Midrasz do Kapłańska 25:11

1) (Vayikra 25:11) ("It is Yovel; the fiftieth year shall be for you. You shall not sow, and you shall not reap its aftergrowth, and you shall not glean (the grapes of) its guarded vine.") "the fiftieth year": What is the intent of this? I might think that just as in its beginning it is sanctified on Rosh Hashanah, so, in its expiration it should extend until Yom Kippur (of the fifty-first year), for "we add from the holy to the profane"; it is, therefore, written: "It is Yovel; the year of the fiftieth year shall be to you" — its sanctity extends only until Rosh Hashanah.

2) "You shall not sow, and you shall not reap its aftergrowth, and you shall not glean its guarded vine": Whatever applies to shemitah (with respect to the tillage of the land) applies to Yovel.