Actually, they started burying their aircraft after the war started. After the coalition Air forces clobbered the Iraqi's Air force, the Iraqis started burying their remaining Migs in the sand.
It is believed that the intention was to recover them after the war and still have some semblance of an Iraqi Air force.
However, coalition forces continued bombing the hidden Migs in the sand.
Their is a segment on this very topic in a F-15 documentary, that just showed on the History channel.
Find a job you love, and you'll never work a day in your life.