The day before the accident, the pilot had made some modifications to the aircraft's spray equipment. Approximately 180 lts of water was then loaded to test the equipment. Early the next morning , the pilot decided to test spray over a paddock. After checking the paddock for hazards, he commenced a spray run from west to east with the sun still below the horizon. The pilot noticed a loss of spray pressure and as he looked down inside the cockpit to adjust the pressure, the main landing gear struck the ground. The aircraft nosed over and slid upside down for approximately 40 m before coming to rest. The pilot was not injured and was able to extricate himself without outside assistance. An emergency locator transmitter (ELT) was not fitted to the aircraft.