[Glorantha] urban percent

[Thompson, Todd L.]

> Total population compared to usable land area also affects these
> figures. Medieval Japan had lots of cities compared to medieval
> England simply because they had a far larger population for a
> similar land area. They did that by devoting their agricultural
> resources to rice so got higher productivity per acre than England
> which practiced mixed farming including livestock.

Strictly speaking potatoes have the highest yield per acre, which is why
the Irish planted so many potatoes in the day and helped set the stage
for the Great Famine.  They tended to have large families and the little
land they did have got divided up among the children until potatoes were
the only crop that could support their families.

The advantage rice has is that it can be harvested a second time in a
season, but the crop as a whole is very labor intensive and requires a
phenomenal amount of water, which works well in areas with lots of low
cost labor, thralls maybe :P