How many crops to support one adult?

[cyst13]

I'm asking this in relation to a post-apocalypse campaign, but it could be relevant for fantasy campaigns as well. How many crops (in acres) have to be harvested to support one adult human for a year?

 

My campaign is going to take place in downtown Portland, OR post-apocalypse. No radiation will be involved. Portland has a number of city blocks given over to grass. I'm assuming survivors convert this area to farming and live in the neighboring apartment buildings. I need to know how many survivors this land will support. Any help will be much appreciated.

[McCoy]

Re: How many crops to support one adult?

 

I'm asking this in relation to a post-apocalypse campaign, but it could be relevant for fantasy campaigns as well. How many crops (in acres) have to be harvested to support one adult human for a year?

 

My campaign is going to take place in downtown Portland, OR post-apocalypse. No radiation will be involved. Portland has a number of city blocks given over to grass. I'm assuming survivors convert this area to farming and live in the neighboring apartment buildings. I need to know how many survivors this land will support. Any help will be much appreciated.

Temperate Rain Forest or has there been Global Warming?

 

Modern agriculture, hunter-gatherer, or somewhere in between?

 

How plentiful are fish and game?

 

Dairy a staple, a luxury, or used to fatten pigs?

 

During the Great Depresson, my mother's family figured an acre per person in the family for the "Kitchen Garden," this was in addition to chicken feed and pasturage for the cow (Pasturage included an informal "commons" methods like sometimes staking the cow out on the shoulders of the road). Again, game and fish were more common on the table than domesticated meat, and was supplemented by wildcrafting (nuts, berries, "polk salad") and gleaning (usually root crops).

[Captain Obvious]

Re: How many crops to support one adult?

 

The people in Biosphere II in Arizona have been using techniques based on those outlined by Ecology Action: they raised 80 percent of their food for two years within a "closed system." Their experience demonstrates that a complete year's diet for one person can be raised on the equivalent of 3,403 square feet!

 

This is an improvement over traditional Chinese practices, which required 5,000 to 7,200 square feet. In contrast, it takes commercial agriculture 22,000 to 42,000 square feet to grow all the food for one person for one year, while bringing in large inputs from other areas.

 

source: http://www.context.org/ICLIB/IC42/Jeavons.htm

 

Post Apoc techniques probably wouldn't be as efficient as Biosphere II, and wouldn't have the resources to be as wasteful as commercial agriculture. I'm not real sure how efficient Chinese agriculture was compared to European agriculture, but that's probably not a bad estimate for game purposes. Especially if you add in things like semi-wild hogs, game, and fishing, that don't require cultivated land.

[McCoy]

Re: How many crops to support one adult?

 

And remember how gaunt the Biosphere inhabitants were after two years, and this was under optimum conditions (they controlled the weather, no weeds and no pest).

[Cancer]

Re: How many crops to support one adult?

 

I googled for "farm productivity medieval" and got a journal paper in JSTOR; not certain whether my institution lets me in there (and would deny you) or not.

 

Anyway, for pre-Black Death England, looks like wheat yield was typically 9.1 bushels per season with a high value of 18, barley yield was typically 12.3 with a high of 20, oats yield was typically 8 with a high of 16.6.

 

24 bushels of wheat a year is about right to make one loaf of bread per day for a person. That would mean very roughly 2.5 to 3 acres of worked farmland per person. But this neglects other food input (like meat from either livestock or wild game, fish caught, and milk from livestock, other fruit & vegetables, etc.). 1 acre is 43,560 square feet.

[Captain Obvious]

Re: How many crops to support one adult?

 

And remember how gaunt the Biosphere inhabitants were after two years' date=' and this was under optimum conditions (they controlled the weather, no weeds and [b']no pest[/b]).

 

Actually, I recall ants going freakin' haywire in there...all over the place.

 

But yeah, they weren't exactly getting fat and happy in there, even without the ants.

[Wyrm Ouroboros]

Re: How many crops to support one adult?

 

Anyway, for pre-Black Death England...

 

That would mean very roughly 2.5 to 3 acres of worked farmland per person. But this neglects other food input (like meat from either livestock or wild game, fish caught, and milk from livestock, other fruit & vegetables, etc.). 1 acre is 43,560 square feet.

