Take a look at the links at the bottom of this page. This might be one case where the Recommended Reading links might actually be on target. For example, here's one: Tires better then tracks?. If you search the site there should be several conversations in the last couple years that cover it pretty exhaustively.
If you even have to question it then tires are the way to go knowing nothing else about your farming conditions. In our hills the tired tractor gives up while the tracked tractor is still laughing at it then tracks are the way to go.