Although the federal government outlawed American participation in the Atlantic slave trade in 1807, after 1820, cultivation of the highly profitable cotton crop exploded in the Deep South, and along with it, the slave population. The Second Great Awakening, especially in the period 1800–1840, converted millions to evangelical Protestantism. In the North, it energized multiple social reform movements, including abolitionism; in the South, Methodists and Baptists proselytized among slave populations.