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 starvation

Somalia (1993)- drought caused political unrest killing 2 million

UN intervention to stop warring factions from stealing relief food sent

North 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.

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: 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 Revolution

Problems: 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

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!!

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

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/SHELLFISH

TRAWL BAGSCod, Flounder,

Snapper, Scallops, Shrimp

BOTTOM FISH/SHELLFISHDRIFT NET

Salmon, 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.

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….