The commercial pilot reported that, while spraying a field during his first agricultural application flight, he flew the airplane over the field east and west and was blinded by the sun. For the next application, he decided to fly north and south over the field, so the sun was not in his eyes. The airplane was operating normally, and he finished spraying the field. He remembered that he was supposed to spray another field to the east, but he could not remember anything after that. The airplane was found resting in the field. The airplane and a 150-ft-tall antenna tower located on the east edge of the field were substantially damaged, and a portion of the tower structure was found entangled with the right wing. The pilot was seriously injured. Review of astronomical data indicated that the sun at the time of the accident in relation to the tower location was almost due east. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.