1. Land and Human Populations

2. Competing uses for land: Forests (31%) Agriculture (37%) Housing and Industry (5%) Roads Waste Disposal

3. …Watersheds were forested -Watersheds are also called drainage basins or catchment areas -They are areas of land that drain into bodies of surface water

4. Functions of Watersheds -Forested watersheds act as giant sponges increasing infiltration -They release water slowly moderating flooding and maintaining stream flows in dry periods

6. They control soil erosion improving water quality They are habitats for many species They regulate rainfall on a small scale Functions of Watersheds

7. Rainfall Impact and Trees Trees break the impact of rainfall on the soil thus reducing soil erosion.

8. Jamaican Watersheds ->1/3 have deteriorated Causes of Jamaican Watershed Destruction 1. Unsuitable hillside agricultural practices 2. Illegal settlements on hillside lands

9. Causes of Jamaican Watershed Destruction cont’d 3. Deforestation due to illegal removal of trees for fuelwood, charcoal production, yam sticks and lumber 4. Forest fires caused by individuals 5. Unapproved quarrying and sand mining

10. Effects of Watershed Destruction 1.Massive soil loss through soil erosion 2.Siltation of drains and rivers 3.Destructive flooding downstream 4.Water pollution 5.Reduced water availability and quality 6.Loss of habitat for flora and fauna

11. Agriculture - the growing of crops & the tending of livestock for subsistence, sale, or exchange

12. Three Main Types of Agriculture 1.Subsistence 2.Industrialised 3.Sustainable

13. Subsistence Agriculture cont’d Features of Low Input / Subsistence Agriculture: Human Labour Slash and Burn Shifting Cultivation Fallow Periods Animal Manure Mixed Cropping

14. Industrialised Agriculture -also called modern or advanced agriculture -one crop or animal for sale -use large amounts of : a)fossil fuel energy b)water

15. Industrialised Agriculture cont’d Features of High Input/Conventional Agriculture: Mechanisation Monocropping Synthetic Pesticides Synthetic Fertilizers Genetic Engineering Irrigation

16. Mechanisation -causes land degradation through soil compaction -exacerbates soil erosion -causes decline in soil fertility -erosion damage causes decreased water quality

17. Soil Erosion - movement of soil components, especially surface litter and topsoil, from one place to another, usually by exposure to wind or flowing water

18. Soil Erosion cont’d Soil Erosion is caused by: Farming Logging Building Overgrazing Four-wheeling

19. Soil Erosion cont’d The 3 Main Effects of Soil Erosion are: 1. Loss of topsoil 2. Reduced productivity 3. Surface water pollution

20. Monocropping: - also called monoculture -cultivation of a single crop, usually on a large area of land -simplifies ecosystems reducing biodiversity -encourages the build up of pests thus increasing the use of pesticides -depletes the soil of nutrients

21. Use of Pesticides Pesticide - any chemical designed to kill or inhibit the growth of an organism that people consider undesirable - fast-breeding insect species undergo natural selection and develop genetic resistance to chemical pesticides

22. Effects of Pesticide Use - harmful to the environment -Pesticides linked to cancers and low sperm count -persistent pesticides adhere to sediment and become bioaccumulated and biomagnified

23. Use of Fertilizers Fertilizers - substances that add plant nutrients to soil and improves its ability to grow crops 2 Main Types of Fertilizers: - Organic Fertilizer - Commercial Inorganic Fertilizer

24. Commercial Inorganic Fertilizer -commercially prepared mixtures of plant nutrients applied to the soil to restore fertility and increase crop yields -supply only 2 or 3 of the 20+ nutrients needed by plants -leads to soil compaction -water pollution

25. Irrigation -The application of water to crops -Types -Natural/Rainfall -Flood irrigation -Overhead/sprinkler -Drip irrigation (most efficient - 90%) -Flood irrigation is wasteful and causes salinisation and waterlogging.

26. Impacts of Agriculture on the Environment cont’d 1. Chemical Damage - pollution of rivers & streams from pesticide runoff - nitrates & pesticides in drinking water, food & air

27. Impacts of Agriculture on the Environment cont’d 2.Disruption of Habitat - over-fertilization of rivers caused by runoff of nitrates and phosphates

31. Impacts of Agriculture on the Environment cont’d 3.Loss of Biodiversity - reduction in nutrient recycling soil organisms - loss of plant genetic diversity - endangerment & extinction of wildlife

32. Impacts of Agriculture on the Environment cont’d 4. Salinisation Due to Irrigation Salinisation: - accumulation of salts in soil that can eventually make the soil unable to support plant growth - lowers crop growth and yields - kills crop plants & ruins the land

33. Impacts of Agriculture on the Environment cont’d 5.Desertification - process whereby agricultural productivity of land falls by 10% - conversion of rangeland to desert-like land

