We don't need any subtags to grassland=* which only describes the location (continent) of the grassland. This is done by the coordinates.
If it's urban grass, the right tag should be landuse=grass.
Tagging of earth surface should not describe linguistic/cultural regional differences in the first place.
We have some natural (uncultivated) grassland here i.e. in the Rhoen or Vogesen mountain which very little looks like "Steppe" or "Puszta", much more like natural=fell (which is per defintion limited to alpine or subalpine regions above the tree line). --Taunide (talk) 06:24, 10 November 2016 (UTC)