Term
| •World food supplies have____with human population growth |
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Definition
kept up
````– 1950 (2.5 billion people) - average daily diet was less than 2,000 calories/person
– 2001 (~6.0 billion people) - world food supply provided more than 2,500 calories/person |
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Term
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Definition
• Most common dietary problem in wealthy countries is over nutrition
– In NA and Europe, average daily caloric intake is 3,500 calories
• Sub-Saharan Africa has not kept food production up with pop. growth
– 35 of 40 countries
– Drought, war, POVERTY, and poor management
• Collapse of Soviet Union also led to significant collapse in food production |
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Term
| Chronic Hunger & Food Security |
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Definition
• 1 in 5 people in developing countries are chronically hungry
– 200 million children
– Leads to permanently stunted growth, mental retardation, and other disorders
– Minor health problems can become very serious when nutrition level is low |
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Term
| •Adequate diet satisfies three needs |
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Definition
–Fuel (chemical energy)
–Organic raw materials
• Used in biosynthesis (i.e., C skeletons to make own molecules)
–Essential nutrients
• Cannot make for itself
• Must obtain from food |
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Term
| •Given proper sources we can synthesize |
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Definition
– Carbohydrates
– Proteins
– Lipids |
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Term
| • Excess food permits allocation to |
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Definition
– Grow
– Reproduction
– Storage in energy depots |
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Term
| • Role of liver and muscle glycogen |
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Definition
– Liver and muscle cells store glucose as glycogen
– Excess glycogen is converted to fat |
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Term
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Definition
• If fewer calories are taken in than expended, fuel is removed from storage and oxidized (broken down)
– Liver glycogen first
– Muscle glycogen second
– Fat third
• Can subsist several weeks on fat
– Only 0.3 kg of fat per day
• Proteins are next; muscles decrease in size, brain becomes protein-deficient
– Death can results if seriously undernourished
– Even if one survives, damage may be irreversible |
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Term
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Definition
missing essential nutrients
– Remember essential AA
– We need more than just calories
• Ex. Giraffe eat bones
• Malnutrition is more common than undernourishment
– Possible for over-nourished individual to be malnourished
• Animal products, such as meat, eggs, and cheese, are “complete”
• Incomplete
– Corn (lysine)
– Vegetarian diet (beans give what corn don’t have)
• Must be eaten each day
– Cannot easily store |
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Term
| Other Essentials: Vitamins |
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Definition
• 13 essential
• Water vs. fat-soluble
– Water – co-enz
– excreted
– Lipid – variety of func.
• D: form bone
• K: clot (blood)
• A: essential for good vision
– Store don’t excrete |
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Term
| Other Essentials Continued… |
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Definition
• Minerals
– Inorganic
– Calcium and phosphorus; bone
– Sodium, potassium, and chloride
• H2O balance
• Blood pressure |
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Term
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Definition
• Starchy foods (corn and rice) don’t have enough
• Folic acid is essential for fetal development
– Microencephaly
– Anencephaly
• Whole grain breads
• Fortified cereals
• Dried peas and bean
• Leafy vegetables
• Fruit |
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Term
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Definition
Iron deficiency is most common dietary imbalance in world
– Leads to anemia
• Increases risk of death from hemorrhage in childbirth
• Affects developement
• Red meat, eggs, legumes, and green vegetables are all good sources of iron |
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Term
children who lack high quality protein
–Reddish-orange hair, bloated stomach |
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Definition
| •Rwashiorker - “Displaced Child” |
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Term
Diet low in both protein and calories
–Very thin, shriveled |
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Definition
| •Maramus - “To Waste Away |
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Term
| •3 crops deliver majority of world’s nutrients: |
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Definition
–Wheat, rice and corn
• Meat and milk distribution highly inequitable
– Developed countries make up 20% of world population, but consume 80% of meat and milk
• 60% of production occurs in lesser developed countries |
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Term
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Definition
• Every 16kg of grain and soybeans fed to cattle produces only 1kg of edible beef
– If eat grain directly, obtain more calories and protein than get from eating beef
– Use of hogs and chickens (2 & 4x) |
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Term
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Definition
• Seafood is an important protein source
