You can [[botanize]] but you can not [[forage]] on steppe tiles.
===Terraforming===
You can dig or pack steppe away. Dropping [[pile of dirt|dirt]] also destroys the steppe tile. You can convert a [[dirt tile]] into a steppe tile by planting [[mixed grass]] botanized from other steppe tiles. Steppe spreads onto dirt tiles on its own, but slower than [[grass]].