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Food Resources G. Tyler Miller’s Living in the Environment 13th Edition Chapter 13 Key Concepts Methods of producing food Increasing food production Environmental effects of food production Increasing sustainability How Is Food Produced? Sources of food Croplands (grain – 76% world’s food) Rangelands (grazing livestock – 17%) Oceanic Fisheries (fish – 7%) Increase in Global Food Production Since 1950 Due to: Increased technology: tractors, farm machinery, fishing boats, etc. Inorganic chemical fertilizers Irrigation Pesticides High yield varieties of corn, rice, and wheat Densely populated feedlots and pens (cattle, pigs, chickens) Aquaculture But, this increase has led to: Environmental degradation Pollution Lack of water for irrigation Overgrazing Overfishing Loss of vital ecological services What plants and animals feed the world? Wheat, rice, and corn provide over half the calories we consume globally Annuals: must be replanted every year 15 plant and 8 terrestrial animal species provide over 90% of our food 2/3 of world’s population survive primarily on grains As incomes rise, people consume more meat (more grain indirectly) Beef, pork, and chicken are main animal sources of food Types of Food Production Industrialized/High-put Agriculture Traditional Major Types of Agriculture INDUSTRIALIZED Plantation agriculture Practiced primarily in tropical developing countries Involves growing cash crops (bananas, coffee, soybeans, sugarcane, cocoa, and vegetables) on large monoculture plantations, mostly for sale to developed countries Major Types of Agriculture INDUSTRIALIZED Industrialized (high-input) Use fossil fuels, water, fertilizer, pesticides to produce large quantities of a single crop (monoculture) Major Types of Agriculture TRADITIONAL 44% of World’s People practice this Traditional subsistence: Uses mostly human labor Draft animals to produce only enough crops and livestock for the family’s survival Major Types of Agriculture TRADITIONAL Traditional intensive Increased input of human and draft labor Increased input of water Increased input of fertilizer Enough food to feed family and Attempt to increase yield to produce make an income extra for sale World Food Production Industrialized agriculture Plantation agriculture Shifting cultivation Nomadic herding Intensive traditional agriculture No agriculture Land Labor Capital Fossil fuel energy Industrialized agriculture in developed countries Land Labor Capital Fossil fuel energy Intensive traditional agriculture in developing countries An average of 60% of the people in developing countries are involved DIRECTLY in producing food, compared with only 8% in developed countries and 2% in the United States. Land Labor Capital Shifting cultivation in tropical forests in developing countries Land Labor Capital Nomadic herding in developing countries Food Type Kilocalories of fossil fuel input per kilocalorie of protein output Feed lot beef 20-78 Pigs 35 22 Broiler chicken Rangeland Beef 10 Sheep 10 Vegetables 2-4 © 2004 Brooks/Cole – Thomson Learning Croplands Ecological Services • Help maintain water flow and soil infiltration Economic Services • Food crops • Fiber crops • Provide partial erosion protection • Can build soil organic matter • Store atmospheric carbon • Provide wildlife habitat for some species • Crop genetic resources • Jobs Producing Food by Green-Revolution Techniques (1950-1970) High-input monoculture Selectively bred or genetically-engineered crops High inputs of fertilizer Extensive use of pesticides High inputs of water Increased intensity and frequency of cropping (> yield, several times/season; saves land) Green Revolutions First green revolution Second green revolution (developed countries) (developing countries) Major International agricultural research centers and seed banks CHINA HIGH-YIELD HYBRID DO NOT POST TO INTERNET INDONESIA Semidwarf Rice called IR-8. Producing Food by Traditional Techniques (Interplanting) Intercropping: 2 or more different crops are grown at the same time Polyvarietal cultivation: several varieties of the same crop are planted at the same time Agroforestry (alley cropping): crops and trees are planted together Polyculture: a complex form of intercropping in which many different plants maturing at different times are planted together ADVANTAGES of POLYCULTURE Less need for fertilizer Less need for water (root systems are at different depths) Protection from wind and water erosion (soil covered year-round) Less need for insecticides (natural predators thrive) Less need for herbicides (weeds have trouble competing) Insurance in case of bad weather because of diversity of crops produced