This document summarizes various topics related to food resources and the impacts of agriculture. It discusses how the majority of the world's food comes from only 15 plant species and a few animal species. The major types of agriculture are described as traditional subsistence, shifting cultivation, nomadic herding, traditional intensive, plantation, and industrialized. The Green Revolution led to higher-yielding crops but also greater dependence on fossil fuels, cash economies, and introduced unintended consequences like invasive species. Environmental effects of food production include biodiversity loss, soil degradation, pollution, and human health impacts.

1. Food Resources
See Miller Chapter 12
Issues and Impacts of Agriculture
ENVS 1 Oct. 14, 2002

2. Main Topics
Methods of producing food
Increasing food production
Environmental effects of food production
Issues of sustainability

3. Sources of food worldwide
Of 30,000 edible plants, only 15 spp.
supply 90% of our food
Primary plants:
wheat, corn, and rice
Provide < ½ calories people consume
Primary animals:
cattle, pigs, and chicken
2ndary: Eggs, milk & cheese

4. Major Types of Agriculture
Traditional subsistence
Shifting cultivation
Nomadic herding
Traditional intensive
Plantation
Industrialized

5. Fig. 12.3a, p. 264
Industrialized
agriculture
in developed
countries
Intensive
traditional
agriculture
in developing
countries
Land
Labor
Capital
Fossil fuel
energy
Land
Labor
Capital
Fossil fuel energy

6. Fig. 12.3b, p. 264
Shifting cultivation
in tropical
forests
in developing
countries
Nomadic
herding in
developing
countries
Land
Labor
Capital
Land
Labor
Capital

7. Industrialized agriculture
Shifting cultivation
Plantation agriculture
Nomadic herding
Intensive traditional agriculture
No agriculture
World Food Production
Fig. 12.2, p. 263

8. Fig. 12.8a, p. 268
2,000
1,500
1,000
500
0
Grainproduction
(millionsoftons)
1950 1960 1970 1980 1990 2000 2010
Total World Grain Production

9. Fig. 12.8b, p. 268
400
350
300
250
150
Percapitagrainproduction
(kilogramsperperson)
1950 1960 1970 1980 1990 2000 2010
Per Capita World Grain Production
200

10. Green Revolutions
First green revolution
(developed countries)
Second green revolution
(developing countries)
Major International agricultural
research centers and seed banks Fig. 12.4, p. 265

11. Producing Food by Green-
Revolution Techniques
High-input monoculture
Selectively bred or genetically-engineered
crops
High inputs of fertilizer
Extensive use of pesticides
High inputs of water
Increased intensity and frequency of
cropping

13. Results of Green Revolution: Mixed
• Higher yields per acre when inputs
available
• Lower yields when inputs unavailable
• Increased dependence on cash economy
• Increased dependence on fossil fuel
• Increased imports of inputs
• Income disparity??
• Migration to cities??

14. Unintended consequences: Killer Bees
Mild-mannered, low honey producing Italian bee
X
Aggressive, high honey producing African bee?
Hope for a mild-
mannered, high
producing bee
Instead, got an
aggressive, low
producing bee
Worse yet – it escaped, and is interbreeding with other
bees making them aggressive & low producing too!

15. Environmental Effects of Food
Production
Biodiversity loss
Soil degradation
Air pollution
Water pollution
Human health