ENVIRONMENTAL SCIENCE CHAPTER 10: Food, Soil, and Pest Management

Core Case Study: Is Organic Agriculture the Answer? (1) Organic agriculture as a component of sustainable agriculture Certified organic farming: Less than 1% of world cropland 0.1% of U.S. cropland 6-18% in many European countries

Core Case Study: Is Organic Agriculture the Answer? (2) Many environmental advantages over conventional farming Requires more human labor Organic food costs 10-75% more than conventionally grown food Cheaper than conventionally grown food when environmental costs are included

Fig. 10-1, p. 206

Industrialized Agriculture Uses synthetic inorganic fertilizers and sewage sludge to supply plant nutrients Makes use of synthetic chemical pesticides Uses conventional and genetically modified seeds Depends on nonrenewable fossil fuels (mostly oil and natural gas) Figure 10.1: Comparison of conventional industrialized agriculture and organic agriculture. In the United States, a label of 100 percent organic means that a product is raised only by organic methods and contains all organic ingredients. Products labeled organic must contain at least 95% organic ingredients. And products labeled made with organic ingredients must contain at least 70% organic ingredients but cannot display the USDA Organic seal on their packages. Produces significant air and water pollution and greenhouse gases Is globally export-oriented Uses antibiotics and growth hormones to produce meat and meat products Fig. 10-1, p. 206

Organic Agriculture Emphasizes prevention of soil erosion and the use of organic fertilizers such as animal manure and compost, but no sewage sludge to help replace lost plant nutrients Employs crop rotation and biological pest control Uses no genetically modified seeds Makes greater use of renewable energy such as solar and wind power for generating electricity Figure 10.1: Comparison of conventional industrialized agriculture and organic agriculture. In the United States, a label of 100 percent organic means that a product is raised only by organic methods and contains all organic ingredients. Products labeled organic must contain at least 95% organic ingredients. And products labeled made with organic ingredients must contain at least 70% organic ingredients but cannot display the USDA Organic seal on their packages. Produces less air and water pollution and greenhouse gases Is regionally and locally oriented Uses no antibiotics or growth hormones to produce meat and meat products Fig. 10-1, p. 206

10-1 What Is Food Security and Why Is It So Difficult to Attain? Concept 10-1A Many of the poor have health problems from not getting enough food, while many people in affluent countries suffer health problems from eating too much. Concept 10-1B The greatest obstacles to providing enough food for everyone are poverty, political upheaval, corruption, war, and the harmful environmental effects of food production.

Poor Lack Sufficient Food Enough food for all – but in developing countries 1/6 do not get enough to eat Poverty – Food insecurity Chronic hunger Poor nutrition Food security

Nutrition Macronutrients and micronutrients Chronic undernutrition Malnutrition Low-protein, high-carbohydrate diet Physical and mental health problems 6 million children die each year Vitamin and mineral deficiencies

Supplement 3, Fig. 11, p. S12

Fig. 10-2, p. 208

Fig. 10-3, p. 209

Overnutrition Too many calories, too little exercise, or both Similar overall health outlook as undernourished 1.6 billion people eat too much 66% of American adults overweight, 34% obese Heart disease and stroke Type II diabetes and some cancers

10-2 How Is Food Produced? Concept 10-2 We have used high-input industrialized agriculture and lower-input traditional methods to greatly increase supplies of food.

Where We Get Food (1) Major sources: Croplands Rangelands, pastures, and feedlots Fisheries and aquaculture

Where We Get Food (2) Since 1960 tremendous increase in food supply Better farm machinery High-tech fishing fleets Irrigation Pesticides and fertilizers High-yield varieties

Only a Few Species Feed the World Food specialization in small number of crops makes us vulnerable 14 plant species provide 90% of world food calories 47% of world food calories comes from rice, wheat, and corn

Industrialized Agriculture (1) High-input agriculture – monocultures Large amounts of: Heavy equipment Financial capital Fossil fuels Water Commercial inorganic fertilizers Pesticides Much food produced for global consumption

Industrialized Agriculture (2) Plantation agriculture primarily in tropics Bananas Sugarcane Coffee Vegetables Exported primarily to developed countries

Traditional Agriculture 2.7 billion people in developing countries Traditional subsistence agriculture Traditional intensive agriculture Monoculture Polyculture

