Although cotton was clearly king in the South, it was not the only agricultural product cultivated. Tobacco, rice, indigo, and sugar were also profitable crops which depended on an abundant supply of labor, but the market for cotton produced as much wealth as all the other products combined. The South also produced large quantities of corn, wheat, and other consumables alongside forage for livestock, which the South cultivated in abundance. Although agricultural reforms were attempted in order to counter the depletion of soil brought by the growing of tobacco and other staples, the abundance of virgin land in the more western areas of the South kept many farmers and their slaves on the move.
As the cotton culture spread westward, slavery strengthened its hold on the South. The demand for slaves was greatest in the Deep South, and the Upper South sold its slaves "down the river" at ever higher prices. Slave trading was a lucrative business, but it sometimes led to the breakup of slave families. As the price of slaves increased, only wealthy Southerners could afford to buy them, so by 1860 only one-quarter of Southern families owned slaves. Slavery was profitable, but it kept Southern capital from being invested in trade and manufacturing. Thus development of transportation systems and manufacturing in the South lagged far behind the North by 1850. Furthermore, much of the wealth generated by the cotton economy flowed northward as Northern merchants, bankers, ship-owners and manufacturers derived substantial income from crops produced by slaves that otherwise might have remained in the South. Southern critics of the slave system repeatedly emphasized that fact.
Hinton R. Helper, one such Southern critic of slavery, recognizing the realities of the slave system, wrote in 1857:68
In one way or another we are more or less subservient to the North every day of our lives. In infancy we are swaddled in Northern muslin; in childhood we are humored with Northern gewgaws; in youth we are instructed out of Northern books; at the age of maturity we sow our "wild oats" on Northern soil; in middle-life we exhaust our wealth, energies and talents... giving aid and succor to every department of Northern power; in the decline of life we remedy our eye-sight with Northern spectacles, and support our infirmities with Northern canes; in old age we are drugged with Northern physic; and, finally, when we die, our inanimate bodies, shrouded in Northern cambric, are stretched upon the bier, borne to the grave in a Northern carriage, entombed with a Northern spade, and memorized with a Northern slab!
At bottom, slavery was a stagnant and inefficient labor system that wasted talent and energy. Since there was no incentive for slaves to work any harder than they had to, they required constant supervision. Tools often broke "accidentally" and thus had to be stronger. Many forms of passive resistance made slave labor far from free. Economic historians have argued over the comparative economic benefits of the Southern slave system and free labor systems.69