APES Ch 13
Food, Soil Conservation and
Pest Management
Food Security and Nutrition

1 in 6 people in developing countries does not
get enough food (most likely due to poverty)

Food security:


Most developing nations can not provide food security to
all their people b/c they cant produce enough food or
they can’t afford to import.
Also depends on reducing harmful environmental effects
of agriculture (erosion, aquifer depletion).
Food Security and Nutrition

Chronic hunger:

Malnutrition:

UN Food and Agriculture Organization (FAO) goal
is to reduce the # of hungry and malnourished to
400 million by 2015 (as of 2005 there were 852
million)
FAO estimated that 6 million children died each
year due to lack of essential food.

Food Security and Nutrition

Famine:



Can lead to mass migrations
Usually caused by crop failure due to drought,
flood, war or other catastrophic events.
Overnutrition:

Can cause some of the same problems as
under-nutrition (lower life expectancy,
diseases, lower life quality)
Food Production

3 systems that supply most food:


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Croplands – 77%
Rangelands – 16%
Oceanic fisheries and aquaculture – 7%
All 3 systems have increased since 1960 due to better
technology and other advances (fertilizers, pesticides,
irrigation).
May not be able to produce enough food by 2050 for the
possible 8.5 billion people.

Environmental degradation, pollution, lack of water,
overgrazing, overfishing, rising temps., increasing fuel
costs
Food Production

Only 14 plants and 9 terrestrial animal
species supply an estimated 90% of
worlds food.

3 types of grain (wheat, rice and corn) provide
more than 50%


Many people can’t afford meats, milk and cheese
products.
Fish and shellfish make up only 7%
Food Production

Industrialized agriculture (high input):


Plantation agriculture:



80% of worlds food supply is produced this way
Cash crops (bananas, soybeans, sugarcane, cocoa,
peanuts and coffee
Must clear tropical rain forests to plant
Livestock


Most are in feedlots
Use lots of energy and water and produces lots of animal
waste and water pollution
Natural Capital
Croplands
Ecological
Services
Economic
Services
• Help maintain water flow and soil infiltration • Food crops
• Provide partial erosion protection
• Fiber crops
• Can build soil organic matter
• Store atmospheric carbon
• Provide wildlife habitat for some species
• Crop genetic resources
• Jobs
Fig. 13-6, p. 276
Food Production

Traditional agriculture (low input)

Traditional subsistence agriculture:

Traditional intensive agriculture:

Interplanting:





Reduces chance of losing all of the years food supply
Polyvarietal cultivation:
Intercropping:
Agroforestry (alley cropping):
Polyculture:
 Keeps soil covered, less fertilizer and water use, less
pesticides.
Soil Erosion and Degradation

Topsoil:


Naturally renewable but very slow (several 100 yrs to
make 1 inch)
Soil erosion:





Increases when vegetation is removed
Sheet erosion:
Rill erosion:
Gully erosion:
Major effects of erosion


Loss of soil fertility
Water pollution due to sedimentation runoff
Soil Erosion and Degradation
Causes
Overgrazing
Consequences
Deforestation
Worsening
drought
Erosion
Famine
Salinization
Economic losses
Soil compaction
Lower living
standards
Natural climate
change
Environmental
refugees
Desertification:
1/3
of the worlds land and 70% of all dryland are suffering from
desertification.
Fig. 13-12, p. 280
Transpiration
Evaporation
Evaporation
Evaporation
Waterlogging
Less permeable clay layer
Salinization:
1. Irrigation water contains small
amounts of dissolved salts
2. Evaporation and transpiration
leave salts behind.
Waterlogging:
1. Precipitation and irrigation water
percolate downward.
2. Water table rises.
3. Salt builds up in soil.
Fig. 13-13, p. 281
Solutions
Soil Salinization
Prevention
Cleanup
Reduce irrigation
Flush soil
(expensive and
wastes water)
Stop growing crops
for 2–5 years
Switch to salttolerant crops
(such as barley,
cotton,
sugarbeet)
Install underground
drainage systems
(expensive)
Fig. 13-15, p. 281
Sustainable Agriculture Through Soil
Conservation

Soil conservation:





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Eliminating plowing and breaking up and tilling
is key to reduce soil erosion.
Conservation-tillage farming:
Terracing:
Contour farming:
Strip cropping:
Wind breaks:
Use cover crops
Sustainable Agriculture Through Soil
Conservation

Organic fertilizer:




Commercial inorganic fertilizer:


Animal manure:
Green manure:
Compost:
Contain nitrogen, phosphorus, and potassium
Crop rotation:

Also helps reduce erosion
The Green Revolution and its
Environmental Impact

Green Revolution:





Plant monoculture plants
Use large amounts of fertilizer, pesticides and water for
higher yield
Increase the # of crops grown per on plot of land
through multiple cropping
1st Green Revolution took place between 19501970 in developed countries
2nd Green Revolution has been taking place since
1967 in developing countries mostly in tropical
areas.
The Green Revolution and its
Environmental Impact

Pros




Has produced more food for growing population
Many countries are now self sufficient with food
Use less land for larger yield
Cons




More fertilizer, pesticides and water
To expensive for subsistence farmers
If expanded- not enough workers (more people moving
to cities for jobs)
More irrigation which can lead to more salinization
The Green Revolution and its
Environmental Impact
More land can be planted with crops but
significant expansion of cropland is
unlikely over the next few decades for
economic and ecological reasons
 Loss of agrobiodiversity – the worlds
genetic variety of animals and plants used
to provide food


Ex: India use to plant 30,000 different types of
rice, now only 10 types are used.
The Green Revolution and its
Environmental Impact

Modern agriculture violates the 4
Principles of Sustainability



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Depends heavily on nonrenewable fossil fuels
Too little recycling of crop and animal wastes
Accelerates soil erosion
Does not preserve agrobiodiveristy
Disrupts natural species interactions that help
control population sizes and pests.
Biodiversity Loss
Soil
Water
Air Pollution
Human Health
Nitrates in
drinking water
Loss and
degradation of
grasslands,
forests, and
wetlands
Erosion
Water waste
Loss of fertility
Aquifer depletion
Greenhouse gas
emissions from
fossil fuel use
Salinization
Increased runoff and
flooding from cleared
land
Pesticide residues
Other air pollutants in drinking water,
from fossil fuel use food, and air
Fish kills from
pesticide runoff
Desertification
Waterlogging
Killing wild predators to
protect livestock
Loss of genetic diversity of
wild crop strains replaced
by monoculture strains
Sediment pollution from
erosion
Fish kills from pesticide
runoff
Greenhouse gas
emissions of
nitrous oxide from
use of inorganic
fertilizers
Surface and groundwater
pollution from pesticides
and fertilizers
Belching of the
greenhouse gas
Overfertilization of
methane by cattle
lakes and rivers from
runoff of fertilizers,
livestock wastes, and
Pollution from
food processing wastes pesticide sprays
Contamination of
drinking and
swimming water
with disease
organisms from
livestock wastes
Bacterial
contamination of
meat
Fig. 13-18, p. 285
The Gene Revolution
For years the use of crossbreeding
through artificial selection to develop
genetically improved varieties of crop
strains has been used.
 Now genetic engineering is being used
(takes a gene of 1 species and inserts it
into the DNA of another species)


Takes ½ the time and cost less then
crossbreeding

Ex: potatoes resist disease because they contain a
certain chicken gene.
The Gene Revolution

Nontraditional foods could help provide
essential nutrients and lower the need for
some crops.



Winged bean has many edible parts and
requires little fertilize.
Quinoa plant is called the worlds most
nutritious plant and can resist frost and
droughts and can grow in saline soils.
Insects are a great source of protein and are
easy to “farm”
Trade-Offs
Genetically Modified Crops and Foods
Projected
Advantages
Need less fertilizer
Projected
Disadvantages
Need less water
Irreversible and
unpredictable genetic
and ecological effects
More resistant to
insects, disease,
frost, and drought
Harmful toxins in food
from possible plant cell
mutations
Grow faster
New allergens in food
Can grow in
slightly salty soils
Lower nutrition
Less spoilage
Better flavor
Increased development
of pesticide-resistant
insects and plant
diseases
Need less pesticides
Can create herbicideresistant weeds
Tolerate higher
levels of herbicides
Can harm beneficial
insects
Higher yields
Lower genetic diversity
Fig. 13-19, p. 287
Producing More Meat


Between 1950-2005 meat production increased
more then 5 fold and is likely to double again by
2050 as more people become affluent.
2 systems for raising livestock


Graze on grass
Feedlots- raise in densely packed areas by feeding them
grain and/or fish meal.



Animals given antibiotics and steroids
Accounts for 43% of worlds beef, 50% of pork and 68% of
eggs, and 75% of poultry production.
Solutions: people can eat more poultry and fish rather
then beef, establish more humane ways to raise livestock
in feedlots.
Trade-Offs
Animal Feedlots
Advantages
Increased meat
production
Higher profits
Less land use
Reduced overgrazing
Reduced soil
erosion
Help protect
biodiversity
Disadvantages
Need large inputs
of grain, fish
meal, water, and
fossil fuels
Concentrate
animal wastes
that can pollute
water
Antibiotics can
increase genetic
resistance to
microbes in
humans
Fig. 13-21, p. 289
Producing More Meat

Catching and raising more fish and
shellfish.