Science Focus: Soil is the Base of Life on Land (1) Soil composed of Eroded rock Mineral nutrients Decaying organic matter Water Air Organisms

Science Focus: Soil is the Base of Life on Land (2) Soil is a key component of earth’s natural capital Soil profile O Horizon A horizon B horizon C horizon

Fig. 10-A, p. 211

How might the picture change if the tree were removed? Oak tree Fern Moss and lichen Organic debris Millipede Honey fungus Rock fragments Grasses and small shrubs Earthworm Wood sorrel O horizon Leaf litter A horizon Topsoil Mole Bacteria B horizon Subsoil Fungus Active Figure 10.A: Soil formation and generalized soil profile. Horizons, or layers, vary in number, composition, and thickness, depending on the type of soil. See an animation based on this figure at CengageNOW. Questions: What role do you think the tree in this figure plays in soil formation? How might the picture change if the tree were removed? C horizon Parent material Bedrock Mite Immature soil Young soil Mature soil Nematode Root system Red earth mite Beetle larva Fig. 10-A, p. 211

Green Revolution Three-step green revolution Selectively bred monocultures High yields through high inputs – fertilizer, pesticides, and water Multiple cropping Second green revolution – fast-growing dwarf varieties of wheat and rice 1950-1996 – world grain production tripled

Fig. 10-4, p. 212

Case Study: Industrialized Food Production in the U.S. Industrialized farming agribusiness Increasing number of giant multinational corporations ~10% U.S. income spent on food Subsidized through taxes

Case Study: Brazil – The World’s Emerging Food Superpower Ample sun, water, and arable land EMBRAPA – government agricultural research corporation 2-3 crops per year in tropical savanna Lack of transportation impeding further growth as food exporter

Production of New Crop Varieties Traditional Crossbreeding Artificial selection Slow process Genetic engineering >75% of U.S. supermarket food genetically engineered

Fig. 10-5, p. 214

Fig. 10-5, p. 214

Fig. 10-5, p. 214

Phase 1 Gene Transfer Preparations A. tumefaciens Plant cell Extract plasmid Extract DNA plasmid Foreign gene if interest Foreign gene integrated into plasmid DNA. Agrobacterium takes up plasmid Phase 2 Make Transgenic Cell Figure 10.5: Genetic engineering: steps in genetically modifying a plant. Question: How does this process change the nature of evolution by natural selection? A. tumefaciens (agrobacterium) Enzymes integrate plasmid into host cell DNA. Host cell Fig. 10-5, p. 214

Foreign DNA Host DNA Nucleus Transgenic plant cell Phase 3 Grow Genetically Engineered Plant Cell division of transgenic cells Cultured cells divide and grow into plantlets (otherwise teleological) Figure 10.5: Genetic engineering: steps in genetically modifying a plant. Question: How does this process change the nature of evolution by natural selection? Transgenic plants with desired trait Fig. 10-5, p. 214

Meat Production Meat and dairy products are good sources of protein Past ~60 years meat production up five-fold Half of meat from grazing livestock, other half from feedlots

Fish and Shellfish Production Have Increased Dramatically Aquaculture – 46% of fish/shellfish production in 2006 Ponds Underwater cages China produces 70% of world’s farmed fish

Fig. 10-6, p. 214

10-3 What Environmental Problems Arise from Food Production? Concept 10-3 Future food production may be limited by soil erosion and degradation, desertification, water and air pollution, climate change from greenhouse gas emissions, and loss of biodiversity.

