The aircraft was taking off from a one-way agricultural strip during spreading operations. As the aircraft became airborne it suffered a complete loss of engine power. The pilot dumped the load and landed the aircraft on the strip remaining. During the landing roll the pilot was forced to swerve the aircraft onto an adjacent cleared area to avoid a gully beyond the strip end. At a low forward speed, the right main landing gear struck a stump. The aircraft groundlooped, collapsing the left main gear and damaging the outer left wing. No mechanical defect of the engine was found. Although vapour lock was suspected, the cause of the loss of power was not determined.