Issues and Impacts of Agriculture Food Resources Issues and Impacts of Agriculture

Main Topics Methods of producing food Increasing food production Environmental effects of food production Issues of sustainability

Sources of food worldwide Of 30,000 edible plants, only 15 species. supply 90% of our food Primary plants: wheat, corn, and rice Provide > ½ calories people consume Primary animals: cattle, pigs, and chicken 2ndary: Eggs, milk & cheese

Major Types of Agriculture Traditional subsistence Shifting cultivation Nomadic herding Traditional intensive Plantation Industrialized

Industrialized agriculture Intensive traditional agriculture Land Industrialized agriculture in developed countries Labor Capital Fossil fuel energy Land Intensive traditional agriculture in developing countries Labor Capital Fossil fuel energy Fig. 12.3a, p. 264

Shifting cultivation in tropical forests in developing countries Land Labor Capital Nomadic herding in developing countries Land Labor Capital Fig. 12.3b, p. 264

World Food Production Plantation agriculture Industrialized agriculture Shifting cultivation Plantation agriculture Nomadic herding Intensive traditional agriculture No agriculture Fig. 12.2, p. 263

Total World Grain Production 2,000 1,500 1,000 500 Grain production (millions of tons) 1950 1960 1970 1980 1990 2000 2010 Fig. 12.8a, p. 268

Per Capita World Grain Production 400 350 Per capita grain production (kilograms per person) 300 250 200 150 1950 1960 1970 1980 1990 2000 2010 Fig. 12.8b, p. 268

Green Revolutions First green revolution (developed countries) Second green revolution (developing countries) Major International agricultural research centers and seed banks Fig. 12.4, p. 265

Producing Food by Green-Revolution Techniques 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

To increase rice yields: More, bigger grain per stalk (heavier head) More stalks per acre (higher density) More plantings per year Heavier heads required: more fertilizer, water, hybrids with shorter stalks (to prevent lodging) Higher density plantings required: more fertilizer, constant water, hybrids with smaller root system More plantings per year required: more fertilizer, year round water, pesticides More fertilizer, water, pesticides & hybrid seed required: more energy, esp. from fossil fuels more cash, especially US dollars

Results of Green Revolution: Mixed Higher yields per acre when inputs available Lower yields when inputs unavailable Increased dependence on cash economy Increased dependence on fossil fuel Increased imports of inputs Income disparity?? Migration to cities??

Unintended consequences: Killer Bees Mild-mannered, low honey producing Italian bee X Aggressive, high honey producing African bee? Hope for a mild-mannered, high producing bee Instead, got an aggressive, low producing bee Worse yet – it escaped, and is interbreeding with other bees making them aggressive & low producing too!

Environmental Effects of Food Production Biodiversity loss Soil degradation Air pollution Water pollution Human health

Biodiversity Loss Soil Loss and degradation of habitat from clearing grasslands and forests and draining wetland Invasive species out competing natives Killing of wild predators to protect livestock Loss of genetic diversity from replacing thousands of wild crop strains with a few monoculture strains Erosion Loss of fertility Salinization from irrigation Desertification Fig. 12.10a, p. 271

Greenhouse gas emissions from fossil fuel use Air & Climate Water Greenhouse gas emissions from fossil fuel use Other air pollutants from fossil fuel use Pesticide drift from spraying Dust / airborne particulates Weather alteration from large scale clearing Aquifer depletion Water diversions Increased runoff and flooding from land cleared to grow crops Sediment pollution from erosion Fish kills from pesticide runoff Surface and groundwater pollution from pesticides, fertilizers & livestock Overfertilization (eutrophication) of lakes and slow-moving rivers from runoff of nitrates and phosphates from fertilizers, livestock wastes, and food processing wastes Fig. 12.10b, p. 271

Nitrates in drinking water Pesticides residues in drinking water, Human Health Nitrates in drinking water Pesticides residues in drinking water, food, and air Contamination of drinking and swimming water with disease organisms from livestock wastes Bacterial contamination of meat Farm worker exposure & working conditions Fig. 12.10c, p. 271

Food Production since Green Rev Rapid increases in total production Prices decreasing Shortages in developing countries Approaching limits on meat production

Increasing World Crop Production Crossbreeding and artificial selection Genetically modified organisms (GMOs) Continued Green Revolution techniques Introducing new foods Working more land

Alternative Solutions: Sustainable Agriculture Low-input agriculture Organic farming See Fig. 12-21 p. 291 Non-meat alternatives Research in sustainable techniques

In Summary: Supplying food for the world’s growing population was and still is an issue. Policy and research play a big role. Efforts to increase production have focused on: Improved varieties thru breeding and genetic engineering Inputs, esp. chemicals, energy and water Agriculture has multiple impacts on the environment and human health Sustainable agricultural techniques are growing but far behind conventional