Related for Gittin 72:18

On the 15th of this [month] the officials of the court go out and declare the mixed crops as ownerless, For what the court has declared as ownerless is considered ownerless and is exempt from the tithes. If [a] man found mixed crops in a vineyard, it is lawful as "robbery" and free from tithes; but is in the field it is forbidden as "robbery" and he is obliged to pay tithes.