A C182's nose gear collapsed during a touch and go takeoff following a soft field practice landing. The aircraft was secured on the runway.

Narrative

I was performing touch and go landings; keeping left closed traffic. The landing that the incident occurred on was my 4th landing of the day and it was a practice soft field landing. I had completed all checks in the traffic pattern; including gear down with a green indication light showing. I landed on the main wheels first and lightly allowed the nose wheel to settle on the runway. I then proceeded to clean the airplane up; by adjusting the trim; turning off the carburetor heat; and moving the flaps to 20 degrees. I then began to add power to accelerate the airplane for takeoff. Before I could reach my rotation speed; I heard a click and the nose wheel began to fall towards the ground. I then proceeded to give the plane full back elevator pressure in order to keep the nose up; but was not able to do so. The nose continued to fall and when saw the prop strike the ground; I promptly reduced power to idle and applied some brakes to stop the plane. Once the plane came to a complete stop; I called the Tower and notified them of the situation. I then turned off all electrical switches and turned off the ignition and removed the key. I then stepped out of the airplane and waited for assistance.