Note: see also my post on Self sufficient tropical diet, rough draft
I've been thinking about how much land would be required to give an adequate, roughly paleodiet (no potatoes, cereal grains, or dairy, minimizing annuals domesticated & bred within the last 10,000 years) in a homesteading situation. My first step has been to figure out what the diet would consist of, in terms of proportion of calories from fruit and berries, meat, tubers, vegetables, etc. I've worked up a very rough draft which I'll jot down here. I welcome input, and will post future drafts as I learn more, think more, and crunch more numbers!
As best I can tell, an ideal hunter/gatherer diet consists of about 50-65% meat, and 35-50% plant foods. Assuming we have some need for land efficiency, this seems unrealistic for a self-sufficient homestead, since it does take a lot more land to raise meat than the equivalent calories in plant food. So for now, I'm figuring a minimal level of meat from the "homestead", with, hopefully, supplemental meat available from hunting and trapping. I haven't tried to do a full nutritional analysis of what a "balanced" diet requires; I'm just figuring that with a wide variety of foods most of that will sort itself out. But again, I welcome input into any of this, especially if I'm missing some important macronutritional info!
In the table below, % of diet refers to calorie intake. "Per day" is about how much of the item would be eaten per day on average. "Cals/lb" is my estimate of how many calories per pound this food type provides. The column for "Land" is a rough estimate of how much space, in square feet, would be needed to provide an annual yield sufficient for 2500 calories/day using this category as a monocrop (not integrated with other foods).
|% of diet||Food type||Per day||Cals/lb||Land||Notes|
|20%||Meat||5/8 lb||800||1 acre?||Good homestead options seem to be beef, chicken, sheep, and maybe goats. Beef & lamb relatively higher in calories, chicken & goat low. Maybe 12 chickens (young males and old stewing hens)/person annually, plus half a pound of other meat per non-chicken-eating day? And 1/3 of a steer per year or its equivalent. No idea how much land required, which obviously is crucial.|
|10%||Eggs||3 eggs||75/egg||1/4 acre?||Chickens or ducks (maybe other possibilities too?) For average 3 eggs/day, would need 4 or 5 fairly productive layers, or more older layers.|
|20%||Protein nuts & seeds||2/3 cup||2900||6900||Mostly thinking walnut, hazelnut, pine nuts, and sunflower seeds. Could also include hickory, pecan, almonds, pistachios, monkey puzzle, etc. Land requirement based on 1200 pounds/acre yield (I think very conservative, this could be doubled with good water/fertilization) and assuming 33% average kernel yield.|
|5%||Chestnuts||1/2 cup||900||1150||Land requirement assumes 2400 lbs/acre (could be more with grafted varieties) and 80% kernel (I can't find any numbers for this, but this seems reasonable). Acorns would be a nice complement to chestnuts, but don't seem realistic for planting and getting a quick return. (Definitely an option for gathering from existing stands, though.)|
|10%||Roots||1.25 lbs||800||1000||Ideally mostly low-maintenance perennials, but for now the common crops for which I can find data are: Jerusalem artichoke, beets, carrots, parsnips, camas, wapato, rutabagas, onions, turnips. Assumes a yield of 1 pound per 2 square feet. The calorie content varies widely for different tubers, so these numbers are very fungible depending on the crop make-up.|
|5%||Starchy seeds||1/5 cup||1600||600||Amaranth, quinoa, other chenopods. Avoiding cereal grains (grass family). Assumes yield of 5 lbs grain per 100 square ft (could get higher yield, but maybe 5 lbs is a good guess for a low-maintenance patch).|
|7.5%||Fruit||2-3 fruits||300||1000||Apples, pears, plums, persimmons, etc. Assumes 50 lbs per tree per year average, and trees and paths taking up a 16' diameter spread per tree.|
|7.5%||Berries||2-3 cups||200||1000||Gooseberries, blueberries, blackberries, grapes, kiwis, etc. Might include melons in this category? 1000 square feet probably an over-estimate, as vines can make use of vertical space.|
|2-3%||Greens||Large salad, 1 lb||70||350||I haven't yet experimented with weighing different greens to understand how much salad 1 pound of greens actually makes. Assume can get 1 pound greens/square foot.|
|5%||Squash, misc veggies||1.25 lbs||100||1000||Other veggies such as squash (including seeds, though maybe they should be included under protein nuts & seeds above, increasing that percentage of diet), shoots (asparagus, Rubus sp., bamboo, etc), tomatoes, peppers, etc. Land requirement assumes can produce 1 lb per 2 square ft.|
|7-8%||Misc||2 tbs honey, 10 olives, and 1/2 cup mushrooms||300||Miscellaneous calories from things like mushrooms, honey, olives, vegetable oils (processing seeds from grape for example, or surplus walnuts?), and whatever else I haven't thought of yet. I pretty much just totally made up the land requirement number.|
So, my very rough conclusion thus far is that for each 2500 calorie diet, you need a bit over a quarter acre (13,300 square feet) for plant food production in a monocrop system, plus 1.25 acres to support 12 chickens for eating, 1/3 of a steer, and 5-6 laying hens (see comments below for my calculations on that). Grand total: about 1.5 acres per person.
The next main research thrust needs to be into how much land you need to support free-range, almost fully pasture-fed animals on a rotational system. (Chickens, of course, will get supplemental feed from kitchen scraps, maggot farm, etc. I also expect it'll prove economical to grow some patches of grains and other vegetation purely for the chickens to pick through or to cut and store as feed for livestock through the winter.) I've read a lot of Joel Salatin's work on integrated livestock systems, but can't remember any details of the numbers.
Another aspect to think about more is how much space can be saved by growing crops under trees, so that it's not 1000 square feet for fruit trees and another 1000 square feet for berries, but rather 1000 square feet of fruit trees with berries growing underneath them, plus maybe another 500 square feet of berries growing in the open, for a total of 1500 square feet instead of 2000. This, of course, is how we're already planning and planting in our food forest plantings on an urban lot...but without mature trees to experiment with, we can't get data from our own experience for what final yields to expect in such an integrated system.