View Full Version : Cultivated area vs population
06-10-2011, 12:11 PM
I searched the forum for this subject but couldn't find anything. If there is a post about it please accept my apologies and direct me to it.
I would like to know if someone has an estimate on how much cultivated land is needed to support a population of X people type of thing. :?:
I know that this may vary, like in the case of fishing settlements and such.
I am asking here first because I would think it is a subject of some interest in fantasy map making. But if no one has any idea I will surely do research on it and post my findings here.
06-10-2011, 02:48 PM
There are a couple of resources. There might be some data in Sigurd's analysis of Herefordshire: http://www.cartographersguild.com/showthread.php?3391-Plausible-Distances-amp-Populations&highlight=hereford
Also, the article Medieval Demographics Made Easy (http://www222.pair.com/sjohn/blueroom/demog.htm) is a good source, and there are some associated calculators linked in at the bottom of the article.
The rule of thumb I use for medieval populations is that an acre of decent farmland can support 4 people, and 5 acres of pasturage can support 2 large animals. That's for typical medieval grain farming techniques. Different kinds of subsistence can be better or worse.
06-10-2011, 03:09 PM
The ratio of arable land (farmable land) in acres to population has a lot of factors. Is the society sustainable? (For example, the US (and most of the Western World) is not; we import a lot of food from other places, so the proportion would be much lower than a country that feeds itself). As you mentioned, what proportion of the food supply is hunted, fished, foraged (or imported and exported)?
I did a little bit of poking around and came up with this table: List of countries by real population density (based on food growing capacity) (http://en.wikipedia.org/wiki/List_of_countries_by_real_population_density_(base d_on_food_growing_capacity)) The table ranks countries by their Real Population Density (population / arable land (in km²) ). The more arable land, the greater ability for a country has to support itself and increase its population.
Another interesting site was this: Food, Land, Population and the US Economy (http://dieoff.org/page40.htm) This site gives some real numbers (ignore the message, if you wish) for 1994.
After a little more research, I discovered another site on how it all is important: Understanding Real Population Density (http://www.bclocalnews.com/opinion/119355494.html?c=y&curSection=/surrey_area/peacearchnews&curTitle=BC+Opinion&bc09=true)
As a bonus, I found this site that discusses how the world's arable land is being depleted with some neat statistics on things like protein sources, etc.: Food and Soil (http://www.theglobaleducationproject.org/earth/food-and-soil.php#2)
So, I guess you could have any ratio of arable land to a population, but the higher the ratio, the happier and more independent the population will be.
(¸.´ (¸.` ¤ 7thDirection
06-10-2011, 04:05 PM
Thank you for the answers guys. I love lists lol, so I went first to the "List of..." link. I was astounded by them saying that Brasil has only 6.93% of arable land. So I looked what arable land means, and learned that the "able" in the expression is fallacious. It is land actually being used, not potential land. As per the FAO definition: "Arable land includes land defined by the FAO as land under temporary crops (double-cropped areas are counted once), temporary meadows for mowing or for pasture, land under market or kitchen gardens, and land temporarily fallow. Land abandoned as a result of shifting cultivation is excluded". Phew!
I have not checked the other links yet, but will soon and give feedback.
06-10-2011, 05:51 PM
How many people can be supported also depends on the crops being grown, climate, and soil fertility. Much of America's farmlands are wasted because they grow corn. Corn is low in nutrition, is only a base ingredient for livestock feed, and has few uses outside of biofuel. Whereas an orchard of crabapple trees provides a lot of nutrition, including many essential vitamins. A Costa Rican farm can provide fruit throughout the year, whereas a Canadian farm only provides fresh vegetables for less than half a year. Soil fertility is also important. A farm in rocky, thin soil will output food in smaller quantities and with less nutrition than a farm in the former swamps of the Netherlands.
Farmland density and type is another factor. Are the farms mostly small gardens attached to houses, worked by peasant families? Or are the farms vast fields worked by organized groups of locals? If the terrain is mountainous or hilly, do the people employ terrace-farming techniques?
There is a lot to consider.
06-15-2011, 11:02 PM
How much of the crop can be harvested and got to table without spoiling or being eaten by pests? This is often a huge factor in how much food people actually have available.
For fantasy map-making, you have to consider magic and fantasy crops like underground fungal forests. Also, if you have non-human populations, they may have considerably different dietary needs compared to humans.
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