On July 30, 2005, about 1130 Pacific daylight time, an Ayres S2R-134, N4003Z, overran the departure end of the runway, became entangled with bushes, and nosed over during the takeoff roll from a private airstrip near Kerman, California. The airplane was owned and operated by Mid Cal Ag Aviation, Inc., in Kerman, and it was substantially damaged. The commercial pilot was not injured during the agricultural flight in the restricted category airplane. The flight was performed under the provisions of 14 CFR Part 137. Visual meteorological conditions prevailed. The local area flight originated from the airstrip about 0800. The pilot reported to the National Transportation Safety Board investigator that during the day he had performed five agricultural spray flights without mishap. The airplane had been hot refueled and reloaded between the flights. For the accident takeoff, the chemical load had been reduced from 350 gallons to 300 gallons at the pilot's request because the ambient air temperature was warming up. According to the operator, as evidenced by wheel marks in the dirt-surfaced runway, on the accident flight/takeoff the airplane had accelerated on the runway and it overran the departure end without lifting off. Thereafter, the airplane encountered weeds. The airplane nosed over when the weeds balled up under the airplane. The pilot reported to the Safety Board investigator that no mechanical malfunctions had occurred with the airplane during the flight.