The pilot stated that while en route to perform an aerial application, he aborted the flight due to weather, and returned to the private airfield from which he departed. On landing, the airplane touched down fast, encountered a bump during landing roll out, and veered to the left. The pilot applied the brakes, and then "lost directional control" of the airplane. The airplane went off the left side of the runway colliding with a "field ditch," which resulted in substantial damage to the airplane.