4.3 Agriculture 11/24/2014. Learning Goals:

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1 4.3 Agriculture Learning Goals: 1. Describe environmental problems caused by agriculture. 2. Describe environmental problems caused by pesticides. 3. Describe environmental problems caused by meat production. A. Overview 1. Currently, there is more than enough food being produced to meet the basic nutritional needs of every person on earth. 2. However, the areas of food production are unevenly distributed amongst the population. 3. Wheat, rice, and corn are the three crops that humans most depend on. B. Feeding a growing population 1. Malnutrition - a lack of sufficient protein, carbohydrates, fats, vitamins, or minerals. 2. Undernutrition - associated with developing countries. 3. Overnutrition - leads to obesity; associated with developed countries. 4. Kwashiorkor - condition results from severe protein deficiency. Symptoms include a bloated, distended belly and puffy skin. 5. Anemia - caused by iron deficiency. 6. Goiter - caused by iodine deficiency, results in enlarged thyroid gland causing a swollen neck. 7. Vitamin a deficiency increases susceptibility to infections diseases and blindness 1

2 B. Types of Agriculture 1. Industrialized Agriculture - provides most of the worlds food by using heavy equipment along with huge quantities of fossil fuels, irrigation water, fertilizers, and pesticides. Monocultures. 2. Plantation Agriculture - common in developing countries to grow cash crops such as coffee, sugarcane, bananas, and cacao. Require large influx of fertilizers and pesticides. 3. Traditional or Subsidence Agriculture - practice of farming to provide for one family s food needs with enough remaining to sell or trade. Most sustainable. 4. Slash-and-Burn Agriculture - practice of cutting down and burning tropical forest to clear land for crops and livestock. C. The Green Revolution set of agricultural practices that dramatically increased crap yields after World War II. 1. Developed high-yielding monoculture crops 2. Increase the use of fertilizers, pesticides, and irrigation. D. Genetic Engineering 1. GMOs genetically modified organisms 2. Helped to develop crops that resist frost, repel pests, and fix nitrogen. 3. There is a concern that GMOs could have unforeseen effects on biodiversity, increase the pesticide resistance of species, lower the nutritional value of food, or create new food allergens. 2

3 II. Environmental Problems A. Soil Erosion: Although soil is a renewable resource, the rate of formation of new soil is slow. Most soils used for agriculture are not being used sustainably 1. Causes: a. Plowing and harvesting b. Excessive irrigation 2. Conservation Strategies: a. No-till agriculture farming without plowing the land b. Terracing converting hills to flat terraces c. Contour plowing plowing across the slope; reduces erosion d. Windbreaks rows of trees planted next to a field to reduce wind-borne erosion. II. Environmental Problems B. Deforestation: increases soil erosion by removing the root infrastructure that held soil into place. C. Fertilizer Runoff: leads to nutrient pollution, which results in cultural eutrophication and hypoxia in waterways. D. Desertification: occurs when lands near deserts are overgrazed; the removal of native vegetation causes the soil to dry out and become incorporated into the expanding desert. E. Soil Salinization: occurs in heavily irrigated lands in arid climates; dissolved salts accumulate in the soil and harms crops. F. Waterlogging: occurs when irrigation water accumulates and raises the water table; harms crops by submerging their roots. 3

4 III. Controlling Pests A. Pest any living thing that competes with humans for food. B. Pesticides chemicals used to kill or control pest populations. 1. Herbicides used to control weeds 2. Fungicides used to control fungus 3. Rodenticides used to control rodents 4. Insecticides used to control insects C. Broad Spectrum Pesticides kill many different species. 1. Problem when they kill good species like bees and spiders 2. Examples include chlorinated hydrocarbons (DDT and dieldrin) and organophosphates (malathion and parathion). D. Narrow Spectrum Pesticides only kill a target species. III. Controlling Pests E. The Pesticide Treadmill: farmers forced to use more increasingly toxic chemicals to control pests that develop pesticide resistance. F. Integrated Pest Management (IPM): goal is not to eradicate pests, but to reduce their numbers to economically tolerable levels. 1. Uses natural enemies of pests 2. Crop rotation 3. Pheromones and sterile males to interfere with reproduction 4. Limited use of narrow spectrum pesticides G. Circle of Poison: when banned pesticides are exported to other countries, the pesticides can return by wind or by imported foods. H. Rachel Carson: author of Silent Spring in 1962; raised public awareness about environmental consequences of DDT 4

5 IV. Animal Use in Agriculture A. Meat Production: increases the burden that agriculture placeson the environment 1. It takes 5-10 pounds of grain to produce one pound of meat 2. Factory Farms (Feedlots) large-scale meat production; environmental concerns include use of antibiotics and growth hormones, massive water consumption, pollution from animal wastes, and increased infectious diseases 3. Aquaculture: practice of farming aquatic organisms; environmental concerns include nutrient pollution from wastes, antibiotics, changes in genetic diversity, and degradation of aquatic ecosystems IV. Animal Use in Agriculture B. Fish Harvesting: overfishing has depleted many of the worlds most abundant fisheries. 1. Long-Lining: uses long fishing lines with thousands of baited hook. Leads to bycatch of sea turtles, dolphins, and seabirds 2. Purse Seine: net used to surround large schools of fish. Bycatch includes any fish in the area 3. Drift Netting: large net that can extend for 40 miles. Large numbers of by catch species. Now illegal in most of the world 4. Trawling: large nets are dragged across the ocean floor behind a boat. Leads to habitat construction of the seafloor C. Whaling: subsided since the 1970s and populations have begun to recover. Still practiced by Iceland, Japan, Norway and Russia 5

6 LEARNING GOAL: 1. Describe environmental problems caused by agriculture. I can propose ways to reduce the environmental problems caused by agriculture. I can describe environmental problems caused by agriculture. I can contrast the different methods of agriculture. I can identify the need for agriculture. LEARNING GOAL: 2. Describe environmental problems caused by pesticides. I can propose ways to reduce the environmental problems caused by pesticides. I can describe environmental problems caused by pesticides. I can contrast the different pesticides used. I can identify why pesticides are used. LEARNING GOAL: 3. Describe environmental problems caused by meat production. I can propose ways to reduce the environmental problems caused by meat production. I can describe environmental problems caused by meat production. I can contrast the different methods of fish harvesting. I can define factory farms and aquaculture. 6