[philman_36]

The issue was not a tractor or a mule. It was what did take to get the crop to the gin. In the Confederate states, I could see that lasting into the early 20th century.

Yet you make my point for me.
Tractor (increased reliability/durability/productivity) over the mule.

You get more to the market/cotton gin with machinery..as you know.
The first successful cotton picking machine did the work of 40 field hands.
What do you suppose the farmer is going to do with those extra field hands?

Sell them, keep them, or free them?
Can't sell them, nobody else wants to buy them now with mechanized gear available.
Can't keep them, they cost too much money now with mechanized gear available.
Free them...about the only thing you can do to keep afloat financially.

[Bull Snipe]

That machinery was not available for decades later than 1860. The Southern planters would have continued to use millions of slaves to tend their crops and households. Once reliable tractors and crop harvesters became available around 1900, the planters would have shifted to their use. My point is that it would have been 40 years or more before slavery ended in the Confederacy.