidly in Africa
Nomadic grazing involves moving herds of animals, often over long distances, to
seasonally productive feeding grounds
 Best practice where soil is low in productivity
b. Sustainable Agriculture
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Sustainable agriculture fulfills the need for food and fiber while enhancing the
quality of the soil, minimizing the use of nonrenewable resources, and allowing
economic viability for the farmer
 Labor intensive
 Relies on many traditional farming methods
Intercropping is when two or more crop species are planted in the same field at the
same time to promote synergistic interaction between them
Crop rotation achieves the same effect as intercropping by rotating the crop species
in the field from season to season
Agroforestry allows trees, or other vegetation, to act as windbreak for food crops by
catching soil that otherwise would have blown away
Contour plowing is plowing and harvesting parallel to the topographic contours of
the land which prevents erosion by water
Some farmers plant an autumn crop to leave in the soil over winter to prevent
erosion
c. No-Till Agriculture
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Plowing and tilling push crop residues under the topsoil, killing weeds and insect
pupae
Plowing and tilling make soil more susceptible to erosion, oxidizes organic matter,
and releases CO2
No-till agriculture involves leaving crop residues in the field between seasons
 Intact roots hold soil, reducing erosion & allowing horizons to naturally
regenerate
 Decrease in release of CO2, no reduction in organic matter
 Herbicides are required before and after planting
d. Integrated Pest Management
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IPM relies on crop rotation, intercropping, use of pest-resistant crop varieties,
habitat creation for pest predators, and limited use of pesticides
 Crop-rotation may foil crop-specific pests that lay eggs in soil and hinder cropspecific diseases
 Intercropping prevents specialized pests from establishing
 Agroforestry encourages pest predators
Pesticides are used after natural controls have been depleted, and in small amounts
Decrease expenditures on pesticides and improves crop yields
Since farmers are paying more attention to their crops they will notice other crop
needs, increasing overall crop management
Especially successful in the developing world
e. Organic Agriculture
 Organic agriculture is the production of crops without the use of synthetic pesticides
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or fertilizers
The Organic Food Production Act (OFPA) established uniform national standards for
the production and handling of foods labeled “organic”
Smaller farms, more labor intensive make organic foods more expensive
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Modern agribusiness includes the farming of meat and fish
a. High-Density Animal Farming
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Concentrated animal feeding operations (CAFOs) are large indoor or outdoor
structures designed for maximum output , aka feed-lots
Keeping animals confined reduces land costs, improves feeding efficiency, and
increases the fraction of food energy that goes into producing animal mass
Animals are given antibiotics and nutrient supplements
Waste lagoons can overflow and contaminate waterways
ii. More Sustainable Animal Farming
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Free-range animals need less antibiotics and meds, have a more natural
diet, require less fossil fuels and disperse their wastes
Free-range operations use more land and make less profit
b. Harvesting of Fish and Shellfish
 Fish are the 3rd major source of food for humans, after grain and meat
 Global fish production has increased 20% since 1980
 Fishery is a commercially harvestable population of fish within a particular
ecological region
 Competition for fish has led to a massive decline in fish populations
 The decline of a fish population by 90% or more is a fishery collapse
 Modern industrial fishing makes it easier to catch large numbers of fish
 Trawler fishing extracts fish and shellfish from the ocean floor.
 Purse-seine fishing is used to catch surface dwelling species.
 Longlining strings out thousands of baited hooks as much as 80 miles long.
 Drift netting involves massive nets that capture thousands of fish
 Bycatch is the unintentional catch of nontarget species
 Reduced populations of sharks and turtles
ii. More Sustainable Fishing
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Since marine ecosystems span national borders and many of the world’s
most important fisheries are in international waters, international
cooperation is crucial
The Sustainable Fisheries Act (1996) shifts fisheries management from
economic focus to conservation-minded, species-sustainability
 Calls for the protection of critical marine habitat
Before a fishing season opens, fishery managers establish a total
allowable catch and distribute or sell quotas to individuals or
companies, favoring those who have worked with the fishery, in a
system of individual transferable quotas (ITQs)
 Individuals can sell all or part of their quota if they cannot reach
it
iii. Aquaculture
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Aquaculture is the farming of aquatic organisms such as fish, shellfish, and
seaweed
 Animals are enclosed, cared for, and protected from predators
 In the US: almost all catfish & trout and 50% of shrimp & salmon
 Pros: can alleviate human-caused pressure on wild populations and
provide protein for undernourished people
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Cons: wastewater pumped into rivers or the ocean contain bacteria,
viruses and pests; fish can escape and compete, interbreed, or spread
disease and parasites
WORKING TOWARD SUSTAINABILITY: Wes Jackson and the Land Institute
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