Frances L. Hunter, The Journal of Negro History Volume 7 Number 1… (1922)
“ The soil of the South was favorable to the growth of cotton, tobacco, rice, and sugar, the cultivation of which crops required large forces of organized and concentrated labor, which the slaves supplied. On the other hand, the soil of the North favored the raising of cereals, which required neither organized nor concentrated labor; for one man working alone was able to produce more than one man working in a group: and thus slave labor was of little or no advantage to the North. ”
