On August 18, 2020, about 1100 central daylight time, a Piper PA-36-285 airplane, N57607, was substantially damaged when it was involved in an accident near Ord, Nebraska. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 agricultural flight. The pilot stated that the engine startup was normal and that he observed a calm surface wind while taxiing to runway 31. The pilot initially observed dark/black engine exhaust while he cycled the propeller during an engine runup before takeoff, but he did not observe any anomalies with the engine or the engine exhaust during a second engine runup and propeller cycle that he completed before takeoff. The pilot stated that the takeoff on runway 31 was uneventful and that after liftoff he kept the airplane in ground effect until it accelerated to a normal climb airspeed. The pilot stated the initial climb was uneventful until the first turn when he observed the airspeed decreasing despite the engine and propeller operating normally at takeoff power. Although he was able to maintain altitude in the turn, the airplane’s airspeed continued to decrease closer to an aerodynamic stall speed. The pilot chose not to dump the load of liquid herbicide because he thought it could have a negative effect on being able to control the airplane and cause it to enter an aerodynamic stall. The airplane's right wing dropped shortly before impact with the ground, which the pilot attributed to the airplane flying at or near aerodynamic stall. The airplane collided with terrain in a right wing down attitude. The pilot stated that before the flight the airplane was loaded with 40 gallons of fuel and 155 gallons of liquid herbicide. He stated he previously flew the airplane with similar or heavier loads without any adverse effects to airplane performance. He reported that the weather conditions earlier in the morning included some rain showers associated with the passage of a weather front; however, at the time of the accident, the wind was calm and there was no precipitation. The pilot reported that there were no mechanical malfunctions or failures of the airplane or its engine during the flight. The airplane’s fuselage and both wings were substantially damaged during the accident. The airplane was partially disassembled and recovered from the accident site before the National Transportation Safety Board or the Federal Aviation Administration (FAA) were notified of the accident. A FAA examination of the airplane and its engine did not reveal any evidence of a mechanical malfunction or failure that would have prevented normal flight.