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Food Resources G. Tyler Miller’s Living in the Environment 13th Edition Chapter 13 NCSU Ag. Institute Club T-Shirt How Is Food Produced? • Sources of food provided by: – cropland (76%) – rangeland (17%) – ocean fisheries (7%) • Primary plants produced – wheat, corn, rice • Primary animals consumed – beef, pork, chicken DID YOU KNOW … • THREE annual grains (wheat, rice, corn) provide more than half the calories people consume. • 2/3 of the worlds pop survives on grains as they cannot afford meat. DID YOU KNOW … • Food productivity has increased due to technological advances BUT env problems (irrigation, overgrazing, overfishing, pollution, degradation) may limit future production. DID YOU KNOW … • Dependence on foreign food makes us vulnerable. • Livestock consume over half of grains grown in developing countries. Carnivores Major Types of Food Production • Monoculture vs. Polyculture – one crop vs. diversified many crops Major Types of Agriculture • Industrialized (high input) – uses large quantities of fossil fuel energy, capital $$, water, machinery, irrigation, commercial fertilizer, and pesticides – produces huge quantities of single crops or livestock (monoculture) – results in high yield crops and increased revenue temporarily – results in soil degradation and potential pesticide resistance • Plantation – growing cash crops on large monoculture plantations – Mostly for sale in developed countries. Major Types of Agriculture • Livestock Production – densely populated feedlots fed grain for plumping before slaughter (CAFO) Major Types of Agriculture • Traditional Agriculture – Traditional subsistence • uses human labor and draft animals • produce only enough food for a family’s survival. – Traditional intensive • increased human and draft labor, fertilizer, and water • higher yields producing enough food for their family and to sell for income. Subsistence Examples • Nomadic Herding – support livestock on arid infertile soil • Shifting Cultivation – short cultivation periods followed by long periods of fallow allowing land to revert back to forest • Slash and Burn – clearing tropical rain forest, quickly depletes soil nutrients Various Growing Techniques • interplanting – many different crops on same plot – polyvarietal cultivation – varieties of same crop on same plot – intercropping – using two or more crops close together, discourages pest buildup (tall vs. short, deep root vs. shallow root) – alley cropping – planting trees/shrubs and crops together in rows – polyculture – differing the maturity rates & harvest time of various crops – http://www.hippocampus.org/Earth%20Science;jsessionid=340D0A82A4EBF826FC EDB7D9051F16FA Land Labor Capital Fossil fuel energy Industrialized agriculture in developed countries Land Labor Capital Fossil fuel energy Intensive traditional agriculture in developing countries World Food Production Industrialized agriculture Plantation agriculture Shifting cultivation Nomadic herding Intensive traditional agriculture No agriculture Challenge to Farmers: Produce More Food! 1. Farm more land 2. Produce higher yields per unit area What about the Green Revolution? Refers to dramatically increased agricultural productivity resulting from the introduction of new, high-yielding strains of grain (rice, wheat, and maize) Ongoing since 1950s Producing Food by Green-Revolution Techniques High-input monoculture Scientifically bred or geneticallyengineered crops High inputs of fertilizer Extensive use of pesticides High inputs of water Increased intensity and frequency of cropping (multiple cropping) Green Revolutions 19501970 1967today First green revolution Second green revolution (developed countries) (developing countries) Major International agricultural research centers and seed banks Producing Food by Traditional Techniques (Low input agrodiversity) Interplanting - simultaneously growing a variety of crops on the same plot 1) Polyvarietal cultivation – Planting several varieties of the same crop in a plot 2) Intercropping – Two or more different crops are grown at the same time on a plot Producing Food by Traditional Techniques (Low input agrodiversity) 3) Agroforestry (alley cropping) – Crops and trees are planted together 4) Polyculture – Different plants maturing at various times are planted together • • • • Less fertilizer Protection from wind and water erosion Little or no insecticides Insurance against bad weather Food Production – Good News Production is increasing!! Total World Grain Production Grain production (millions of tons) 2,000 1,500 1,000 500 0 1950 1960 1970 1980 Year 1990 2000 2010 Food Production – bad news Population growth outstripped production Per capita grain production (kilograms per person) World Grain Production per Capita 400 350 300 250 200 150 1950 1960 1970 1980 Year 1990 2000 2010 Did you know …. • 1 in 6 people in developing countries are undernourished or malnourished • 1 in 7 adults in developed countries suffer from overnutrition/obesity • 61% of Americans are overweight • 27% of Americans are obese Human Nutrition • Macronutrients – Protein, carbohydrates, and fats • Micronutrients – Vitamins A, C, and E – Minerals (iron, iodine, and calcium) Undernutrition – consuming insufficient food to meet one’s minimum daily energy needs, suffer from stunted growth and development, more susceptible to disease Nutrition Malnutrition – faulty nutrition, caused by a diet that does not have enough protein, essential fats, vitamins, minerals and other nutrients needed for good health. • Marasmus – Diet low in both calories and protein • Kwashiorkor – Severe protein deficiency Marasmus – “wasting disease” Kwashiorkor “displaced child” What’s the Deal? Enough food is produced to meet the basic nutritional needs of every human on the planet. However, it is NOT DISTRIBUTED EQUALLY due to differences in soil climate political power economic power average per capita income (POVERTY) POVERTY is the problem, not the common misconception that the globe is not producing enough food! 