34. Impacts of Agriculture on the Environment cont’d 6.Slash & Burn Cultivation - also called Shifting Cultivation - plots abandoned after 2-5 years due to loss of soil fertility

35. Impacts of Agriculture on the Environment cont’d 7. Overgrazing - destruction of vegetation when too many grazing animals feed too long & exceed the carrying capacity of a rangeland area

36. Sustainable Agriculture - Crops grown in harmony with the environment - Health of humans and livestock important - Environment important - Workers important - e.g. Organic agriculture

37. Sustainable Agriculture Cont’d Includes the use of: - Companion cropping/mixed farming - Soil conservation - Addition of organic matter - Use of alternatives to pesticides

38. Soil Conservation Methods -methods used to: ◦ reduce soil erosion ◦ prevent depletion of soil nutrients ◦ restore nutrients -most methods involve keeping the soil covered with vegetation

39. Soil Conservation Methods cont’d Major Methods Include: 1.Conservation tillage 2.Contour farming, Terracing, Strip cropping, & Alley cropping 3.Gully reclamation & Windbreaks 4.Land-Use Classification & Control 5.Maintaining & Restoring soil fertility

40. Soil Conservation Methods cont’d 1.Conservation Tillage - crop cultivation with little or no soil disturbance ▪ Minimum Tillage ▪ No-till Farming

41. Soil Conservation Methods cont’d 2.Contour Farming, Terracing, Strip Cropping & Alley Cropping - used mainly on sloping land which is more prone to erosion ▪ Contour Farming - used on gently sloping land

42. Soil Conservation Methods cont’d 2.Contour Farming, Terracing, Strip Cropping & Alley Cropping cont’d ▪ Terracing - used on steeper slopes

43. Soil Conservation Methods cont’d 2.Contour Farming, Terracing, Strip Cropping & Alley Cropping cont’d ▪ Alley Cropping (Agroforestry) - planting crops with rows of trees on each side

44. Soil Conservation Methods cont’d 3. Gully Reclamation & Windbreaks ▪ Gully Reclamation

45. Soil Conservation Methods cont’d 3. Gully Reclamation & Windbreaks cont’d ▪ Windbreaks (Shelterbelts) - row of trees planted to block wind flow

46. Soil Conservation Methods cont’d 4. Land Use Classification System - describes different categories of land that are suitable and unsuitable for cultivation

47. Soil Conservation Methods cont’d 5. Maintaining & Restoring Soil Fertility Involves the use of: 1. organic fertilizers 2. crop rotation

48. Alternatives to Pesticides 1.Cultivation Practices - mow weeds - rotate crops - plant rows of hedges or trees 2.Resistant Varieties - genetically resistant to certain pest insects, fungi and diseases

49. Alternatives to Pesticides cont’d 3. Natural Enemies (Biological Control) - predators, parasites & pathogens can be encouraged or imported to regulate pest populations 4. Birth Control (Reproductive Controls) - males are lab-raised and sterilized, then released into population.

50. Alternatives to Pesticides cont’d 5.Insect Sex Attractants (Pheromones) - when a female is ready to mate she releases a pheromone (chemical sex attractant) 6.Insect Hormones - hormones: chemicals produced by an organism to control its growth & development

51. Alternatives to Pesticides cont’d 7. Zapping Foods With Radiation - gamma irradiation of foods is used to kill insects & prevent them from reproducing 8. Biopesticides - plant & microbe toxins are synthesized for mass production

52. Alternatives to Pesticides cont’d 9.Quarantine - restriction of the importation of exotic plant and animal material that might harbour pests 10.Integrated Pest Management (IPM) - biological and cultivation techniques are used first, then biopesticides when necessary

53. Organic Fertilizer - organic materials, such as animal manure, applied as a source of plant nutrients 3 Basic Types of Organic Fertilizer - Animal Manure - Green Manure - Compost

54. Organic Fertilizer cont’d Animal Manure - dung and urine of farm animals - improves soil structure - stimulates beneficial bacteria and fungi Green Manure - freshly-cut or still-growing vegetation that is ploughed into the soil

55. Organic Fertilizer cont’d Compost - partially decomposed organic plant and animal matter - made up of animal manure, topsoil, kitchen scraps - rich, natural fertilizer

56. Other Solutions to Land Pollution sustaining existing forests and national parks restoring damaged areas support efforts to protect, expand, mend Jamaica’s national park system support efforts to protect large areas of remaining undeveloped lands reduce or eliminate the input of pollutants or waste

57. Legislations The Watersheds Protection Act - law governing watersheds in Jamaica - administered by NEPA - reduces soil erosion - ensures proper land use - maintain optimum levels of groundwater - promote regular flows in waterways

58. Other Legislation Relevant to Land Pollution Forest Act Rural Agricultural Development Act Water Resources Act Town and Country Planning Act Land Development and Utilization Act Country Fires Act The Mining Act Wildlife Protection Act