ORIGINAL: Tired Old Man
Lots of flying fields that overfly farmland. A good plan might be to consult the AMA accident/insurance fiels to review gas engine crashes that resulted in fire. Then again, with the amount of insurance coverage for a covered club and site, I don't know of too many farmers where that coverage would not easily extend to about triple the value of any given harvest.
I think the OP should go back a little deeper (the people) into the origin of his club though. The farm field thing was an excuse. The people that started the club did not like gas engines and the planes associated with them at the time. Fire was just the excuse needed to exclude gas engines.
I'll have to discuss more with some of the club members. Most of the current officers are pro-gas and would like to see the ban lifted. However I believe they are hesitant to approach the farmer because he's comfortable with the ban, even if it is ill-founded. Removing the limitation would probably seem to him to be an increase in risk.
BTW, the crop is always just grass which his cattle graze on...and where the snakes live
Last year I emailed the AMA safety guy and he basically just sympathized. I didn't think about asking about insurance claims or incident reports. That could be a good idea.
Dave