1. Agriculture & Aquaculture
APES Final Review
Agriculture & Aquaculture

2. Where our food comes from…
Croplands (77%)
Rangelands, pastures & feedlots (29%)
Aquaculture (7%)
There are 50,000 plant species that we can eat, yet 14 supply 90% of the worlds calories!!!

3. Food Sustainability 14 varieties of plants
2/3 of the world survives primarily on corn, wheat & rice alone
Small number of species provide for meat & fish
This all leads to food specialization
Disease
Environmental degradation
Climate change

4. Industrialized Agriculture
Heavy machinery
Goal is to produce more food per area of land
Characteristics include high fertilizer use, pesticide use, irrigation, genetic engineering, factory-like conditions
Monocultures
High resource use

5. Case Study: Industrialized Food Production in the United States
Industrialized agriculture uses about 17% of all commercial energy in the U.S. and food travels an average 2,400 kilometers from farm to plate.
Figure 13-7

6. Traditional Agriculture
Labor- intensive
Polyculture
Usually lower resource use
Can have a higher output than Industrialized
Less susceptibility to changes

7. Traditional Agriculture: Low Input Polyculture
Many farmers in developing countries use low-input agriculture to grow a variety of crops on each plot of land (interplanting) through:
Polyvarietal cultivation: planting several genetic varieties.
Intercropping: two or more different crops grown at the same time in a plot.
Agroforestry: crops and trees are grown together.
Polyculture: different plants are planted together.

8. SUSTAINABLE AGRICULTURE THROUGH SOIL CONSERVATION
Modern farm machinery can plant crops without disturbing soil (no-till and minimum tillage.
Conservation-tillage farming:
Increases crop yield.
Raises soil carbon content.
Lowers water use.
Lowers pesticides.
Uses less tractor fuel.

9. Contour Farming –sloping your growing crops, etc.
You run terraces parallel to the ground to stop soil from running down a steep slope. Plowing and planting crops in rows across, rather than up and down, the sloped contour of the land.

10. Terracing – (what you use for contour farming
Terracing – (what you use for contour farming.) Dirt goes up to hold the dirt in place. Broad, nearly level terraces that run across the land contour. Helps to retain water for crops at each level and reduce soil erosion by controlling runoff.

11. SUSTAINABLE AGRICULTURE THROUGH SOIL CONSERVATION
Terracing, contour planting, strip cropping, alley cropping, and windbreaks can reduce soil erosion.
Figure 13-16

12. Strip Cropping – a row crop such as corn alternates in strips with another crop that completely covers the soil, reducing erosion. It catches and reduces water runoff and helps prevent the spread of pests and plant diseases.

13. Cover Cropping (alley cropping) – several crops are planted together in strips or alleys between trees and shrubs that can provide shade (which reduces water loss by evaporation) and helps to retain and slowly release soil moisture.

14. Irrigation Techniques
Conventional center-pivot irrigation- allows 80% of the water input to reach crops
Gravity-flow irrigation- Valves that send water down irrigation ditches.
Drip irrigation- Can raise water efficiency to 90-95% and reduce water use by 37-70%.
Floodplain irrigation- allowing the natural floods to irrigate the crops. Soils in flood zones tend to be nutrient rich and fertile.

15. The Green Revolution
Increased food production using industrialized crop production (heavy machinery)
Steps of the Green Revolution
1. Plant monocultures of high yield crops (wheat, corn, rice). Often genetically modified.
2. Use high amounts of fertilizers and pesticides to increase yield
3. Increase the number of crops grown per year

16. Meat consumption on the rise
Effects:
More densely packed feedlots
High use of grain and or fish meal
Increased need of grain can lead to dependance on other countries

17. Increased meat production
Trade-Offs
Animal Feedlots
Advantages
Disadvantages
Increased meat production
Need large inputs of grain, fish meal, water, and fossil fuels
Higher profits
Concentrate animal wastes that can pollute water
Less land use
Reduced overgrazing
Figure 13.21
Trade-offs: advantages and disadvantages of animal feedlots. QUESTION: Which single advantage and which single disadvantage do you think are the most important?
Reduced soil erosion
Antibiotics can increase genetic resistance to microbes in humans
Help protect biodiversity
Fig , p. 289

18. PRODUCING MORE MEAT
Efficiency of converting grain into animal protein.
Figure 13-22

19. Harmful Environmental Impacts of Agriculture
Erosion
Degradation of soil
Water depletion
Water pollution
Greenhouse gasses
Air pollution
Biodiversity loss
**according to the EPA, agriculture is responsible for 75% of water quality issues in US rivers & streams

20. Higher use of Biofuel Biofuel is a renewable energy alternative
However, using too much biofuel aggravates the problems brought on by agriculture.
Are we replacing one problem with another?

23. Aquaculture Raising fish in ponds and underwater cages (43%)
Helps with over-fishing
Decrease contamination (ex. Mercury)

24. Trade-Offs Aquaculture Advantages Disadvantages High efficiency
Needs large inputs of land, feed, and water
High yield in small volume of water
Large waste output
Destroys mangrove forests and estuaries
Can reduce overharvesting of conventional fisheries
Uses grain to feed some species
Figure 13.24
Trade-offs: advantages and disadvantages of aquaculture. QUESTION: Which two advantages and which two disadvantages do you think are the most important?
Low fuel use
Dense populations vulnerable to disease
High profits
Tanks too contaminated to use after about 5 years
Profits not tied to price of oil
Fig , p. 292

25. Fishing

26. Purse Seines
A large purse-like net is put into the ocean and is then closed like a drawstring purse to trap the fish.
Tuna is a fish typically caught in purse seines
Dolphins are a by-catch of purse seines

27. Long-line fishing
Lines are put out that can be up to 80 miles long w/ thousands of baited hooks on them. These are left out free- floating for days and then the boat comes back and picks them up.
Pilot whales, dolphins, sea turtles, and birds are by-catch of this technique.

28. Drift-net fishing
Each net hangs as much as 50 feet below the surface and up to 34 miles long.
Anything that comes into contact w/ these nearly invisible nets are entangled.
This leads to overfishing
Many unwanted fish and marine mammals, turtles and seabirds are caught.