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Feeding the World Chapter 11
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Human Nutrition ~24,000 starve each day; 8.8 million each year
~1 billion lack access to adequate food supply Population keeps growing requires more land to be used for agriculture, eat less meat, and harvest more fish Due to decrease in government assistance for agricultural development in much of developing world Increase in fuel prices
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Nutritional Requirements
Undernutrition a. not consuming enough calories b. 100 to 400 less kilocalories a day c. susceptible to disease, less energy, improper brain development * Avg diet should consist of ~2,200 kilocalories a day
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Malnourished a. diet lacks correct balance of protein, carbohydrates, vitamins and minerals b. doesn’t matter how many calories consumed c. ~3 billion according to WHO
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Famine a. deaths occur due to extreme food insecurity b. crop failures, drought, etc
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Results of malnourishment a. blindness – Vitamin A deficiency
b. anemia – iron deficiency * most widespread nutritional deficiency * malaria, AIDS, parasite infections Anemia can be reduced by consuming iron rich foods such as grains, herbs, vegetables, and meats
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* Type II diabetes, hypertension, heart disease, stroke
Overnutrition a. too many calories b. obesity * > 20% ideal weight * Type II diabetes, hypertension, heart disease, stroke c. due to availability/affordability of certain foods About 1 billion people are overnourished 300 million are obese
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Variety of foods available a. grains (corn, rice, wheat) – 300kg
b. meat (livestock and poultry) – 40kg c. fish – 21kg Corn, rice, and wheat make up 60% of human diet Availability depends on income
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Reasons for undernutrition and
malnourishment a. #1 – poverty b. rise in food prices c. large amounts of crops are grown to feed livestock and poultry rather than people * corn and soybeans
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d. grain production. depends on 1. amount of land used 2
d. grain production * depends on 1. amount of land used 2. global weather and precipitation 3. price of grain 4. productivity of land
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Industrial Agriculture
Farming more mechanized Increase use of fossil fuels Green Revolution a. small farms/human labor industrial operations/machinery b. fertilization, irrigation, mechanization, pesticides, monocropping c. increased food production significantly * Abundance of food supplied by agriculture had led to exponential growth of human population (positive feedback loop)
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Green Revolution Mechanization Irrigation a. benefits
- efficient use of H20 b. consequences - waterlogging - salinization - depletion of groundwater - saltwater intrusion Mechanization Machines don’t necessarily do the work better than humans, but it is more time efficient Irrigation Increases crop growth rates where they were not able to grow Waterlogging – soil remains under water for too long and impairs root growth allowing them to not get enough oxygen Salinization – increased concentrations of salt in soil due to small amounts of salt in irrigation water. Happens through evaporation leaving the salt behind and causes toxic levels in soil impede plant growth
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- decomposed animal manure c. synthetic - produced commercially
Fertilizers a. N, P, and K b. organic - decomposed animal manure c. synthetic - produced commercially - advantages * easy application, targeted nutrient content, easily absorbed - disadvantages * fossil fuel energy required, run-off, don’t add organic matter to soil Agriculture removes organic matter and nutrients from the soil and fertilizers replace tem Synthetic a. nitrogen fertilizers are composed by combusing nitrogen gas; highly concentrated b. run-off can create algae blooms c.
