Weasil, in CA. and the rest of the States, insurance minimums have made it difficult to break into the ag industry. Also, because of the FDA, Dept. of Ag., drought, farm economy, ground rigs to name a few have made the number of seats availible limited. Your student needs to take an ag course initially.
Meeting insurance minimums is the #1 deterent, normally:
1,500 to 3000 ag for a recip
500 turbine tailwheel + 1500 to 3000 ag for turbine equipment
hope this helps