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APES Ch 13

APES Ch 13. Food, Soil Conservation and Pest Management. Food Security and Nutrition. 1 in 6 people in developing countries does not get enough food (most likely due to poverty) Food security :

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APES Ch 13

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  1. APES Ch 13 Food, Soil Conservation and Pest Management

  2. Food Security and Nutrition • 1 in 6 people in developing countries does not get enough food (most likely due to poverty) • Food security: • Most developing nations can not provide food security to all their people b/c they cant produce enough food or they can’t afford to import. • Also depends on reducing harmful environmental effects of agriculture (erosion, aquifer depletion).

  3. Food Security and Nutrition • Chronic hunger: • Malnutrition: • UN Food and Agriculture Organization (FAO) goal is to reduce the # of hungry and malnourished to 400 million by 2015 (as of 2005 there were 852 million) • FAO estimated that 6 million children died each year due to lack of essential food.

  4. Food Security and Nutrition • Famine: • Can lead to mass migrations • Usually caused by crop failure due to drought, flood, war or other catastrophic events. • Overnutrition: • Can cause some of the same problems as under-nutrition (lower life expectancy, diseases, lower life quality)

  5. Food Production • 3 systems that supply most food: • Croplands – 77% • Rangelands – 16% • Oceanic fisheries and aquaculture – 7% • All 3 systems have increased since 1960 due to better technology and other advances (fertilizers, pesticides, irrigation). • May not be able to produce enough food by 2050 for the possible 8.5 billion people. • Environmental degradation, pollution, lack of water, overgrazing, overfishing, rising temps., increasing fuel costs

  6. Food Production • Only 14 plants and 9 terrestrial animal species supply an estimated 90% of worlds food. • 3 types of grain (wheat, rice and corn) provide more than 50% • Many people can’t afford meats, milk and cheese products. • Fish and shellfish make up only 7%

  7. Food Production • Industrialized agriculture (high input): • 80% of worlds food supply is produced this way • Plantation agriculture: • Cash crops (bananas, soybeans, sugarcane, cocoa, peanuts and coffee • Must clear tropical rain forests to plant • Livestock • Most are in feedlots • Use lots of energy and water and produces lots of animal waste and water pollution

  8. Natural Capital Croplands Ecological Services Economic Services • Help maintain water flow and soil infiltration • Food crops • Provide partial erosion protection • Fiber crops • Can build soil organic matter • Crop genetic resources • Store atmospheric carbon • Jobs • Provide wildlife habitat for some species Fig. 13-6, p. 276

  9. Food Production • Traditional agriculture (low input) • Traditional subsistence agriculture: • Traditional intensive agriculture: • Interplanting: • Reduces chance of losing all of the years food supply • Polyvarietal cultivation: • Intercropping: • Agroforestry (alley cropping): • Polyculture: • Keeps soil covered, less fertilizer and water use, less pesticides.

  10. Soil Erosion and Degradation • Topsoil: • Naturally renewable but very slow (several 100 yrs to make 1 inch) • Soil erosion: • Increases when vegetation is removed • Sheet erosion: • Rill erosion: • Gully erosion: • Major effects of erosion • Loss of soil fertility • Water pollution due to sedimentation runoff

  11. Soil Erosion and Degradation Causes Consequences Overgrazing Worsening drought Deforestation Famine Erosion Economic losses Salinization Lower living standards Soil compaction Natural climate change Environmental refugees • Desertification: • 1/3 of the worlds land and 70% of all dryland are suffering from desertification. Fig. 13-12, p. 280

  12. Transpiration Evaporation Evaporation Evaporation Waterlogging Less permeable clay layer Salinization: Waterlogging: 1. Irrigation water contains small amounts of dissolved salts 1. Precipitation and irrigation water percolate downward. 2. Evaporation and transpiration leave salts behind. 2. Water table rises. 3. Salt builds up in soil. Fig. 13-13, p. 281

  13. Solutions Soil Salinization Prevention Cleanup Reduce irrigation Flush soil (expensive and wastes water) Stop growing crops for 2–5 years Switch to salt-tolerant crops (such as barley, cotton, sugarbeet) Install underground drainage systems (expensive) Fig. 13-15, p. 281

  14. Sustainable Agriculture Through Soil Conservation • Soil conservation: • Eliminating plowing and breaking up and tilling is key to reduce soil erosion. • Conservation-tillage farming: • Terracing: • Contour farming: • Strip cropping: • Wind breaks: • Use cover crops

