On July 22, 2001, at 2030 central daylight time, a Piper PA-38-112, N23475, operated by a commercial pilot, was destroyed when it overran runway 17 (1,918 feet by 200 feet, dry grass/turf) at the Tracy Municipal Airport, Tracy, Minnesota, went through crops, and impacted two fences during takeoff roll. Visual meteorological conditions prevailed at the time of the accident. The instructional flight was being conducted under the provisions of 14 CFR Part 91 without a flight plan. The instructor pilot and dual student, a commercial pilot, on board the airplane reported no injuries. The cross-country flight was originating at the time of the accident. In his written statement, the instructor pilot said he was conducting a biennial flight review for the dual student. The instructor pilot said the student held back pressure during the initial takeoff to get the nose wheel off of the runway. He said he noted the airspeed as approximately 50 to 55 knots indicated. The student pilot started to get the main gear off the runway, but the airspeed was still low. The instructor pilot said he allowed the student pilot to increase back pressure on the yoke. The instructor pilot said this stalled the airplane and increased the sink rate. The airplane hit the ground on the south end of the runway. It struck a fence and stopped in a soybean field. A Federal Aviation Administration inspector examined the airplane at the accident scene. The airplane was resting upright in a soybean field south of the airport. Preceding the airplane, 40 foot long tire marks were observed in an alfalfa field just off the end of the runway. The airport perimeter fence approximately 200 feet from the end of the runway was broken. Additionally, the perimeter fence around the soybean field was broken. The airplane's left main landing gear was located at this fence. The airplane's cowling was crushed aft and bent. The airplane's nose gear was broken aft. The bottom 1/4 of the airplane's firewall was bent aft. The propeller showed torsional bending and chordwise scratches. Both wings were crushed aft along the wings' leading edges. The fuselage was twisted aft of the doors. The empennage was twisted left approximately 30 degrees. Flight control continuity was confirmed. An examination of the engine, engine controls and other airplane systems revealed no anomalies.