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Unit 4: Land and Resource Use. Chapter 11 agriculture, aquaculture, and the Environment. 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. Can We Feed the World?.
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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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Doomsday Seed Vault Svalbard, Norway Goal is to preserve crop seed biodiversity
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
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
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
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
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)
Contour plowing • Is plowing to match the topography of the land • Prevents wind and water erosion of topsoil
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
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
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
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
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
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
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
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
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
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
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
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
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