1. Ch 14: Agricultural Methods and Pest Management

2. Outline 14.1 The Development of Agriculture 14.2 Fertilizer and Agriculture 14.3 Agricultural Chemical Use 14.4 Problems with Pesticide Use 14.5 Why Are Pesticides So Widely Used? 14.6 Alternatives to Conventional Agriculture

3. 14.1 The Development of Agriculture Development of agriculture involved manipulating the natural environment to produce food desired by humans. This allowed an increase in the size of the human population. Three different types of farming: – Shifting agriculture – Labor-intensive agriculture – Mechanized monoculture agriculture

5. 14.1 The Development of Agriculture Shifting agriculture- cutting down and burning the trees and other vegetation in a small area of the forest. – Burning releases nutrients bound up in biomass. – The cleared soil is useful for 2-3 years. – Forest eventually recolonizes the area. – Particularly useful on thin tropical soils. – Not suitable for large, densely populated areas. – Requires a long recovery time between cycles.

6. 14.1 The Development of Agriculture Shifting agriculture often employs polyculture – The planting of a mixture of plants. Labor-intensive agriculture is practiced in much of the developing world. – Three situations favor this type of agriculture: The growing site does not allow mechanization. The crop does not allow mechanization. The economic condition does not allow purchase of mechanized equipment.

7. 14.1 The Development of Agriculture The primary reason for the use of labor-intensive agriculture is economic. – Many densely populated countries have numerous small farms that can be effectively managed with human labor.

9. 14.1 The Development of Agriculture Mechanized monoculture agriculture is typical of industrialized countries. – Fossil fuel replaces human muscle power. – This method requires large amounts of energy and flat land. – Monocultures promote more efficient planting, cultivating, and harvesting. – Farmers often rely on hybrids to provide uniform monocultures.

10. 14.1 The Development of Agriculture Labor reduction in the United States: – 1913: 135 hours of labor required to produce 2,500 kg of corn. – 1980: 15 hours of labor required to produce 2,500 kg of corn. It takes 5 metric tons of fossil fuel to produce 1 metric ton of fertilizer. – The developed world is dependent on oil to produce energy to manufacture pesticides and fertilizer and to run machines. – The price of oil has wide ramifications on the world’s ability to feed itself.

11. 14.1 The Development of Agriculture Problems with mechanized monoculture agriculture include: – Large tracts of bare land increases soil erosion. – The planting of genetically identical seeds results in the loss of genetic diversity. – Little genetic differentiation often leads to increased pesticide use. – No crop rotation depletes soil nutrients, increasing fertilizer use. – Fossil fuel energy use has replaced human muscle power.

13. 14.1 The Development of Agriculture The Green Revolution has greatly increased worldwide food production. – Introduction of new plant varieties and farming methods has increased food production per hectare. – Drawbacks: Modern varieties of plants require fertilizer and pesticides that traditional varieties did not need. Requires larger amounts of water and irrigation.

14. 14.1 The Development of Agriculture Increased production has not solved the world’s food problem because population continues to increase. Global answers are needed for difficult problems. – Governments protect farmers with subsidies and trade barriers. Farming is hindered in poorer nations. – High fuel costs increase food costs. – High energy prices divert crops to be used as fuel crops. – Higher demand for meat uses crops that could have been consumed directly by humans.

15. 14.1 The Development of Agriculture Increased yields resulting from modern technology and the total amount of land available for cultivation.