The airplane sustained substantial damage during a forced landing to a cornfield after a loss of engine power. The pilot reported that he had departed from a grass airstrip with the fuel selector set to the right fuel tank. He reported that the fuel gauges indicated that most of the fuel on board the airplane was in the right fuel tank, and "very little" fuel in the left fuel tank. He reported that the engine lost power "shortly after takeoff," and he executed a forced landing to a cornfield. The inspection of the airplane revealed that there was about 20 gallons of fuel in the left fuel tank. When electric power was applied to the airplane, the right fuel gauge read 1/2 fuel remaining and the left fuel gauge indicated low fuel. The airplane's Pilot's Operating Handbook (POH) stated that the fuel selector should be set to BOTH during takeoff.