How many people could you feed if...

[johndaw16]

Here's a question thats been bugging me as I design a region in my homebrew world.

How many people could you feed if you had roughly 40 sq. miles of fertile soil to farm. I'm looking for a rough guess maybe by the thousands, it doesn't have to be super specific. I have no real clue about this sort of thing but I do have a passion for believability in my worlds so I like to keep things in the realm of possibility.

Some things to keep in mind:

1. There's no magic at all.
2. There's ample access to water, and ideal temperate climate and weather conditions for growing.
3. Agricultural technology allows for simple irrigation and the use of the iron plow.
4. The people possess a set of traditional "rules" on what to plant that simulate modern knowledge about soil fertility and maintaining a fields productivity over time.

Anyways I hope someone can help, otherwise I'll just guess.

John

 

[airwalkrr]

That's a situation with a LOT of variables. For instance, a peasant in medieval Russia at times had well over a hundred acres and couldn't raise enough to feed his family, let alone tithe his lord (usually a fraction of about 1/3 to 1/2). However, there were situations where peasants with excellent plots of land in Ukraine of 10-20 acres could feed their families, tithe their lord, and make a profit (though this was rare). It depends a lot on the quality of the land. Russia is my area of expertise but I know in the middle ages conditions varied wildly across Europe. French soil was particularly arable and I think you could probably feed up to 200 people per square mile assuming best case scenario conditions there. Of course it would vary from year to year depending upon droughts, famine, pestilence, and plague.

 

[Starman]

You want this.

 

[jgbrowning]

Here's a question thats been bugging me as I design a region in my homebrew world.

How many people could you feed if you had roughly 40 sq. miles of fertile soil to farm. I'm looking for a rough guess maybe by the thousands, it doesn't have to be super specific. I have no real clue about this sort of thing but I do have a passion for believability in my worlds so I like to keep things in the realm of possibility.

Some things to keep in mind:

1. There's no magic at all.
2. There's ample access to water, and ideal temperate climate and weather conditions for growing.
3. Agricultural technology allows for simple irrigation and the use of the iron plow.
4. The people possess a set of traditional "rules" on what to plant that simulate modern knowledge about soil fertility and maintaining a fields productivity over time.

Anyways I hope someone can help, otherwise I'll just guess.

John

A good rough guess would be around 50,000. However the actual area taken over by all the other aspects of living would probably be at least 240 sq. miles which would put you around 200 people per sq. mile. Medieval France was often around 130 people per square mile and as your look like you're going for a fairly concentrated area of production, I wouldn't balk at a 200 per sq. mile average.

Also, the people aren't being just feed by vegetable matter in my estimation. They're also engaging in carnivory via animal husbandry, hunting, and fishing.

joe b.

 

[jgbrowning]

You want this.

Yes, if he's interested in such matters, it's hard to find a source that approches this one.



joe b.

 

[johndaw16]

Well thanks for the quick response to such a mundane question guys. I totally understand how its a really tricky question with too many variables to really answer. So would you think it'd be within reason to say a rural area of roughly 40-50 sq. of excellent/highly productive farming land could support a small city/large town population of say 25,000 people? That is in a good season of course. What do you think, more...less ?

Thanks a ton,

John

 

[godawful]

i dunno if you can do a search for my name or maybe i think the post was named "age of empires d20 style" but i did a lot of research on this and came up with what you will find posted.
hope it helps

 

[Wil]

Try this out...not sure if it's 100% but some numbers are better than none:

http://dannyman.toldme.com/2005/10/12/notes-on-medieval-agriculture/

 

[Rothe]

Well thanks for the quick response to such a mundane question guys. I totally understand how its a really tricky question with too many variables to really answer. So would you think it'd be within reason to say a rural area of roughly 40-50 sq. of excellent/highly productive farming land could support a small city/large town population of say 25,000 people? That is in a good season of course. What do you think, more...less ?

Thanks a ton,

John

This sounds reasonable assuming good crop storage. Here's why, with some rounding on the numbers to make the calculation easy. 40 sq. miles = 25,600 acres. I'll round down to 25,000 acres to make it a nice 1 acre per person. Let's let the people eat well roughly 2,000 calorie diet. 1kg grain = 2,000 cal. Thus, each acres needs to yield 365 kg. Numbers are generally available by volume. 1 cubic meter of grain weighs about 750 kg, or 0.75 kg per liter. Thus, 365 kg grain = 487 liters. Yields of grain can vary. Wheat is much lower than say rye and barley. A yield, for example, of rye/barley of 500 liters an acre is pretty conservative (700 liters might be better). Thus, it appears that 40 square miles could readily provide enough grain to feed 25,000 people. The grain will mostly be rye/barley/millet/spelt etc. and not wheat. This accords nicely with the medieval diet.

I have ignored the effects of exhausting the land and loss due to crop storage. Wheat, besides having nutritional advantages, was often preferred because it could be made into white flour. White flour keeps far better than whole wheat flour.

A note on "Magical Medieval Society." Population density numbers contain many more variables than pure crop yield. A good example of this is to compare the size of medieval cities to those of the Roman Empire. Using medieval data a city the size of Rome (1 million, some say up to 2 million) wouldn't be possible. Yet we know it was and it lasted for centuries. It sounds like your lands are rich, well supplied with water, use iron ploughs (with moldboard? and/or horses?), possessing a fine climate and the people practice crop rotation. Other things being equal, I'd suspect your population densities to be greater than the historical ones found in medieval Europe.

If you are interested in some more information, see what you can find on the Buster Ancient Farm Project. This was an actual experiment conducted to explore the yields of iron age farms in Britian.

Finally, to get an