Alms Tax: Giving Half a Sa' of Different Items
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 2029
A person cannot give as fiṭrah half a ṣāʿ of one item, such as wheat, and half a ṣāʿ of another item, such as barley. In fact, even if he gives half a ṣāʿ with the intention of paying the value of the fiṭrah [as opposed to giving the quantity of the item], it is not sufficient.
-Ayatullah Sistani, Practical Laws of Islam, Alms Tax (Zakat)