Agricultural petroleum use


by aquitaine
Tags: agricultural, petroleum
aquitaine
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#1
Jun29-10, 12:48 PM
P: 201
All this recent talk of peak oil, high oil prices, etc, it made me wonder, in the US how much oil does agriculture use, excluding packaging, refrigeration, transportation?
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EnumaElish
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#2
Jul2-10, 04:02 PM
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Quote Quote by FTW
Agriculture directly accounts for 17% of all the energy used in this country. As of 1990, we were using approximately 1,000 liters (6.41 barrels) of oil to produce food [on] one hectare of land.
... Time unit (per day? per year?) not stated. I am guessing it must be per year, based on the current 20 million barrels/day U.S. oil consumption (http://maps.unomaha.edu/peterson/fun...nsumption.html), which implies 7.3 billion barrels/year.
Quote Quote by CIA
U.S. land: 9,161,966 sq km* [= 916,196,600 hectares**]
Quote Quote by FTW
Approximately three-quarters of the land area in the United States is devoted to agriculture and commercial forestry.
Quote Quote by FTW
Agricultural energy consumption is broken down as follows:

31% for the manufacture of inorganic fertilizer

19% for the operation of field machinery

16% for transportation

13% for irrigation

08% for raising livestock (not including livestock feed)

05% for crop drying

05% for pesticide production

08% miscellaneous
From http://www.fromthewilderness.com/fre...ating_oil.html, which has some eye-popping statistics, like:

"In 1994, David Pimentel and Mario Giampietro estimated the output/input ratio of agriculture to be around 1.4. For 0.7 Kilogram-Calories (kcal) of fossil energy consumed, U.S. agriculture produced 1 kcal of food. The input figure for this ratio was based on FAO (Food and Agriculture Organization of the UN) statistics, which consider only fertilizers (without including fertilizer feedstock), irrigation, pesticides (without including pesticide feedstock), and machinery and fuel for field operations. Other agricultural energy inputs not considered were energy and machinery for drying crops, transportation for inputs and outputs to and from the farm, electricity, and construction and maintenance of farm buildings and infrastructures. Adding in estimates for these energy costs brought the input/output energy ratio down to 1. Yet this does not include the energy expense of packaging, delivery to retail outlets, refrigeration or household cooking."

"In their refined study, Giampietro and Pimentel found that 10 kcal of exosomatic energy are required to produce 1 kcal of food delivered to the consumer in the U.S. food system. This includes packaging and all delivery expenses, but excludes household cooking). The U.S. food system consumes ten times more energy than it produces in food energy. This disparity is made possible by nonrenewable fossil fuel stocks."

"Assuming a figure of 2,500 kcal per capita for the daily diet in the United States, the 10/1 ratio translates into a cost of 35,000 kcal of exosomatic energy per capita each day. However, considering that the average return on one hour of endosomatic labor in the U.S. is about 100,000 kcal of exosomatic energy, the flow of exosomatic energy required to supply the daily diet is achieved in only 20 minutes of labor in our current system. Unfortunately, if you remove fossil fuels from the equation, the daily diet will require 111 hours of endosomatic labor per capita; that is, the current U.S. daily diet would require nearly three weeks of labor per capita to produce."
________________________________
*https://www.cia.gov/library/publicat...k/geos/us.html
**http://www.onlineconversion.com/area.htm
aquitaine
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#3
Jul6-10, 07:26 AM
P: 201
... Time unit (per day? per year?) not stated. I am guessing it must be per year, based on the current 20 million barrels/day U.S. oil consumption (http://maps.unomaha.edu/peterson/fun...nsumption.html), which implies 7.3 billion barrels/year.

Interesting. But I have a question, it is clear that in the future petroleum production will be in decline, what alternatives are there for fertilizer?

alxm
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#4
Jul14-10, 05:15 AM
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Agricultural petroleum use


Synthetic fertilizer is produced using the Haber-Bosch process, which requires a lot of energy, but does not in any way require that it has to be from fossil fuels.

This statistic, that it takes more energy to produce a meal than is contained in the meal, is often quoted, but I've never seen the relevance. This was the case even prior to the mechanization of agriculture (using beasts of burden). It's just not the case that fossil fuel is necessary for this. It can be replaced with renewable sources.

In fact, fertilizer is a given and inevitable byproduct of biofuel generation. If you consider the balance of chemical elements involved, we're only interested in producing hydrocarbons (possibly with oxygen as well, in the case of alcohol). Anything else, including minerals and nitrogen compounds, i.e. fertilizer, is a natural byproduct. We only want the carbon, and the plants get that from the air. It's the stuff they need from the soil that's fertilizer. (And in fact, for the sake of sustainability, we more or less have to return this stuff to the soil)

There's this strange attitude that the way we currently do things is the only way. That our dependency on fossil fuels is there because it's the only way of doing things. This isn't true. The reasons for this are mainly economic: Fossil fuels are cheap. (you literally just dig it out of the ground and burn it) If you discount our technological and (above all) economical adaptivity, you're forgetting one of the main reasons why we have a market economy in the first place.
mugaliens
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#5
Aug16-10, 04:37 AM
P: 594
Quote Quote by EnumaElish View Post
"Assuming a figure of 2,500 kcal per capita for the daily diet in the United States, the 10/1 ratio translates into a cost of 35,000 kcal of exosomatic energy per capita each day. However, considering that the average return on one hour of endosomatic labor in the U.S. is about 100,000 kcal of exosomatic energy, the flow of exosomatic energy required to supply the daily diet is achieved in only 20 minutes of labor in our current system. Unfortunately, if you remove fossil fuels from the equation, the daily diet will require 111 hours of endosomatic labor per capita; that is, the current U.S. daily diet would require nearly three weeks of labor per capita to produce."
That's a good analysis, and some great hip-pocket numbers to work with!

Solar combines, anyone? Or at least ones recharable via solar power?


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