The South was being exploited as a raw materials producer by the industrialized North. They just took over where the English left off. Read Gone With the Wind, or the sequel... Rhett Butler's People, by Donald McCaig (historica fiction)

(non-fiction) The Cotton Kingdom, by Frederick Law Olmsted, is worth reading. Olmsted traveled extensively in the South in the 1850's, and was well acquainted with the plantation system and the slave trade. Also, Tombee, by Theodore Rosengarten... from the journals of a Sea Island cotton and indigo planter, before and after the war. There are actually historic sources that are more reliable than the Internet.