Miller Chapter 12A. Vitamin A deficiency in some developing countries leads to Blindness Death ...
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Transcript of Miller Chapter 12A. Vitamin A deficiency in some developing countries leads to Blindness Death ...
Miller Chapter 12A
Vitamin A deficiency in some developing countries leads to Blindness Death
1999: Porrykus and Beyer Genetically engineered rice with beta-
carotene and more iron
Many of the poor suffer health problems from chronic lack of food and poor nutrition, while many people in developed countries have health problems from eating too much food.
The greatest obstacles to providing enough food for everyone are poverty, political upheaval, corruption, war, and the harmful environmental effects of food production.
Food security : daily access to enough nuritious food
Food insecurity : live with chronic hunger snd poor nutrition 1 in 6 in developing countries Root cause: poverty
Macronutrients Carbohydrates Proteins Fats
Micronutrients Vitamins Minerals
Chronic under nutrition, hunger , mental retardation, stunted growth
Chronic malnutrition: low protein, high-carbohydrate weak, more susceptible to disease, hinders
development
Vitamin and mineral deficiencies in people in developing countries : Iron, Vitamin A, Iodine
Goiter in Bangladesh
Famine : severe shortage of food Usually caused by
crop failures from Drought Flooding War Mass migration
of starving people to other areas
War and the Environment: Starving Children in Famine-Stricken Sudan, Africa
Overnutrition : when food energy intake exceeds energy use and causes excess body fat
Similar health problems to those who are underfed Lower life expectancy Greater susceptibility to disease and illness Lower productivity and life quality
Three systems produce most of our food Croplands: grains 77% use 11% of land area Rangelands, pastures, and feedlots:
16% ,using 29% of the world’s land area Aquaculture: 7%
Importance of wheat, rice, and corn: provide about 47% of the calories , 42% of
the protein Tremendous increase in global food
production technological advancement , machinery
Industrialized agriculture, high-input agriculture uses heavy equipment and large amounts of
financial capital, fossil fuels, water,fertilizer Goal is to steadily increase crop yield Plantation agriculture: developing countries cash crops – bananas, soybeans,
sugarcane,coffee, vegetables on monocultures
Increased use of greenhouses to raise crops
Traditional subsistence agriculture : human labor and draft animals, enough food to feed family only
Traditional intensive agriculture : human and draft animals, fertilizer, water, enough to feed family, sell some for income
Polyculture : several crops on the same plot, crop diversity Benefits over monoculture Slash-and-burn agriculture- clearing in tropical
forests growing a variety of cash crops – 20 types
mature at different times ,keeps soil covered
Soil composition: complex mixture of eroded rock, mineral nutrients, decaying organic matter, water, air and billions of living organisms
Soil formation :bedrock subject to mechanical and chemical weathering and biological processes to form soil
Layers (horizons) of mature soils O horizon: leaf litter A horizon: topsoil , humus B horizon: subsoil, inorganic matter,
(sand,silt,clay,gravel) C horizon: parent material, often bedrock
Soil erosion : water and wind
Green Revolution: increase crop yields(since 1988) Monocultures of high-yield key crops
E.g., rice, wheat, and corn Use large amounts of fertilizers, pesticides, and water Multiple cropping
Second Green Revolution -1967. FAst growing dwarf varieties of rice and wheat . India , China, Central and South America
World grain has tripled in production
Agribusiness : giant multinational increasingly control the growing
Annual sales : more than automative , steel, housing combined .1/5 of the country’s GDP
Food production: very efficient
Percent of income spent on food : 2% of income
Gene Revolution Cross-breeding
through artificial selection
Slow process – 15 years or more to produce a crop
Resulting varieties remain useful for only 5-10 years.
