Ocarina of Time Walkthrough Help?

No, you don't need it. I've beaten the game several times without using the scarecrows song. He's probably referring to the song of time (>,a, down arrow) which can make blue blocks appear or disappear so you can reach different places. Sometimes Zelda's lullaby (<,^,>) can also make things appear or happen but usually there is a triforce on the ground to tell you when to play it.