According to the pilot of the tailwheel-equipped airplane, after performing a local flight, he made a normal approach to a dirt and grass covered airstrip. He reported that he executed a wheel landing and the airplane veered left of the airstrip heading as the left main landing gear began to sink into the mud. The airplane struck a barbed wire fence and came to rest nose down in a water filled ditch. The pilot reported that he shut off the aircraft systems and he and his passenger exited the airplane; however, he reported that he did see fuel leaking from the fuel tanks as a result of the angle at which the airplane came to rest. The pilot recounted that as he and his passenger were walking away from the airplane they heard the fuel ignite and the airplane became engulfed with flames. The airplane sustained substantial fire damage to the wings and fuselage. The pilot reported that there were no mechanical failures or anomalies with the airplane prior to or during the flight that would have prevented normal flight operation.