Genetic engineering Genetic modified
organisms (GMOs): transgenic organisms
Age of Genetic Engineering: developing crops that are resistant to Heat and cold Herbicides Insect pests Parasites Viral diseases Drought Salty or acidic soil
Advanced tissue culture techniques
Animals for meat raised in Pastures Densely Packed Feedlots Confined animal feeding
operations
Meat production increased fourfold between 1961 and 2007
Demand is expected to go higher as countries become more industrialized and incomes increase
Aquaculture, blue revolution World’s fastest-
growing type of food production
Raising marine and freshwater species in ponds and underwater cages
Dominated by operations that raise herbivorous species –carp,catfish,tilapia
Integrate crop growing and aquaculture by using rice straw, pig and duck manure to fertilize farm ponds and rice paddies in order to produce phytoplankton eaten by various species of carp
Food production in the future may be limited by its serious environmental impacts, including soil erosion and degradation, desertification, water and air pollution, greenhouse gas emissions, and degradation and destruction of biodiversity.
Fig. 12-9, p. 286
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
SalinizationIncreased runoff, sediment pollution, and flooding from cleared land
Greenhouse gas emissions (N2O) from use of inorganic fertilizersWaterlogging
Killing wild predators to protect livestock
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
Environmental Impacts of food production
Soil erosion : movement of soil components Natural causes-wind, water Human causes-
Two major harmful effects of soil erosion Loss of soil
fertility:depletion of plant nutrients in topsoil
Water pollution in surface waters, sediment, residues of fertilizers and pesticides
Fig. 12-11, p. 287
Stepped Art
Stable or nonvegetative
Serious concern
Some concern
Global Soil Erosion
Desertification Moderate: 10-25% dropSevere : 25-50% drop
Very severe ; more than 50% - gullies, dunes
Effect of global warming on desertification increase drought in arid areasdrop in food production,
Sahel region in W Africa
Irrigation problems Salinization: accumulation of salts -Asia Waterlogging : water accumulates
underground and raises the water table
Expansion of the green revolution requires huge inputs of fertilizer, pesticide, water,
otherwise yields not much more than traditional crops
costs too much for subsistence farmers Depletion of water, soil salinization, climate
changeSolutions Irrigating more cropland? 80% increase by 2050 Cultivating more land? mostly marginal land. Using GMOs? increase yield /acre Multicropping
Industrialized food production and consumption have a large net energy loss
Industrialized Agriculture uses ~17% of All Commercial Energy Used in the U.S.
Fig. 12-16, p. 291
Projected Advantages
Projected DisadvantagesIrreversible and unpredictable genetic and ecological effects
Need less fertilizer
Need less water
More resistant to insects, disease, frost, and drought
Harmful toxins in food from possible plant cell mutations
Grow faster New allergens in foodCan grow in slightly salty soils
Lower nutrition
Increase in pesticide- resistant insects, herbicide- resistant weeds, and plant diseases
May need less pesticides
Tolerate higher levels of herbicides
Higher yieldsCan harm beneficial insects
Less spoilage Lower genetic diversity
GENETICALLY MODIFIED FOODS
Biodiversity threatened when Forest and grasslands are replaced with
croplands tropical forests and cerrado (savanna) in Brazil
Agrobiodiversity threatened when Human-engineered monocultures are used Replacing nature’s resilient genetic diversity India – 30,000 varieties of rice, now only 10
Importance of seed banks Newest: underground vault in the Norwegian
Arctic
Fig. 12-18, p. 293
Aquaculture
Advantages Disadvantages
Needs large inputs of land, feed, and water
High efficiency
High yield in small volume of water
Large waste output
Can destroy mangrove forests and estuaries
Can reduce overharvesting of fisheries
Uses grain to feed some speciesLow fuel use
High profitsDense populations vulnerable to disease
Producing Fish through Aquaculture Can Harm Aquatic Ecosystems
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).