  15. Sustainable Agriculture Through Soil Conservation • Organic fertilizer: • Animal manure: • Green manure: • Compost: • Commercial inorganic fertilizer: • Contain nitrogen, phosphorus, and potassium • Crop rotation: • Also helps reduce erosion

  16. The Green Revolution and its Environmental Impact • Green Revolution: • Plant monoculture plants • Use large amounts of fertilizer, pesticides and water for higher yield • Increase the # of crops grown per on plot of land through multiple cropping • 1st Green Revolution took place between 1950-1970 in developed countries • 2nd Green Revolution has been taking place since 1967 in developing countries mostly in tropical areas.

  17. The Green Revolution and its Environmental Impact • Pros • Has produced more food for growing population • Many countries are now self sufficient with food • Use less land for larger yield • Cons • More fertilizer, pesticides and water • To expensive for subsistence farmers • If expanded- not enough workers (more people moving to cities for jobs) • More irrigation which can lead to more salinization

  18. The Green Revolution and its Environmental Impact • More land can be planted with crops but significant expansion of cropland is unlikely over the next few decades for economic and ecological reasons • Loss of agrobiodiversity – the worlds genetic variety of animals and plants used to provide food • Ex: India use to plant 30,000 different types of rice, now only 10 types are used.

  19. The Green Revolution and its Environmental Impact • Modern agriculture violates the 4 Principles of Sustainability • Depends heavily on nonrenewable fossil fuels • Too little recycling of crop and animal wastes • Accelerates soil erosion • Does not preserve agrobiodiveristy • Disrupts natural species interactions that help control population sizes and pests.

  20. Biodiversity Loss Soil Air Pollution Human Health Water Loss and degradation of grasslands, forests, and wetlands Erosion Water waste Nitrates in drinking water Greenhouse gas emissions from fossil fuel use Aquifer depletion Loss of fertility Pesticide residues in drinking water, food, and air Salinization Increased runoff and flooding from cleared land Other air pollutants from fossil fuel use Waterlogging Desertification Fish kills from pesticide runoff Sediment pollution from erosion Contamination of drinking and swimming water with disease organisms from livestock wastes Greenhouse gas emissions of nitrous oxide from use of inorganic fertilizers Fish kills from pesticide runoff Killing wild predators to protect livestock Surface and groundwater pollution from pesticides and fertilizers Belching of the greenhouse gas methane by cattle Loss of genetic diversity of wild crop strains replaced by monoculture strains Bacterial contamination of meat Overfertilization of lakes and rivers from runoff of fertilizers, livestock wastes, and food processing wastes Pollution from pesticide sprays Fig. 13-18, p. 285

  21. The Gene Revolution • For years the use of crossbreeding through artificial selection to develop genetically improved varieties of crop strains has been used. • Now genetic engineering is being used (takes a gene of 1 species and inserts it into the DNA of another species) • Takes ½ the time and cost less then crossbreeding • Ex: potatoes resist disease because they contain a certain chicken gene.

  22. The Gene Revolution • Nontraditional foods could help provide essential nutrients and lower the need for some crops. • Winged bean has many edible parts and requires little fertilize. • Quinoa plant is called the worlds most nutritious plant and can resist frost and droughts and can grow in saline soils. • Insects are a great source of protein and are easy to “farm”

  23. Trade-Offs Genetically Modified Crops and Foods Projected Advantages Projected 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 Lower nutrition Can grow in slightly salty soils Increased development of pesticide-resistant insects and plant diseases Less spoilage Better flavor Can create herbicide-resistant weeds Need less pesticides Tolerate higher levels of herbicides Can harm beneficial insects Higher yields Lower genetic diversity Fig. 13-19, p. 287

  24. Producing More Meat • Between 1950-2005 meat production increased more then 5 fold and is likely to double again by 2050 as more people become affluent. • 2 systems for raising livestock • Graze on grass • Feedlots- raise in densely packed areas by feeding them grain and/or fish meal. • Animals given antibiotics and steroids • Accounts for 43% of worlds beef, 50% of pork and 68% of eggs, and 75% of poultry production. • Solutions: people can eat more poultry and fish rather then beef, establish more humane ways to raise livestock in feedlots.

