Crop waste

 is a byproduct of farming and is used to produce peat and maggots, or broken down via alchemy. Alternatively, it can be purchased from the Farmer and sold to the Shepherd.

Alchemy
Crop waste is decomposable to powder at the Alchemy mill. Having unlocked Master of Alchemy will produce one additional reagent.

Trading
Ernteabfall Déchet_Agricole