The pilot was flying the agricultural airplane, low-level, applying fertilizer to a field, and running parallel to power lines that bordered the field. When he finished the center of the field, he flew several cleanup passes on some of the edges of the field. He thought that the power lines were to the south of his position and stated that they blended into the tree line. As he came down into the field for a pass, his top wing blocked his forward view, and when he leveled out, he could not avoid the power lines in front of him. The airplane collided with the power lines and impacted the field which was adjacent to a roadway. The airplane came to rest inverted and sustained substantial damage to the wings, the fuselage, and empennage. As the power lines came down, they impacted a moving semi-truck, and pulled down adjacent power line poles. The pilot and the driver of the semi-truck sustained minor injuries. After the accident, the pilot stated that the accident could have been avoided if he had flown around the boarders to double check for obstacles.