chapter 18
DESCRIPTION
CHAPTER 18. FOOD RESOURCES: A CHALLENGE FOR AGRICULTURE. NUTRITIONAL REQUIREMENTS Men: ~2,500 kcal/day Women: ~2,000 kcal/day. Interesting Facts… 100 species of plants are commercially grown to meet nutritional needs - PowerPoint PPT PresentationTRANSCRIPT
FOOD RESOURCES: A
CHALLENGE FOR AGRICULTURE
CHAPTER 18
NUTRITIONAL REQUIREMENTS Men: ~2,500 kcal/day Women: ~2,000
kcal/day
Carbohydrates Metabolized readily Creates energy 4 cal/g Should be 60% of diet
Proteins Release amino acids Some are enzymes Creates 4 cal/g Should be 30% of diet
LipidsDeliver more energy than carbs or proteinsCreates 9 cal/gShould be 10% of diet
Mineralso Iron, iodine, calcium
Interesting Facts…
100 species of plants are commercially grown to meet nutritional needs16 lbs of grain to produce 1 lb of edible
meat (90% of US grain is grown for animal feed)20x increase in the amount of calories
available & 8 fold increase in amount of protein available if we consumed grain directly
Malnutrition86 countries are considered food-deficient
Can’t produce enough food or afford to import food to feed pop.
Undernourished: Consume less than the daily required calories for an extended
period Health and stamina decline sometimes death. 1/3 of all children under 5 in developing countries (WHO)
Malnourished: Receive enough calories, but do not receive enough specific,
essential nutrients such as protein, vitamin A, iodine etc. Rice: enough cal, but lack needed protein, lipids & minerals Susceptible to disease & have less strength- kids do not dev. well
Affects cognitive development- kids do worse in school 3 Billion people worldwide are malnourished (WHO)
Overnourished: People that eat in excess- diet high in saturated fat, sugar &
salt Diabetes & heart disease prevalent as well as cancers WHO estimates 55% of developed pop is over-nourished.
Common diseases of malnutrition
Marasmus: progressive emaciation caused by a diet low in total calories & protein
Common in children of poor families in developing countries/or POWs
Slow growth & muscle atrophy
Kwashiorkor: malnutrition resulting from protein deficiency.
Common among childrenEdema (fluid retention & swelling),
stunted growth, sometimes mental retardationTypical feature: pronounced swelling
of the abdomen
Producing enough foodOur yield has increased, but so has our population….
washoutGlobal food production can be increased in the short
term, but the long term solution to food supply problems is to control population
FaminesCrop failures caused by drought, war, flood or
catastrophic event may result in a severe food shortage.
Worst Famine was in 1983-1985 in Africa (Ethiopia & Sudan)
1.5 million people died of starvationSomalia (1993)- drought caused political unrest killing
2 million UN intervention to stop warring factions from stealing relief
food sentNorth Korea- late 1990’s killed over 2 million
Several years of floods & drought wiping out farming
World Grain Carryover Stocks: the amounts of rice, wheat, corn and other grains remaining from previous harvests as estimated at the start of a new harvest.
Think of it like a bank account… A measure of world food security where all people have
access at all times to adequate amounts and kinds of food needed
Poverty & Food: Providing enough food for all people is complicated by poverty, problems of distribution, and cultural acceptance of nutritious but unfamiliar foods.
Food producing nations cannot simply give food away indefinitely.
The cost of food for one week
Compare # of family members
Cost of food for 1 weekAmount of food for 1 weekTypes of food for 1 week
Germany : The Melander family of Bargteheide
Food expenditure for one week: $500.39
United States : The Revis family of NC
Food expenditure for one week: $341.98 US
Japan : The Ukita family of Kodaira City
Food expenditure for one week: $317.25 US
Italy : The Manzo family of SicilyFood expenditure for one week:
$260.11 US
Mexico: The Casales family of Cuernavaca
Food expenditure for one week: $189.09 US
Poland : The Sobczynscy family of Konstancin-Jeziorna
Food expenditure for one week: $151.27 US
Egypt : The Ahmed family of Cairo
Food expenditure for one week: $68.53 US
Ecuador : The Ayme family of Tingo
Food expenditure for one week: $31.55 US
Bhutan : The Namgay family of Shingkhey Village
Food expenditure for one week: $5.03 US
Chad : The Aboubakar family of Breidjing Camp
Food expenditure for one week: $1.23 US
Principle Types of Agriculture
Industrialized (High-Input Agriculture) Large inputs of capital and energy (fossil fuels) to produce
and run machinery, irrigate crops and produce agrochemicals
Produces high yields enabling forests and natural areas to remain wild
Problems: soil degradation, increase in pesticide resistance
Subsistence Agriculture Production of enough food to feed oneself and family with
little left over to sell or reserve. Requires a lot of human & animal energy Many types (next slide)
Agroforestry
Harvestable trees or shrubs are grown among or around crops or on pasture land as a means of preserving or enhancing the productivity of the land
Alley Cropping
Planting crops in strips with rows of trees or shrubs on each side. Increases biodiversity, reduces runoff & erosion, reduces wind erosion, improves habitat
Crop Rotation
Planting a field with different crops from year to year to reduce soil nutrient depletion.