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 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 Traditional Crossbreeding Apple 1) Slow process Offspring Cross breeding Best results New offspring Desired result 2) Can combine traits only from closely related species 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 1) Half the time as conventional crossbreeding 2) Cuts costs 3) Allows insertion of genes from almost any other organism Transgenic cell from Phase 2 Cell division of transgenic cells Culture cells to form plantlets Transgenic plants with new traits Increasing World Crop Production • Continued Green Revolution techniques? – Without fertilizer, water, and pesticides green revolution varieties are no more productive than traditional varieties – Green revolution varieties and their needed inputs cost too much for subsistence farming. – Grain yields are increasing at a much slower pace. Increasing World Crop Production • Continued Green Revolution techniques? – Actual gains from green and gene revolutions may be overstated. – Crop yield may start dropping for a number of environmental reasons. – Increased loss of biodiversity can limit genetic raw material. Increasing World Crop Production • Introducing new foods – Getting farmers to take risk of growing new types of food. – Getting consumers to try new foods. Increasing World Crop Production • Working more land Cultivated Grazed Tropical forest Arid land 11%10% 8% 6% 14% Forests, arid lands 51% “Many analysts believe that significant expansion of cropland is unlikely over the next few decades.” Ice, snow, deserts mountains Not usable How about producing more meat… • Rangeland is land that is… – too dry – too steeply sloped – too infertile …to grow crops (40% of ice-free land area) • Pastures – managed grasslands or enclosed meadows How is meat produced? • Open grazing – 80% of cattle, sheep and goats are raised on rangeland •Feedlots –Account for 40% of the world’s meat production Kilograms of grain needed per kilogram of body weight Beef cattle 7 Pigs Chicken Fish (catfish or carp) 4 2.2 2 Producing more meat • Condition of the world’s rangelands – DECLINING! • Environmental consequences of meat production – See Connections page 299 – Read Spotlight page 300 Catching and Raising More Fish • Fisheries – concentrations of aquatic species suitable for commercial harvesting in a given body of water • 55% of annual commercial catch comes from the ocean. • 33% from aquaculture. • 12 % from inland freshwater fishing. Commercial Fishing Methods Trawler fishing Fish farming in cage sonar Spotter airplane Purse-seine fishing trawl trawl flap lines fish school trawl bag Long line fishing lines with hooks Fish caught by gills float Drift-net fishing buoy Potential to harvest more fish • 1950-1982 + Fish catch increased 5-fold + Per capita seafood catch doubled • Since 1982 – Little increase in commercial fish catch – Per capita commercial fish catch falling Potential to harvest more fish The primary cause of depletion of fish stocks is too many fishing boats pursuing too few fish or OVERFISHING (Tragedy of the Commons) • Habitat destruction • Global warming Aquaculture • Fish farming – Cultivating fish in a controlled environment. – Harvesting them when they reach the desired size. – Catfish are the leading aquaculture product in the US Aquaculture • Problems – Raises demand for ocean fish as fish meal to feed aquaculture species – Creating vast amounts of animal waste in coastal areas – Farming of carnivorous fish increases over-fishing of smaller marine species. Future • Increasing wild catch and aquaculture will not increase world food supplies significantly. • Fish and shellfish supply only 1% of the energy and 6% of the protein in the human diet. Government Agricultural Policy • Financially risky business • Forms of assistance. – Keep food prices artificially low. – Give farmers subsides to keep them in business and encourage them to increase food production. – Eliminate price controls and subsides and let farmers and fishers respond to market demand without government control. • Increase aid for the poor Future limitations to increased food production • • • • Lack of water for irrigation Reduced genetic diversity Leveling off of yields Environmental effects which degrade existing cropland Solutions: Sustainable Agriculture 1) Slowing population growth 2) Reducing poverty 3) Phasing in systems of sustainable agriculture (also called organic farming) ‘Organic’ foods Plants • Produced without synthetic pesticides, fungicides, and herbicides • Cannot include genetically engineered foods or be irradiated • Cannot be grown on soils fertilized with sewage sludge Animals • Produced from 100% organically grown feed. • Given access to outdoor range or pasture • Produced without use of hormones and antibiotics Principles of Sustainability • Most ecosystems use renewable solar energy as the primary source of energy. • Ecosystems replenish nutrients and dispose of wastes by recycling chemicals. Principles of Sustainability • Biodiversity helps maintain the sustainability of ecological functioning of ecosystems and serves as a source of adaptation to changing environmental conditions. • In nature there are always limits to population growth and resource consumption.
