The pilot reported that he was landing the airplane at a privately-owned grass airstrip. He stated that the airplane bounced on landing, and during the roll out, the nose wheel "clogged" with dirt and the nose gear dug into the soft dirt then collapsed rearward. The airplane subsequently nosed over and came to rest inverted, which resulted in substantial damage to the left wing and vertical stabilizer. The pilot reported that there were no mechanical deficiencies with the airplane prior to the accident.