The pilot reported that during takeoff roll in a tail wheeled airplane for the aerial application flight, as he rotated the airplane, it would not lift off and he applied full flaps. The airplane would still not lift off the runway, so he jettisoned the entire load from the hopper. Subsequently, the airplane pitched up and despite his control inputs, stalled, and impacted the ground. Substantial damage was sustained to the wings and fuselage. The pilot reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation. The pilot added that he felt that either a downdraft or change in wind direction occurred at the time of the accident.