Fun With Math

I had Tom spray the wheat with fungicide. This is something we do as a standard practice on our seed wheat, since the crop is so valuable. Most wheat gets sprayed by plane to avoid making tracks like this through the field. I think the better coverage achieved with a ground rig makes up for the tracks. (A way to avoid this would be to leave tram lines through my fields, but as I plant without markers using a simple WAAS corrected gps lightbar, I can't plant straight enough to make any tram lines effective.)

So here is the fun part. Assume lobiwan had 348 acres sprayed. Assume Tom has a ninety foot boom. Assume his tire tracks are 10" wide each. Assume that the yield of the wheat, if sprayed by plane, would be 60 bushels per acre. Assume wheat grin will be worth $6 at harvest. Now, assuming that there is no yield difference (per acre not destroyed by wheel tracks) between either method of spraying, and assuming the application cost is the same, how much money did lobiwan lose by having his wheat sprayed by ground? How much better (in bushels per acre) would the yield need to be to make up this money 'lost'?