"Irrogation" is not a standard English word. It's likely a misspelling of one of the following:

* Irrigation: This is the process of supplying water to land to help crops grow, usually through a system of canals, ditches, or sprinklers.

* Interrogation: This is the process of questioning someone formally, especially by the police, to get information.

If you can provide more context or the full sentence where you encountered "irrogation," I might be able to give you a more specific answer.