On the history of tobacco: "The uncultivated Virginia soil was reportedly too rich for traditional European crops, especially cereals like barley. Tobacco "broke down the fields and made food crops more productive" by depleting the soil of nutrients.""

Wow, tobacco was used in colonial America because it actually destroyed soil structure. Of course this has been a common theme across American agriculture..we fit the plant into the soil, and forget to ask whether it even belongs there in the first place.