There are reasons why the economy in the South relied on slave labor. The South was mainly an agricultural region. The climate was very suited for farming, and the soil was very fertile. As farming grew in the South, southern farmers brought in slaves to do the work. An important factor in this development was the invention of the cotton gin.
Before the cotton gin was invented, most cotton was grown near the coast. This long-staple cotton was a profitable crop, and the seeds could easily be separated by machine. The short-staple cotton crop was grown inland, and the seeds had to be separated by hand. Once the cotton gin was invented, cotton could be grown anywhere, and the seeds could be separated by using machines. This led to an explosion in cotton growing in the South, as plenty of lands was available for growing cotton. This led to an increased demand for slaves. Growing cotton was very profitable, as southern cotton was in big demand in Europe. The southerners believed their economy could not survive without slaves. They believed there would be a collapse of their economy if slavery ended. As a result, southerners fiercely fought to maintain slavery and to work for the spread of it to other regions where farming was done.