The pilot reported the airplane would not climb out of ground effect during takeoff. The airplane settled into a corn field located off the end of the 3,100 foot long asphalt runway. The left landing gear collapsed and the airplane nosed over resulting in substantial damage to the wings. The maximum certified gross weight of the airplane was 4,500 pounds with a basic empty weight of 3,093.8 pounds. The airplane was loaded with 80 gallons of fuel (480 pounds) and 170 gallons (1,419.5 pounds) of water/chemical mix. The pilot's weight was approximately 185 pounds. The airplane was approximately 678.3 pounds over the maximum gross weight at the time of the takeoff.