Chapter 11Feeding the World

Global Undernutrition

Nutritional Requirements

Overnutrition

too many calories and improper foods

that causes a person to become overweight.

Undernutrition

not consuming enough calories to be

healthy.

Malnourished

a persons diet lacks the correct balance

of proteins, carbohydrates, vitamins, and minerals even

though they get enough calories.Global Nutrition Imbalance

Related terms:• Food Insecurity• Famine• Anemia

A Balanced Dietvs. malnutrition

Nutrient FunctionMajor Food Sources

Carbohydrates

Supplies Energy Bread, Cereals, Potatoes, Beans

Proteins Used to build and maintain the body

Meat, Fish, Poultry, Eggs, Dairy, Beans

Lipids (fats and solids)

Used to build membranes and some hormones. May help store energy.

Butter, Vegetable Oils, Animal Fats

Annual Meat ConsumptionInterpreting Graphs:

How does the United States compare to the rest of the world in terms of meat consumption?

What are some issues regarding agriculture (or environmental effects) of eating more or less meat?

Global Grain Production, 1950-2006

Interpreting Graphs:

Why does lower graph (b) appear to remain level while the upper graph (a) is increasing?

What do you think are primary sources/examples of grain from various parts of the world?• Asia• Africa• Central America• North America

Economy – Poverty vs. Wealthy

Society – influenced by media

Political factors (war, genocide, etc.)

Reasons for Undernutrition and Malnutrition

Agricultural resources being diverted to feed livestock and ethanol (fuel) rather than people

Since the Industrial Revolution in the 1800’s, agriculture became more “industrialized”, burning fossil fuels to replace human & animal labor.

Between the 1950’s - 1970’s: new management techniques and mechanization as well as the triad of fertilization, irrigation, and improved crop varieties increased food production dramatically.

The Green Revolution

Pros The introduction of new

grains and new farming techniques allowed for a much greater “yield”.

Cons New varieties require

more fertilizer, pesticides, and water.

Farming Challenges

Soil Conservati

on

ErosionDesertificationSalinization

Irrigation

Pest Contr

ol

BiologicalGenetic

Chemical

Fertilizer

Climate

Seasonal ChangesAir PollutionFloods/Drought

Industrial vs

Sustainable

 Some people speak of agriculture collectively as “the single most harmful human action that has taken place.”

- Friedland p.287 

Soil Conservation

Issues: Arable Land (suitable for

farming) decreased 1/5 from 1985 to 2000.

Over ½ of the fertile “TopSoil” has been lost in the U.S. just in the past 200 years due to erosion: the wearing away of topsoil by wind and water.

Desertification: areas with this topsoil are easily destroyed, and the land becomes desert-like.

Salinization: accumulation of salts in soil – often from irrigation.

Solutions:

Contour plowing: following the terrain

No-till farming: leaving the remain of previous crops to decompose and retain soil.

Low-input farming: using as little fertilizer, pesticide, energy and water as possible.

Composting!

o Waterlogging- when the soil remains under water for prolonged periods which impairs root growth because the roots cannot get oxygen.

o Salinization- when the small amounts of salts in irrigation water become highly concentrated on the soil surface through evaporation.

o DROUGHT!

Irrigation Problems

Desertification- When soil is degraded by agriculture to the point at which they are not longer productive.

Desertification

Organic fertilizers- organic matter from plants and animals. Typically made from animal manure that has been allowed to decompose.

Inorganic fertilizers (synthetic)- fertilizers that are produced commercially. This is usually done by combusting natural gas, which allows nitrogen from the atmosphere to be fixed and captured in fertilizer.

Fertilizers

Growing a large amount of a single species of plant. Advantages:

allows large expanses of land to be planted, and then harvested, all at the same time.

Monocropping

Disadvantages: • When monocropped fields are

readied for planting or harvesting all at once, soil will be exposed over many hectares at the same time.

• Some farmland in the United States loses an average of 1 metric ton of topsoil per hectare/year to wind erosion.

• Pests easily invade monocrops and reproduce rapidly.

• Monocropping removes habitat for predators that might otherwise control the pest population.

Pesticide- a substance that kills or controls organisms that people consider pests. Related to: Insecticide- target insects Herbicides- target plants

Pesticides

Selective – pesticides designed to kill a narrower range of organisms.

Broad-spectrum - pesticides designed to kill many

different types of pests.

Persistent - pesticides that do not break down and thus remain in the environment,

accumulating in water and soil.

