1. Crops and Soil Chapter 15 Section Two
Food and Agriculture
Crops and Soil
Chapter 15
Section Two

2. Agriculture: Modern vs. Traditional
Machinery
Synthetic fertilizers
Sprinkler systems
Drip irrigation
Pest management
Manual labor
Organic fertilizers
Weeds removed by hand
Relied on rainfall
Ditch irrigation systems

3. Fertile Soil: The Living Earth
Supports the growth of healthy plants
Topsoil – surface layer, rich in organic matter
Subsoil – poorer in quality than topsoil
Billions of organisms per hectare: bacteria, insects, arthropods, earthworms, algae

4. Soil structure

5. Soil Erosion and Degradation
Erosion – wearing away of rock and soil by wind and water
Degradation – human activity or natural processes damage the land so it can no longer support the local ecosystem
Desertification – land becomes more desertlike because of human activities

6. Soil Conservation Many ways to prevent downhill erosion
Contour plowing – follow natural land contours
Terracing – many small level fields
No-till farming – harvest and plant next crop without plowing, reduces erosion to 1/10 of traditional methods

7. Enriching the Soil
Traditionally – organic material such as manure & leaves which adds nutrients
Modern methods include inorganic matter which can lead to runoff issues
Best method – combination of both; compost, partly decomposed organic matter, combined with inorganic fertilizers

8. Salinization Accumulation of salts in the soil
California and Arizona – irrigation water is saltier than rainwater and when it evaporates, salt is left behind
Eventually, plants will not grow

9. Chapter 15 Section Two Part Two
Crops and Soil
Chapter 15
Section Two
Part Two

10. Pest Control & Pesticides
In NA, insects 13% of all crops
Worldwide, pests destroy 33% of crops
Pest – any organism that is where it isn’t wanted or in large enough numbers to cause economic damage
Pesticides – chemicals used to kill weeds, insects & other crop pests

11. Pesticides can kill/harm good plants, insects, wildlife, and people
Causes cancer in farmers, manufacturing plant workers,
Resistance – ability to survive exposure to certain pesticide
Persistence – does not break down easily or quickly in the environment, build up in soil or water
Some have been banned (DDT – made in US and sold overseas)

12. Biological Pest Control
Use of living organisms to control pests
Pathogens – cause disease in pests
Some plants have natural defenses and come make defensive chemicals
Disrupt pest breeding cycles

13. Integrated Pest Management – don’t eliminate the pest, just reduce the amount of damage

14. Engineering and Sustainability
Genetic engineering – modify genetic material so plant can resist/kill pests
Bt corn
Sustainable agriculture – conserve resources and keep land productive
Low-input farming – plant pest resistant crops that minimize use of water, energy, pesticides & fertilizer

15. Genetically Modified Crops