Related for Yevamot 146:5

There is a stringency with Terumah (the priestly portion of produce) that there is not with second tithe (which is exchanged for money and brought to Jerusalem) or first fruits, and [a stringency] with second tithe that there is not with Terumah. [With respect to the stringency of Terumah], we may not take [Terumah] except out of a mass [of produce] in close proximity (המוקף), nor may we take it except from [produce that is in] a finished state, nor may we take it except from the pure on behalf of the impure, or the medumma (a forbidden mixture of Terumah and chullin), and we are liable on it for an extra fifth, and it applies to all [species of] produce, which is not the case with first fruits. And it applies to all the years [of the seven-year agricultural cycle other than the seventh year], all of which is not the case with second tithe [which only applies to the first, second, fourth, and fifth years].