The student pilot reported that, while approaching a farm field for landing in his unregistered aircraft, he elected to perform a go-around. As he increased pitch, the aircraft entered a stall about 200 feet above ground level. He lowered the nose to increase airspeed; however, there was insufficient altitude to recover and the aircraft crashed into a field. The wooden structure in the fuselage fractured in several places, resulting in substantial airframe damage. The pilot reported no mechanical malfunctions or failures during the flight that would have precluded normal operation. He also cited his indecisiveness as a factor.