The pilot reported that he was maneuvering to perform an agricultural application. He noticed a ground application operator was located inside of the cab of the ground application equipment. The pilot decided to perform a "close fly-by" over the ground equipment. The left main landing gear struck the ground equipment cab, and the pilot chose to return to the airport. He landed on the gravel taxiway that paralleled the runway. The airplane sustained substantial damage to the left main landing gear attachment points. Per the National Transportation Safety Board Pilot Aircraft Accident Report, the pilot reported that the accident could have been prevented if "the pilot [had] used better judgement and not done a close fly-by the ground application equipment," which was also owned by the operator. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.