The purpose of the flight was for the pilot to practice landing his tail-wheel equipped airplane on a grass airstrip. After departure, he remained in the airstrip’s traffic pattern and configured the airplane for a wheel landing. During the landing roll, with the airplane’s main landing on the grass and the tailwheel still airborne, the pilot applied brake pressure. The airplane nosed over, sustaining damage to the firewall. The pilot reported that there were no pre impact mechanical malfunctions or failures with the airplane that would have precluded normal operation.