Demai 5:11-6:1

Demai 5:11

If one took terumah from demai (doubtfully-tithed produce) for other demai, or from demai for tevel (definitely untithed produce), what he took is treated as terumah but he must take terumah again properly. If he took from tevel for demai, it is terumah but the kohein may not eat it until he takes terumah and maaser from it. (As we explained in the previous mishna, if one takes terumah from obligated produce for exempt produce, it is considered tevel and must be tithed.)

Demai 6:1

If a person receives a field as a sharecropper from a Jew, a non-Jew or a Samaritan (quasi-Jew), he just delivers the landowner’s portion untithed. If he rents the field from a Jew, the renter must take terumah from the crop and he deducts it from the produce he owes the landlord as payment. Rabbi Yehuda says that this is only when he pays the landlord with the same type of crop taken from the same field; if he pays his rent with another type of crop or from another field, then the renter must tithe even what he gives the landlord as payment.