 

This is roughly correct, presuming a basic temperate clime for your post-apocalyptic campaign. Truck farming (i.e. a comparatively small 1-acre plot for veggies and such), fishing, milk and dairy, wild game (usually small -- rabbits and the like) essentially enhances that food quality, but doesn't really replace any acreage.

 

A good rule of thumb is 3 acres/person, plus any overage required by overlordship or desiring trade. 20-40 acres is thus an intelligent amount to plant, presuming you get a decent harvest.

[Captain Obvious]

Re: How many crops to support one adult?

 

I believe I read once that in medieval times, each peasant could work 4 acres. That would make for a pretty small non-farming population (not that that is bad...just an observation), but then again, there's probably a lot of non-farming work thrown in there too, so someone who farms but doesn't bother fetching wood or digging ditches for a lord might be able to work more acreage.

 

Of course, I may be totally remembering this thing wrong...

[Lawnmower Boy]

Re: How many crops to support one adult?

 

Whippin' out the 9th Edition Britannica, turning to "Agriculture," 1: 401--405 I get a range of tables.

In 1895, per acre yield was (bushels) Wheat: 26.33/Barley 32.1/Oats 38.7/Beans 23/Peas 22.6/[tons] potatoes 5.6/turnips 13.1/[hundredweights --yeah, whatever] hay (in rotation) 29.08/ hay (meadow) 25.2.

It is not clear to me whether this is before or after superphosphates, but note an average yield from another source for the 1850s, certainly before scientific fertilisers, of 28 (60lb) bushels wheat per acre.

A more telling table in many ways gives per acre yield by dry weight

separating fruit from straw and giving the "nitrogen" content of both:

Wheat: 1530(34)/2653 (16); barley 1747(35)/2080(14); oats 1625(34)/2353(18); corn 1500(28)/1877 (15)/meadow hay 0/2822(49); beans 1613(78)/1848 (99); turnips 3126 (61)/1531 (49); potatoes [NB: this is dry weight, so think instant mashed potatoes!] 3360(46). YMMV, but not very much, in Oregon.

Just to clarify, that's "fruit" first, and the nitrogen content is the estimated weight in lbs of elemental nitrogen, without considering what proteins it might constitute in a given case.

This doesn't give yield in flour, but most of the dry weight of wheat is going into a whole grain flour, and supposedly 2lbs wheat constitute a garrison ration.

That said, I have doubts about whether anyone has the digestive system to deal with 3300 calories of wheate flour a day. And notice that grass turns out to be the most efficient food of all, if not for people. Bring on the beef, I say!

PS: For converting into distances on the ground, I convert to hectares (1 acre=0.42 hectares). A hectare is 100 square meters, so a typical city block is about 6 hectares.

[Comic]

Re: How many crops to support one adult?

 

Per acre, the most nutritious food plant is the oak tree.

 

Acorns taste like crap, though. It takes a famine to force people to try to live on the things.

 

If you're willing to make compromises and supplement from non-farm sources (poach, plunder, glean, gather, fish, scavenge, bait, trade), you can get by on as little as .4 acres per person.

 

But you have to really mean it, and eat stuff that'd make the goat puke, if you hadn't eaten it first.

[McCoy]

Re: How many crops to support one adult?

 

Per acre, the most nutritious food plant is the oak tree.

 

Acorns taste like crap, though. It takes a famine to force people to try to live on the things.

Actually they're not that bad if you blanch them first to remove the tannin. Then they can be roased and ground, and used as a corse flour.

[braincraft]

Re: How many crops to support one adult?

 

Keep in mind that the minimum for subsistence isn't nearly good enough. Especially in a post-apocalyptic world, where dangers are commonplace and there is no bailout infrastructure; if you're not socking away some of your harvest into storage, you'll starve the first time your fields get hit by drought, or flooding, or disease, or pests, or bandits.

[cyst13]

Re: How many crops to support one adult?

 

Thanx all for replying so quickly to this thread. Much appreciated. Unfortunately, you've given me an overabundance of information. The most useful inormation was in the form of a rule of thumb (3 acres/person). However, this is only truly useful if it is accurate. I wish I had thought to include a polling option for this thread. In lieu of that, I ask you to indulge me once more. Would everyone who considers themselves to be knowledgeable on this subject please leave a brief reply to the following question:

 

Is 3 acres to feed one person per year an accurate rule of thumb?

