On September 26, 1998, about 0705 eastern daylight time, a Cessna 172P, N54013, collided with a tractor during landing on a grass strip in Farmville, North Carolina. The airplane was owned and operated by the commercial pilot under the provisions of Title 14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed and no flight plan was filed. The pilot was not injured, and the airplane sustained substantial damage. The flight originated from Kinston Regional Jetport in Kinston, North Carolina, at 0650. The pilot stated that he flew a left traffic pattern for runway 03. He stated the final approach was flown at approximately 65 to 70 knots with 30 degrees of flaps. He said he landed about 500 feet down the runway, and during initial braking the aircraft began to slow down. However, the pilot said, that after a short time the brakes locked, and the aircraft slid off the left side of the wet grass runway striking a tractor and farm equipment. No mechanical problems with the airplane were reported by the pilot. Examination of the aircraft, found impact damage to the right wing strut, right wing spar, right upper and lower engine cowlings, prop spinner, and sudden stoppage to the engine.