Answer:
The economy of the southern United States was based on agricultural and livestock production, where large landowners exploited their lands using slave labor to produce cotton, horsefly, grains, and livestock products.
Now, the vast majority of the southern white population could not afford to have slaves, as they did not have the funds to acquire or maintain them. Thus, these people exploited their own land for themselves, consequently producing less than the richest and most powerful landowners.
Within this group were, in turn, the poorest whites. These people did not even have their own land to exploit, so they had to work as wage laborers for slave landowners, often as foremen or guards for the slaves themselves.