solutions to environmental problems associated with food production ch. 12
TRANSCRIPT
Solutions to Environmental Problems Associated with Food Production
Ch. 12
BUT, I’m HUNGRY!What can we do?
Answer: 1. Adopt sustainable agriculture (low input
practices that cost less and are less damaging) 2. Change Food Subsidies 3. Coupled with genetic engineering. 3. Eat new foods
#1. What is sustainable agriculture?
Two major ways to increase world’s food production: 1. Increase crop yields2. Increase the amount of land used
Sustainable Agriculture
Method of growing crops and raising livestock based on organic fertilizers, soil conservation, water conservation, biological pest control, and minimal use of nonrenewable fossil fuel energy.
Fig. 12-34, p. 310
Solutions
More Sustainable Agriculture
More Less
High-yield polyculture Soil erosion
Organic fertilizers
Biological pest control
Water pollution
Soil salinization
Aquifer depletion
Integrated pest management
Overgrazing
Efficient irrigation
Perennial crops
Loss of biodiversity and agrobiodiversity
Crop rotationFossil fuel use
Overfishing
Water-efficient crops Greenhouse gas emissions
Soil conservationSubsidies for unsustainable farming
Subsidies for sustainable farming
Organic Food
• Produced without synthetic pesticides, herbicides, & fungicides
• No GMFs
Organic meat/dairy- 100% organically grown feed- Outdoor pasture- No hormones/antibiotics
Produce Meat More Efficiently and Humanely
• Shift to more grain-efficient forms of protein
• Beef from rangelands and pastures, not feedlots
• Develop meat substitutes; eat less meat
Efficiency of Converting Grain into Animal Protein
Fig. 12-33, p. 309
Sustainable Practices
A. Diversifying products1. Crop rotation2. Conservation tillage3. Contour plowing
Sustainable Practices
B. Low input farming with water/energy conservation
Sustainable Practices
C. Natural predator/prey relationships over chemical pesticides
Sustainable Practices
D. Natural fertilizers from manure vs. commercial fertilizers
#2. Government Agriculture Policy
Government Assistance– Keep food prices artificially low– Give farmers subsidies– Eliminate most or all price controls and
subsidies and let farmers/fishers respond to market demand
Environmentalists think…
Use subsidies to reward farmers/fishers/ranchers who:
- Protect the soil- Conserve water- Reforest degraded land- Protect and restore wetlands- Conserve wildlife- Practice more sustainable agriculture/fishing/ranching
#3 Genetic Engineering
• Crossbreeding and artificial selection• Genetic engineering (gene splicing)• Genetically modified organisms (GMOs)
Crop
Cross breeding
Desired trait(color)
ApplePear
Offspring
Cross breeding
Best results
Newoffspring
Desiredresult
Traditional Crossbreeding
1) Slow process
2) Can combine traits only from closely related species
What are Genetically Modified Foods? *
Genetic Engineering/Gene Splicing/GMFs*
Inserting alien/preferred gene into valuable plant for new traits, quick results, cheaper
Genetic Engineering
• Wild plants/animals genetic diversity• Domesticated plants/animals genetic
diversity as certain characteristics are selected for
• Genetic diversity means species are more susceptible to new strains of disease, increasing risk of total species loss.
Phase 1Make Modified Gene
Identify and extractgene with desired trait
Identify and removeportion of DNAwith desired trait
Remove plasmidfrom DNA of E. coli
Insert extracted DNA(step 2) into plasmid(step3)
Insert modifiedplasmid into E. coli
Grow in tissueculture tomake copies
cell
gene
DNA
Plasmid
E. coliDNA
Geneticallymodifiedplasmid
plasmid
Phase 2Make Transgenic Cell
Transfer plasmidcopies to a carrier
agrobacterium
Agrobacteriuminserts foreignDNA into plantcell to yieldtransgenic cell
Transfer plasmidto surfacemicroscopic metalparticle
Use gene gunto inject DNAinto plant cell
A. tumefaciens(agrobacterium)
Plant cell
Nucleus
Host DNA
Foreign DNA
Phase 3Grow Genetically Engineered Plant
Transgenic cellfrom Phase 2
Cell division oftransgenic cells
Culture cellsto form plantlets
Transgenic plantswith new traits
1) Half the time as conventional crossbreeding
2) Cuts costs
3) Allows insertion of genes from almost any other organism
Fig. 12-18, p. 294
Trade-Offs
Genetically Modified Crops and Foods
Advantages Disadvantages
Need less fertilizer Unpredictable genetic and ecological effectsNeed less water
Harmful toxins and new allergens in food
More resistant to insects, disease, frost, and drought
No increase in yields
Grow fasterMore pesticide-resistant insects and herbicide-resistant weeds
May need less pesticides or tolerate higher levels of herbicides
Could disrupt seed market
May reduce energy needs
Lower genetic diversity
Advantages vs. Disadvantages
• may produce food plants that are more nutritious
• develop crops resistant to pests/disease/drought/hot/cold/herbicides/acidic-basic soils
• develop disease resistant vaccines for livestock
• DID YOU KNOW … 2/3 of food products in US markets contain GM crops!
#4 Try New Foods
Ant Larvae, waterbugs, caterpillers, cockroaches, butterflies, fried ants
I DON’T WANT TO EAT BUGS…
Can we cultivate more land instead?
Not really – most land is marginal land with poor fertility/steep slopes and would require high inputs of fertilizer/water/energy which are expensive.
How can we increase crop/stock yields?
• In developed countries: – Fertilizer– Pesticides– Selective breeding– Machinery
GREEN REVOLUTION: increase food production per acre
Increase Livestock Yields by:
hormone and antibiotic injections.
European Union (EU) banned use due to health concernsBUT US/Canada still use practice
Should we continue Green Revolution techniques?
– Without fertilizer, water, and pesticides green revolution varieties are no more productive than traditional varieties
– Green revolution varieties and their needed inputs cost too much for subsistence farming.
– Grain yields are increasing at a much slower pace.– Actual gains from green and gene revolutions may
be overstated.– Crop yield may start dropping for a number of
environmental reasons.– Increased loss of biodiversity can limit genetic raw
material.
Tools to reduce hunger & malnutrition
• Slow population growth• Reduce poverty• Sustainable agriculture