Huh? What's agriculture got to do with the South? The states where agriculture is biggest are as a rule midwestern, not southern.
The best identifying mark of the south is an at least formerly large rural Black population.
Traditionally, the South was agricultural, probably at least until 1960. Further, it wasn't mechanized until after WWII, at least at the same rate as the midwest.
You really didn't see a highly urbanized Black population until well after WWII. You had pockets, but most of my neighbors had fathers or grandfathers that "came up" from the south, generally after WWII.
It's the untold story in white America.