Industrial Farming
Characterized by mechanization, monocultures and the use of synthetic inputs (fertilizers & pesticides) with an emphasis on maximizing productivity & profitability
Lo & No-till farming
Soil is disturbed little or not at all. Lower labor cost, reduces the need for energy and fertilizer.
PlantationCultivation of economically desirable species of tropical plants at the expense of widespread replacement of natural/native flora. Essentially export orientated
Poly-Varietal
Planting a plot of land with several varieties of the SAME crop.
TillageSurface is plowed exposing the soil. Followed by planting. Lots of water/wind erosion.
Types of Subsistence Agriculture
Shifting CultivationShort periods of
cultivationare followed by periods offallow in which land
revertsto forest.1. Slash-and-Burn: clear
small parts of forest to plant crops. Must move to another area ~ 3 yrs.(land intensive)
2. Nomadic: Livestock is supported by land that is too arid for successful crop growth
Intercropping (aka Strip-Cropping)Involves growing a varietyof plants simultaneously
on the same field. Produce higher yields (pest control).
Native Americans used this method very successfully.
1.Polyculture: several kinds of plants that mature at different times are planted together.
Genetic Diversity
When plants and animals are domesticated, much of the genetic diversity found in the wild pop. is lost Agriculture protects domesticated plants & animals from pests and
disease Globally, a few agricultural varieties are replacing the hundreds of
varieties developed by farmer-breeders over centuries SEED BANKS!!
Genetic Engineered Crops (GMO): moving genes from one species to another with desirable characteristics PROS: Require less water/fertilizer, higher yields, less spoilage,
faster growth, resistant to disease/drought/ insects CONS: unknown ecological effects, less biodiversity, harm
beneficial insects, mutations with unknown consequences, pesticide resistance.
Increasing Crop Yields: GREEN REVOLUTION
Production of more food per acre of cropland by using modern cultivation methods and using the new, high yielding varieties of certain staple crops. Began in the 1950’s (post-WWII) METHODS: Planting monocultures, high application of
inorganic fertilizers and pesticides as well as extensive irrigation systems
Gave Latin American & Asian countries the chance to produce adequate supplies of food.
Increased yield 200% with only a 25% land usage increase Second Green Revolution (1970’s) continues today with
the use of genetically engineered crops that produce more yield per acre.
Problems with the Green RevolutionProblems:
Made developing countries dependent on imported technology (rather than traditional methods)
Environmental problems such as intensive use of inorganic fertilizers & pesticides Require a large amount of energy to produce Building of dams for irrigation Fossil fuels to produce/run farm equipment
Benefited large land owners but not subsistence farmers Dependence on small number of genetic varieties
Ex) US Wheat: 50% comes from 9 varieties
LIVESTOCK & the Green Revolution: Use of hormones & antibiotics are used to increase yield Unknown human effects- EU currently bans all imports of
hormone-treated beef because of health concerns.
Environmental Impact of Agriculture
1. Agricultural use of fossil fuels & pesticides Air poll.2. Untreated waste & chemicals (fert. & pest.) Water poll.
Reduce biological diversity, harm fisheries, inc. nuisance species Single largest cause of surface water pollution in the US!
3. Agribusiness: livestock are concentrated in small areas Air & water pollution- quantity of manure is a severe waste prob. Ex) Hurricane Fran & hog lagoons: 22 large lagoons spilled into the
floodplain and streams causing major fish kills.
