If you want no Grass on your Server, the only Option without Modding is: "setTerrainGrid 50;". But if you set this, the Landscape is horrible (sunken Buildings and units in the distance >600 m).
Can we have a seperat option to disable Grass Global (Server)? Well, if you have a low setTerrainGrid (3.125), you have much Grass around a player, this is a big impact on the client FPS -50 %.