APES Ch 13

1
APES Ch 13

• Food, Soil Conservation and Pest Management

2
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 cant afford to
  import.
• Also depends on reducing harmful environmental
  effects of agriculture (erosion, aquifer
  depletion).

3
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.

4
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)

5
Food Production

• 3 systems that supply most food
• 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

6
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 cant afford meats, milk and cheese
  products.
• Fish and shellfish make up only 7

7
Food Production

• Industrialized agriculture (high input)
• 80 of worlds food supply is produced this way
• Plantation agriculture
• 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

8
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
Crop genetic resources
Store atmospheric carbon
Jobs
Provide wildlife habitat for some species
Fig. 13-6, p. 276
9
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.

10
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

11

Soil Erosion and Degradation
Causes
Consequences
Overgrazing
Worsening drought
Deforestation
Famine
Erosion
Economic losses
Salinization
Lower living standards
Soil compaction
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
12

Transpiration
Evaporation
Evaporation
Evaporation
Waterlogging
Less permeable clay layer
Salinization
Waterlogging
1. Irrigation water contains small amounts of
dissolved salts
1. Precipitation and irrigation water percolate
downward.
2. Evaporation and transpiration leave salts
behind.
2. Water table rises.
3. Salt builds up in soil.
Fig. 13-13, p. 281
13

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
14
Sustainable Agriculture Through Soil Conservation

• Soil conservation
• 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

15
Sustainable Agriculture Through Soil Conservation

• Organic fertilizer
• Animal manure
• Green manure
• Compost
• Commercial inorganic fertilizer
• Contain nitrogen, phosphorus, and potassium
• Crop rotation
• Also helps reduce erosion

16
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 1950-1970
  in developed countries
• 2nd Green Revolution has been taking place since
  1967 in developing countries mostly in tropical
  areas.

17
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

18
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.

19
The Green Revolution and its Environmental Impact

• Modern agriculture violates the 4 Principles of
  Sustainability
• 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.

20

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
21
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.

22
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

23

Trade-Offs
Genetically Modified Crops and Foods
Projected Disadvantages
Projected Advantages
Irreversible and unpredictable genetic and
ecological effects
Need less fertilizer
Need less water
Harmful toxins in food from possible plant cell
mutations
More resistant to insects, disease, frost, and
drought
New allergens in food
Grow faster
Lower nutrition
Can grow in slightly salty soils
Increased development of pesticide-resistant
insects and plant diseases
Less spoilage
Better flavor
Can create herbicide-resistant weeds
Need less pesticides
Tolerate higher levels of herbicides
Can harm beneficial insects
Higher yields
Lower genetic diversity
Fig. 13-19, p. 287
24
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.

25
Trade-Offs
Animal Feedlots
Advantages
Disadvantages
Increased meat production
Need large inputs of grain, fish meal, water, and
fossil fuels
Higher profits
Concentrate animal wastes that can pollute water
Less land use
Reduced overgrazing
Reduced soil erosion
Antibiotics can increase genetic resistance to
microbes in humans
Help protect biodiversity
Fig. 13-21, p. 289
26
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

27
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

28
Producing More Meat

• Aquaculture
• Fishing farms
• Fishing ranches
• Mainly carp in China and India, catfish in US,
  tilapia and shellfish in other countries

29

Trade-Offs
Aquaculture
Advantages
Disadvantages
High efficiency
Needs large inputs of land, feed, and water
High yield in small volume of water
Large waste output
Destroys mangrove forests and estuaries
Can reduce overharvesting of conventional
fisheries
Uses grain to feed some species
Low fuel use
Dense populations vulnerable to disease
High profits
Tanks too contaminated to use after about 5 years
Profits not tied to price of oil
Fig. 13-24, p. 292
30

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
31
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

32
Solutions Moving Toward Global Food Security

• We can increase global food security by
• 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

33
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

34
Protecting Food Resources Pest Control

• 2 generations of pest control
• 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.

35

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
36
Protecting Food Resources Pest Control

• Other ways to control pests
• Fool pest
• Provide homes for pest enemies
• Implant genetic resistance
• Bring in natural enemies
• Use insect perfumes
• Bring in hormones
• Scald pests

37

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