4. Pesticide resistance- forces farmers to use more 5. Degradation of the future land ability to produce crops.
Soil erosion (1/5 of US farm land is vulnerable to soil erosion)
6. Habitat Fragmentation decrease biological diversity!
Solutions to Agricultural Problems #1
1. Sustainable Agriculture Cause fewer environmental problems Relies on benefical biological processes & env.
friendly chem. Farm diversification (crops, animals, fruit, nuts) Water & energy conservation /use pred.-prey to
control pests. Planting crops appropriate for the area (native) Organic agriculture- use of NO pesticides; use IPM
Solutions to Agricultural Problems #2
2. Genetic Engineering Taking one specific gene from a cell of one kind of
organism and place it into a cell of an unrelated organism .
May produce food plants that are more nutritious, resistant to insect pests and viral diseases or are tolerant to drought, heat, cold herbicides or salty soil.
Can use ANY organism- not traditional breeding GM crops were cultivated on 75M acres in 2000 Concern that the inserted genes could spread to weeds
or wild relatives of crop plants and harm natural ecosystems.
Genetic Engineering
GM
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90% of the world’s total marine catch is FISH6% clam, oyster, squid, octopus, & other mollusks
3% lobster, shrimp, crab1% is algae or seaweed
Fish & other seafood are highly nutritious because they contain high-quality protein.
About 80% of the global ocean pollution comes from human activities on land.
Is this a problem???
Fisheries of the World
Types of Fishing
No nation lays claim to the ocean, so resources are more susceptible to overuse ~ TRAGEDY of COMMONS
According to the FAO, 62% of the world’s fish stocks are in urgent need of management action. Growing human population requiring protein Technological advances….. Fish don’t have a chance!
Sonar, Radar, Computers, Airplanes, Satellites Long lines- lines with thousands of hooks. Can be 128 mi long. Purse-seine: 2000m long used to encircle fish and trap them Trawl net: funnel shaped net pulled along the bottom. As much
as 27 metric tons can be caught at once. Destroy habitat! Drift net: plastic nets up to 64 km that entangles thousands of
fish and other marine organisms. Banned by most countries.
Modern Commercial
Fishing Methods
Methods have become so
successful that many fish species are commercially
extinct.
Organisms are accidentally
caught and killed in addition to the target species.
LONG LINESurface: Sharks,
TunaDeep: Cod, HalibutPURSE SEINES
Anchovies, Herring, Mackerel, Tuna SURFACE FISH
TRAWL BAGSCod, Flounder,
Snapper, Scallops, Shrimp
BOTTOM FISH/SHELLFISHDRIFT NETSalmon, TunaOPEN WATERS
BAD!!
Fishing Problems
Bycatch: dead or dying organisms that are unintentionally caught & discarded. ~25% of the total catch
Open Enclosure Policy: organisms within 200 mi of land are under the jurisdiction of the country bordering the ocean. In response to overharvesting.
Magnuson Fishery Conservation Act Magnuson Fishery Conservation Act (1977):
Established 8 regional fishery mgmt. councils
that developed quotas. Revised in 1996 (Magnuson-Stevens) to
protect essential fish habitat for more than 600 fish species, reduce overfishing, rebuild populations & minimize bycatch.
Sustainable McDonalds!
AQUACULTURE The rearing of aquatic organisms
Fastest growing type of food production- 1 out of 3 fish destined for humans comes from fish farms. 6% of all US fish- all striped bass & rainbow trout as well
as > ½ the salmon served.To optimize quality of their “crops”, farmers
control the diets, breeding cycles & env. conditions of ponds.
Try to reduce pollution & keep predators away.Important crops include: seaweeds, oysters,
mussels, clams, lobsters & crabs.Developing nations produce more fish by
aquaculture than dev. nations.
If coastlines are not used for habitat, other competing uses will take over such as development
Produces wastes that pollute adjacent water Causes a net loss of wild fish because many farmed
fish are carnivorous. Expensive to set up and run Not profitable for all organisms. Population must be constantly monitored for diseases. Receptivity of animals to domestication
ex: lack of territorialism
AQUACULTURE PROBLEMS
GROWING BUSINESS….
Solutions to Agricultural Problems
Using your knowledge of environmental science from the whole
year, what do YOUYOU think are some solutions?
1. WRITE THEM DOWN2. Discuss with a partner
3. Class Discussion5 minutes MAXIMUM!!