Tosefta zu Bikkurim 2:14

These are the things that have no set amount: the peah, the bikkurim, the r'iyah, charity, and learning Torah. Peah has a minimum amount but does not have a maximum amount. [If] one makes his entire field peah, it is not peah.

These are the things that have no set amount: the peah, the bikkurim, the r'iyah, charity, and learning Torah. Peah has a minimum amount but does not have a maximum amount. [If] one makes his entire field peah, it is not peah.

The stringency with second tithe is that [with respect to wine from] second tithe, he "acquires the jugs" (see Mishneh Torah), and money [exchanged for it] is forbidden, and [with respect to] mixtures, a doubt as to a mixture [potentially involving second tithe forbids it] in any amount, [and] it is forbidden to a mourner, and [its violation] requires [the payment of] a fifth and requires a confession, and it is not permitted to eat except when it is redeemed, and it may not light it on fire, all of which is not the case with Terumah.

And so too Rabbi Shimon would say, [the Sages] did not state that produce that grows from [the seeds of] first fruits must be eaten in Jerusalem. "Tithes" -- about which "tithes" did they speak [when the Sages ruled that aftergrowths must be treated as tithes (see Ter. 9:6)]? [They ruled that aftergrowths are treated as tithes only] with regards to anything whose seed disintegrates [after planting], with regards to [produce] that is taken in and out of Jerusalem, with regards to [produce] that does not have the value of a perutah, and with regards to [produce] that is not [subject to the laws of] redemption. Rabbi Shimon ben Yehuda says in the name of Rabbi Shimon, one is not liable [to bring] first fruits that are attached to the ground.

A k'vi (see Bikkurim 2:8) -- how is it like a wild animal? Its blood requires covering like a wild animal. Rabbi Eliezer says, they are liable to bring a variable guilt-offering for [partaking in] their [forbidden] fats. How is it like both a wild animal and a domesticated animal? One who flays (המפשיט not מפסיד, see GR"A) it, [the laws regarding whether its hide is] connected [to its flesh is] like wild animals and domesticated animals (see Tos. Chullin 8:6). And [the laws of] the sciatic nerve apply to it, like they do to wild animals and domesticated animals. If he said, "Behold, I will become a nazirite if [the k'vi] is [neither] a wild animal or a domesticated animal," behold, he has become a nazirite. Rabbi Yosei says, a k'vi is a unique creation unto itself, and the Sages were unable to render a decision about it, if it it is a wild animal or a domesticated animal.

Rebbi Yehuda says, “A person who made his whole field into sheaves [in order to later] stook them [into stooks, which in turn will be taken to the final stack] is [considered to be] like someone who bundles [sheaves] in [order to put them in a] stack [of sheaves, which makes the sheaves inside the stooks eligible to become Shikcha (forgotten sheaves),] and [then] rounded it (i.e. the stack) out [as if he has completed the stack] and [then brought more sheaves and] pressed [them] into the stack [after the stack seemed to be already finished, which is still considered to be the final act of bundling, which makes these sheaves eligible to become Shikcha].” Bet Shammai and Bet Hillel agree that if [a person] proclaimed [his produce to be] ownerless [only] to people, but not to animals, [or only] to Jews, but not to Non-Jews, [it is still considered to be] ownerless [and anyone can come and take it].