Energy in Agriculture

An article that only became available non-subscription recently called Eating Fossil Fuels has a number of interesting facts.

This piece covers some of the same ground as the recent Harper's article reviewed here. Both equally bleak, I desk-checked many of the numbers for consistency. I could find no misleading computations.
Particulary alarming were these numbers that I factored out :

• 6 million equivalent oil barrels/day used per day in producing USA food (apparently not including transportation and a few other post-production factors)


• 400 gallons of oil equivalent annually to feed each American


• Current USA daily diet would require 3 weeks of (slave)¹ labor capita to produce (this desk-checks with energy usage assuming 22% efficiency converting fuel to mechanical energy)


• We use 400x more water daily than oil

One area that I did not get a good handle on is the difference in energy usage for exported food versus USA consumed food. USA is a huge exporter of food, so this may make us look more gluttonous in energy usage than we appear to be. Natural gas also is important and I did not get a good feel on how much more it is used (especially for fertilizer) than oil.

¹That is my reading