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Food and Agriculture Land Use • 11% of the earth’s land is used in agricultural production – Less land cultivated in NA now than 100 years ago Types of Food Production 1. Traditional subsistence agriculture – mostly human and animal labor • • Produces only enough crops for a family’s survival Africa, Asia, South America Types of Food Production 2. Industrialized agriculture (high input agriculture) • • Large amount of fossil fuel energy, water, fertilizers and pesticides to produce large quantities of monocultures Example: Plantation agriculture – Used in tropical developing nations – Cash crops grown for export » May provide non-food products (latex) » Provide products that do not make up primary nutrition (tea, coffee) Agroecosystems • Ecosystem created by agricultural practices – characterized by low • Genetic diversity • Species diversity • Habitat diversity Agroecosystems Differ from natural ecosystems in five major ways: 1. Farming attempts to stop ecological succession 2. Species diversity is low • Monoculture ↓ soil fertility 3. Plant species (crops) in an orderly fashion – pest control more difficult 4. Simple food chains 5. Plowing • ↑ erosion • Nutrient loss Farm Numbers Number of People Fed Annually By One Farmer Food Supply • 15 to 20 species provide vast majority (90%) of man’s food needs – Wheat, rice, corn, potatoes, barley • Wheat and rice supply ~60% of human caloric intake – 90% of grain grown in NA is used to feed livestock Meat Sources • 20% of the richest countries consume 80% of the world’s meat • About 90% of the grain grown in the United States is used for animal feed • 16 lbs of grain → 1 lb of meat World Food Supply and the Environment • Enough food, unevenly distributed – 815 million people do not have enough to eat • Parts of Africa, southeast Asia – In richest countries, 11 million do not have enough to eat • Food production depends upon favorable environmental conditions Food Distribution • Food is not distributed equally due to: – Soil and climate differences – Political and economic power – Average per capita income throughout the world Malnutrition/Famines • Malnutrition – Undernutrition – Overnutrition • Famine – Environmental conditions are immediate trigger, but politics and economics are often underlying problems. • Famine conditions – Major droughts – Population sizes – Massive immigration – Floods – Wars -- Political instability -- Land Seizures -- Distribution breakdown -- Chaos in economy Risk of Inadequate Nutrition Undernutrition Problems • Iron deficiency – Most common – Leads to anemia • Red meat, eggs, legumes, and green vegetables are all good sources of iron. • Vitamin A deficiencies – Can cause blindness Obesity • Most common dietary problem in wealthy countries – According to U.S. Surgeon General: • 62% of Americans are overweight. – 33% are obese. Land Use and Degradation • Overgrazing and soil erosion • Eliminates millions of acres a year • Desertification-degrading once fertile land into desert • Surface runoff • Dry surface reflects heat, changing wind patterns Global Soil Degradation Mechanisms of Erosion • Wind and water are erosive forces – Intensive farming practices: • Salinization • Waterlogging – Impairs root growth, roots cannot get oxygen • No crop rotation • Removal of windbreaks • Continued monocultures Alternatives to Industrial Farming Methods Sustainable Agriculture • Through soil conservation – – – – Intercropping Crop rotation Agroforestry Contour Plowing Soil Conservation Cont. • Providing Ground Cover – No till agriculture – Plant cover crops • Improved irrigation and utilization of water – Drip irrigation New vs. Old Agriculture Methods to Increase Food Supply • Food distribution modification – Teach locals • In the 1960s: – Green Revolution-increased yields per unit of area of cropland • Mechanization – Monocultures of selectively bred or genetically engineered high yield variety of key crops (rice, corn, wheat) » Corn yields jumped from 25 bushels per acre to 130 per acre in last century. • Using high inputs of fertilizer, pesticides, and water on crops to produce high yields • Increasing the intensity and frequency of cropping Genetic Engineering • Genetically Modified Organisms (GMO’s) – Crops resistant to drought, frost, diseases, pests, etc. – Animals that grow faster, gain weight on less food, produce more milk, etc. – Estimated at least 70% of all processed foods in NA contain transgenic products. Is Genetic Engineering Safe ? • Environmental and consumer groups have campaigned against transgenic organisms. – “Frankenfoods” – Opponents fear traits could spread to wild varieties – U.S. Food and Drug Administration declined to require labeling of foods containing GMO’s. • New varieties are “substantially equivalent” to related traditionally-bred varieties. How Would You Vote? • Do the advantages of genetically engineered foods outweigh their disadvantages? • Should labeling of GMOs be required? Increasing Food Supply: Producing More Meat • ½ of the world’s meat is produced by livestock grazing on grass. • ½ half is produced under factory-like conditions (feedlots). – Concentrated animal feeding operations (CAFOs) • High density, confined or allowed very little moving room – A CAFO may contain as many as 2500 hogs or 55,000 turkeys in a single building Trade-Offs Animal Feedlots Advantages Increased meat production Higher profits Less land use Reduced overgrazing Reduced soil erosion Help protect biodiversity Disadvantages Need large inputs of grain, fish meal, water, and fossil fuels Concentrate animal wastes that can pollute water Antibiotics can increase genetic resistance to microbes in humans Fig. 13-21, p. 289 Sustainable Animal Farming • Free-range • Organic • Smaller scale farms Buy Local! • The average American foodstuff travels an estimated 1500 miles before being consumed. Catching and Raising More Fish • Fisheries – third major food-producing system • ~55% of annual commercial catch from ocean • ~45% from use of aquaculture to raise marine and freshwater fish Fishing methods Catching and Raising More Fish – Commercial fish amounts have been declining since 1980 • Overfishing – Tragedy of the commons – Bycatch Raising More Fish Aquaculture: Aquatic Feedlots • Raising large numbers of fish and shellfish in ponds and cages in a controlled environment and harvesting them in captivity. Trade-Offs Aquaculture Advantages High efficiency High yield in small volume of water Can reduce overharvesting of conventional fisheries Low fuel use High profits Profits not tied to price of oil Disadvantages Needs large inputs of land, feed, and water Large waste output Destroys mangrove forests and estuaries Uses grain to feed some species Dense populations vulnerable to disease Tanks too contaminated to use after about 5 years Solutions Managing Fisheries Fishery Regulations Set catch limits well below the maximum sustainable yield Bycatch Use wide-meshed nets to allow escape of smaller fish Improve monitoring and enforcement of regulations Use net escape devices for seabirds and sea turtles Economic Approaches Sharply reduce or eliminate fishing subsidies Ban throwing edible and marketable fish back into the sea Charge fees for harvesting fish and shellfish from publicly owned offshore waters Aquaculture Restrict coastal locations for fish farms Certify sustainable fisheries Control pollution more strictly Protected areas Establish no-fishing areas Depend more on herbivorous fish species Establish more marine protected areas Nonnative Invasions Kill organisms in ship ballast water Rely more on integrated coastal management Filter organisms from ship ballast water Consumer Information Label sustainably harvested fish Publicize overfished and threatened species Dump ballast water far at sea and replace with Deep-sea water