What is a "dry stadium"? a stadium where no concessions are sold a stadium with artificial turf that does not require maintenance a stadium where no alcoholic beverages are allowed a stadium with a roof to keep rain from falling on the playing field

A "dry stadium" is a stadium where no alcoholic beverages are allowed.
It is 'dry' because there is no alcohol sold in this type of a stadium. The reasons for this are numerous, but the most important one is that alcohol instigates violence and aggression, especially in football fans, so the organizers of such events tend to want to avoid that.