Related על שביעית 9:1

1) And whence is it derived that the thirty day period before Rosh Hashanah is regarded as the entire year? From "And on the seventh year a Sabbath of resting shall there be for the land" (the month of Rosh Hashanah being regarded as a year in itself) — whence they ruled: The shevi'ith year of benoth shuach (a type of fig) is the second year (after the shevi'ith in which it matured) because it matures every three years. R. Yehudah says: The shevi'ith year of the Persian figs is the end of Shevi'ith, for they mature every two years. They said to him: They stated it only about benoth shuach.

3) (Vayikra 25:5) ("The after-growth of your harvest you shall not reap, and the grapes of your guarded vine you shall not glean; a year of rest shall there be for the land.") This is the source for the sages' ban on the after-growths of the seventh year. "and the grapes of your guarded vine you shall not glean": From what is guarded in the land you may not glean, but you may glean from hefker (what you relinquished ownership of.) "you shall not glean": in the (usual) way of the gleaners — whence they ruled: Figs of shevi'ith are not to be cut with a muktzeh (the usual tool), but with a knife. Grapes are not to be trod in a vat, but n a kneading trough. Olives are not to be processed in a (bad) (an olive-press) or in a kotiv (a smaller press), but may be crushed and put into a bedidah (a small press). R. Shimon says: They may also be ground in a bad and put into a bedidah.