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a. dominant agricultural practice in US (wheat and cotton) b. benefits
Monocropping a. dominant agricultural practice in US (wheat and cotton) b. benefits 1. increased efficiency and productivity c. drawbacks 1. soil erosion 2. vulnerability to pests Encouraged by use of synthetic fertilizers Plantings of single species or variety of species Allows large expanses of land to be planted as well as harvested all at the same time Soil erosion: since it’s harvested all at once, the soil is exposed over large amounts of land at once. With just soil being exposed, wind can carry it off easily removing the top soil which contains all of the important nutrients
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b. insecticides, herbicides c. broad spectrum v. selective
Pesticides a. kill or control pests b. insecticides, herbicides c. broad spectrum v. selective d. persistant v. non-persistant - DDT - bioaccumulation - Roundup e. can kill other species in addition to the targeted pests f. pesticide treadmill Great because they prevent crop damage and allow for greater crop yields Broad spectrum – kill many different types of pests Selective – only for a targeted pest Persistant – remain in the environment for a long time (DDT) DDT builds up in the fatty tissues of organisms and accumulates as it’s moved through the trophic levels meaning that it is at a very toxic level the higher it is in the trophic levels Non-persistant – breaks down pretty quickly but must be applied more often Pests can evolve a resistance to pesticides over time leaving the farmers to use higher doses or new pesticides and then the pests eventually evolve resistance to that and it starts all over (pesticide treadmill)
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Genetic Engineering Higher crop yields Better food quality
Reductions in pesticide use Higher profits Lower costs Farmers create strains of organisms that are resistant to certain pests or harsh conditions in order to get a higher crop yield A crop has been created that has the “roundup ready” gene in it so that it is resistant to roundup. Therefore it can continue to grow while the weeds are being controlled Concerns - some are worried about the consumption of GMOs by humans but there are still no proven incidents of this
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Alternatives to Industrial Farming
Industrial agriculture = conventional agriculture Traditional farming a. shifting agriculture b. nomadic grazing c. intercropping d. agroforestry Industrial agrictulture: successful in reducing labor inputs Traditional farming is very successful when the cost of labor is not the most important concern. Very common where labor is less expensive than machinery and fossil fuels
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b. moderately warm climate and nutrient-poor soils
Shifting Agriculture a. “slash and burn” b. moderately warm climate and nutrient-poor soils c. large amounts of nutrients found in vegetation d. desertification Clears the land, uses it for a few years until the soil is depleted of nutrients Slash and burn - existing vegetation is cut down, put in piles, burned - ash leftover provides nutrients making the soil more fertile Desertification - irrigation causing salinization and erosion of topsoil in semiarid dry/nutrient poor soil locations
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a. move herds of animals to seasonally productive feeding grounds
Nomadic Grazing a. move herds of animals to seasonally productive feeding grounds Sustainable Agriculture a. fulfills need for food b. enhances quality of soil c. less use of nonrenewable resources d. emphasizes conservation and soil improvement Only sustainable way for people to use soil types with very low productivity Sustainable agriculture - requires more labor but ensures improved long-term productivity of the land - use animal wastes as fertilizers
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e. intercropping 1. 2 or more crop species planted in same field at same time f. agroforestry 1. intercropping trees with vegetables 2. reduces soil erosion * Tress are allowed to act as wind breakers
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a. avoid soil degradation b. leaves roots intact in soil
No-till Agriculture a. avoid soil degradation b. leaves roots intact in soil c. reduces emissions of CO2 d. negative - increases use of herbicides Organic agriculture a. production of crops without the use of synthetic fertilizers/pesticides Conventional agriculture relies on plowing and tilling, turning the soil upside down; in turn makes soil more susceptible to erosion Leaves crop residues in the field between seasons Reduces CO2 emissions because the organic matter deep within the soil is less exposed to oxygen therefore it will undergo less oxidation
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Integrated Pest Management
a. techniques designed to minimize pesticide inputs b. crop rotation, intercropping, pest-resistant crops, limited use of pesticides
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Farming of Meat and fish
High – Density Animal Farming a. CAFOs (concentrated animal feeding operations) b. “feedlots” c. used for beef cattle, dairy cows, hogs, and poultry d. minimizes land costs while improving feeding efficiency e. animals given antibiotics and nutrients f. serious waste disposal problem CAFOS Large indoor/outdoor structures designed for maximum output Very little room for movement
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Free-Range Chicken and Beef a. graze on land
b. little to no supplemental feeding c. little to no use of antibiotics d. uses more land e. higher costs of meat
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a. fishery – commercially harvestable population of fish
Harvesting Fish a. fishery – commercially harvestable population of fish b. caught through a variety of techniques c. can unintentionally catch nontargeted fish declining their population (some are keystone species) d. aquaculture - farming of aquatic organisms - catfish and trout in US In Asia and Africa, fish makes up the majority of the animal protein in their diet Most are caught by nets pulled behind ships, long fishing lines with multiple baited hooks, drag nets (can harm the bottom of the ocean floor) Aquaculture - designed due to high demand for fish - constructs an aquatic ecosystem by stocking the organisms, feeding them and protecting them from disease and predators - done within enclosures - has potential to boost the economies for developing countries - negative * clean water is pumped in at one end but the wastes are released back into the water at the other end
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