unit 4 land and resource use n.
Skip this Video
Loading SlideShow in 5 Seconds..
Unit 4: Land and Resource Use PowerPoint Presentation
Download Presentation
Unit 4: Land and Resource Use

Unit 4: Land and Resource Use

130 Vues Download Presentation
Télécharger la présentation

Unit 4: Land and Resource Use

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Unit 4: Land and Resource Use

  2. Chapter 11agriculture, aquaculture, and the Environment

  3. Agroecosystems • Are ecosystems that are arrested in early stages of succession • Have simplified food chains • Are planted in rows in fields • Require plowing and other maintenance

  4. Can We Feed the World? • Yes, if we can overcome environmental obstacles that prevent increases in food production • Soil fertility and productivity • Amount of land available for agriculture • 38% of Earth’s land currently used for agriculture • Availability of healthy crop seeds and plants • Eat lower on the food chain

  5. Human nutrition • 10,000 years ago • Humans were hunters and gatherers • Starvation was common • Agriculture was developed • 10,000 years ago to now • Agriculture has evolved into an industry • Starvation still is common in some parts of the world

  6. Human nutrition • Undernutrition • Not consuming enough calories to maintain the body • Malnutrition • Lacking sufficient protein, vitamins, and minerals • Even a single missing nutrient can have drastic consequences • Anemia (iron), blindness (vitamin A) • Overnutrition • Consuming too many calories, usually from poor quality foods Manuel Uribe, 1235 lbs world’s fattest man…..ever

  7. Food Availability • Food Security • Access to safe and healthy food • Most developed nations have strong food security • Food Insecurity • Inadequate access to safe and healthy food • Causes • Poverty • Political unrest • Lack of agricultural land • Famine • Deaths result from extreme food insecurity

  8. Human Diet • Grains • Largest component of our diet overall • Rice, corn, soybeans, wheat, barley, oats, rye • Enough grain is produced globally each year to feed 8 billion people • 40% of the grain grown is used to feed livestock

  9. Human Diet • Meat • Second largest component of our diet • Beef, pork, sheep, goat, chicken, turkey, duck • Requires more land and resources to produce than grain • Contains more energy per unit than grain

  10. The Green Revolution • Started in the 1950s • Made improvements to crop plants, irrigation, and fertilizers • Also started the mechanization and automation of many processes • Most agriculture is now industrial agriculture, or agribusiness sorghum peanuts pistachios corn hops rice soybeans coffee

  11. Mechanization • Much of farm work is now accomplished by machine • Economically advantageous • Reduces labor costs • Increases production • Increases profits • Environmentally damaging • Increased fossil fuel use • Increased pollution

  12. Fertilizers • Necessary to replace nutrients lost to plant growth or erosion • Organic fertilizers contain matter from plants and animals • Care must be taken to not introduce pathogens • Overuse can still cause eutrophication

  13. Fertilizers • Synthetic/inorganic fertilizers are produced chemically • Concentrate limiting nutrients such as nitrogen and phosphorus • Easy to apply and for plants to absorb • Use a lot of energy to produce • Overuse creates eutrophication • Can add salts to soil

  14. Irrigation • Improved techniques improved crop yields • Can deplete groundwater and cause saltwater intrusion • Waterlogging • Soil remains underwater • Deprives roots of oxygen • Salinization • Salts in water and fertilizer are left behind after evaporation

  15. Pesticides • Substances that kill or control pests • Kill insects, rodents, and weeds • Allow greater crop yields • Can kill or harm organisms other than the intended target • Broad-spectrum • Kill lots of different species of pest • Selective • Kill only one species or type of pest

  16. Pesticides • Persistent • Do not break down easily • Kill organisms longer • Remain in the air, soil, or body tissues like fat or bone • Nonpersistent • Can break down easily • Must be applied more often

  17. Pesticides • Resistance • Some pests survive exposure to pesticides • They pass their resistant genes and traits on to offspring • Resistant pest population increases • Pesticide Treadmill • Stronger pesticides must continually be developed to kill resistant pests

  18. Genetic Engineering • Genetic material can be transferred from one organism to another • Genes for desirable traits in crops can be identified and manipulated • “Terminator” genes can make plants sterile • Organisms that contain non-standard genes are called genetically modified organisms (GMOs) or transgenic organisms

  19. Genetic engineering • Benefits • Increased crop yield • Increased pest resistance • Increased nutritional value • Impacts • Decreases biodiversity • Legal problems • Expensive • Ownership of living organisms and valuable crop plants

