Circumstances:
The aircraft was to spread 600 Kilograms of nitrate on a local wheat crop. The weather was clear with a gusting 10 knot crosswind/tailwind from the left. Take-off from runway 04 was normal until as the tail was raised a swing developed to the left which could not be corrected by opposite rudder and braking. The aircraft veered off the runway the throttle was closed and the aircraft settled back on three wheels but continued to swing to the left. The pilot concerned he would collide with a levy bank to the left of the strip applied left brake in an attempt to ground loop the aircraft and stop. However, the right mainwheel sank into the soft surface resulting in damage to the right wing tailplane and tailwheel. The pilot later said that the gusting crosswind from the right plus the natural tendency of the aircraft to swing to the left could not be counteracted by opposite rudder and brake.
