From Indigo To Coffee: Displacement
El Salvador's landed elite depended on production of a single export crop, indigo. This led the elite to be attracted to certain lands while leaving other lands, especially those around former volcanic eruptions, to the poor subsistence farming mestizos and the Indian communes. In the middle of the 19th century, however, indigo was replaced by chemical dyes. The landed elite replaced this crop with a newly demanded product, coffee.
The lands that had once been dependent for the product (indigo) were suddenly quite valuable. The elite-controlled legislature and president passed vagrancy laws that removed people from their land and the great majority of Salvadorans became landless. Their former lands were absorbed into the coffee plantations (fincas).
Read more about this topic: History Of El Salvador