|This article is about an older version of DF.|
Bone meal is an item with no use that appears frequently in lairs in Adventure mode, but does not normally appear in Dwarf fortress mode except maybe in HFS. It currently has no use (although obviously made of bone, [BONECARN] creatures have never yet been observed consuming it) and appears only to be a prop, but word of god is that it'll eventually be a fertilization component (going the way of potash). There is a custom food stockpile options for bone meal that does not actually do anything except confuse the occasional wayward player; perhaps that is how you ended up at this page in the first place.
In real life, bone meal is a primitive food supplement made by grinding bones into a fine powder. Producing it in a future version of Dwarf Fortress would be simplicity itself: just mill leftover bones at a millstone or quern.