The 19th century was an era of dramatic change in the lives of African Americans. By the early 1800s, cotton was the most profitable cash crop, and slave owners focused on clearing lands and securing laborers to proliferate cotton production. The lack of available, fertile land in coastal areas compelled the move into the southern interior, sparking a massive westward migration of planters and slaves. The demands and rewards of the "King Cotton" economy resulted in a fivefold population increase during the first six decades of the 19th century, but it kept the South an unsophisticated agricultural economy. Because it produced few other goods, it needed to import goods from northern manufacturing states; and because prices for cotton fluctuated