How much land to feed one person?

From Tiny Farm Wiki

How much land it takes to feed a person depends a lot on a couple of things:

• climate: The shorter your growing season, the more land you need, to produce for immediate use and for off-season (winter) storage.
• diet: Do you eat meat, or are you a vegetarian? There's a lot of nutritional value packed in meat, but it also takes a lot more area to feed the livestock that will feed you. Also, will you be supplementing with (hunted) game or fish?

There's an interesting set of replies to this question here.

[edit] Estimates

"The minimum amount of agricultural land necessary for sustainable food security, with a diversified diet similar to those of North America and Western Europe (hence including meat), is 0.5 of a hectare per person. This does not allow for any land degradation such as soil erosion, and it assumes adequate water supplies. Very few populous countries have more than an average of 0.25 of a hectare. It is realistic to suppose that the absolute minimum of arable land to support one person is a mere 0.07 of a hectare–and this assumes a largely vegetarian diet, no land degradation or water shortages, virtually no post-harvest waste, and farmers who know precisely when and how to plant, fertilize, irrigate, etc." - [FAO, 1993]

Of course, these estimates could be wildly off given the apparent effects of climate change since the early 2000's. As it stands now, historic climate data is no longer reliable for farm planning. Planting dates, performance of particular seed varieties, and pest cycles are all erratic. Therefore, "farmers who know precisely when and how to plant, fertilize, irrigate, etc" is no longer a reasonable consideration. Planting frequently is the simplest countermeasure to erratic weather, but this requires a lot more land, since you're overplanting to account for potentially poor performance. Add 25% land area? 50%? More?

[edit] DIY calculation

One DIY approach is to calculate the number of calories (food energy) we require, and compare that value to the calories available from various food crops and the amount of land they need. You could refine the calculation further accounting for sources of essential nutrients: protein, carbohydrates, fat, vitamins, minerals.

An interesting article on agricultural land use takes this approach. It's assumed that humans need 3,000 calories per day. That figure is applied to a study of agricultural land used for all the food eaten in the Netherlands. For example, potato is the most efficient crop, and according to the study requires 0.2 square meters to produce 1kg, which contains 800 calories. It would therefore take 274m2 to produce enough calories for one person for one year. That's an area less than 10m x 30m (about 33 x 100 ft). To get 3000 calories from vegetables other than potatoes requires 1314m2, eggs 2395m2, and at the high end, beef 8173.

[edit] Most efficient food sources

The potato seems to be the most efficient veggie for producing calories on the least amount of land. Of course, potatoes are not a complete food, a potato diet would have to be supplemented with additional protein and other required nutrients.

[edit] Other discussions & answers

• Most of what you need for good nutrition can be grown on an acre or less
• a well rounded diet for a year from half an acre
• about 15,000 to 30,000 square feet of land to feed one person the average U.S. diet," he says. "I've figured out how to get it down to 4,000 square feet" - John Jeavons
• There is an old adage that you shouldn't try to farm more land than you can throw a stone over...