Hair particles are not fitting my fractal ground I created an object composed of 6 different forms and I want it to simulate grasses and my plane that contains "mountains" and a generally altered surface (so its not a plane any more ^^).

When coming to add particles, my object does not fit the ground. If I use rotation and altered my Y axis object, I don’t have a pretty natural result, and nothing is sitting on my floor...
Set Random velocity to 0

As state by the Blender manual's page about the option:


  Gives the starting speed a random variation


Each object, having a different emission speed, is found at a different distance from the surface at the current frame (even if it is the staring one).