On average, low-input polyculture, with 4 or 5 different crop species, produces higher yields per hectare of land than high-input monoculture. Nutrition Undernutrition: lack of food to meet basic needs (getting 100-400 fewer calories per day than needed) Malnutrition: deficiency of nutrients in diet (deficiency of protein and other key nutrients) Overnutrition: too many calories lead to overweight MARASMUS: “to waste away” Occurs when a diet is both low in calories and protein Usually occurs in young children KWASHIORKOR: “displaced child” Severe protein deficiency Usually occurs in children 1 – 3 years of age Undernutrition and Malnutrition About 1 in 6 people in developing countries is chronically undernourished or malnourished Each year at least 10 million people, half of them children under 5, die prematurely from: Undernutrition Malnutrition Increased susceptibility to normally nonfatal diseases Infectious diseases from contaminated drinking water Poverty Decreased energy Decreased resistance to disease Malnutrition Decreased ability to learn Decreased ability to work Feedback loop High death rate for children Shortened life expectancy Micronutrient Deficiencies The most widespread micronutrient deficiencies include Vitamin A, Iron and Iodine. Vitamin A - plays essential roles in vision, growth, and development; the development and maintenance of healthy skin, hair, and mucous membranes; immune functions; and reproduction (found in foods like sweet potato, carrot, mango, broccoli, spinach) Iron – is an essential component of hemoglobin which transports oxygen throughout the body and is important in many metabolic reactions (found in foods like chick peas, boiled spinach, dried apricots and figs) Iodine – plays an essential role in hormone development in the human body. If you don't have enough iodine in your diet, it can lead to an enlarged thyroid gland (goitre) or other iodine deficiency disorders (found in seafood, iodized salt and some vegetables) Overnutrition Food energy intake exceeds energy use and causes body fat (obesity) About 1 out of every 7 adults in developed countries is obese In the U.S. about 1 out of every 5 adults is obese Environmental Effects of Food Production Biodiversity loss Soil Air pollution Water Human health 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 Soil Erosion Loss of fertility Salinization Waterlogging Desertification Air Pollution Water Greenhouse gas emissions from fossil Fuel issue Aquifer depletion Other air pollutants from fossil fuel use Increased runoff and flooding from land cleared to grow crops Pollution from pesticide sprays 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 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 Increasing World Crop Production Crossbreeding and artificial selection Genetic engineering (gene splicing) Genetically modified organisms (GMOs) Continued Green Revolution techniques Introducing new foods Working more land Crop Desired trait (color) Cross breeding Pear Apple Offspring Cross breeding Best results New offspring Desired result Phase 1 Make Modified Gene cell Identify and extract gene with desired trait Identify and remove portion of DNA with desired trait gene DNA Plasmid Remove plasmid from DNA of E. coli E. coli DNA Insert extracted DNA (step 2) into plasmid (step3) Genetically modified plasmid plasmid Insert modified plasmid into E. coli Grow in tissue culture to make copies Phase 2 Make Transgenic Cell Transfer plasmid copies to a carrier agrobacterium A. tumefaciens (agrobacterium) Agrobacterium inserts foreign DNA into plant cell to yield transgenic cell Plant cell Nucleus Host DNA Foreign DNA Transfer plasmid to surface microscopic metal particle Use gene gun to inject DNA into plant cell Phase 3 Grow Genetically Engineered Plant Transgenic cell from Phase 2 Cell division of transgenic cells Culture cells to form plantlets Transgenic plants with new traits Concerns with GMO’s “Frankenfood” We know far too little GMO’s cannot be recalled if they cause harm No mandatory labeling (at this time) Crop seeds with “terminator genes” Projected Advantages Need less fertilizer Advantages and Disadvantages of Genetically Modified Foods 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 conventional pesticides Tolerate higher levels of herbicide use Projected Disadvantages Irreversible and unpredictable genetic and ecological effects Harmful toxins in food from possible plant cell mutations New allergens in food Lower nutrition Increased evolution of pesticideresistant insects and plant diseases Creation of herbicideresistant weeds Harm beneficial insects Lower genetic diversity Will People Try New Foods? Winged bean-protein rich legume