The airplane came to rest inverted after attempting to land in a soft dirt field. The pilot was attempting to land in an alfalfa field next to his home. He had successfully completed landings in the field prior to the accident. The dirt in the field had recently been lightly disked. Upon touchdown, the airplane's main landing gear sunk into the soft terrain. The airplane nosed over and came to rest inverted. The pilot reported no preimpact mechanical malfunctions or failures with the airplane.