What is the Torah source and underlying principle that determines when biyur must be performed?
Leviticus 25:7 states 'for the animal and the beast in your land' — as long as a wild beast can eat that species in the field, you may eat it at home. Once no more is available to the beast, biyur must be performed.
Question 2
If a person must perform biyur but cannot find anyone to receive the produce, what should he do?
According to the Rambam, biyur means destruction. If no recipients are available, one must burn the produce or cast it into the Mediterranean Sea (or destroy it by any means), as the obligation is to actively eliminate it from one's possession.
Question 3
Three species share a unified biyur deadline across all of Eretz Yisrael rather than following regional rules. Which three?
Carobs, olives, and dates have little variation in ripening time across Eretz Yisrael's regions and remain on the tree long after ripening. Therefore, the entire land is treated as one unit for these species, with dates until Purim, olives until Shavuot, and grapes until Pesach of the eighth year.
Question 4
Three types of produce were pickled together in one barrel. If only one type is no longer available in the field, what must be removed?
Only the species subject to biyur must be removed. Although it has imparted its flavor to the other two types, this does not render them forbidden. The absorbed flavor alone does not trigger the biyur obligation for the remaining species.
Question 5
Which of the following plants does NOT require biyur even though the laws of Sabbatical year apply to it?
Madder is a dye plant that remains rooted in the ground continuously, making it always accessible to animals. Since it is perpetually 'available in the field,' the biyur obligation never triggers — one may benefit from it until Rosh HaShanah without needing to perform removal.