Fig. 10-7, p. 215

Natural Capital Degradation Food Production Biodiversity Loss Soil Water Air Pollution Human Health Loss and degradation of grasslands, forests, and wetlands Erosion Water waste Greenhouse gas emissions (CO2) from fossil fuel use Nitrates in drinking water (blue baby) Loss of fertility Aquifer depletion Pesticide residues in drinking water, food, and air Fish kills from pesticide runoff Salinization Increased runoff, sediment pollution, and flooding from cleared land Greenhouse gas emissions (N2O) from use of inorganic fertilizers Waterlogging Killing wild predators to protect livestock Figure 10.7: Natural capital degradation: major harmful environmental effects of food production (Concept 10-3). According to a 2008 study by the U.N. Food and Agriculture Organization (FAO), more than 20% of the world’s cropland (65% in Africa) has been degraded to some degree by soil erosion, salt buildup, and chemical pollution. This threatens the food supply for about a quarter of the world’s population who are trying to eke out a living on such degraded land. Question: Which item in each of these categories do you believe is the most harmful? Contamination of drinking and swimming water from livestock wastes Desertification Pollution from pesticides and fertilizers Greenhouse gas emissions of methane (CH4) by cattle (mostly belching) Loss of genetic diversity of wild crop strains replaced by monoculture strains Algal blooms and fish kills in lakes and rivers caused by runoff of fertilizers and agricultural wastes Bacterial contamination of meat Other air pollutants from fossil fuel use and pesticide sprays Fig. 10-7, p. 215

Soil Erosion Flowing water Wind Soil fertility declines Water pollution occurs Some natural Much due to human activity

Fig. 10-8, p. 216

Fig. 10-9, p. 216

Figure 10. 9: Natural capital degradation: global soil erosion Figure 10.9: Natural capital degradation: global soil erosion. Question: Can you see any geographical pattern associated with this problem? (Data from U.N. Environment Programme and the World Resources Institute). Serious concern Some concern Stable or nonvegetative Stepped Art Fig. 10-9, p. 216

Drought and Human Activities Desertification Combination of prolonged draught and human activities 70% of world’s drylands used for agriculture Will be exacerbated by climate change

Fig. 10-10, p. 217

Effects of Irrigation Leaves behind salts in topsoil Salinization Affects 10% of global croplands Waterlogging Attempts to leach salts deeper but raises water table

Fig. 10-11, p. 217

Limits to Expanding Green Revolutions High-inputs too expensive for subsistence farmers Water not available for increasing population Irrigated land per capita dropping Significant expansion of cropland unlikely for economic and ecological reasons

Industrialized Food Production Requires Huge Energy Inputs Mostly nonrenewable oil Run machinery Irrigation Produce pesticides Process foods Transport foods In U.S., food travels an average of 1,300 miles from farm to plate

Controversies over Genetically Engineered Foods Potential long-term effects on humans Ecological effects Genes cross with wild plants Patents on GMF varieties

Fig. 10-12, p. 219

Trade-Offs Genetically Modified Crops and Foods Projected Advantages Disadvantages Need less fertilizer Irreversible and unpredictable genetic and ecological effects Need less water Harmful toxins in food from possible plant cell mutations More resistant to insects, disease, frost, and drought New allergens in food Grow faster Can grow in slightly salty soils Lower nutrition Figure 1012: Projected advantages and disadvantages of genetically modified crops and foods. Questions: Which two advantages and which two disadvantages do you think are the most important? Why? May need less pesticides Increase in pesticide-resistant insects, herbicide-resistant weeds, and plant diseases Tolerate higher levels of herbicides Can harm beneficial insects Higher yields Less spoilage Lower genetic diversity Fig. 10-12, p. 219

Food and Biofuel Production Lead to Major Losses of Biodiversity Forests cleared Grasslands plowed Loss of agrobiodiversity Since 1900, lost 75% of genetic diversity of crops Losing the genetic “library” of food diversity

Industrial Meat Production Consequences Uses large amounts of fossil fuels Wastes can pollute water Overgrazing Soil compaction Methane release: greenhouse gas

Aquaculture Problems Fish meal and fish oil as feed Depletes wild fish populations Inefficient Can concentrate toxins such as PCBs Produce large amounts of waste

Fig. 10-13, p. 220

Trade-Offs Aquaculture Advantages Disadvantages High efficiency Needs large inputs of land, feed, and water High yield in small volume of water Large waste output Can destroy mangrove forests and estuaries Can reduce overharvesting of fisheries Figure 10.13: Advantages and disadvantages of aquaculture. Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Uses grain, fish meal, and fish oil to feed some species Low fuel use Dense populations vulnerable to disease High profits Fig. 10-13, p. 220

10-4 How Can We Protect Crops from Pests More Sustainably? Concept 10-4 We can sharply cut pesticide use without decreasing crop yields by using a mix of cultivation techniques, biological pest controls, and small amounts of selected chemical pesticides as a last resort (integrated pest management).

