Calories Per Acre

useful way to measure food production (Family Farm, Agriculture). See related PermaCulture, Aquaculture.

Note this is a per-year number.

On the consumption-side, people need ~2500 cal/day, which is 912kcal/yr (or roughly 1M).

http://www.waldeneffect.org/blog/Calories_per_acre_for_various_foods/

• grains 6-18 Mcal/acre (potatoes/corn much better than wheat)
• meats 1-3
  • Grass-Fed beef is actually lower, I think, but can use land that isn't good for growing staple crops anyway.

http://www.localharvest.org/blog/15945/entry/calories_per_acre_with_apples

• apples 12-23M! (latter is commercial production)

http://www.marksdailyapple.com/can-we-feed-the-world-on-the-primal-blueprint-diet-part-3

• romain lettuce 1.3
• sweet potato 8.5
• apples 8.5
• cherries 2.4
• see section on insects!

almonds 5.4k? (2k lbs/acre, 170 cal/oz)

http://news.ycombinator.com/item?id=1701724

http://urbanevolution.org/thinktank/viewtopic.php?f=6&t=11

http://www.permies.com/t/11778/permaculture/Feasibility-food-self-reliance

So taking a crude fake avg of 8M/acre, I conclude that each acre can support 8 people, or a sqmi can support 5k people. (Population Density)