AFAIK no compost is used in traditional citrus cultivation. Compost is relatively modern; most of the stuff we used today to make compost back then were fed to chicken/pigs, or, if it was vegetable, was used to pave barns, to help cattle's rest/catch their droppings.
Then this matter was mixed with chicken/cattle feces and left to decompose for months. This lead to manure.
Traditional citrus growing made ample use of aged manure (even years old). Aged manure is a nutritious permeable matter which is a good growing medium. It needs to be left for a very long time outside to be leached by rain/sun by any excess of salt. I cant give more detail on that stuff because i never made it.
For traditional fertilization of potted citrus here i have seen in uses mostly 2 things: ground white lupin seeds (
https://en.wikipedia.org/wiki/Lupinus_albus ) used probably ad nitrogen source, and oxen's blood (I guess this helps with iron and micronutrients). Water can also play a role, but it's pretty rare nowadays to be able to water citrus with something different from faucets.