On August 6, 2002, about 1430 central daylight time, an Air Tractor AT-301, N3164E, registered to a private owner, doing business as Baker Flying Service Inc., operating as a 14 CFR Part 137 agricultural flight, ground looped during a precautionary landing in the vicinity of Memphis, Tennessee. Visual meteorological conditions prevailed and no flight plan was filed. The airplane sustained substantial damage. The commercial pilot reported no injuries. The flight originated from Memphis, Tennessee at 1200. The pilot stated he experienced a rough running engine after making a swath run. The engine started to sputter, cleared, and started to sputter again. The pilot suspected water was in the fuel system, and he elected to make a precautionary landing to a grass strip located on President's Island instead of continuing the flight. The pilot stated he was nervous and felt he should land. He made an approach to the north, and did not notice the height of the grass on the runway. During the approach he observed a dusty road located to the left of the runway, but elected to continue to the grass runway. On landing rollout, the airplane encountered the high grass, and he experienced a loss of directional control. The airplane ground looped to the right. Examination of the airplane disclosed that the main landing gear was spread, the tail wheel assembly had separated, and the left and right wings sustained damage. Examination of the dirt road revealed that ample surface condition existed for a landing. A functional examination of the engine assembly was accomplished.