Nature’s Pest Control Polycultures – pests controlled by natural enemies Monocultures and land clearing Loss of natural enemies Require pesticides

Fig. 10-14, p. 221

Increasing Pesticide Use Up 50-fold since 1950 Broad-spectrum agents Selective agents Persistence Biomagnification – some pesticides magnified in food chains and webs

Fig. 10-15, p. 222

Trade-Offs Conventional Chemical Pesticides Advantages Disadvantages Save lives Promote genetic resistance Increase food supplies Kill natural pest enemies Profitable Figure 10.15: Advantages and disadvantages of conventional chemical pesticides. Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Pollute the environment Work fast Can harm wildlife and people Safe if used properly Are expensive for farmers Fig. 10-15, p. 222

Advantages of Modern Pesticides Save human lives Increase food supplies Increase profits for farmers Work fast Low health risks when used properly Newer pesticides safer and more effective

Disadvantages of Modern Pesticides Pests become genetically resistant Some insecticides kill natural enemies May pollute environment Harmful to wildlife Threaten human health Use has not reduced U.S. crop losses

Laws Regulate Pesticides Environmental Protection Agency (EPA) United States Department of Agriculture (USDA) Food and Drug Administration (FDA) Congressional legislation Laws and agency actions criticized

Fig. 10-16, p. 224

Individuals Matter: Rachel Carson Biologist DDT effects on birds 1962: Silent Spring makes connection between pesticides and threats to species and ecosystems

Fig. 10-B, p. 223

Science Focus: Ecological Surprises Dieldrin killed malaria mosquitoes, but also other insects Poison moved up food chain Lizards and then cats died Rats flourished Operation Cat Drop Villagers roofs collapsed from caterpillars – natural insect predators eliminated

Alternatives to Pesticides Fool the pest Provide homes for pest enemies Implant genetic resistance Natural enemies Pheromones to trap pests or attract predators Hormones to disrupt life cycle

Fig. 10-18, p. 226

Integrated Pest Management Evaluate a crop and its pests as part of ecological system Design a program with: Cultivation techniques Biological controls Chemical tools and techniques Can reduce costs and pesticide use without lowering crop yields

10-5 How Can We Improve Food Security? Concept 10-5 We can improve food security by creating programs to reduce poverty and chronic malnutrition, relying more on locally grown food, and cutting waste.

Use Government Policies to Improve Food Production and Security Control food prices Helps consumers Hurts farmers Provide subsidies to farmers Price supports, tax breaks to encourage food production Can harm farmers in other countries who don’t get subsidies Some analysts call for ending all subsidies

Reducing Childhood Deaths $5–$10 annual per child would prevent half of nutrition-related deaths Strategies Immunization Breast-feeding Prevent dehydration from diarrhea Vitamin A Family planning Health education for women

10-6 How Can We Produce Food More Sustainably? Concept 10-6 More sustainable food production involves reducing overgrazing and overfishing, irrigating more efficiently, using integrated pest management, promoting agrobiodiversity, and providing government subsidies only for more sustainable agriculture, fishing, and aquaculture.

Reduce Soil Erosion (1) Terracing Contour plowing Strip cropping Alley cropping Windbreaks

Reduce Soil Erosion (2) Shelterbelts Conservation-tillage farming No-till farming Minimum-tillage farming Retire erosion hotspots

Fig. 10-19, p. 229

Fig. 10-19, p. 229

Fig. 10-19, p. 229

Fig. 10-19, p. 229

(a) Terracing (b) Contour planting and strip cropping (c) Alley cropping (d) Windbreaks Figure 10.19: Soil conservation methods include (a) terracing, (b) contour planting and strip cropping, (c) alley cropping, and (d) windbreaks (Concept 10-6). The problem is that modern industrialized farming operations make little use of these well-known and effective ways to conserve fertile topsoil. Stepped Art Fig. 10-19, p. 229

Government Intervention Governments influence food production Control prices Provide subsidies Let the marketplace decide Reduce hunger, malnutrition, and environmental degradation Slow population growth Sharply reduce poverty Develop sustainable low-input agriculture

Case Study: Soil Erosion in the United States Dust Bowl in the 1930s 1935 Soil Erosion Act Natural Resources Conservation Service Helps farmers and ranchers conserve soil One-third topsoil gone Much of the rest degraded Farmers paid to leave farmland fallow

