On May 16, 1994, at 0730 central daylight time, an Ayres S2R-G6, N448AT, was substantially damaged during the takeoff near De Witt, Arkansas. The commercial pilot did not receive injuries. Visual meteorological conditions prevailed for the local aerial application flight. During a telephone interview the operator reported the left main gear hit a levee at the departure end of the 2,500 foot sod runway. Left wing spar, engine, and propeller damage occurred as a forced landing was made to a field. The airplane was loaded with 400 pounds of herbicide and this was the fifth load for the day. There were no mechanical discrepancies reported. The pilot/operator report stated that during the takeoff roll the flaps were lowered to 10 degrees. While moving his hand from the flap switch back to the power lever, the flaps were inadvertently bumped to zero degrees at the time of airplane rotation. "This caused a settling effect and contact with embankment" according to the enclosed report.