There isn't really a specific 10-code list for the Iowa State Patrol out there because they're supposed to avoid using them... they sometimes cause confusion when they're talking with other agencies using 10-codes. But despite that, the 10-codes have some common meanings across all agencies. A list is here: http://www.phreak.org/radio/tencode.html
As for disposition codes, good luck... it's better off just to ask the agency for a list (that is, if they still use disposition codes). Usually they are used only to file reports, if at all. And they vary by agency. Sorry for being so vague on this.