Plants.
You mean fertiliser?? No.
Guys and guyesses, why don `t you follow simple logic in your guessing?
I said twice: it is food but not for eating.
If not for eating, it is for WHAT, then???? What is the other remaining option?
Of course, you can only see the top part of the bigger picture. Below there is sth much more important but right now I am not showing it.
Hint - you can see only dregs now.