My lawn is properly watered and fertilized. The grass appears green and lush, and grows quickly. I use a 22'' push mower, with a new, sharpened blade. My problem is when I mow, the tires leave tracks. It doesn't matter which direction I mow. The tracks do not die - they as as lush as the rest of the grass, but the track marks are visible until the next time I mow - the grass remains pushed down. I do not observe this in neighboring lawns. Any help appreciated.