 

If so, answer yes. If not, answer either "too high" or "too low".

 

I thank you for your help.

 

And for the record, I was assuming the climate to be the same as present day Portland, OR and the farming method to be the three field rotation system possibly with oxen-drawn plows.

[McCoy]

Re: How many crops to support one adult?

 

Is 3 acres to feed one person per year an accurate rule of thumb?

 

If so, answer yes. If not, answer either "too high" or "too low".

 

I thank you for your help.

 

And for the record, I was assuming the climate to be the same as present day Portland, OR and the farming method to be the three field rotation system possibly with oxen-drawn plows.

With oxen? Too low. (They, and their mothers and brother have to be fed too).

[Lawnmower Boy]

Re: How many crops to support one adult?

 

A three-field rotation makes things more complicated because you get three crops in two years, one spring sown, two fall sown, and I don't know if my data is for spring crops. But, 1 acre produces 7300lb straw, 4700lb grain (wheat and barley). assuming that works out to 4200lb flour and 500lb bran, at 2 lbs grain/person/day for two years and 25lb straw/oxen, 1 acre feeds 2 2/3 people and 1/2 of an oxen. (Warning, sums done in head. Throw in another 1.5 acre of permanent meadow yielding two mows a year, and you get enough for a nuclear family and two oxen.

However, in order to work like a nineteenth century British draught animal (which is to say, a lot harder than a medieval one), you would have to throw in some concentrated feed. So 3 acres will cover the basic calorie needs of a small family.

You still need to cover the family's textile needs, though. I have no idea where you'd get figures for yards/linen/acre, but I've a hunch that the 6 acres you have left over above would run enough sheep to keep your family clothed. And provide you with a margin in case of bad weather, like that ever happens up here in the Northwest.

[Curufea]

Re: How many crops to support one adult?

 

I thought the definition of one acre WAS "the land needed to support an adult".

Although that's based on living in England of course.

[Comic]

Re: How many crops to support one adult?

 

I asked my local expert, who opined that with current knowledge of methods using 1905-era tools and post-apocalyptic materials (glass for greenhouses, etc.), barring bad weather a mixed farming community in this climate could bear a concentration of one adult per arable acre. You'd want to have more land to account for non-arable land, bush, housing, ponds, roads, fences, commons, etc. So 3 acres per works.

[Wyrm Ouroboros]

Re: How many crops to support one adult?

 

And for the record' date=' I was assuming the climate to be the same as present day Portland, OR and the farming method to be the three field rotation system possibly with oxen-drawn plows.[/quote']

 

As I made the recommendation for the Rule of Thumb, yes, I'd say so. HOWEVER.

 

If you're working in the Oregon area, understand that Oregon is a fantastic place to post-apocalyp -- it hasn't been overfarmed, there's a sizeable amount of essentially 'long-term stands' of trees, the weather cycles are functionally perfect. If you haven't read S.M. Stirling's 'Dies the Fire' trilogy (Dies the Fire, The Protector's War, A Meeting at Corvalis), you should -- it takes place in exactly the area you're speaking of, with pretty much exactly the sort of events you're considering, save that tech that relies on 'pressure' -- gaseous or electrical -- doesn't work. No functional gunpowder, no steam locomotives, no electric lights, etc.

 

On the other hand, I very much get the idea that you're doing a 'Dies the Fire' campaign. If you are, be aware that S. M. Stirling puts a fair amount of research into his stories; Portland and the Wilamette are pretty much the way he portrays. If you aren't, and haven't read the books, go read them, and you'll get a very good idea of the type of zone you're dealing with.

[cyst13]

Re: How many crops to support one adult?

 

Wyrm,

 

Thanx for the tip. I've never heard of this guy. I chose Portland cuz I live here. Before I ever considered a PA game, I used to walk around my neighborhood (downtown) and wonder, "what if I were the only one left? What would I do?" It definitely makes you pay closer attention to your surroundings when you are considering how to convert everything to PA utility. I'll definitely check-out this trilogy. Closely researched "realism" is exactly what I'm looking for. Thanx again.

[AmadanNaBriona]

Re: How many crops to support one adult?

 

The Wilamette valley is also the setting for most of David Brinn's The Postman.

 

As mentioned, it's a likely place to try and start over.