Is there a ratio of population and farmland needed to support the population ?

Question

you know for like every 100 people you need 100 acres of land to feed them ?

Answer 1

This is highly variable depending upon the culture and diet of the population and also upon the percentage of fish and aquatic food sources available and used.

In America, prior to perhaps 1950, the figure of 160 acres per person was often stated for the typical American diet. As the diet changes and agricultural methods improve, the figure has been decreasing. Understand that "feeder lots" for cattle and "tiered chicken boxes" take up very little room compared to wild range and old farm chicken houses.

A diet of mostly rice uses very little land in comparison.