What is a pest – interferes with human welfare
Natural enemies—predators, parasites, disease organisms—control pests In natural ecosystems In many polyculture agroecosystems
Pesticides Insecticides – insects killers Herbicides – weed killers Fungicides – fungus killers Rodenticides – rat and mouse killers
Herbivores overcome plant defenses through natural selection: coevolution
First-generation pesticides-natural chemicals from plants
Second-generation pesticides Paul Muller: DDT Nobel Prize 1948 Benefits versus harm
Broad-spectrum agents – toxic to many pests and non-pest species. Chlorinated hydrocarbons: DDT, organophosphates : malathion, parathion
Selective or narrow spectrum agents - Persistence – length of time they remain
deadly in the environment for years, biologically magnified in food webs
Biologist : DDT use was increasing to control mosquitoes
Silent Spring - 1962 Potential threats of
uncontrolled use of pesticides
Gave impetus to the US environmental movement
Save human lives prevented deaths from malaria, typhus and bubonic plague : at least 7 million people
Increases food supplies and profits for farmers protect 55% of the world’s food supply. Profit $1:$4
Work quickly, long shelf life, easily shipped and applied
Health risks are very low relative to their benefits
New pest control methods: safer and more effective
Accelerate the development of genetic resistance, 5 to 10 years, sooner in
the tropics
Financial treadmill
Kill natural predators and parasites that help control
Only 0.1-2% of the pesticide applied by aerial or ground spraying reaches
the target pest. Rest pollutes air, water, harm wild life, affect human
health
Expensive for farmers
Some insecticides kill natural predators and parasites that help control the
pest population
Pollution in the environment
Some harm wildlife
Some are human health hazards
David Pimentel: Pesticide use has not reduced U.S. crop loss to pests Loss of crops is about 31%, even with 33-
fold increase in pesticide use High environmental, health, and social
costs with use, $5-10 in damages for every $1 spent
Use alternative pest management practices could halve the use of chemical pesticides on 40 major US crops
Pesticide industry refutes these findings Campbell soup tomatoes in Mexico, Rice in
Indonesia, Sweden
Best-selling herbicide (Roundup), Monsanto
Advantages – does not harm living things, degrades into harmless substances within weeks
Disadvantages - resistant weeds , expensive to develop other pesticides
1955: Dieldrin sprayed to control mosquitoes
Malaria was controlled
Dieldrin didn’t leave the food chain
Domino effect of the spraying
Happy ending
U.S. federal agencies EPA USDA FDA
Effects of active and inactive pesticide ingredients are poorly documented
Circle of poison, boomerang effect – residues of banned chemicals exported to other countries may come back on food, winds carry persistent pesticides such as DDT
1998 – 50 countries developed treaty that requires exporting countries to have consent from importing countries for exports of 22 pesticides , 5 industrial chemicals
2000 – 100 countries signed to phase out 12 of the most hazardous persistent organic pollutants (POP’s), 9 of them hydrocarbons (DDT)
United States has not signed this agreement
Fool the pest : rotate crops, adjust plant times
Provide homes for pest enemies
Implant genetic resistance : GMO’s
Bring in natural enemies : natural predators
Use insect perfumes
Hormones Scald them
Integrated pest management (IPM) Coordinate:
cultivation, biological controls, and chemical tools to reduce crop damage to an economically tolerable level
Disadvantages expert knowledge
Control prices – keep artificially low Provide subsidies – price supports, tax
breaks, subsidies for 31% of global farm income Developed : $280 billion /year Substitute traditional subsidies with ones
that promote sustainable farming practices Subsidies to fishing – promotes destructive
fishing practices Let the marketplace decide
United Nations Children’s Fund (UNICEF) suggests these measures. Can be done at an average annual cost of $5-10 / child Immunizing children against childhood
diseases Encourage breast-feeding Prevent dehydration in infants and children Prevent blindness – Vitamin A capsule
(75c/child) Provide family planning services Increase education for women
Sustainable food production will require reducing topsoil erosion, eliminating overgrazing and overfishing, irrigating more efficiently, using integrated pest management, promoting agrobiodiversity, and providing government subsidies for more sustainable farming, fishing, and aquaculture.
