[SanchoP]

Eli Whitney and John Deere freed the slaves.

[Romans Nine]

“Eli Whitney and John Deere freed the slaves.”

Where is the “like” button?

I haven’t heard that in very very long time.

[DoodleDawg]

Eli Whitney and John Deere freed the slaves.

Say what?

[pierrem15]

Well, that and sugar beets:

By 1840 about 5% of the world's sugar was derived from sugar beets, and by 1880 this number had risen more than tenfold to over 50%

Wikipedia.

Certainly explains why Brazil ended slavery in 1888: it was no longer profitable.

[Chuckster]

Eli Whitney, with his cotton gin, made slavery profitable.

[Bubba Ho-Tep]

Eli Whitney and John Deere freed the slaves.

Eli Whitney's cotton gin revived the fading institution of slavery by making cotton farming practical. The fact is that the demand for and price of slaves boomed because of the cotton gin.

And John Deere's self-cleaning steel plow had much more effect in breaking up prairie sod in the upper midwest than it did in the slave belt.

If you're speaking of mechanization in general, cotton farming wasn't mechanized until the 1940s, when the first practical cotton harvester was developed. That combined with advances in herbicides, which reduced the amount of hand "chopping" of cotton fields, to reduce the amount of manual labor cotton production required. Not coincidentally, this is when sharecropping, the southern agricultural labor system that replaced slavery with debt peonage, died off.