The Energy Subsidy in Agriculture
Energy subsidy- the energy input per calorie of food produced
- Energy input per calorie of food obtained is greater for modern agricultural practices than for traditional agriculture
- Fossil fuel energy is the primary energy subsidy for large-scale modern food production (used to produce fertilizers and pesticides, to operate tractors, to pump water for irrigation, and to harvest food and prepare it for transport)
- Average food item travels 2,000 km from the farm to your plate (far more energy transporting food than from the food itself)
- Think of mass "inputs"
- Example: Let's say it takes 20 kg of grain to feed to cattle to produce 1 kg of beef. This means the beef has an energy subsidy of 20 because it took 20 kg of grain to produce the beef.
- Energy inputs for hunting and gathering and for small-scale food production are mostly in the form of human energy
- If you eat the average modern U.S. diet obtained from a typical supermarket, containing primarily foods produced by modern agricultural methods, there is a 10-calorie energy input for every calorie you eat
Try these problems!
Question #1: Using the energy subsidy chart above, if you input a total of 3,000,000 calories of energy into small-scale corn farming, about how many calories of food will you produce?
- Small-scale corn farming energy subsidy = 0.2
- 3,000,000 calories/0.2 = 15,000,000 calories
Question #2: Using the energy subside chart above, if you input a total of 3,000,000 calories of energy into far-offshore fishing, about how many calories of food will you produce?
- Far-offshore fishing energy subsidy = 20
- 3,000,000 calories/20 = 150,000 calories