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3.5 Food Resources
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Human food systems: Croplands Rangelands Oceanic fisheries
Food Resources Human food systems: Croplands Rangelands Oceanic fisheries
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To feed the increasing world population we must:
Solar Capital Air resources and purification Climate control Recycling vital chemicals Renewable energy Nonrenewable mineral Potentially renewable matter Biodiversity and gene pool Natural pest and disease Waste removal and detoxification Soil formation renewal Water To feed the increasing world population we must: Produce and equitably distribute more food than ever before. Do this in a environmentally sustainable way.
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Limitations: Environmental degradation Pollution Lack of water for
irrigation Overgrazing Overfishing Loss of ecological services
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4 Types of agriculture systems:
Uses large amounts of fossil fuels energy, water, commercial fertilizer, and pesticides to produce huge quantities of single crops or livestock animals for sale. 25% of croplands in developed countries. Industrialized agriculture in developed countries Land Labor Capital Fossil fuel energy
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Intensive traditional agriculture in developing countries
Land Labor Capital Fossil fuel energy Uses large amounts of human input and draft labor, water, and fertilizer, to produce enough food to feed their families and sell for income. In North America 2.4% of labor force is used in agriculture vs 45-65% in developing countries.
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Shifting cultivation in tropical forests in developing countries
Land Labor Capital Growing cash crops on large monoculture plantations, mostly for sale. A large amount of livestock production is industrialized. Mostly pigs and chicken are raised in densely populated pens and cages and are fed mostly grain from croplands.
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Practiced by 2.7 billion people (44% of the world’s population).
Nomadic herding in developing countries Land Labor Capital Uses mostly human labor and draft animals to produce only enough crops or livestock for a farm family’s survival. Practiced by 2.7 billion people (44% of the world’s population). Provide 20% of the world’s food supply.
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Industrialized agriculture
Shifting cultivation Plantation agriculture Nomadic herding Intensive traditional agriculture No agriculture
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Rangelands About 40% of the earth’s ice-free land.
This land provides forage or vegetation for grazing and browsing animals.
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Stock raising on ranges
Nomadic herding Stock raising on ranges
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Kilocalories of fossil fuel input per kilocalorie of protein output
Food Type Feed lot beef 20-78 Pigs 35 Broiler chicken 22 Rangeland Beef 10 Sheep 10 Vegetables 2-4
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Fisheries The world’s third major food-producing system.
55% of the annual commercial catch comes from the ocean. Harvesting methods: Trawler fishing Purse-seine Longlineing Drift-net
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float buoy Spotter airplane Trawler fishing Fish farming in cage
Purse-seine sonar trawl flap trawl lines trawl bag Long line fishing lines with hooks Drift-net fishing Fish caught by gills float buoy fish school
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The rest of the annual catch comes from using
Aquaculture (33%) Inland freshwater fishing from lakes, rivers and reservoirs (12%) About 1/3 of the catch is used as animal feed, fish meal and oils. Hake Haddock Cod Sardine Anchovy Herring Mackerel Tuna Krill Shrimp Lobster Crab Oyster Clam Octopus Squid
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Kilocalories of fossil fuel input per kilocalorie of protein output
Seafood type Marine Fisheries Shrimp 3-98 Salmon 18-52 20 Cod Ocean Aquaculture Salmon cage culture 50 Salmon ranching 7-12 Seaweed 1
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Comparing Food Production
Aquatic Food is harvested from higher trophic levels mostly because of human taste. Energy conversions are more efficient along the food chain. Terrestrial Food is harvested from low trophic levels. More efficient fixing of solar energy by photosynthesis.
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Major environmental effects of food production
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Soil Erosion Loss of fertility Salinization Waterlogging Desertification Biodiversity Loss Loss and degradation of habitat from clearing grasslands and forests and draining wetland Fish kills from pesticide runoff Killing of wild predators to protect livestock Loss of genetic diversity from replacing thousands of wild crop strains with a few monoculture strains
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Greenhouse gas emissions from fossil Fuel issue
Water Aquifer depletion Increased runoff and flooding from land cleared to grow crops Sediment pollution from erosion Fish kills from pesticide runoff Surface and groundwater pollution from pesticides and fertilizers Overfertilization of lakes and slow-moving rivers from runoff of nitrates and phosphates from fertilizers, livestock wastes, and food processing wastes Air Pollution Greenhouse gas emissions from fossil Fuel issue Other air pollutants from fossil fuel use Pollution from pesticide sprays
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Human Health Nitrates in drinking water Pesticide residues in drinking water, food, and air Contamination of drinking and swimming water with disease organisms from livestock wastes Bacterial contamination of meat
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Increasing Crop Production
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Genetic engineering Projected Advantages Projected Disadvantages
Need less fertilizer Need less water More resistant to insects, plant disease, frost, and drought Faster growth Can grow in slightly salty soils Less spoilage Better flavor Less use of con- ventional pesticides Tolerate higher levels of herbicide use Irreversible and unpredictable genetic and eco- logical effects Harmful toxins in food from possible plant cell mutations New allergens in food Lower nutrition Increased evolution of pesticide- resistant insects and plant diseases Creation of herbicide- resistant weeds Harm beneficial insects Lower genetic diversity
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Try new foods Increase cultivation of less widely known plants to supplement or replace staple foods. Insects – microlivestock – could be an important potential source of protein.
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Irrigate & Cultivate More Land
In use Not usable Arid land 6% Tropical forest 8% Cultivated 10% Grazed 11% Forests, arid lands 14% 51% Ice, snow, deserts mountains Irrigate & Cultivate More Land
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