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.