On August 25, 1998, at 0830 eastern daylight time, a Rockwell International S-2R, N5506X, collided with a field irrigation system during an aerial application flight, near Colquitt, Georgia. The aerial application flight was operated by the pilot under the provisions of Title 14 CFR Part 137 and visual flight rules. There was no flight plan filed. Visual meteorological conditions existed at the time of the accident. The pilot sustained serious injuries. The aircraft was destroyed by the impact and post crash fire. The flight departed from Colquitt, Georgia, at 0800. The pilot had finished his first load and returned to the air field to pick up his second load of the day, the weather was good with good visibility. He loaded 70 gallons of fuel and 150 gallons of chemicals in his S-2R airplane. At approximately 0800 the pilot departed en route to a cotton field seven miles northwest. Upon arriving at the cotton field, the pilot completed his first swath run. During the second swath run, the pilot noticed irrigation equipment in the same field. The pilot stated he diverted his attention from the irrigation equipment and continued the swath run. When the pilot returned his scan to the irrigation equipment, he realized he was too close to fly over it, although he tried to, the airplane struck the equipment. The pilot tried to maintain control of the airplane as it traveled 40 feet into the field. The airplane collided with the ground, and nosed over. The pilot was able to egress the airplane and was hospitalized for observation for greater than 48 hours. The airplane was destroyed by the crash and post crash fire. Examination of the airplane at the accident site disclosed that, the collision severed the four inch water pipe of the irrigation system. The wing, and the propeller assemblies were damaged during the initial collision. The airplane rested inverted, and fuel spilled from the wing tank. The airframe also sustained extensive fire damage. The pilot stated that the airplane was running fine and that he misjudged the distance to the irrigation equipment.