What were the crucial economic changes occurring in the north and south during the reconstruction era?

During the reconstruction, the North started developing more and more since they completely switched to heavy industry and had numerous factories that manufactured goods out of resources attained elsewhere. They would have steel companies or coal mines or similar things and this helped them industrialize and become vastly rich.

The south didn't fare well during the reconstruction since their economy depended on slavery and cotton. Slavery was abolished so they had to pay workers now, while cotton was falling out of grace since they couldn't sell their produce since it was not popular any more since other fabrics started being used and they couldn't export it.