Fisheries:

3rd major food producing system.



2/3 comes from oceans, lakes, rivers and ponds
1/3 comes from aquaculture
Scientists project a decline in global fish catch
due to overfishing, coastal water pollution and
wetland destruction
Producing More Meat


125 out of 128 depleted fish stocks could recover
with careful management.
Ecolabels help shoppers identify wild fish that
have been caught by more sustainable fishing
practices.


Walmart said that within 5 yrs it would sell only fish
certified by the Marine Stewardship Council)
Govt's subsides given to the fishing industry are
a major cause of overfishing.

Subsides $ should be used to buy out some fishing boats
and retrain their crew for other occupations
Producing More Meat

Aquaculture:

Fishing farms:

Fishing ranches:

Mainly carp in China and India, catfish in US,
tilapia and shellfish in other countries
Trade-Offs
Aquaculture
Advantages
High efficiency
High yield in
small volume
of water
Can reduce
overharvesting
of conventional
fisheries
Low fuel use
High profits
Profits not tied
to price of oil
Disadvantages
Needs large inputs
of land, feed, and
water
Large waste
output
Destroys
mangrove forests
and estuaries
Uses grain to feed
some species
Dense populations
vulnerable to
disease
Tanks too
contaminated to
use after about 5
years
Fig. 13-24, p. 292
Solutions
More Sustainable Aquaculture
• Use less fishmeal feed to reduce depletion of other fish
• Improve management of aquaculture wastes
• Reduce escape of aquaculture species into the wild
• Restrict location of fish farms to reduce loss of
mangrove forests and estuaries
• Farm some aquaculture species in deeply submerged
cages to protect them from wave action and predators
and allow dilution of wastes into the ocean
• Certify sustainable forms of aquaculture
Fig. 13-25, p. 293
Solutions: Moving Toward Global Food
Security
People in urban areas could save money
by growing more of their own food.
 We can waste less food (70% of food is
wasted through spoilage, inefficient
processing and plate waste).


US households throw away food worth as
much as $43 million/yr – twice the $24 million
it would take to eliminate global hunger
Solutions: Moving Toward Global Food
Security

We can increase global food security by –


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Slow pop growth
Reduce poverty
Reduce soil erosion
Halt desertification
Eliminate overgrazing
Slow removal of groundwater
Protect cropland from development
Reduce rate of global warming
Protecting Food Resources: Pest
Control

Pest:
Only 100 species cause 90% of the
damage to crops
 In nature natural enemies control 98% of
the potential pests species


Pesticides:
Protecting Food Resources: Pest
Control

2 generations of pest control

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1st generation (copy nature): before 1930s many
pesticides were derived from organisms (mostly plants).
They were natural defenses.
2nd generation: the development of pesticides in labs.
Started in 1939 when DDT was discovered. Some lab
made pesticides last in environment for years and can
biologically magnified in food chains.
¾ of pesticides is used for crops, ¼ is used for homes,
gardens, and golf courses.
Federal Insecticide, Fungicide, Rotenticide Act (FIFRA) is
suppose to assess the health risks of the active
ingredients in pesticide products.
Solutions
More Sustainable Aquaculture
• Use less fishmeal feed to reduce depletion of other fish
• Improve management of aquaculture wastes
• Reduce escape of aquaculture species into the wild
• Restrict location of fish farms to reduce loss of
mangrove forests and estuaries
• Farm some aquaculture species in deeply submerged
cages to protect them from wave action and predators
and allow dilution of wastes into the ocean
• Certify sustainable forms of aquaculture
Fig. 13-25, p. 293
Protecting Food Resources: Pest
Control

Other ways to control pests:

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Fool pest
Provide homes for pest enemies
Implant genetic resistance
Bring in natural enemies
Use insect perfumes
Bring in hormones
Scald pests
Solutions
Sustainable Organic Agriculture
More
High-yield
polyculture
Organic fertilizers
Biological pest
control
Integrated pest
management
Efficient
irrigation
Perennial crops
Crop rotation
Water-efficient
crops
Soil conservation
Subsidies for
sustainable farming
and fishing
Less
Soil erosion
Soil salinization
Aquifer depletion
Overgrazing
Overfishing
Loss of
biodiversity
Loss of prime
cropland
Food waste
Subsidies for
unsustainable
farming and
fishing
Population
growth
Poverty
Fig. 13-33, p. 302