Removing grass in Dayz SA:
1) Go to ...\Steam\SteamApps\common\DayZ\Addons
2) Find plants2_clutter.pbo
3) Cut and paste to Dayz Standalone folder
4) Run Dayz, wait till loading and minimize the application (alt+tab).
5) Cut plants2_clutter.pbo from Dayz Standalone folder and paste to Addons folder.
6) You can play without grass now.