Chapter 11 Feeding the World. Food Production Major food sources: croplands, rangelands, and oceans...
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Transcript of Chapter 11 Feeding the World. Food Production Major food sources: croplands, rangelands, and oceans...
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