Running fiber to another building

I am applying for a grant but I must come up with the best method to run fiber from our high school to our middle school about 1/4 mile away. Because of the monthly or annual fees in leasing lines, I would prefer to own the fiber by digging a trench and laying it in there. Our facilities director seems to think it would be a fairly simple matter to do that especially since the parking lot is going to be ripped up next summer anyway. He does not think conduit is necessary – that it can just be laid in the trench as it is dug by a special machine. Any thoughts or advice on this?