• Since 1989, 13/17 major fisheries have declined or become commercially unproductive
– Due in part to technology
• Between 1970-1990, number and average vessel size of world fishing fleet doubled
– Nets are huge and destructive (jumbo jets)
– Have twice the capacity needed to extract total annual sustainable harvest
• Catching $70 billion cost $124 billion
– 1/4 animals are considered trash |
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Term
| SOIL: A RENEWABLE RESOURCE |
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Definition
• Complex mixture of weathered minerals, partially decomposed materials, and a host of living organisms
• At least 20,000 different soil types in US
– Vary due to influences of: parent material, climate, and organisms
• Can be replenished and renewed |
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Term
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Definition
• Particle size affects soil characteristics
– Spaces between sand particles give sandy soil good drainage and allows aeration
• Can easily dry out
– Tight packing of small particles in silty or clay soils makes them less permeable to air and water |
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Term
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Definition
• Soils exhibit wide ranges of organic content
– Humus – Insoluble residue from partially decomposed plants and animals
• Most significant factor in soil structure
• Again, activity of organisms living in soil help create structure and fertility, |
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Term
WAYS WE USE AND ABUSE SOILS
• Approximately 38% of earth’s land area is currently in agricultural production
– Additional land suffers from constraints: |
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Definition
• Slope ,
• Shallow soil,
• Poor drainage,
• Low nutrients,
• Poor pH... |
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Term
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Definition
• Important NATURAL process; results in redistribution of geologic weathering
– Is part of both soil formation and soil loss
– Tends to begin subtly
• Worldwide, erosion reduces crop production by 1% per year
• Typically, we make up for this by adding fertilizers |
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Term
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Definition
• Rill Erosion - running water gathers and cuts small channels in soil
• Gully Erosion - Rills enlarge forming bigger channels
– Too large to removed by normal tillage
• Stream Bank Erosion – washing of soil from established banks
– riparian and buffer strips
– Stupid cows! |
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Term
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Definition
• Wind and intensive farming can equal water as an erosive forces; especially in a _____ climate and on flat land
– Leave soil exposed
• Row crops
• Weed-free fields
– Removal of removal
– No crop-rotation or resting periods
• Continued monocultures
• Next slide….. |
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Term
OTHER AGRICULTURAL RESOURCES
• Water |
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Definition
– Agriculture accounts for largest share of global water use
– 80% of water withdrawn for irrigation never reaches intended destination
• Colorado river rarely reaches the gulf!
• Cheap cost encourages over-use
– Water-logging
– Salinization |
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Term
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Definition
• Lack of N, P, and K limits plant growth
– Adding nutrients via fertilizer stimulates growth and crop yields
• 1950 - 20 kg/ha fertilizer
• 1990 - 91 kg/ha
– Causes eutrophication
• Discussed later…
– Manure and nitrogen-fixing bacteria are alternative methods of replenishing soil nutrients
• _Legumes |
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Term
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Definition
• Farming is extremely energy-intensive
– Between 1920-1980, energy use rose with:
• Mechanization of agriculture
• Indirectly with spraying of chemicals
– US food system consumes 16% of total energy
• More energy to prodiuce process, and transport than we yield
• Average food product travels 1250 m |
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Term
| NEW CROPS AND GENETIC ENGINEERING |
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Definition
• Most of worlds food comes from 16 widely grown crops
– Only ~3,000 plants have been used on large scale (Monoculture)
• Possible 80,000
– Many new or unconventional varieties might be valuable food supplies
• Winged-bean
• Triscale
• Rise of dwarf varieties |
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Term
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Definition
• Green Revolution - New technologies and varieties around world
– Improvements from technological advances and modification (Next slide…)
• Corn yields from 25 bushels/acre to 130/acre in last century
• High Respondents vs. traditional varieties
– Same yield different requirements |
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Term
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Definition
Soil Conservation
• Managing Topography
– Contour Plowing - Plowing across slope to slow flow of water
– Strip Farming - Planting different crops in alternating strips along land contours
– Terracing - Shaping land to create level shelves of earth to hold water and soil |
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Term
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Definition
• Providing Ground Cover
– Row crops cause high rate of erosion because leaves soil bare for much of year
• Leave crop residue after harvest
– Increase soil moisture and replenish soil
– However, can increase disease and pests
• Plant cover crop after harvest |
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