Restoring Soil Fertility Organic fertilizers Animal manure Green manure Compost Crop rotation uses legumes to restore nutrients Inorganic fertilizers – pollution problems

Fig. 10-20, p. 230

Solutions Soil Salinization Prevention Cleanup Flush soil (expensive and wastes water) Reduce irrigation Stop growing crops for 2–5 years Figure 10.20: Methods for preventing and cleaning up soil salinization (Concept 10-6). Questions: Which two of these solutions do you think are the most important? Why? Switch to salt-tolerant crops (such as barley, cotton, and sugar beet) Install underground drainage systems (expensive) Fig. 10-20, p. 230

Fig. 10-21, p. 231

Sustainable Meat Production Shift to eating herbivorous fish or poultry Eat less meat Vegetarian

Fig. 10-22, p. 231

Beef cattle 7 Pigs 4 Chicken 2.2 Fish (catfish or carp) 2 Figure 10.22: Efficiency of converting grain into animal protein. (Data in kilograms of grain per kilogram of body weight added.) Question: If you eat meat, what changes could you make in your meat-eating habits to reduce your environmental impact? (Data from U.S. Department of Agriculture) Fish (catfish or carp) 2 Fig. 10-22, p. 231

Fig. 10-23, p. 232

Solutions Sustainable Organic Agriculture More Less High-yield polyculture Soil erosion Aquifer depletion Organic fertilizers Overgrazing Biological pest control Overfishing Integrated pest management Loss of biodiversity Efficient irrigation Food waste Perennial crops Figure 10.23: Major components of more sustainable, low-throughput agriculture based mostly on mimicking and working with nature (Concept 10-6). Questions: Which two solutions do you think are the most important? Why? Subsidies for unsustainable farming and fishing Crop rotation Water-efficient crops Soil salinization Soil conservation Subsidies for sustainable farming and fishing Population growth Poverty Fig. 10-23, p. 232

Shift to More Sustainable Agriculture Organic farming Perennial crops Polyculture Renewable energy, not fossil fuels

Six Strategies for Sustainable Agriculture Increase research on sustainable agriculture Set up demonstration projects International fund to help poor farmers Establish training programs Subsidies only for sustainable agriculture Education program for consumers

Fig. 10-24, p. 233

Solutions Organic Farming Improves soil fertility Reduces soil erosion Retains more water in soil during drought years Uses about 30% less energy per unit of yield Lowers CO2 emissions Reduces water pollution by recycling livestock wastes Figure 10.24: Environmental benefits of organic farming over conventional farming, based on 22 years of research comparing these two systems at the Rodale Institute in Kutztown, Pennsylvania (USA). (Data from Paul Mader, David Dubois, and David Pimentel) Eliminates pollution from pesticides Increases biodiversity above and below ground Benefits wildlife such as birds and bats Fig. 10-24, p. 233

Fig. 10-25, p. 234

Science Focus: The Land Institute and Perennial Culture Polycultures of perennial crops Live for years without replanting Better adapted to soil and climate conditions Less soil erosion and water pollution Increases sustainability

Fig. 10-B, p. 233

Three Big Ideas from This Chapter - #1 About 925 million people have health problems because they do not get enough to eat and 1.6 billion people face health problems from eating too much.

Three Big Ideas from This Chapter - #2 Modern industrialized agriculture ha a greater harmful impact on the environment than any other human activity.

Three Big Ideas from This Chapter - #3 More sustainable forms of food production will greatly reduce the harmful environmental impacts of current systems while increasing food security and national security for all countries.

Animation: Land Use PLAY ANIMATION

Animation: Soil Profile PLAY ANIMATION

Animation: Resources Depletion and Degradation PLAY ANIMATION

Animation: Acid Deposition PLAY ANIMATION

Animation: Transferring Genes into Plants PLAY ANIMATION

Animation: Effects of Deforestation PLAY ANIMATION

Animation: Ocean Provinces PLAY ANIMATION

Animation: Pesticide Examples PLAY ANIMATION

Video: The Problem with Pork PLAY VIDEO

Video: Food Allergy Increase PLAY VIDEO

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Video: Desertification in China PLAY VIDEO