Related su Demai 6:16

[Produce purchased in] Cheziv [=Achziv, a town in northern Israel] alone is exempt from Demai (cf. Dem. 1:3). [But] the presumption is that [produce purchased elsewhere in] the Land of Israel is liable, unless it is known [with certainty] that it is exempt. [Conversely] the presumption is that [produced purchased] outside the Land of Israel is exempt until it is known [with certainty] that it is liable. [One who purchases produce from] Israelite landowners [who are presently residing] in Syria need not separate Demai [for the purpose of tithing], but if it is known that the majority of the produce is theirs (i.e., grown on their land in Israel), behold, it is liable.

A chaver that leases from an am ha'aretz (i.e., the chaver works the land and shares in the produce, see Dem. 6:1] fig trees or vineyards [lit. "fig roots (cf. Sifra Shemini Ch. 12:2) or vine branches"), he tithes and gives him [his portion], but he does not give him [anything] but what is his [portion]. [Note: Since the am ha'aretz presumably will not tithe, the chaver tithes the entire harvest before splitting up the remainder, as opposed to splitting up everything and then tithing, since in the latter case the chaver will need to take all the tithes out of his own portion and thus wind up with less.]

One who receives a field from a Gentile (i.e., to perform work on in exchange for a share of the yield) tithes [first] and [then] gives [the Gentile's portion] to him (but see Dem. 6:1). Said Rabbi Shimon ben Gamliel, "What if this Gentile [does not agree and] wants that the produce not be tithed [first]? [In this case,] rather [the Jew should] divide [the produce first] and give it to him directly [although here the Jew would only be able to take tithes from his own portion, resulting in his share being smaller than the Gentile's share].

One who receives a field from a Jew (i.e., to perform work on in exchange for a share of the yield), [first separates] Terumah and [then] gives [the field owner the remainder of his portion (see Dem. 6:1)]. Rabbi Meier says, "He tithes and gives him." Rabbi Yehudah says, "If he gives [the field-owner his portion of the yield] from the same field and from the same species, he [first separates] Terumah and [then] gives him. If from a different field or from a different species, he [first] tithes and [then] gives him" (Dem. 6:1). But the Sages say, "If [the produce given as payment is] from the same field [harvested], he gives it to him [as follows]: Whether from the same species or from a different species, he [separates] Terumah and gives him. And if it is from a different field he gives it to him [as follows]: Whether from the same species or from a different species, he tithes and gives him." If he received from [another Jew] seed [in exchange for] produce [already] in the threshing floor, he tithes and gives him. [However,] if from a place that they divide up the threshing floor, he gives him his portion in front of him. If he received from [the Jew] money to give him [in exchange for] produce [already] in the threshing floor, everyone agrees that he tithes and gives him.

A convert and a Gentile that inherited from their Gentile father, [the convert] has the right to say to [the Gentile], "You take the idols and I [will take] the utensils," [or] "You the wine and I the fruits" (cf. Dem. 6:10). Onkelos the Convert divided [his Gentile father's inheritance] with his [Gentile] brothers, and was stringent on himself. He cast his portion into the Dead Sea. If they inherited a thermal bath [=מרחץ, see Avodah Zarah 3:4], [the convert] has the right to say to [the Gentile], "Let it be your portion on Shabbat, and my portion on the weekdays."

[With respect to] a Yisrael who received a field from a Kohen [as a sharecropper], the Terumah (priestly portion) goes to the Kohen, [and the] first and second tithes are divided between them. [With respect to] one who received a field from a Levite, the first tithe, Terumah, and second tithe are divided between them. [With respect to] a Levite who received a field from a Kohen, the Terumah goes to the Kohen, and the first and second tithes are divided between them. A Kohen who received a field from a Levite, the first tithe goes to the Levite, and the Terumah and second tithe are divided between them. A Yisrael that received a field from a Kohen and told him [that he received it] on the condition that "the tithe is mine," on the condition that "the tithes are yours," on the condition that "the tithes are mine and yours" -- this is forbidden. A Kohen who received a field from a Yisrael on the condition that "the tithes are mine" -- this is permitted; on the condition that "the tithes are yours" -- this is forbidden; on the condition that "the tithes are mine and yours" -- if he purchased it in the manner [that it is customarily purchased], it is permitted, and if not, it is forbidden.

[In the case of] a cow of a Kohen that was put in a Yisrael’s care [on the condition that the Kohen and the Yisrael share the profits from the offspring] and that gave birth to a firstborn calf, the firstborn calf belongs to the Kohen, the words of Rabbi Yehudah. (Y. Dem. VI.4.3). But the Sages say, the firstborn calf belongs to both of them. Rabbi Yehudah said to them, "Do you not agree that the produce [per Yerushalmi, "tithes"] of the field is his?" They said back to him, "The body of the field is his, and the body of the cow belongs to both of them. Nevertheless, if the body of the cow belonged [solely] to him (i.e., the Kohen, see ibid.), its firstborn would belong to the Kohen."

[If] an am ha'aretz who said to a chaver, "Buy me a bunch of vegetables," [or] "[Buy me] a loaf of bread," Rabbi Yosei says, there is no need [for the chaver] to tithe [what he purchased for the am ha'aretz, see Dem. 6:12]. Rabbi Yehudah says, he needs to tithe. Rabbi Shimon ben Gamaliel says, if he exchanges the money (i.e., he uses his own money rather than the am ha'aretz's money to purchase the vegetables or the bread, see Minchat Yitzchak here), he needs to tithe.

[If] five said to one, "Go and bring us ten loaves of bread" [or] "[Go and bring us] ten bunches of vegetables," [and] he brings each one to his face (i.e., he brings that person what was purchased with that person's money), [then the] chaverim that are among them (i.e., among the purchasers) do not need to tithe except for their own portions. [But if] he brings them mixed together [so that he cannot tell which produce was purchased with which money], [then] the chaverim that are among them need to tithe on everything. If they gave him one in addition (i.e., the seller delivered one more item than was ordered, e.g., a baker's dozen), Rabbi Yehudah says, "It belongs to the messenger," and Rabbi Yosei says, "It is in the middle," (i.e., they all divide it, see Y. Dem. VI.8.6 ["רִבִּי יוֹסֵי אוֹמֵר שֶׁל שְׁנֵיהֶן"]).