On June 7, 2012, approximately 1315 central daylight time, a Grumman G-164B agricultural airplane, N779EF, sustained substantial damage during a forced landing following a partial loss of engine power near Higginson, Arkansas. The commercial pilot, who was the sole occupant, was not injured. The airplane was registered to and operated by J.P. Freppon Flying Service, LLC, of Bald Knob, Arkansas, under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual flight rules (VFR) conditions prevailed for the flight, which did not operate on a VFR flight plan. The local flight was originating at the time of the accident.According to the pilot, he was departing the local airstrip to perform an aerial application when the accident occurred. Approximately 50 feet above ground level (agl), the pilot noticed a partial loss of engine power and felt a vibration from the engine. The pilot attempted to dump the load of fertilizer and performed a forced landing to a field. The airplane came to rest upright in a wheat field and a postimpact fire ensued. The fire consumed the airplane. Post accident examination of the airplane by a Federal Aviation Administration inspector revealed a small crack in the number five cylinder on the Pratt & Whitney R-1340 engine. The engine was not disassembled for further examination, and it could not be determined if the crack was a result of the impact. The pilot thought that a magneto may have failed; however, due to the fire damage, the magnetos and accessories could not be tested. The reason for the partial loss of engine power was not determined.