Chapter 11Feeding the World

Food Production• Major food sources: croplands, rangelands, and oceans

• Large increase in food production since 1950

• Need for environmental-friendly food production

• Impact of genetic engineering

• Primary crops: wheat, corn, and rice

• Primary meat sources: fish, chicken, pigs, and cattle

Nutrition

• Undernutrition

• Malnutrition

• Overnutrition

Soil Components

Five soil forming factors

1)Parent material : Rocks

2)Climate : Precipitation, Temperature changes

3)Organisms : Bacterial and fungal colonies, worms, rodents

4)Topography : Slope, Landscape position

5)Time : How long climate has been altering parent material geologic time

An E horizon can develop in this area.

Bedrock can lie below the C horizon. In this position, the bedrock is called an R horizon.

TextureTexture is often the first characteristic soil scientists determine. It is the relative proportion of sand, silt, & clay sized particles in

the fine earth fraction of a soil horizon. The fine earth fraction is all of the individual particles that are

smaller than 2mm in diameter. Everything larger than sand is excluded.

.

.

2mm sand particlemagnified 133x

Silt Particle

Clay particle

Industrial Agriculture

• 80% of the world’s food• the Green Revolution

Food Production in the Green Revolution

• Develop plant monocultures

• High yields with fertilizers, pesticides, and irrigation

• Multiple cropping

• High fossil fuel needs

Traditional Subsistence Agriculture

• 20% of the world’s food, 75% of the World’s cultivated land

• utilizes: intercropping, polycultures, crop rotation

• human and animal labor

Shifting Agriculture• Slash and burn – major contributing

factor to tropical deforestation

Fig. 10-10, p. 213

Areas of serious concern

Areas of some concern

Stable or nonvegetative areas

Global Soil Erosion

Moderate Severe Very Severe

Fig. 10-11, p. 214

World Desertification

Fig. 10-12, p. 215

ConsequencesCauses

Worsening drought

Famine

Economic losses

Lower living standards

Environmentalrefugees

Overgrazing

Deforestation

Erosion

Salinization

Soil compaction

Natural climate change

Causes and Consequences of Desertification

Fig. 10-13, p. 215

EvaporationEvaporation

Transpiration

Evaporation

Waterlogging

Less permeableclay layer

Salinization and Waterlogging in Soils

Salinization from Heavy Irrigation

Fig. 10-14, p. 215

Organic Fertilizers

• Animal manure

• Green manure

• Compost

Conservation Tillage

– No-Till Agriculture

o Reduces soil erosiono Slows the decomposition or organic matter

Usually requires increased herbicide use

Terracing

Fig. 10-16a, p. 217

Fig. 10-16b, p. 217

Contour Planting and Strip Cropping

Windbreaks

Fig. 10-16d, p. 217

World Grain Production

Fig. 10-17, p. 218

Major Environmental Effects of Food Production

Fig. 10-18a,p. 220

Producing More Food

• traditional crossbreeding• genetic engineering

ProjectedDisadvantages

Need less fertilizer

Need less water

More resistant to insects,plant disease, frost, anddrought

Faster growth

Can grow in slightly saltysoils

Less spoilage

Better flavor

Less use of conventionalpesticides

Tolerate higher levels ofpesticide use

Higher yields

ProjectedAdvantages

Trade-OffsGenetically Modified Food and Crops

Irreversible andunpredictable genetic and ecological effects

Harmful toxins in foodFrom possible plant cellMutations

New allergens in food

Lower nutrition

Increased evolution ofPesticide-resistantInsects and plant disease

Creation of herbicide-Resistant weeds

Harm beneficial insects

Lower genetic diversity

Fig. 10-19, p. 221

Tradeoffs of Genetically Modified Foods

More Meat!• CAFO’s• puts pressure on the worlds grain supply• overgrazing• methane (global warming)• water pollution

Kilograms of grain needed per kilogram of body weight

Beef cattle

Pigs

Chicken

Fish (catfishor carp)

7

4

2.2

2

Fig. 10-21, p. 224

Efficiency of Converting Grain into Animal Protein

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

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

• Bycatch- unintentional catch of non-target species.

Harvesting of Fish and Shellfish

Fig. 10-22, p. 225

Spotter airplane

Fish farmingin cage

Trawlerfishing

Purse-seine fishingsonar

trawl flaptrawllines

trawl bag

Long line fishing

lines withhooks

Drift-net fishing

fish caughtby gills

float buoy

fish school

Fishing Methods

Fig. 10-23a, p. 225

Fish Catch

Aquaculture Species

shrimpshellfishsalmontrouttilapia

Tradeoffs of Aquaculture

Advantages• High Yield • Profitable• Takes stress off

conventional fisheries

Disadvantages• Water pollution• Loss of mangrove habitat• Some quality issues

Protecting Food Supplies

Pest Management

The Case For Pesticides

The Case Against Pesticides

Integrated Pest Management

• Ecological thinking• Reducing pest damage to an “economically

tolerable” level• Changing cultivation practices• Utilizing biological control• Using selective pesticides as a last resort