Produces its own nitrogen Has multiple edible parts Microlivestock (INSECTS)-there are about 1500 edible species; 3 – 4 times as protein rich as beef, fish, or eggs Black ant larvae (Mexico) Giant waterbugs (Thailand) Emperor moth caterpillars (South Africa) Cockroaches (Kalahari desert) Butterflies (Bali) Ants (Colombia) Producing More Meat Rangeland Pasture Efficiency Kilograms of grain needed per kilogram of body weight Beef cattle 7 Pigs Chicken Fish (catfish or carp) 4 2.2 2 Adaptations of rangeland plants Range condition and management Environmental consequences Rangeland and Pasture Rangeland is land that is too dry, too steeply sloped, or too infertile to grow crops (makes up about 40% of ice-free land) Pasture is managed grasslands or enclosed meadows usually planted with domesticated grasses Ecology of Rangeland Plants. Rangeland grasses grow from the bottom up and are renewable as long as the bottom half of the plant (where photosynthesis takes place) is not eaten. Ungrazed Grazed Metabolic reserve Recovery Metabolic reserve intact Metabolic reserve If the metabolic reserve is eaten (like during overgrazing) the plant is weakened and can die. Ungrazed Overgrazed Metabolic reserve Death Most of metabolic reserve eaten Death Rangeland: Overgrazed (left) and lightly grazed (right.) DO NOT POST TO INTERNET Overgrazed Riparian Zone Arizona’s San Pedro River Recovery 10 Years Later Undergrazing Can reduce the net primary productivity of grassland vegetation and grass cover More likely in arid areas Environmental Consequences of Meat Production More than half of world’s cropland is used to produce livestock feed Livestock consume 36% of world’s grain Livestock use more than half the water drawn from rivers and aquifers (irrigation) Manure runoff leads to water pollution Erosion resulting from grazing Cattle produce 16% of methane (greenhouse gas) Catching and Raising More Fish The World’s 3rd major food-producing system Fisheries – concentrations of particular aquatic species in a given ocean area Fishing methods (bycatch – thrown back in) Sustainable yield Overfishing (Tragedy of the Commons) Commercial extinction (over fishing) Aquaculture Fish farming and ranching Spotter airplane Trawler fishing Fish farming in cage Purse-seine fishing trawl flap trawl lines sonar fish school trawl bag Fish caught by gills Drift-net fishing Long line fishing lines with hooks float buoy 800 80 Abundance 70 600 60 50 400 40 30 200 20 0 1960 1970 1980 Year 1990 2000 Abundance (kilograms/tow) Harvest (thousands of metric tons) Harvest Human capture Fish change form Salmon processing plant Fish enter rivers and head for spawning areas To hatchery In the fall spawning salmon deposit eggs in gravel nests and die Modified Life Cycle Grow to maturity in Pacific Ocean in 1-2 years Eggs are taken from adult females and fertilized with sperm “milked” from males Fry hatch in the spring... Normal Life Cycle Eggs and young are cared for in the hatchery And grow in the stream for 1-2 years Grow to smolt and enter the ocean... Fingerlings migrate downstream Fingerlings are released into river Advantages Highly efficient High yield in small volume of water Increased yields through crossbreeding and genetic engineering Disadvantages Large inputs of land, feed, and water needed Produces large and concentrated outputs of waste Destroys mangrove forests Can reduce overharvesting of conventional fisheries Increased grain production needed to feed some species Little use of fuel Fish can be killed by pesticide runoff from nearby cropland Profit not tired to price of oil High profits Dense populations vulnerable to disease Tanks too contaminated to use after about 5 years AQUACULTURE Government Agricultural Policy Artificially low prices – consumers are happy, but farmers don’t make much money Subsidies – given to farmers to keep them in business (comes from taxpayer’s money) Elimination of price controls – let farmers respond to market demand without government interference Food aid – with any excess food Solutions: Sustainable Agriculture Low-input agriculture Organic farming More benefits to the poor Increasing funding for research in sustainable techniques Increase High-yield polyculture Decrease Soil erosion Soil salinization Organic fertilizers Aquifer depletion Biological pest control Integrated pest management Irrigation efficiency Perennial crops Overgrazing Overfishing Loss of biodiversity Loss of prime cropland Crop rotation Food waste Use of more waterefficient crops Soil conservation Subsidies for more sustainable farming and fishing Subsidies for unsustainable farming and fishing Population growth Poverty Components of More SUSTAINABLE, LOW THROUGHPUT Agriculture