Retractable Field

Retractable Roof - OK. Retractable Field - Whaa???

The Arizona Cardinals are getting a new stadium for 06. When completed,
the field will weigh nearly 121⁄2 million pounds and will roll in and
out of the stadium on specialized tracks. The natural turf will grow
in a series of trays filled with a foot of growing mixture. It will
remain outside the stadium where it can receive sunlight and water
until it is needed for a football game. Then a series of one
horsepower motors will move the field along the tracks into the
stadium.

Seems like a lot of work to get grass to grow in a dome.