Explain what role geography played in the growth of slavery in the plantation system in the south

The area was very good for plantations, and so they needed more workers and the slaves were perfect for it.

The geography of southern United States is a prime location for the growth of "cash crops". These were in high demand at the time, so an increase in slaves was necessary to produce the amount of crops needed. Also, the areas where plantations thrived were generally flat plains, which have many advantages in agricultural production themselves.