  25. Trade-Offs Animal Feedlots Advantages Disadvantages Increased meat production Need large inputs of grain, fish meal, water, and fossil fuels Higher profits Concentrate animal wastes that can pollute water Less land use Reduced overgrazing Reduced soil erosion Antibiotics can increase genetic resistance to microbes in humans Help protect biodiversity Fig. 13-21, p. 289

  26. Producing More Meat • Catching and raising more fish and shellfish. • Fisheries: • 3rd major food producing system. • 2/3 comes from oceans, lakes, rivers and ponds • 1/3 comes from aquaculture • Scientists project a decline in global fish catch due to overfishing, coastal water pollution and wetland destruction

  27. Producing More Meat • 125 out of 128 depleted fish stocks could recover with careful management. • Ecolabels help shoppers identify wild fish that have been caught by more sustainable fishing practices. • Walmart said that within 5 yrs it would sell only fish certified by the Marine Stewardship Council) • Govt's subsides given to the fishing industry are a major cause of overfishing. • Subsides $ should be used to buy out some fishing boats and retrain their crew for other occupations

  28. Producing More Meat • Aquaculture: • Fishing farms: • Fishing ranches: • Mainly carp in China and India, catfish in US, tilapia and shellfish in other countries

  29. 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 Destroys mangrove forests and estuaries Can reduce overharvesting of conventional fisheries Uses grain to feed some species Low fuel use Dense populations vulnerable to disease High profits Tanks too contaminated to use after about 5 years Profits not tied to price of oil Fig. 13-24, p. 292

  30. Solutions More Sustainable Aquaculture • Use less fishmeal feed to reduce depletion of other fish • Improve management of aquaculture wastes • Reduce escape of aquaculture species into the wild • Restrict location of fish farms to reduce loss of mangrove forests and estuaries • Farm some aquaculture species in deeply submerged cages to protect them from wave action and predators and allow dilution of wastes into the ocean • Certify sustainable forms of aquaculture Fig. 13-25, p. 293

  31. Solutions: Moving Toward Global Food Security • People in urban areas could save money by growing more of their own food. • We can waste less food (70% of food is wasted through spoilage, inefficient processing and plate waste). • US households throw away food worth as much as $43 million/yr – twice the $24 million it would take to eliminate global hunger

  32. We can increase global food security by – Slow pop growth Reduce poverty Reduce soil erosion Halt desertification Eliminate overgrazing Slow removal of groundwater Protect cropland from development Reduce rate of global warming Solutions: Moving Toward Global Food Security

  33. Protecting Food Resources: Pest Control • Pest: • Only 100 species cause 90% of the damage to crops • In nature natural enemies control 98% of the potential pests species • Pesticides:

  34. Protecting Food Resources: Pest Control • 2 generations of pest control • 1st generation (copy nature): before 1930s many pesticides were derived from organisms (mostly plants). They were natural defenses. • 2nd generation: the development of pesticides in labs. Started in 1939 when DDT was discovered. Some lab made pesticides last in environment for years and can biologically magnified in food chains. • ¾ of pesticides is used for crops, ¼ is used for homes, gardens, and golf courses. • Federal Insecticide, Fungicide, Rotenticide Act (FIFRA) is suppose to assess the health risks of the active ingredients in pesticide products.

  35. Solutions More Sustainable Aquaculture • Use less fishmeal feed to reduce depletion of other fish • Improve management of aquaculture wastes • Reduce escape of aquaculture species into the wild • Restrict location of fish farms to reduce loss of mangrove forests and estuaries • Farm some aquaculture species in deeply submerged cages to protect them from wave action and predators and allow dilution of wastes into the ocean • Certify sustainable forms of aquaculture Fig. 13-25, p. 293

  36. Protecting Food Resources: Pest Control • Other ways to control pests: • Fool pest • Provide homes for pest enemies • Implant genetic resistance • Bring in natural enemies • Use insect perfumes • Bring in hormones • Scald pests

  37. Solutions Sustainable Organic Agriculture More Less High-yield polyculture Soil erosion Soil salinization Organic fertilizers Aquifer depletion Biological pest control Overgrazing Overfishing Integrated pest management Loss of biodiversity Efficient irrigation Loss of prime cropland Perennial crops Food waste Crop rotation Subsidies for unsustainable farming and fishing Water-efficient crops Soil conservation Population growth Subsidies for sustainable farming and fishing Poverty Fig. 13-33, p. 302

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