Producing enough food to feed the rapidly growing human population will require growing crops in a mix of monocultures and poly cultures and decreasing the enormous environmental impacts of industrialized food production.
Soil conservation, some methods Terracing Contour
planting Strip cropping
with cover crop Alley
cropping, agroforestry
Windbreaks or shelterbeds
Conservation-tillage farming
No-till Minimum
tillage
Identify erosion hotspots
Poor cultivation and prolonged drought
Plowing prairie dug up root system
Severe wind erosion
Largest internal migration from the Midwest
Soil Erosion Act 1935
Organic fertilizer Animal manure – dung , urine Green manure – freshly cut, growing green
vegetation Compost microorganisms to break down organic
waste Commercial inorganic fertilizer active ingredients
Nitrogen Phosphorous Potassium
Crop Rotation
Soil salinization Prevention Clean-up
Desertification, reduce Population growth Overgrazing Deforestation Destructive forms
of planting, irrigation, and mining
Reduce irrigation
Switch to salt-tolerant crops (such as barley, cotton, and sugar beet
Flush soil (expensive and wastes water
Stop growing crops for 2–5 years
Install underground drainage systems (expensive)
Open-ocean aquaculture – US developing, raising large carnivorous fish in underwater pens
located 300 Km offshore. Fish fattened with fish meal
Raising shrimp far inland in zero-discharge freshwater ponds to minimize damage to Florida coastal areas: salmon, trout, tuna, grouper, cod
Choose herbivorous fish – carp, tilapia Polyaquaculture : raise fish, shrimp, algae, seaweeds
and shellfish coastal lagoons
Shift to more grain-efficient forms of protein
Shift to farmed herbivorous fish Develop meat substitutes; eat less meat Whole Food Markets: more humane
treatment of animals World Organization for Animal Health –
humane transportation and slaughter of livestock animals
People food habits changing – eating lower down on the food chain
Paul Mader and David Dubois 22-year study Compared organic and conventional farming
Benefits of organic farming little or no use of synthetic pesticides,
fertilizers or genetically engineered seeds, fields free for 3 years
livestock raised without genetic engineering
Strategies for more sustainable agriculture Research on organic agriculture with
human nutrition in mind Show farmers how organic agricultural
systems work Subsidies and foreign aid Training programs; college curricula
Fig. 12-32, p. 308
SOLUTIONS
Organic Farming
Improves soil fertilityReduces soil erosionRetains more water in soil during drought years
Uses about 30% less energy per unit of yield
Lowers CO2 emissionsReduces water pollution by recycling livestock wastes
Eliminates pollution from pesticidesIncreases biodiversity above and below ground
Benefits wildlife such as birds and bats
Effect of different fertilizers on nitrate leaching in apple trees calcium nitrate and alfalfa residues,
composted chicken manure, integrated approach (combined)
Less nitrate leached into the soil after organic fertilizers were used – 4.4 to 5.6 times less
Polycultures of perennial crops
Wes Jackson: natural systems agriculture benefits No need to plow soil and replant each year Reduces soil erosion and water pollution Deeper roots – less irrigation needed Less fertilizer and pesticides needed
Annual Wheat Crop
Plant
Roots of a tall grass prairie
plant
Better at using water and nutrients
Supports local economies Does not have to be transported far –
reduces greenhouse gas emissions, 5 to 17 times less
Reduces environmental impact on food production – grow organic food or buy organic food grown locally
Community-supported agriculture (CSA)
Modern industrial agriculture ……………. depends on nonrenewable fossil fuels too little recycling of crop and animal wastes accelerates soil erosion does not preserve agro biodiversity destroy or degrade wildlife habitat disrupt natural species interactions that help
to control pest population sizes
rely more on solar energy than oil sustaining nutrient cycling by soil
conservation and by returning crop residues and animal wastes to the soil
sustain natural /agricultural biodiversity by relying on a greater variety of crop and animal strains
controlling pest populations broader use of polyculture and IPM