Tithe Grade refers to the amount of materials an Imperial world must supply to the Administratum. The size of the tithe depends on the type of world it is applied to. A tithe can be any form of material: food, weapons, minerals, people, etc.
Space Marine homeworlds do not normally have tithes, and are given the tithe grade Aptus Non.
Agri world tithes generally refer to how much of the planet's food production must be supplied.
Known Tithe Grades1
- Aptus Non (also Adeptus Non)
- Solutio Tertius
- Solutio Prima
- Solutio Extremis
- Decuma Particular
- Exactis Tertius
- Exactis Prima
- Exactis Particular
- Exactis Extremis
Sources
- 1Warhammer 40,000 3rd Edition Rulebook, pp. 114–115