Around 1640, the working and living conditions of indentured servants began to affect the numbers of those willing to enter the arrangement. The loss of this source of labor drove landowners to seek new forms of labor that would be cost efficient and profitable. With the loss of European indentured workers and the need for a high volume of cheap labor, the colonialists turned to Africans, which became advantageous and profitable.
The english revolution influenced this. Part of the reason there was so many willing (and interested) in leaving England was the political and social realities (and the population explosion) in England.