  20. Doomsday Seed Vault Svalbard, Norway Goal is to preserve crop seed biodiversity

  21. Unsustainable agriculture • Overuse of land leads to: • Topsoil erosion • Soil compaction • Salinization • Causes desertification • More than 10% of the productivity of the land is lost • Occuring fastest in African Sahara and Chinese Gobi areas

  22. Unsustainable Agriculture • Shifting Agriculture • Also called slash-and-burn or swidden agriculture • Nutrient-rich vegetation is cut down and burned • Resulting ash fertilizes the land • Nutrients last for a few years, then the land is abandoned for a new area • Heavy rainfall can wash soil and nutrients away

  23. Sustainable Agriculture • Agricultural land is farmed in a way that the land is continually usable • Minimizes the use of nonrenewable resources • Maintains or enhances soil quality • Conserves crop diversity • Preserves economic viability • Often uses techniques found in traditional agriculture • Listed on the following slides • Treats farming as ecosystem management • Models a food chain

  24. Crop Rotation • Changes the crop species in a field for each growing season • Helps minimize nutrient loss • Legumes (beans, peas) replace nitrogen in soil • Grasses (corn, wheat) absorb nitrogen

  25. Intercropping • Is planting multiple crops in the same field • Achieves the same goals as crop rotation • Allows for the growth of multiple crops in a smaller space • Can also include planting crops in orchards (agroforestry)

  26. Contour plowing • Is plowing to match the topography of the land • Prevents wind and water erosion of topsoil

  27. No-till agriculture • Does not turn over the soil during planting like traditional plowing or tilling • Soil is less susceptible to erosion • Soil loses fewer nutrients • Leaves crop remains in the field • Fertilize the soil • Can require more herbicides to kill weeds

  28. Integrated Pest Management (IPM) • Combines multiple agricultural techniques to control pests and minimize pesticide use • Crop rotation • Prevents crop-specific pests and diseases • Intercropping • Uses plants that deter pests • Pest-resistant crops • Creating habitats for predators of pests • Ladybugs, parasitic wasps

  29. Biological Pest Control • Also called biocontrol • Involves using natural predators and diseases of pests • Ladybugs • Parasitic wasps • Myxomatosis virus • Can be disastrous if not researched properly • Mongoose • Cane toads

  30. Organic Agriculture • Production of crops without synthetic pesticides or fertilizers • Maintains the organic and nutrient content of the soil • Uses ecological principles to maintain an ecosystem or community structure

  31. Ecosystem-Based Farming • Cattle graze fields and fertilize grass with manure • Produce meat and dairy for consumers • Poultry eat bugs and other organisms attracted by manure • Produce meat and eggs for consumers • Manure that collects inside a barn is layered with grass and corncobs • Makes food for pigs • Breaks down and creates compost for fertilizer Joel Salatin, Polyface Farms p. 283-84 in book

  32. Aigamo Farming • Ecosystem farming for rice paddies • Aigamo ducks are released into rice paddies • Eat pests • Churn up water and nutrients • Fertilize rice plants • Protein source or income source • Can also add fish or shellfish to paddies

  33. Growing livestock • Is raising animals for their meat, eggs or milk • Is extremely energy and labor intensive • Requires a large amount of land per unit of food produced

  34. High-Density Animal Farming • Also called feedlots, or concentrated animal feeding operations (CAFOs) • Animals are confined to a small space • Allows feeding to occur more efficiently • Animal biomass increases more quickly • Minimizes land use, labor costs • Animal waste can contaminate surface and ground water • Antibiotics are overused to prevent infection

  35. Feedlot Alternatives • Free-range • Animals are allowed to wander free in large enclosed areas • Fewer antibiotics are used • Synthetic feeds are not used • Animals use the available natural resources • Animals fertilize the land • More land is required • Meat costs more

  36. Nomadic Grazing • Occurs in areas with low plant productivity • Herds of livestock are moved as the vegetation in an area becomes scarce • Often occurs seasonally • If livestock are left in one area too long it can become overgrazed

  37. Aquaculture • Is not a new technology • Can be freshwater or marine (mariculture) • Can be done for almost all aquatic organisms • Seaweed and algae • Shellfish (oysters, shrimp) • Fish (trout, salmon, tuna) • Can be for food, recreation, or consumer products

  38. aquaculture • High-density cultivation of fish and shellfish • Can be a solution to declining fisheries • Can occur in tanks on land or in open water • Excess feed and animal waste in open water can cause eutrophication • Can spread disease to wild populations

  39. Chapter 12Landscapes: Forests, Parks, and Wilderness

  40. How Forests Affect the Planet • Evaporate water • Slow erosion • Provide wildlife habitat • Add oxygen and remove carbon dioxide • Affect the amount of sunlight absorbed by the Earth’s surface • Change wind speeds