I didn't see it mentioned but I had heard that the Haitians deforested most of their more mountainous side of Hispaniola so what little top soil was there was washed away. This is also why there is a torrential flood risk especially during and after tropical storms.

The Cibao on the Dominican side is a really fertile and productive agricultural area.

Haitians are pretty much screwed, especially with friends like the Clinton Foundation, who needs enemies.