1. Where does our food come from?
Croplands (mostly grain) – provide 77% of the world’s food
Rangelands (meat) supply 16%
Oceanic fisheries (fish and shellfish) – 7%

2. How Is Food Produced? Sources of food
Primary plants: Wheat, corn, and rice
Primary animals: fish, beef, pork, and chicken
14 plant and 8 animal species provide 90% of the global food calories

3. Major Types of Agriculture
Industrialized agriculture
Large amounts of fossil fuel, water, fertilizer, and pesticides to produce monoculture crops or livestock animals
Plantation
Form of industrialized agriculture – single ownership
Traditional subsistence agriculture
Produce only enough for the family
Traditional intensive agriculture
Increase outputs for profit

4. Industrialized Agricultural Wastes and Land Pollution
Animal Confinement
Waste runoff
Overgrazing
Increases soil erosion
Sedimentation
Nutrient application
Irrigation
Pesticides

5. Waste runoff increases nutrients
and pathogens in streams

6. Overgrazing typically strips the land of any natural protection and leaves the soil very susceptible to erosion

7. Runoff carries sediments, nutrients and
pesticides into streams that damages
fish habitat

8. Agriculture alters native habitats
and reduces native biodiversity

9. Major Types of Agriculture
Plantation - Form of agriculture that involves concentrated ownership of land with the means of production in the hands of one family or corporation, the use of hired labor, and mono-crop production for sale.
Cash crops mostly for sale in developed countries
Bananas, coffee, soybeans

10. Traditional
Plantation
Industrialized

11. World Food Production
Industrialized
Traditional

12. Producing Food by Green-Revolution Techniques
Since 1950, increase in global food production has come from increased yields per unit area of crop land.

13. Producing Food by Green-Revolution Techniques
Green revolution involves three steps:
High-input monoculture using selectively bred or genetically-engineered crops
High yields using high inputs of fertilizer, extensive use of pesticides and high inputs of water
Multiple cropping – increase the number of crops grown per year on a plot of land.

14. Green Revolutions First green revolution (developed countries)
Second green revolution
(developing countries)
Major International agricultural
research centers and seed banks

15. Producing Food by Traditional Techniques
Interplanting – simultaneously grow several crops on the same ground. Reduces chance of
losing year’s crop to pests, bad weather, etc.

16. Producing Food by Traditional Techniques
Types of Interplanting
Polyvarietal cultivation – planting several varieties of the same crop
Intercropping – grow two or more different crops at the same time (grain+nitrogen fixing plant)
Agroforestry (alley cropping) – crops and trees are grown together
Polyculture – many different types of plants that mature at different times are grown together

17. Causes of Soil Erosion Wind Water
People – farming, logging, construction (or any activities that weaken root strength)

19. Soil erosion in a wheat field

20. Areas of serious concern Stable or nonvegetative areas
Global Soil Erosion
Areas of serious concern
Areas of some concern
Stable or nonvegetative areas

21. Soil Degradation on Irrigated Land
Salinization
Waterlogging
Evaporation
Transpiration
Waterlogging
Less permeable
clay layer

22. Reducing and Cleaning Up Salinization
Reduce irrigation
Switch to salt-tolerant crops
Flush soils
Not growing crops for 2-5 years
Install underground drainage

23. Saltwater and drainage is a continual problem for lowland agriculture near Puget Sound.

24. Tidegate – lets water out, but not back in.

25. Solutions: Soil Conservation

27. Soil Restoration Organic fertilizer Animal manure
Green manure – fresh cut vegetation
Compost
Crop rotation – legume crops add nitrogen to soil
Commercial inorganic fertilizer

28. Catching and Raising More Fish
Fisheries
Fishing methods
Overfishing
Commercial extinction
Aquiculture
Fish farming and ranching

29. And our commercial fleets

30. Pesticides: Types Chemicals that kill undesirable organisms
Insecticides - insects
Herbicides - plants
Fungicides - fungus
Rodenticides - rodents

31. First Generation Pesticides
Primarily natural substances
Sulfur, lead, arsenic, mercury
Plant extracts: nicotine, pyrethrum

32. Second Generation Pesticides
Primarily synthetic organic compounds
Broad-spectrum agents – toxic to many species
Narrow-spectrum agents – toxic to few species
Persistence in the environment

33. The Case for Pesticides
Save human lives – spread of disease
Increase food supplies and lower costs
Work better and faster than alternatives
Health risks may be insignificant compared to benefits
Newer pesticides are becoming safer
New pesticides are used at lower rates

34. Characteristics of an Ideal Pesticide
Affects only target pests
Harms no other species
No genetic resistance
Breaks down quickly in the environment
Be more cost-effective than doing nothing

35. The Case Against Pesticides
Genetic resistance
The pesticide treadmill – pay more for less effect
Can kill non-target and natural control species
Can cause an increase in other pest species
Pesticides do not stay put
Can harm wildlife
Potential human health threats

36. Bioaccumulation and Biomagnification
Persistent (non-biodegradable) toxins build up in an animal over time = bioaccumulation
Become more concentrated at higher trophic levels = biomagnification

37. Integrated Pest Management
Ecological system approach
Reduce pest populations to economic threshold
Field monitoring of pest populations
Use of biological agents – natural predators, parasites, disease
Chemical pesticides are last resort

38. Why is Integrated Pest Management not More Widely Used?
Requires expert knowledge
Slower than conventional pesticides
Initial costs may be high
Hindered by pesticide industry

39. Solutions: Sustainable Agriculture
Low-input agriculture
Organic farming
Profitable
Increasing funding for research in sustainable techniques