1)
Seeing as the Dinim of a Sedeh Mikneh are largely similar to those of a Sedeh Achuzah, why does the Torah present them independently?
1.
Rashi: Because whereas, a Sedeh Achuzah, in the event that the owner does not redeem it until the Yovel, goes to the Kohanim, a Sedeh Mikneh reverts to the owner. 1
1
Rashi: That is because the purchaser does not have the authority to declare Hekdesh the field that he purchased - only the Peiros up until the beginning of the Yovel year (Rashbam).
