15-2 Crops and Soil

1. 15-2 Crops and Soil Page 384

2. A. Fertile Soil: The Living Earth • 1. Soil must be fertile to produce healthy plants.

3. A. Fertile Soil: The Living Earth • 2. Topsoil, the surface layer of soil, is where plant roots grow.

4. A. Fertile Soil: The Living Earth • 3. Soil primarily comes from the weathering of rocks. • Mechanical • Chemical

5. B. Soil Erosion: A Global Problem • 1. Erosion is the movement of rock, soil, and sand by wind and water.

6. B. Soil Erosion: A Global Problem • 2. U.S. topsoil has been eroded by 50% in the last 200 years.

7. B. Soil Erosion: A Global Problem • 3. Farming increases the rate of erosion.

8. C. Land Degradation • 1. Occurs when human processes or natural activity damage the land to the extent that the ecosystem can not be supported.

9. C. Land Degradation • 2. Leads to desertification, where land in arid (lacking moisture) areas becomes even more desert like.

10. D. Soil Conservation • 1. To prevent down hill erosion: • Soil-retaining terraces • Contour plowing • No-till farming

11. E. Enriching the Soil • 1. Through the use of manures and fertilizers.

12. E. Enriching the Soil • 2. Compost uses partly decomposed organic material.

13. F. Salinization • 1. accumulation of salts in the soil.

14. G. Pest Control • 1. Pesticides are chemicals used to kill insects, weeds, and other crop pests.

15. G. Pest Control • 2. A negative is that pests can develop resistance.

16. G. Pest Control • 3. There are human health concerns such as cancer risks and nervous system disorders.

17. G. Pest Control • 4. Persistent pesticides do not break down and accumulate in the soil and water.

18. H. Biological Pest Control • 1. form of pest management that uses living organisms.

19. H. Biological Pest Control • 2. Pathogens, such as bacteria, may be used to infect insect pests.

20. H. Biological Pest Control • 3. Plant defenses are incorporated into plants, such as tomatoes, so that they are unaffected by certain fungi, worms, or viruses.

21. H. Biological Pest Control • 4. Natural pesticides produced by plants that are biodegradable.

22. H. Biological Pest Control • 5. Disrupting insect breeding by use of pheromones or chemicals that disrupt development. Ex: Fleas

23. I. Integrated Pest Management • 1. uses a mixture of techniques to control pests and cause the least amount of economic damage.

24. J. Engineering a Better Crop • 1. Genetic engineering is a technique in which genetic material in a living cell is modified for medical or industrial use.