To really stop the Fairfax County Government from rezoning, you should use some online petition system like http://www.change.org
to explain your position and capture the signature of our supporters.
My take is that rezoning is a natural part of a growing area. Tysons Corner was probably zoned agricultural land many many years ago. It now has 4 Metro Stops and an ever growing sea of hi rise buildings. I don't live or work in Tysons, but I think it has become a useful area for many people & businesses as well as the government.
So where are these 13000 parcels of agricultural land, and why exactly would you oppose the rezoning?