The pilot was engaged in the spraying of sugar cane. During one of the swath runs as he turned the aircraft to follow the line of the cane the right wing struck the cane. The aircraft impacted the ground and bounced several times before coming to rest. The configuration of the spray run chosen, by the pilot, involved a turn through 33 degrees during the run. The aircraft was being operated at a lower altitude than was necessary under the prevailing conditions to complete the task. The combination of both these facts made the judgement of wingtip clearance during the run extremely difficult.