Non-persistent - pesticides that breaks down relatively rapidly, usually in weeks to months.

vs.

vs.

Bioaccumulation- some pesticides build up over time in the fatty tissues of predators.

An example was DDT. When an organism

containing the pesticide is eaten, the chemical is transferred to the consumer.

This eventually leads to very high pesticide concentrations at high trophic levels.

Pesticides

Resistance - pest populations may evolve resistance to a pesticide over time.

Pesticide treadmill - the cycle of pesticide development followed by pest resistance, requiring development of a new pesticide.

Pesticides

Agricultural Effects on the Climate

From Farming in general…… CO2 releases linked to deforestation

Methane releases from rice farming Methane releases from fermenting cattle feces Nitrous oxide releases from fertilizer application

From livestock…… 9% of global Carbon dioxide emissions 35–40% of global methane emissions (chiefly due to manure/fecal

fermentation)

64% of global nitrous oxide emissions (chiefly due to fertilizer use)

GMOsGenetically Modified Organisms

Greater yield

More profit

Increase nutrition

Pest resistance

Herbicide tolerance

Disease resistance

Cold tolerance

Drought tolerance

Salinity tolerance

Pharmaceuticals

Environmental hazards Harm to other organisms Reduced effectiveness of

pesticides Gene transfer to non-target species

Human health risks Unlabeled / Unregulated

Allergens, Carcinogens (cause cancer)

Unwanted Steroids & Hormones Antibiotics lose effectiveness

http://www.csa.com/discoveryguides/gmfood/overview.php

PROs CONs

Traditional farming - still used in the developing world where human labor is used and not machinery.

Nomadic grazing - moving herds of animals to find productive feeding grounds.

Conventional agriculture - “industrial agriculture” where labor is reduced and machinery is used.

Shifting agriculture - used in areas with nutrient poor soils. It involves planting an area for a few years until the land is depleted of nutrients and then moving to another area and repeating the process.

Farming Methods

CAFOs (concentrated animal feeding operations) - large structures or lots where animals are being raised in high density numbers.

High-Density Animal Farming

• High-density animal farming is used for beef cattle, dairy cows, hogs, and poultry, all of which are confined or allowed very little room for movement.

• Animals are given antibiotics to reduce the risk of adverse health effects and diseases which would normally be high in such highly concentrated animal populations.

o contributing to an increase in antibiotic-resistant strains of microorganisms that can affect humans.

Fishery - a commercially harvestable population of fish within a particular ecological region.

Bycatch - unintentional catch of non-target species.

Fishery collapse - the decline of a fish population by 90% or more.

Harvesting of Fish and Shellfish

Aquaculture- the farming of aquatic organisms such as fish, shellfish, and seaweeds.

Aquaculture

PRO:can alleviate some of the human-caused pressure on overexploited fisheries while providing much-needed protein for the more than 1 billion under-nourished people in the world.

CON:environmental problems:• wastewater containing

feces, uneaten food, and antibiotics is pumped back into the river or ocean

• may contain bacteria, viruses, and pests that thrive in the high-density habitat

• fish that escape from aquaculture facilities spread diseases and parasites in surrounding waters.

Sustainable agriculture- producing enough food to feed the world’s population without destroying the land, polluting the environment, or reducing biodiversity.

Sustainable Agriculture

• Intercropping- two or more crop species are planted in the same field at the same time.

• Crop rotation- rotating crops species from season to season.

• Agroforestry- intercropping trees with vegetables.

• Contour plowing- plowing and harvesting parallel to the land to prevent erosion.

• No-till agriculture- not tilling the land after each harvest helps to stop soil degradation by leaving crop residues in the fields.

Integrated pest management- using a variety of techniques designed to minimize pesticide inputs. Techniques:

Crop rotation Intercropping Planting pest resistant crop

varieties Creating habitats for

predators Limited use of pesticides

Integrated Pest Management (IPM)

Organic agriculture- production of crops without the use of synthetic pesticides or fertilizers.

Organic agriculture follows several basic principles:

Organic Agriculture

• Use ecological principles and work with natural systems rather than dominating them.

• Keep as much organic matter and as many nutrients in the soil and on the farm as possible.

• Avoid the use of synthetic fertilizers and pesticides.

• Maintain the soil by increasing soil mass, biological activity, and beneficial chemical properties.

• Reduce the adverse environmental effects of agriculture.